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Sample records for images saturne revisitee

  1. Radar imaging of Saturn's rings

    Science.gov (United States)

    Nicholson, Philip D.; French, Richard G.; Campbell, Donald B.; Margot, Jean-Luc; Nolan, Michael C.; Black, Gregory J.; Salo, Heikki J.

    2005-09-01

    We present delay-Doppler images of Saturn's rings based on radar observations made at Arecibo Observatory between 1999 and 2003, at a wavelength of 12.6 cm and at ring opening angles of 20.1°⩽|B|⩽26.7°. The average radar cross-section of the A ring is ˜77% relative to that of the B ring, while a stringent upper limit of 3% is placed on the cross-section of the C ring and 9% on that of the Cassini Division. These results are consistent with those obtained by Ostro et al. [1982, Icarus 49, 367-381] from radar observations at |B|=21.4°, but provide higher resolution maps of the rings' reflectivity profile. The average cross-section of the A and B rings, normalized by their projected unblocked area, is found to have decreased from 1.25±0.31 to 0.74±0.19 as the rings have opened up, while the circular polarization ratio has increased from 0.64±0.06 to 0.77±0.06. The steep decrease in cross-section is at variance with previous radar measurements [Ostro et al., 1980, Icarus 41, 381-388], and neither this nor the polarization variations are easily understood within the framework of either classical, many-particle-thick or monolayer ring models. One possible explanation involves vertical size segregation in the rings, whereby observations at larger elevation angles which see deeper into the rings preferentially see the larger particles concentrated near the rings' mid-plane. These larger particles may be less reflective and/or rougher and thus more depolarizing than the smaller ones. Images from all four years show a strong m=2 azimuthal asymmetry in the reflectivity of the A ring, with an amplitude of ±20% and minima at longitudes of 67±4° and 247±4° from the sub-Earth point. We attribute the asymmetry to the presence of gravitational wakes in the A ring as invoked by Colombo et al. [1976, Nature 264, 344-345] to explain the similar asymmetry long seen at optical wavelengths. A simple radiative transfer model suggests that the enhancement of the azimuthal

  2. Saturn

    CERN Document Server

    Vescia, Monique

    2017-01-01

    Saturn is one of the most surreal of all the planets in our solar system. With this intriguing curriculum-correlated book, young readers can learn just why. Saturn has many unusual features, such as rings made of ice, ammonia storms, and methane rain. Its density is less than that of water so theoretically it could float on water. The features of its many moons are sometimes even stranger. The Pioneer and Voyager missions in 1970s and 1980s offered stunning images included in the book, which will allow readers to have an armchair experience of exploring this fascinating planet.

  3. A Strong High Altitude Narrow Jet At Saturn'S Equator From Cassini/ISS Images

    Science.gov (United States)

    Garcia-Melendo, Enrique; Sánchez-Lavega, A.; Legarreta, J.; Pérez-Hoyos, S.; Hueso, R.

    2010-10-01

    The intense equatorial eastward jets observed at cloud level in Jupiter and Saturn, represent a major challenge for geophysical fluid dynamics. Saturn's equatorial jet is of particular interest in view of its three dimensional structure, suspected large temporal variability, and related stratospheric semiannual oscillation. Here we report the discovery at the upper cloud level of an extremely narrow and strong jet centered in the middle of the broad equatorial jet. Previously published works on Saturn's equatorial winds at cloud level provided only a partial coverage. Automatic correlation of brightness scans and manually tracked cloud features, retrieved from images obtained by the Cassini Imaging Science Subsystem (ISS), show that the jet reaches 430 ms-1 with a peak speed difference of 180 ms-1 relative to nearby latitudes at 60 mbar and 390 ms-1 at depths > 500 mbar. Images were obtained in two filters: MT3, centred at the 889nm strong methane absorption band, and CB3 centred at the near infrared 939nm continuum, which are sensitive to different altitude levels at the upper clouds and hazes. Contrarily to what is observed in other latitudes, its velocity increases with altitude. Our findings helps to extend the view we have of the equatorial stratospheric dynamics of fast rotating planets beyond the best known terrestrial environment, and extract more general consequences of the interaction between waves and mean flow. It remains to be known if this equatorial jet structure, now determined in detail in three dimensions, is permanent or variable with the seasonal solar insolation cycle, including the variable shadow cast by the rings. EGM, ASL, JL, SPH, and RH have been funded by the Spanish MICIIN AYA2009-10701 with FEDER support and ASL, JL, SPH, and RH by Grupos Gobierno Vasco IT-464-07

  4. Searching for a traveling feature in Saturn's rings in Cassini Imaging Science Subsystem data

    Science.gov (United States)

    Aye, Klaus-Michael; Rehnberg, Morgan; Brown, Zarah; Esposito, Larry W.

    2016-10-01

    Introduction: Using Cassini UVIS occultation data, a traveling wave feature has been identified in the Saturn rings that is most likely caused by the radial positions swap of the moons Janus and Epimetheus [1]. The hypothesis is that non-linear interferences between the linear density waves when being relocated by the moon swap create a solitary wave that is traveling outward through the rings. The observations in [1] further lead to the derivation of values for the radial travel speeds of the identified traveling features, from 39.6 km/yr for the Janus 5:4 resonance up to 45.8 for the Janus 4:3 resonance.Previous confirmations in ISS data: Work in [1] also identified the feature in Cassini Imaging Science Subsystem (ISS) data that was taken around the time of the UVIS occultations where the phenomenon was first discovered, so far one ISS image for each Janus resonances 2:1, 4:3, 5:4, and 6:5.Search guided by predicted locations: Using the observation-fitted radial velocities from [1], we can extrapolate these to identify Saturn radii at which the traveling feature should be found at later times. Using this and new image analysis and plotting tools available in [2], we have identified a potential candidate feature in an ISS image that was taken 2.5 years after the feature causing moon swap in January 2006. We intend to expand our search by identifying candidate ISS data by a meta-database search constraining the radius at future times corresponding to the predicted future locations of the hypothesized solitary wave and present our findings at this conference.References: [1] Rehnberg, M.E., Esposito, L.W., Brown, Z.L., Albers, N., Sremčević, M., Stewart, G.R., 2016. A Traveling Feature in Saturn's Rings. Icarus, accepted in June 2016. [2] K.-Michael Aye. (2016). pyciss: v0.5.0. Zenodo. 10.5281/zenodo.53092

  5. Analyses of the Behavior of Spokes in Saturn's B Ring as Observed in Cassini ISS Images

    Science.gov (United States)

    Mitchell, Colin; Porco, C.; Dones, L.; Spitale, J.

    2008-09-01

    We report on analyses of the spokes in Saturn's B ring as observed by the Cassini spacecraft, from the first sighting in September 2005 to the present. Following Porco and Danielson (1982), we calculate as a function of time the spoke activity level, defined as the area-integrated optical depth of the spokes. We convert the spoke I/F into optical depth, using a radiative transfer "doubling code" and assuming that the presence of microscopic particles in the spokes is the only change in the optical properties of the ring region within a spoke. We search for periodicities in the variation of spoke activity and also correlations with magnetic longitude using a magnetic longitude system derived from the emission of the Saturn Kilometric Radiation (SKR), the rotation of which varies slightly from a constant rate (Kurth et al. 2008). Additionally, we track the activity over a period of years in order to characterize the seasonal nature of this phenomenon. We also report on the photometric profiles of spokes during different phases of their evolution. We present an analysis of spoke kinematics, measuring the motion on timescales of tens of minutes of the leading and trailing edges of spokes that appear in multiple consecutive images. Assuming that the small ice particles which comprise the spokes are in circular orbits, the azimuthal motion is a measure of their charge-to-mass ratio. While most spoke edges have exhibited normal Keplerian orbital motion and shear, some spokes were observed during their active phase in which the spoke's optical depth increases and its edges move at different rates, broadening the spoke. We acknowledge the financial support of the Cassini Project.

  6. Confirmation of a traveling feature in Saturn's rings in Cassini Imaging Science Subsystem data

    Science.gov (United States)

    Aye, K. M.; Rehnberg, M.; Esposito, L. W.

    2017-12-01

    Introduction: Using Cassini UVIS occultation data, a traveling wave feature has been identified in the Saturn rings that is most likely caused by the radial positions swap of the moons Janus and Epimetheus [1]. The hypothesis is that non-linear interferences between the density waves when being relocated by the moon swap create a solitary wave that is traveling outward through the rings. The observations in [1] further lead to the derivation of values for the radial travel speeds of the identified traveling features, from 39.6 km/yr for the Janus 5:4 resonance up to 45.8 for the Janus 4:3 resonance. Previous confirmations in ISS data: Work in [1] also identified the feature in Cassini Imaging Science Subsystem (ISS) data that was taken around the time of the UVIS occultations where the phenomenon was first discovered, so far one ISS image for each Janus resonances 2:1, 4:3, 5:4, and 6:5. Searches performed in ISS data: Filtering all existing ISS data down to the best resolutions that include both a clearly identifiable minimum and maximum ring radius, we have visually inspected approx. 200 images, both with and without known resonances within the image, but unbeknownst to the inspector. Identification of a feature of interest happens when train waves are being interrupted by anomalies. Comparing the radial locations of identified ISS features with those in UV data of [1], we have identified several at the same radii. Considering the vast differences in radial resolution, we conclude that the traveling feature causes observable anomalies at both small scales of meters, up to large scales of hundreds of meters to kilometers.References: [1] Rehnberg, M.E., Esposito, L.W., Brown, Z.L., Albers, N., Sremčević, M., Stewart, G.R., 2016. A Traveling Feature in Saturn's Rings. Icarus, accepted in June 2016. [2] K.-Michael Aye (2016, November 11). michaelaye/pyciss: . v0.6.0 Zenodo. https://doi.org/10.5281/zenodo.596802

  7. Haze and cloud structure of Saturn's North Pole and Hexagon Wave from Cassini/ISS imaging

    Science.gov (United States)

    Sanz-Requena, J. F.; Pérez-Hoyos, S.; Sánchez-Lavega, A.; Antuñano, A.; Irwin, Patrick G. J.

    2018-05-01

    In this paper we present a study of the vertical haze and cloud structure in the upper two bars of Saturn's Northern Polar atmosphere using the Imaging Science Subsystem (ISS) instrument onboard the Cassini spacecraft. We focus on the characterization of latitudes from 53° to 90° N. The observations were taken during June 2013 with five different filters (VIO, BL1, MT2, CB2 and MT3) covering spectral range from the 420 nm to 890 nm (in a deep methane absorption band). Absolute reflectivity measurements of seven selected regions at all wavelengths and several illumination and observation geometries are compared with the values produced by a radiative transfer model. The changes in reflectivity at these latitudes are mostly attributed to changes in the tropospheric haze. This includes the haze base height (from 600 ± 200 mbar at the lowest latitudes to 1000 ± 300 mbar in the pole), its particle number density (from 20 ± 2 particles/cm3 to 2 ± 0.5 particles/cm3 at the haze base) and its scale height (from 18 ± 0.1 km to 50 ± 0.1 km). We also report variability in the retrieved particle size distribution and refractive indices. We find that the Hexagonal Wave dichotomizes the studied stratospheric and tropospheric hazes between the outer, equatorward regions and the inner, Polar Regions. This suggests that the wave or the jet isolates the particle distribution at least at tropospheric levels.

  8. Moons Around Saturn

    Science.gov (United States)

    1996-01-01

    This series of 10 Hubble Space Telescope images captures several small moons orbiting Saturn. Hubble snapped the five pairs of images while the Earth was just above the ring plane and the Sun below it. The telescope captured a pair of images every 97 minutes as it circled the Earth. Moving out from Saturn, the visible rings are: the broad C Ring, the Cassini Division, and the narrow F Ring.The first pair of images shows the large, bright moon Dione, near the middle of the frames. Two smaller moons, Pandora (the brighter one closer to Saturn) and Prometheus, appear as if they're touching the F Ring. In the second frame, Mimas emerges from Saturn's shadow and appears to be chasing Prometheus.In the second image pair, Mimas has moved towards the tip of the F Ring. Rhea, another bright moon, has just emerged from behind Saturn. Prometheus, the closest moon to Saturn, has rounded the F Ring's tip and is approaching the planet. The slightly larger moon Epimetheus has appeared.The third image pair shows Epimetheus, as a tiny dot just beyond the tip of the F Ring. Prometheus is in the lower right corner. An elongated clump or arc of debris in the F ring is seen as a slight brightening on the far side of this thin ring.In the fourth image pair, Epimetheus, in the lower right corner, streaks towards Saturn. The long ring arc can be seen in both frames.The fifth image pair again captures Mimas, beyond the tip of the F Ring. The same ring arc is still visible.In addition to the satellites, a pair of stars can be seen passing behind the rings, appearing to move towards the lower left due to Saturn's motion across the sky.The images were taken Nov. 21, 1995 with Wide Field Planetary Camera-2.The Wide Field/Planetary Camera 2 was developed by the Jet Propulsion Laboratory and managed by the Goddard Spaced Flight Center for NASA's Office of Space Science.This image and other images and data received from the Hubble Space Telescope are posted on the World Wide Web on the Space

  9. Saturn and How to Observe it

    CERN Document Server

    Benton, Julius L

    2005-01-01

    Saturn is the second largest planet in the solar system, and the only one with a spectacular ring system easily visible from Earth. Julius Benton's Saturn and How to Observe It provides a compendium of the latest information, amateur and professional images of Saturn. These images are followed by advice on how to observe Saturn using a variety of telescope apertures, color filters and magnifications. This text is a goldmine of information for all levels of amateur observers, from the beginner to the highly experienced. Brought to life by crisp color photographs, Saturn and How to Observe It is a modern comprehensive review of Saturn as a planet and its magnificent ring system. The book includes some of the latest detailed theories and physical descriptions of Saturn and its satellites. The techniques for observing Saturn are outlined in this book, giving the reader a thorough explanation of what they are viewing.

  10. Saturn satellites

    International Nuclear Information System (INIS)

    Ruskol, E.L.

    1981-01-01

    The characteristics of the Saturn satellites are discussed. The satellites close to Saturn - Janus, Mimas, Enceladus, Tethys, Dione and Rhea - rotate along the circular orbits. High reflectivity is attributed to them, and the density of the satellites is 1 g/cm 3 . Titan is one of the biggest Saturn satellites. Titan has atmosphere many times more powerful than that of Mars. The Titan atmosphere is a peculiar medium with a unique methane and hydrogen distribution in the whole Solar system. The external satellites - Hyperion, Japetus and Phoebe - are poorly investigated. Neither satellite substance density, nor their composition are known. The experimental data on the Saturn rings obtained on the ''Pioneer-11'' and ''Voyager-1'' satellites are presented [ru

  11. The Faces of Saturn: Images and Texts from Augustus through Dürer to Galileo

    Science.gov (United States)

    Shank, M. H.

    2013-04-01

    This paper follows the thread(s) of Saturn in astrology and art from the Babylonians to Galileo, paying special attention to the planet's political importance from Augustus to the Medici and to its medical/psychological significance from Ficino through Dürer. In passing, I extend David Pingree's astrological interpretation of Dürer's Melencholia I and propose a very personal rationale for the engraving, namely as a memorial to his mother.

  12. Cassini at Saturn Huygens results

    CERN Document Server

    Harland, David M

    2007-01-01

    "Cassini At Saturn - Huygens Results" will bring the story of the Cassini-Huygens mission and their joint exploration of the Saturnian system right up to date. Cassini is due to enter orbit around Saturn on the 1 July 2004 and the author will have 8 months of scientific data available for review, including the most spectacular images of Saturn, its rings and satellites ever obtained by a space mission. As the Cassini spacecraft approached its destination in spring 2004, the quality of the images already being returned by the spacecraft clearly demonstrate the spectacular nature of the close-range views that will be obtained. The book will contain a 16-page colour section, comprising a carefully chosen selection of the most stunning images to be released during the spacecraft's initial period of operation. The Huygens craft will be released by Cassini in December 2004 and is due to parachute through the clouds of Saturn's largest moon, Titan, in January 2005.

  13. Saturn's ringlets

    International Nuclear Information System (INIS)

    Bastin, J.A.; Smith, D.H.

    1982-01-01

    This paper suggests that Saturn's magnetic field is, in part, responsible for the very fine-scale radial features, or ringlets, seen in the ring-system. The planet's dipole field interacts with slight radial variations in plasma density, and the operation of an instability segregates the magnetic flux and plasma in the ring-plane into narrow alternating zones. It is suggested that this mechanism may act by itself to give rise to the inner ringlets. At greater radial distances the authors believe it amplifies gravitational resonances. (Auth.)

  14. Saturn's Rings Edge-on

    Science.gov (United States)

    1995-01-01

    In one of nature's most dramatic examples of 'now-you see-them, now-you-don't', NASA's Hubble Space Telescope captured Saturn on May 22, 1995 as the planet's magnificent ring system turned edge-on. This ring-plane crossing occurs approximately every 15 years when the Earth passes through Saturn's ring plane.For comparison, the top picture was taken by Hubble on December 1, 1994 and shows the rings in a more familiar configuration for Earth observers.The bottom picture was taken shortly before the ring plane crossing. The rings do not disappear completely because the edge of the rings reflects sunlight. The dark band across the middle of Saturn is the shadow of the rings cast on the planet (the Sun is almost 3 degrees above the ring plane.) The bright stripe directly above the ring shadow is caused by sunlight reflected off the rings onto Saturn's atmosphere. Two of Saturn's icy moons are visible as tiny starlike objects in or near the ring plane. They are, from left to right, Tethys (slightly above the ring plane) and Dione.This observation will be used to determine the time of ring-plane crossing and the thickness of the main rings and to search for as yet undiscovered satellites. Knowledge of the exact time of ring-plane crossing will lead to an improved determination of the rate at which Saturn 'wobbles' about its axis (polar precession).Both pictures were taken with Hubble's Wide Field Planetary Camera 2. The top image was taken in visible light. Saturn's disk appears different in the bottom image because a narrowband filter (which only lets through light that is not absorbed by methane gas in Saturn's atmosphere) was used to reduce the bright glare of the planet. Though Saturn is approximately 900 million miles away, Hubble can see details as small as 450 miles across.The Wide Field/Planetary Camera 2 was developed by the Jet Propulsion Laboratory and managed by the Goddard Spaced Flight Center for NASA's Office of Space Science.This image and other images and

  15. The Rings of Saturn

    Science.gov (United States)

    Cuzzi, J. N.; Filacchione, G.; Marouf, E. A.

    2018-03-01

    One could become an expert on Saturn's iconic rings pretty easily in the early 1970s, as very little was known about them beyond the distinction between the A, B, and C rings, and the Cassini Division or "gap" between rings A and B (Alexander, 1962; Bobrov, 1970). Water ice was discovered spectroscopically on the ring particle surfaces, and radar and microwave emission observations proved that the particles must be centimeters to meters in size, consisting primarily, not just superficially, of water ice (Pollack, 1975). While a 2:1 orbital resonance with Mimas had long been suspected of having something to do with the Cassini Division, computers of the time were unable to model the subtle dynamical effects that we now know to dominate ring structure. This innocent state of affairs was exploded by the Voyager 1 and 2 encounters in 1980 and 1981. Spectacular images revealed filigree structure and odd regional color variations, and exquisitely detailed radial profiles of fluctuating particle abundance were obtained from the first stellar and radio occultations, having resolution almost at the scale of single particles. Voyager-era understanding was reviewed by Cuzzi et al. (1984) and Esposito et al. (1984). While the Voyager data kept ring scientists busy for decades, planning which led to the monumentally successful NASA-ESA-ASI Cassini mission, which arrived in 2004, had been under way even before Voyager got to Saturn. A review of pre-Cassini knowledge of Saturn's Rings can be found in Orton et al. (2009). This chapter will build on recent topical and process-specific reviews that treat the gamut of ring phenomena and its underlying physics in considerable detail (Colwell et al., 2009; Cuzzi et al., 2009; Horányi et al., 2009; Schmidt et al., 2009; Esposito, 2010; Tiscareno, 2013b; Esposito, 2014). We will follow and extend the general organization of Cuzzi et al. (2010), the most recent general discussion of Saturn's rings. For brevity and the benefit of the

  16. SMM Observations of Saturn

    Science.gov (United States)

    Schnopper, Herbert; Mushotzky, Richard (Technical Monitor)

    2001-01-01

    During the past year I have participated in a series of team telecons to I plan our observation of Saturn with SMM. The observation, scheduled for this month (September), was canceled and a new observation is being planned for 2002.

  17. Saturn's Misbegotten Moonlets

    Science.gov (United States)

    Spitale, Joseph N.

    2017-06-01

    Saturn's rings are interspersed with numerous narrow (tens of km wide) gaps. Two of the largest of these gaps -- Encke and Keeler -- contain satellites -- Pan and Daphnis -- that maintain their respective gaps via the classical Goldreich/Tremaine-style shepherding mechanism wherein angular momentum is transferred across the essentially empty gap via torques acting between the satellites and the ring. Other prominent gaps are shepherded by resonances with external satellites or planetary modes: Mimas shepherds the outer edge of the B ring, clearing the inner part of the Cassini Division, Titan shepherds the Columbo ringlet / gap, and the Maxwell ringlet / gap is likely maintained by a resonance with a planetary mode. Prior to Cassini, it was expected that all of the gaps would be shepherded in a similar manner.However, many small gaps do not correspond with known resonances, and no satellites were spotted within those gaps during Cassini's prime and extended mission. To address this issue, a series of Cassini imaging observations were planned to examine 11 gaps in the C ring and Cassini division at a resolution and longitudinal coverage sufficient to either discover the shepherds or rule out their presence. The survey discovered no embedded satellites. Longitudinal coverage was incomplete, but within longitudes covered by the survey, satellites are ruled out to sizes in the 100-m range, far too small keep the observed gaps open. It is possible (about even odds) that there could be a larger satellite residing at a longitude not covered in the survey, but the probability that the survey was unfortunate enough to miss significant satellites in all 11 gaps is exceedingly small (~0.002%). Moreover, these gaps appear in earlier imaging sequences, with some high-resolution coverage, so the true probability is smaller yet. Therefore, a new theory is likely needed to explain the presence of the gaps.

  18. At Saturn: Tripping the Flight Fantastic

    Science.gov (United States)

    Porco, Carolyn C.

    2008-05-01

    Boulder planetary scientist Carolyn Porco, leader of the imaging team for NASA's Cassini mission to Saturn and science advisor for the forthcoming movie "Star Trek," guides you on a magical mystery tour around the ringed planet. Come and witness the wonders, discoveries, and the awesome natural beauty of this amazing planet and its family of rings and moons.

  19. 7. Saturne study meeting

    International Nuclear Information System (INIS)

    1996-01-01

    This Saturne workshop has welcomed 120 scientists. 3 sessions have been organized: accelerators, physics and miscellaneous. The most recent experiments realized or scheduled at Saturne have been presented and the discussions which followed showed the high scientific interest taken in that equipment and made the participants regret its definitive closing down. Presentations by european teams about existent equipment, machines under construction or new projects opened the way to new perspectives. A lot of contributions were dedicated to the realization of high intensity particle beams and to the applications of accelerators. (A.C.)

  20. Collage of Saturn's smaller satellites

    Science.gov (United States)

    1981-01-01

    This family portrait shows the smaller satellites of Saturn as viewed by Voyager 2 during its swing through the Saturnian system. The following chart corresponds to this composite photograph (distance from the planet increases from left to right) and lists names, standard numerical designations and approximate dimensions (radii where indicated) in kilometers: 1980S26Outer F-ringshepherd120 X 100 1980S1Leadingco-orbital220 X 160 1980S25TrailingTethys trojanradii: 25 1980S28Outer Ashepherdradii: 20 1980S27Inner F-ringco-orbital145 X 70 1980S3TrailingTethys trojan140 X 100 1980S13LeadingTethys trojanradii: 30 1980S6LeadingDione trojanradii: 30 These images have been scaled to show the satellites in true relative sizes. This set of small objects ranges in size from small asteroidal scales to nearly the size of Saturn's moon Mimas. They are probably fragments of somewhat larger bodies broken up during the bombardment period that followed accretion of the Saturnian system. Scientists believe they may be mostly icy bodies with a mixture of meteorite rock. They are somewhat less reflective than the larger satellites, suggesting that thermal evolution of the larger moons 'cleaned up' their icy surfaces. The Voyager project is managed for NASA by the Jet Propulsion Laboratory, Pasadena, Calif.

  1. Resonance capture and Saturn's rings

    International Nuclear Information System (INIS)

    Patterson, C.W.

    1986-05-01

    We have assigned the resonances apparently responsible for the stabilization of the Saturn's shepherd satellites and for the substructure seen in the F-ring and the ringlets in the C-ring. We show that Saturn's narrow ringlets have a substructure determined by three-body resonances with Saturn's ringmoons and the sun. We believe such resonances have important implications to satellite formation. 17 refs., 1 fig., 1 tab

  2. Spallation studies at Saturne

    Energy Technology Data Exchange (ETDEWEB)

    Frehaut, J. [Centre d`Etudes de Bruyeres-le-Chatel (France)

    1995-10-01

    SATURNE is a synchrotron accelerator which can deliver particles of momentum P and charge Z up to P/Z = 4 GeV/c. Monokinetic neutron beams of momentum up to 2 GeV/c can be produced. The spallation studies deal with measurements of: (i) differential neutron production cross sections from thin targets, (ii) neutron multiplicity distribution for proton and {sup 3}He induced reactions, and (iii) nuclide production in thin target. Measurements on thick or composite targets are under consideration.

  3. Cassini-Huygens Science Highlights: Surprises in the Saturn System

    Science.gov (United States)

    Spilker, Linda; Altobelli, Nicolas; Edgington, Scott

    2014-05-01

    The Cassini-Huygens mission has greatly enhanced our understanding of the Saturn system. Fundamental discoveries have altered our views of Saturn, its retinue of icy moons including Titan, the dynamic rings, and the system's complex magnetosphere. Launched in 1997, the Cassini-Huygens spacecraft spent seven years traveling to Saturn, arriving in July 2004, roughly two years after the northern winter solstice. Cassini has orbited Saturn for 9.5 years, delivering the Huygens probe to its Titan landing in 2005, crossing northern equinox in August 2009, and completing its Prime and Equinox Missions. It is now three years into its 7-year Solstice mission, returning science in a previously unobserved seasonal phase between equinox and solstice. As it watches the approach of northern summer, long-dark regions throughout the system become sunlit, allowing Cassini's science instruments to probe as-yet unsolved mysteries. Key Cassini-Huygens discoveries include icy jets of material streaming from tiny Enceladus' south pole, lakes of liquid hydrocarbons and methane rain on giant Titan, three-dimensional structures in Saturn's rings, and curtain-like aurorae flickering over Saturn's poles. The Huygens probe sent back amazing images of Titan's surface, and made detailed measurements of the atmospheric composition, structure and winds. Key Cassini-Huygens science highlights will be presented. The Solstice Mission continues to provide new science. First, the Cassini spacecraft observes seasonally and temporally dependent processes on Saturn, Titan, Enceladus and other icy satellites, and within the rings and magnetosphere. Second, it addresses new questions that have arisen during the mission thus far, for example providing qualitatively new measurements of Enceladus and Titan that could not be accommodated in the earlier mission phases. Third, it will conduct a close-in mission at Saturn yielding fundamental knowledge about the interior of Saturn. This grand finale of the

  4. Voyager 1 Saturn targeting strategy

    Science.gov (United States)

    Cesarone, R. J.

    1980-01-01

    A trajectory targeting strategy for the Voyager 1 Saturn encounter has been designed to accomodate predicted uncertainties in Titan's ephemeris while maximizing spacecraft safety and science return. The encounter is characterized by a close Titan flyby 18 hours prior to Saturn periapse. Retargeting of the nominal trajectory to account for late updates in Titan's estimated position can disperse the ascending node location, which is nominally situated at a radius of low expected particle density in Saturn's ring plane. The strategy utilizes a floating Titan impact vector magnitude to minimize this dispersion. Encounter trajectory characteristics and optimal tradeoffs are presented.

  5. Saturn's outer magnetosphere

    Science.gov (United States)

    Schardt, A. W.; Behannon, K. W.; Carbary, J. F.; Eviatar, A.; Lepping, R. P.; Siscoe, G. L.

    1983-01-01

    Similarities between the Saturnian and terrestrial outer magnetosphere are examined. Saturn, like Earth, has a fully developed magnetic tail, 80 to 100 RS in diameter. One major difference between the two outer magnetospheres is the hydrogen and nitrogen torus produced by Titan. This plasma is, in general, convected in the corotation direction at nearly the rigid corotation speed. Energies of magnetospheric particles extend to above 500 keV. In contrast, interplanetary protons and ions above 2 MeV have free access to the outer magnetosphere to distances well below the Stormer cutoff. This access presumably occurs through the magnetotail. In addition to the H+, H2+, and H3+ ions primarily of local origin, energetic He, C, N, and O ions are found with solar composition. Their flux can be substantially enhanced over that of interplanetary ions at energies of 0.2 to 0.4 MeV/nuc.

  6. Accretion in Saturn's F Ring

    Science.gov (United States)

    Meinke, B. K.; Esposito, L. W.; Stewart, G.

    2012-12-01

    Saturn's F ring is the solar system's principal natural laboratory for direct observation of accretion and disruption processes. The ring resides in the Roche zone, where tidal disruption competes with self-gravity, which allows us to observe the lifecycle of moonlets. Just as nearby moons create structure at the B ring edge (Esposito et al. 2012) and the Keeler gap (Murray 2007), the F ring "shepherding" moons Prometheus and Pandora stir up ring material and create observably changing structures on timescales of days to decades. In fact, Beurle et al (2010) show that Prometheus makes it possible for "distended, yet gravitationally coherent clumps" to form in the F ring, and Barbara and Esposito (2002) predicted a population of ~1 km bodies in the ring. In addition to the observations over the last three decades, the Cassini Ultraviolet Imaging Spectrograph (UVIS) has detected 27 statistically significant features in 101 occultations by Saturn's F ring since July 2004. Seventeen of those 27 features are associated with clumps of ring material. Two features are opaque in occultation, which makes them candidates for solid objects, which we refer to as Moonlets. The 15 other features partially block stellar signal for 22 m to just over 3.7 km along the radial expanse of the occultation. Upon visual inspection of the occultation profile, these features resemble Icicles, thus we will refer to them as such here. The density enhancements responsible for such signal attenuations are likely due to transient clumping of material, evidence that aggregations of material are ubiquitous in the F ring. Our lengthy observing campaign reveals that Icicles are likely transient clumps, while Moonlets are possible solid objects. Optical depth is an indicator of clumping because more-densely aggregated material blocks more light; therefore, it is natural to imagine moonlets as later evolutionary stage of icicle, when looser clumps of material compact to form a feature that appears

  7. Success of Saturn: A Case Study of the Saturn Automobile

    Science.gov (United States)

    1993-04-01

    speed in production with nearly 20,000 cars per month coming off the assembly line.133 MARKETING THE PRODUCT ADVERTISING STRATEGY Saturn’s approach to...Satisfaction Index.𔄁 5 In the Sales Satisfaction category Saturn finished sixth behind Lexus, Cadillac, Infiniti, Lincoln and Mercedes Benz , all...quality, inexpensive, fuel efficient automobiles. They put their cars on the market in the U.S. and Americans bought Japanese instead of expensive

  8. Saturn's Irregular Moon Ymir

    Science.gov (United States)

    Denk, Tilmann; Mottola, S.

    2012-10-01

    Ymir (diameter 18 km), Saturn's second largest retrograde outer or irregular moon, has been observed six times by the Cassini narrow-angle camera (NAC) during the first 7 months in 2012. The observations span phase angles from 2° up to 102° and were taken at ranges between 15 and 18 million kilometers. From such a distance, Ymir is smaller than a pixel in the Cassini NAC. The data reveal a sidereal rotation period of 11.93 hrs, which is 1.6x longer than the previously reported value (Denk et al. 2011, EPSC/DPS #1452). Reason for this discrepancy is that the rotational light curve shows a rather uncommon 3-maxima and 3-minima shape at least in the phase angle range 50° to 100°, which was not recognizable in earlier data. The data cover several rotations from different viewing and illumination geometries and allow for a convex shape inversion with possibly a unique solution for the pole direction. The model reproduces the observed light curves to a very good accuracy without requiring albedo variegation, thereby suggesting that the lightcurve is dominated by the shape of Ymir. Among Saturn's irregular moons, the phenomenon of more than two maxima and minima at moderate to high phase angles is not unique to Ymir. At least Siarnaq and Paaliaq also show light curves with a strong deviation from a double-sine curve. Their rotation periods, however, remain unknown until more data can be taken. The light curve of Phoebe is fundamentally different to Ymir's because it is mainly shaped by local albedo differences and not by shape. Other reliable rotation periods of irregular satellites measured by Cassini include: Mundilfari 6.74 h; Kari 7.70 h; Albiorix 13.32 h; Kiviuq 21.82 h. More uncertain values are: Skathi 12 h; Bebhionn 16 h; Thrymr 27 h; Erriapus 28 h.

  9. SACLAY: Eta mesons at Saturne

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    1992-05-15

    Using a nuclear reaction, the new tagged eta meson facility now operating at the French Saturne National Laboratory in Saclay produces eta mesons (together with recoil helium-3 nuclei) by proton bombardment of a deuterium target. The proton beam is extracted from the Saturne synchrotron at 893 MeV, stabilized to 80 keV. This is a scant 1.5 MeV above the reaction threshold and close to the energy where eta production peaks.

  10. SACLAY: Eta mesons at Saturne

    International Nuclear Information System (INIS)

    Anon.

    1992-01-01

    Using a nuclear reaction, the new tagged eta meson facility now operating at the French Saturne National Laboratory in Saclay produces eta mesons (together with recoil helium-3 nuclei) by proton bombardment of a deuterium target. The proton beam is extracted from the Saturne synchrotron at 893 MeV, stabilized to 80 keV. This is a scant 1.5 MeV above the reaction threshold and close to the energy where eta production peaks

  11. 7. Saturne study meeting; Septiemes journees d`etudes saturne

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-12-31

    This Saturne workshop has welcomed 120 scientists. 3 sessions have been organized: accelerators, physics and miscellaneous. The most recent experiments realized or scheduled at Saturne have been presented and the discussions which followed showed the high scientific interest taken in that equipment and made the participants regret its definitive closing down. Presentations by european teams about existent equipment, machines under construction or new projects opened the way to new perspectives. A lot of contributions were dedicated to the realization of high intensity particle beams and to the applications of accelerators. (A.C.)

  12. 7. Saturne study meeting; Septiemes journees d`etudes saturne

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-12-31

    This Saturne workshop has welcomed 120 scientists. 3 sessions have been organized: accelerators, physics and miscellaneous. The most recent experiments realized or scheduled at Saturne have been presented and the discussions which followed showed the high scientific interest taken in that equipment and made the participants regret its definitive closing down. Presentations by european teams about existent equipment, machines under construction or new projects opened the way to new perspectives. A lot of contributions were dedicated to the realization of high intensity particle beams and to the applications of accelerators. (A.C.)

  13. Saturn Dynamo Model (Invited)

    Science.gov (United States)

    Glatzmaier, G. A.

    2010-12-01

    There has been considerable interest during the past few years about the banded zonal winds and global magnetic field on Saturn (and Jupiter). Questions regarding the depth to which the intense winds extend below the surface and the role they play in maintaining the dynamo continue to be debated. The types of computer models employed to address these questions fall into two main classes: general circulation models (GCMs) based on hydrostatic shallow-water assumptions from the atmospheric and ocean modeling communities and global non-hydrostatic deep convection models from the geodynamo and solar dynamo communities. The latter class can be further divided into Boussinesq models, which do not account for density stratification, and anelastic models, which do. Recent efforts to convert GCMs to deep circulation anelastic models have succeeded in producing fluid flows similar to those obtained from the original deep convection anelastic models. We describe results from one of the original anelastic convective dynamo simulations and compare them to a recent anelastic dynamo benchmark for giant gas planets. This benchmark is based on a polytropic reference state that spans five density scale heights with a radius and rotation rate similar to those of our solar system gas giants. The resulting magnetic Reynolds number is about 3000. Better spatial resolution will be required to produce more realistic predictions that capture the effects of both the density and electrical conductivity stratifications and include enough of the turbulent kinetic energy spectrum. Important additional physics may also be needed in the models. However, the basic models used in all simulation studies of the global dynamics of giant planets will hopefully first be validated by doing these simpler benchmarks.

  14. HST SATURN WFPC2 3 RING PLANE CROSSING V1.0

    Data.gov (United States)

    National Aeronautics and Space Administration — This data set contains images of the Saturn system taken by the Wide Field/Planetary Camera 2 (WFPC2) aboard the Hubble Space Telescope (HST) through November 1995....

  15. Cassini UVIS Observations of Saturn during the Grand Finale Orbits

    Science.gov (United States)

    Pryor, W. R.; Esposito, L. W.; West, R. A.; Jouchoux, A.; Radioti, A.; Grodent, D. C.; Gerard, J. C. M. C.; Gustin, J.; Lamy, L.; Badman, S. V.

    2017-12-01

    In 2016 and 2017, the Cassini Saturn orbiter executed a final series of high inclination, low-periapsis orbits ideal for studies of Saturn's polar regions. The Cassini Ultraviolet Imaging Spectrograph (UVIS) obtained an extensive set of auroral images, some at the highest spatial resolution obtained during Cassini's long orbital mission (2004-2017). In some cases, two or three spacecraft slews at right angles to the long slit of the spectrograph were required to cover the entire auroral region to form auroral images. We will present selected images from this set showing narrow arcs of emission, more diffuse auroral emissions, multiple auroral arcs in a single image, discrete spots of emission, small scale vortices, large-scale spiral forms, and parallel linear features that appear to cross in places like twisted wires. Some shorter features are transverse to the main auroral arcs, like barbs on a wire. UVIS observations were in some cases simultaneous with auroral observations from the Hubble Space Telescope Space Telescope Imaging Spectrograph (STIS) that will also be presented. UVIS polar images also contain spectral information suitable for studies of the auroral electron energy distribution. The long wavelength part of the UVIS polar images contains a signal from reflected sunlight containing absorption signatures of acetylene and other Saturn hydrocarbons. The hydrocarbon spatial distribution will also be examined.

  16. Upstream waves in Saturn's foreshock

    Science.gov (United States)

    Bavassano Cattaneo, M. B.; Cattaneo, P.; Moreno, G.; Lepping, R. P.

    1991-01-01

    An analysis based on plasma and magnetic-field data obtained from Voyager 1 during its Saturn encounter is reported. The plasma data provided every 96 sec and magnetic-field data averaged over 48 sec are utilized. The evidence of upstream waves at Saturn are detected. The waves have a period, in the spacecraft frame, of about 550 sec and a relative amplitude larger than 0.3, are left- and right-hand elliptically polarized, and propagate at about 30 deg with respect to the average magnetic field. The appearance of the waves is correlated with the spacecraft being magnetically connected to the bow shock.

  17. Diagram of Saturn V Launch Vehicle

    Science.gov (United States)

    1971-01-01

    This is a good cutaway diagram of the Saturn V launch vehicle showing the three stages, the instrument unit, and the Apollo spacecraft. The chart on the right presents the basic technical data in clear detail. The Saturn V is the largest and most powerful launch vehicle in the United States. The towering 363-foot Saturn V was a multistage, multiengine launch vehicle standing taller than the Statue of Liberty. Altogether, the Saturn V engines produced as much power as 85 Hoover Dams. Development of the Saturn V was the responsibility of the Marshall Space Flight Center at Huntsville, Alabama, directed by Dr. Wernher von Braun.

  18. Spallation neutron experiment at SATURNE

    Energy Technology Data Exchange (ETDEWEB)

    Meigo, Shin-ichiro [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    1998-11-01

    The double differential cross sections for (p,xn) reactions and the spectra of neutrons produced from the thick target have been measured at SATURNE in SACLAY from 1994 to 1997. The status of the experiment and the preliminary experimental results are presented. (author)

  19. Positional Catalogues of Saturn's and Jupiter's Moons

    Science.gov (United States)

    Yizhakevych, O.; Andruk, V.; Pakuliak, L.; Lukianchuk, V.; Shatokhina, S.

    In the framework of the UkrVO national project (http://ukr-vo.org/) we have started the processing of photographic observations of Saturn's (S1-S8) and Jupiter's (J6-J8) moons. Observations were conducted during 1961-1993 with three astrographs DLFA, DWA, DAZ and Z600 reflector. Plate images were digitized as tif-files with commercial scanners. Image processing was carried out by specific software package in the LINUX-MIDAS-ROMAFOT environment with Tycho2 as reference. The software was developed at the MAO NASU. Obtained positions of objects were compared with theoretically predicted ones in IMCCE (Paris) (www.imcce.fr/sat) online. Rms error of divergence between observed and calculated positions is of 0.20' - 0.35'.

  20. Atmospheres of Jupiter and Saturn

    International Nuclear Information System (INIS)

    Hunt, G.E.

    1981-01-01

    In this paper the current knowledge of the atmospheres of Jupiter and Saturn are reviewed making use of the extensive telescopic studies, International Ultraviolet Explorer Satellite observations and the measurements made during the recent Pioneer and Voyager flybys which have been supported by detailed theoretical studies. A detailed discussion is given of the composition of these atmospheres and the abundance ratios which provide insight into their original state and their evolution. The Voyager observations indicate a surprisingly close similarity between the weather systems of the Earth and the giant planets. Although both Jupiter and Saturn have internal heat sources, and are therefore star-like in their interiors, they appear to produce terrestrial-style weather systems. A detailed discussion is given of this work, which forms a major study of the Laboratory for Planetary Atmospheres at University College London. (author)

  1. Detection of arsine in Saturn

    International Nuclear Information System (INIS)

    Bezard, B.; Drossart, P.; Lellouch, E.; Tarrago, G.; Maillard, J.P.

    1989-01-01

    The detection of arsine (AsH3) in Saturn's atmosphere using high-resolution observations near 4.7 microns is reported. A strong broad absorption at the position of the nu3 Q-branch of AsH3 and weaker features where the R(1) lines of the nu1 and nu3 bands occur are noted in this high-resolution spectral range. Comparison with synthetic spectra derived from a model atmosphere indicates the following: both the thermal emission and the reflected solar radiation contribute to Saturn's 5 micron flux; the mole fraction of arsine is (2.4 + 1.4 or - 1.2) x 10 to the -9th in the approx. 4 bar region (T about 200 K) from which the thermal emission originates; AsH3 is 2.5 to 10 times less abundant in the upper troposphere (0.2-0.4 bar), a possible consequence of UV photolysis. The current observation of arsine implies upward transport from the 360 K region that is sufficiently rapid to inhibit conversion reactions. A reanalysis of 5-micron spectroscopic observations of Jupiter by Bjoraker, Larson, and Kunde (1986) indicated that arsine is much less abundant on Jupiter (AsH3/H2 less than or roughly equal to 3 x 10 to the -10th) than on Saturn. 27 refs

  2. Propellers in Saturn's rings

    Science.gov (United States)

    Sremcevic, M.; Stewart, G. R.; Albers, N.; Esposito, L. W.

    2013-12-01

    Theoretical studies and simulations have demonstrated the effects caused by objects embedded in planetary rings. Even if the objects are too small to be directly observed, each creates a much larger gravitational imprint on the surrounding ring material. These strongly depend on the mass of the object and range from "S" like propeller-shaped structures for about 100m-sized icy bodies to the opening of circumferential gaps as in the case of the embedded moons Pan and Daphnis and their corresponding Encke and Keeler Gaps. Since the beginning of the Cassini mission many of these smaller objects (~data from Cassini Ultraviolet Imaging Spectrograph (UVIS) and Imaging Science Subsystem (ISS) experiments. We show evidence that B ring seems to harbor two distinct populations of propellers: "big" propellers covering tens of degrees in azimuth situated in the densest part of B ring, and "small" propellers in less dense inner B ring that are similar in size and shape to known A ring propellers. The population of "big" propellers is exemplified with a single object which is observed for 5 years of Cassini data. The object is seen as a very elongated bright stripe (40 degrees wide) in unlit Cassini images, and dark stripe in lit geometries. In total we report observing the feature in images at 18 different epochs between 2005 and 2010. In UVIS occultations we observe this feature as an optical depth depletion in 14 out of 93 occultation cuts at corrotating longitudes compatible with imaging data. Combining the available Cassini data we infer that the object is a partial gap located at r=112,921km embedded in the high optical depth region of the B ring. The gap moves at Kepler speed appropriate for its radial location. Radial offsets of the gap locations in UVIS occultations are consistent with an asymmetric propeller shape. The asymmetry of the observed shape is most likely a consequence of the strong surface mass density gradient, as the feature is located at an edge between

  3. Photometric changes on Saturn's Titan: Evidence for active cryovolcanism

    Science.gov (United States)

    Nelson, R.M.; Kamp, L.W.; Lopes, R.M.C.; Matson, D.L.; Kirk, R.L.; Hapke, B.W.; Wall, S.D.; Boryta, M.D.; Leader, F.E.; Smythe, W.D.; Mitchell, K.L.; Baines, K.H.; Jaumann, R.; Sotin, Christophe; Clark, R.N.; Cruikshank, D.P.; Drossart, P.; Lunine, J.I.; Combes, M.; Bellucci, G.; Bibring, J.-P.; Capaccioni, F.; Cerroni, P.; Coradini, A.; Formisano, V.; Filacchione, G.; Langevin, Y.; McCord, T.B.; Mennella, V.; Nicholson, P.D.; Sicardy, B.; Irwin, P.G.J.; Pearl, J.C.

    2009-01-01

    We report infrared spectrophotometric variability on the surface of Saturn's moon Titan detected in images returned by the Visual and Infrared Mapping Spectrometer (VIMS) onboard the Cassini Saturn Orbiter. The changes were observed at 7??S, 138??W and occurred between October 27, 2005 and January 15, 2006. After that date the surface was unchanged until the most recent observation, March 18, 2006. We previously reported spectrophotometric variability at another location (26??S, 78??W). Cassini Synthetic Aperture RADAR (SAR) images find that the surface morphology at both locations is consistent with surface flows possibly resulting from cryovolcanic activity (Wall et al., companion paper, this issue). The VIMS-reported time variability and SAR morphology results suggest that Titan currently exhibits intermittent surface changes consistent with present ongoing surface processes. We suggest that these processes involve material from Titan's interior being extruded or effiised and deposited on the surface, as might be expected from cryovolcanism. ?? 2009.

  4. Saturn's Ring: Pre-Cassini Status and Mission Goals

    Science.gov (United States)

    Cuzzi, Jeff N.; DeVincenzi, Donald L. (Technical Monitor)

    1999-01-01

    In November 1980, and again in August 1981, identical Voyager spacecraft flew through the Saturn system, changing forever the way we think about planetary rings. Although Saturn's rings had been the only known ring system for three centuries, a ring system around Uranus had been discovered by stellar occultations from Earth in 1977, and the nearly transparent ring of Jupiter was imaged by Voyager in 1979 (the presence of material there had been inferred from charged particle experiments on Pioneer 10 and 11 several years earlier). While Saturn had thus temporarily lost its uniqueness as having the only ring system, with Voyager it handily recaptured the role of having the most fascinating one. The Voyager breakthroughs included spiral density and bending waves such as cause galactic structure; ubiquitous fine-scale radial 'irregular' structure, with the appearance of record-grooves; regional and local variations in particle color; complex, azimuthally variable ring structure; empty gaps in the rings, some containing very regular, sharp-edged, elliptical rings and one containing both a small moonlet and incomplete arcs of dusty material; and shadowy 'spokes' that flicker across the main rings. One of the paradigm shifts of this period was the realization that many aspects of planetary rings, and even the ring systems themselves, could be 'recent' on geological timescales. These early results are reviewed and summarized in the Arizona Space Science series volumes 'Saturn'. (An excellent review of ring dynamics at a formative stage is by Goldreich and Tremaine.) From the mid 1980's to the time of this writing, progress has been steady, while at a less heady pace, and some of the novel ring properties revealed by Voyager 1 and 2 are beginning to be better understood. It is clearly impossible to cite, much less review, every advance over the last decade; however, below we summarize the main advances in understanding of Saturn's rings since the mid 1980's, in the context

  5. Gravitoelectrodynamics in Saturn's F ring: encounters with Prometheus and Pandora

    International Nuclear Information System (INIS)

    Matthews, Lorin Swint; Hyde, Truell W

    2003-01-01

    The dynamics of Saturn's F ring have been a matter of curiosity ever since Voyagers 1 and 2 sent back pictures of the ring's unusual features. Some of these images showed three distinct ringlets with the outer two displaying a kinked and braided appearance. Many models have been proposed to explain the braiding seen in these images; most of these invoke perturbations caused by the shepherding moons or kilometre-sized moonlets embedded in the ring and are purely gravitational in nature. These models also assume that the plasma densities and charges on the grains are small enough that electromagnetic forces can be ignored. However, Saturn's magnetic field exerts a significant perturbative force on even weakly charged micron- and submicron-sized grains causing the grains to travel in epicyclic orbits about a guiding centre. This study examines the effect of Saturn's magnetic field on the dynamics of micron-sized grains along with gravitational interactions between the F ring's shepherding moons, Prometheus and Pandora. Due to the differences in charge-to-mass ratios of the various sized grains, a phase difference between different size populations is observed in the wavy orbits imposed by passage of the shepherding moons

  6. Hubble again views Saturn's Rings Edge-on

    Science.gov (United States)

    1995-01-01

    Saturn's magnificent ring system is seen tilted edge-on -- for the second time this year -- in this NASA Hubble Space Telescope picture taken on August 10, 1995, when the planet was 895 million miles (1,440 million kilometers) away. Hubble snapped the image as Earth sped back across Saturn's ring plane to the sunlit side of the rings. Last May 22, Earth dipped below the ring plane, giving observers a brief look at the backlit side of the rings. Ring-plane crossing events occur approximately every 15 years. Earthbound observers won't have as good a view until the year 2038. Several of Saturn's icy moons are visible as tiny starlike objects in or near the ring plane. They are from left to right, Enceladus, Tethys, Dione and Mimas. 'The Hubble data shows numerous faint satellites close to the bright rings, but it will take a couple of months to precisely identify them,' according to Steve Larson (University of Arizona). During the May ring plane crossing, Hubble detected two, and possibly four, new moons orbiting Saturn. These new observations also provide a better view of the faint E ring, 'to help determine the size of particles and whether they will pose a collision hazard to the Cassini spacecraft,' said Larson. The picture was taken with Hubble's Wide Field Planetary Camera 2 in wide field mode. This image is a composite view, where a long exposure of the faint rings has been combined with a shorter exposure of Saturn's disk to bring out more detail. When viewed edge-on, the rings are so dim they almost disappear because they are very thin -- probably less than a mile thick.The Wide Field/Planetary Camera 2 was developed by the Jet Propulsion Laboratory and managed by the Goddard Spaced Flight Center for NASA's Office of Space Science.This image and other images and data received from the Hubble Space Telescope are posted on the World Wide Web on the Space Telescope Science Institute home page at URL http://oposite.stsci.edu/pubinfo/

  7. Conclusions and recommendations: Exploration of the Saturn system

    Science.gov (United States)

    Hunten, D. M.

    1978-01-01

    Saturn missions have the following principal goals, in order of importance: (1) Intensive investigation of the atmosphere of Saturn; (2) determination of regional surface chemistry and properties of the surface features of satellites and properties of ring particles; (3) intensive investigation of Titan; and (4) atmospheric dynamics and structure of Saturn satellites and Saturn rings.

  8. IMF dependence of Saturn's auroras: modelling study of HST and Cassini data from 12–15 February 2008

    Directory of Open Access Journals (Sweden)

    E. S. Belenkaya

    2010-08-01

    Full Text Available To gain better understanding of auroral processes in Saturn's magnetosphere, we compare ultraviolet (UV auroral images obtained by the Hubble Space Telescope (HST with the position of the open-closed field line boundary in the ionosphere calculated using a magnetic field model that employs Cassini measurements of the interplanetary magnetic field (IMF as input. Following earlier related studies of pre-orbit insertion data from January 2004 when Cassini was located ~ 1300 Saturn radii away from the planet, here we investigate the interval 12–15 February 2008, when UV images of Saturn's southern dayside aurora were obtained by the HST while the Cassini spacecraft measured the IMF in the solar wind just upstream of the dayside bow shock. This configuration thus provides an opportunity, unique to date, to determine the IMF impinging on Saturn's magnetosphere during imaging observations, without the need to take account of extended and uncertain interplanetary propagation delays. The paraboloid model of Saturn's magnetosphere is then employed to calculate the magnetospheric magnetic field structure and ionospheric open-closed field line boundary for averaged IMF vectors that correspond, with appropriate response delays, to four HST images. We show that the IMF-dependent open field region calculated from the model agrees reasonably well with the area lying poleward of the UV emissions, thus supporting the view that the poleward boundary of Saturn's auroral oval in the dayside ionosphere lies adjacent to the open-closed field line boundary.

  9. SATURN. Studying Atmospheric Pollution in Urban Areas

    DEFF Research Database (Denmark)

    Moussiopoulos, N.; Hout, K. D. van den; Mestayer, P.

    SATURN is a subproject under EUROTRAC-2. (EUROTRAC-2 is the EUREKA Project on the Transport and Chemical Transformation of Environmentally Relevant Trace Constituents in the Troposphere over Europe; Second Phase)....

  10. Birth and next future of SATURNE II

    International Nuclear Information System (INIS)

    Vienet, R.

    1978-01-01

    The renewal SATURNE project started in 1974. SATURNE I desassembling began in may 1977 and in july 1978 with the new ring, we just get more that ten to the eleventh particules in the very first hour of starting. The main parameters of SATURNE II was presented at the IX 0 International Conference on High Energy Accelerator at Stanford in may 1974 (Proceedings p. 615). SATURNE II is a strong focusing synchrotron and the injected particules fill the synchrotron space with very few betatron oscillation. So a small emittance external beam should be obtained, which is very important for experimental nuclear physics. The realization main difficulties will be mentionned. The results obtained with the first days beam will be presented. We will described the forecasted characteristics of the accelerator and the experimental areas to be reached in 1979

  11. Resistive Heating in Saturn's Thermosphere

    Science.gov (United States)

    Vriesema, Jess W.; Koskinen, Tommi; Yelle, Roger V.

    2016-10-01

    The thermospheres of the jovian planets are several times hotter than solar heating alone can account for. On Saturn, resistive heating appears sufficient to explain these temperatures in auroral regions, but the particular mechanism(s) responsible for heating the lower latitudes remains unclear. Smith et al. (2005) suggested that electrodynamics of the equatorial region—particularly resistive heating caused by strong electrojet currents—might explain the observed temperatures at low latitudes. Müller-Wodarg et al. (2006) found that their circulation model could reproduce low-latitude temperatures only when they included resistive heating at the poles and applied a uniform, generic heating source globally. Smith et al. (2007) concluded that heating at the poles leads to meridional circulation that cools low latitudes and argued that in-situ heating is required to explain the temperatures at low latitudes.Resistive heating at low latitudes, arising from enhanced current generation driven by thermospheric winds, is a potentially important in-situ heating mechanism. Ion drag caused by low-latitude electrodynamics can modify global circulation and meridional transport of energy. We present an axisymmetric, steady-state formulation of wind-driven electrodynamics to investigate these possibilities throughout Saturn's thermosphere. At present, we assume a dipole magnetic field and neglect any contributions from the magnetosphere. We use ion mixing ratios from the model of Kim et al. (2014) and the observed temperature-pressure profile from Koskinen et al. (2015) to calculate the generalized conductivity tensor as described by Koskinen et al. (2014). Our model solves the coupled equations for charge continuity and Ohm's law with tensor conductivity while enforcing zero current across the boundaries. The resulting partial differential equation is solved for the current density throughout the domain and used to calculate the net resistive heating rate. We demonstrate

  12. Starting up the Saturne synchrotron

    International Nuclear Information System (INIS)

    Salvat, M.

    1958-02-01

    Illustrated by many drawings and graphs, this report describes and comments all operations and measurements to be performed for starting up the Saturne synchrotron until particle acceleration exclusively. The author reports the study of beam as it goes out of the Van de Graaff: experiment of position and stability of the beam axis, study of beam current and geometric characteristics (calibration of the induction probe), experiment of mass separation and proton percentage, and adjustment of regulation and Van de Graaff fall law. In a second part, he reports the optics alignment and the study of optics property (installation of the different sectors, study of inflector end voltage, and influence of inflector position in the chamber). The third part addresses the examination of phenomena associated with injection: injection method and definition of the initial instant, search for injection optimum conditions, study of particle lifetime and of phenomena on the inner probe. The fourth part proposes theoretical additional elements regarding the movement of particles at the injection in the useful area, and phenomena occurring on targets and on the inner probe

  13. Charged dust in saturn's magnetosphere

    International Nuclear Information System (INIS)

    Mendis, D.A.; Hill, J.R.; Houpis, H.L.F.

    1983-01-01

    Gravito-electrodynamic theory of charged dust grains is used to explain a variety of phenomena in those portions of the Saturnian ring system that are known to be dominated by fine (micron- and submicron-sized) dust, and in which collisional forces and Coulomb drag can be neglected. Among the phenomena discussed are the formation and evolution of the rotating near-radial spokes in the B-ring, the formation of waves in the F-ring, the cause of eccentricities of certain isolated ringlets, and the origin and morphology of the broad diffuse E-ring. Several novel processes predicted by the gravitoelectrodynamic theory, including 'magneto-gravitational capture' of exogenic dust by the magnetosphere, '1:1 magneto-gravitational orbital resonances' of charged dust with nearby satellites, and 'gyro-orbital resonances,' are used to explain individual observations. The effect of a ring current associated with this charged dust is also evaluated. Finally, the cosmogonic implications of the magneto-gravitational theory are briefly discussed. While several (although not all) of these processes have been discussed by one or more of the present authors elsewhere, the purpose of this paper is to synthesize all these processes within the framework of gravito-electrodynamics, and also to show its range of applicability within Saturn's ring system

  14. Polar heating in Saturn's thermosphere

    Directory of Open Access Journals (Sweden)

    C. G. A. Smith

    2005-10-01

    Full Text Available A 3-D numerical global circulation model of the Kronian thermosphere has been used to investigate the influence of polar heating. The distributions of temperature and winds resulting from a general heat source in the polar regions are described. We show that both the total energy input and its vertical distribution are important to the resulting thermal structure. We find that the form of the topside heating profile is particularly important in determining exospheric temperatures. We compare our results to exospheric temperatures from Voyager occultation measurements (Smith et al., 1983; Festou and Atreya, 1982 and auroral H3+ temperatures from ground-based spectroscopic observations (e.g. Miller et al., 2000. We find that a polar heat source is consistent with both the Smith et al. determination of T∞~400 K at ~30° N and auroral temperatures. The required heat source is also consistent with recent estimates of the Joule heating rate at Saturn (Cowley et al., 2004. However, our results show that a polar heat source can probably not explain the Festou and Atreya determination of T∞~800 K at ~4° N and the auroral temperatures simultaneously. Keywords. Ionosphere (Planetary ionosphere – Magnetospherica physics (Planetary magnetospheres – Meterology and atmospheric dynamics (Thermospheric dynamics

  15. Saturn's equatorial jet structure from Cassini/ISS

    Science.gov (United States)

    García-Melendo, Enrique; Legarreta, Jon; Sánchez-Lavega, Agustín.; Pérez-Hoyos, Santiago; Hueso, Ricardo

    2010-05-01

    Detailed wind observations of the equatorial regions of the gaseous giant planets, Jupiter and Saturn, are crucial for understanding the basic problem of the global circulation and obtaining new detailed information on atmospheric phenomena. In this work we present high resolution data of Saturn's equatorial region wind profile from Cassini/ISS images. To retrieve wind measurements we applied an automatic cross correlator to image pairs taken by Cassini/ISS with the MT1, MT2, MT3 filters centred at the respective three methane absorbing bands of 619nm, 727nm, and 889nm, and with the adjacent continuum CB1, CB2, and CB3 filters. We obtained a complete high resolution coverage of Saturn's wind profile in the equatorial region. The equatorial jet displays an overall symmetric structure similar to that shown the by same region in Jupiter. This result suggests that, in accordance to some of the latest compressible atmosphere computer models, probably global winds in gaseous giants are deeply rooted in the molecular hydrogen layer. Wind profiles in the methane absorbing bands show the effect of strong vertical shear, ~40m/s per scale height, confirming previous results and an important decay in the wind intensity since the Voyager era (~100 m/s in the continuum and ~200 m/s in the methane absorbing band). We also report the discovery of a new feature, a very strong and narrow jet on the equator, about only 5 degrees wide, that despite the vertical shear maintains its intensity (~420 m/s) in both, the continuum and methane absorbing band filters. Acknowledgements: Work supported by the Spanish MICIIN AYA2009-10701 with FEDER and Grupos Gobierno Vasco IT-464-07.

  16. Managing Cassini Safe Mode Attitude at Saturn

    Science.gov (United States)

    Burk, Thomas A.

    2010-01-01

    The Cassini spacecraft was launched on October 15, 1997 and arrived at Saturn on June 30, 2004. It has performed detailed observations and remote sensing of Saturn, its rings, and its satellites since that time. In the event safe mode interrupts normal orbital operations, Cassini has flight software fault protection algorithms to detect, isolate, and recover to a thermally safe and commandable attitude and then wait for further instructions from the ground. But the Saturn environment is complex, and safety hazards change depending on where Cassini is in its orbital trajectory around Saturn. Selecting an appropriate safe mode attitude that insures safe operation in the Saturn environment, including keeping the star tracker field of view clear of bright bodies, while maintaining a quiescent, commandable attitude, is a significant challenge. This paper discusses the Cassini safe table management strategy and the key criteria that must be considered, especially during low altitude flybys of Titan, in deciding what spacecraft attitude should be used in the event of safe mode.

  17. Wideband Photometry of Saturn: 1995-2007

    Science.gov (United States)

    Schmude, Richard W.

    2007-10-01

    The writer has measured the brightness of Saturn + rings at four wavelengths (0.44 to 0.86 microns) every year since 1995 using a single channel photometer. Filters transformed to the Johnson B, V, R and I system were used in all measurements. The main conclusions of this 12 year study are: 1) The color of Saturn + rings does not change in visible light as the solar phase angle drops from 6 to 2 degrees. 2) The color of Saturn + rings becomes a few percent bluer in visible light as the solar phase angle drops below 1.0 degree due to the opposition surge. 3) In visible wavelengths, the color of Saturn + rings does not change as the ring tilt changes from 4 to 27 degrees. 4) The R-I color index value increases by about 0.1 magnitudes as the ring tilt angle rises from 4 to 27 degrees. The opening of the rings is probably the cause of this change. 5) The solar phase angle coefficient of Saturn + rings is 0.027 magnitude/degree for a ring tilt angle of 14 degrees and it rises by about 0.0005 magnitude/degree for each 1 degree increase in ring tilt angle and it drops by about the same amount for each 1 degree drop in ring tilt angle. The writer would like to thank Gordon College for providing financial support for attending this meeting.

  18. Saturn V Instrument Unit Being Checked At MSFC

    Science.gov (United States)

    1967-01-01

    A technician checks the systems of the Saturn V instrument unit in a test facility in Huntsville. This instrument unit was flown aboard Apollo 4 on November 7, 1967, which was the first test flight of the Saturn V. The towering 363-foot Saturn V was a multi-stage, multi-engine launch vehicle standing taller than the Statue of Liberty. Altogether, the Saturn V engines produced as much power as 85 Hoover Dams.

  19. Saturn facility oil transfer automation system

    Energy Technology Data Exchange (ETDEWEB)

    Joseph, Nathan R.; Thomas, Rayburn Dean; Lewis, Barbara Ann; Malagon, Hector Ricardo.

    2014-02-01

    The Saturn accelerator, owned by Sandia National Laboratories, has been in operation since the early 1980s and still has many of the original systems. A critical legacy system is the oil transfer system which transfers 250,000 gallons of transformer oil from outside storage tanks to the Saturn facility. The oil transfer system was iden- ti ed for upgrade to current technology standards. Using the existing valves, pumps, and relay controls, the system was automated using the National Instruments cRIO FGPA platform. Engineered safety practices, including a failure mode e ects analysis, were used to develop error handling requirements. The uniqueness of the Saturn Oil Automated Transfer System (SOATS) is in the graphical user interface. The SOATS uses an HTML interface to communicate to the cRIO, creating a platform independent control system. The SOATS was commissioned in April 2013.

  20. Quasi-periodic latitudinal shift of Saturn's main auroral emission

    Science.gov (United States)

    Roussos, E.; Palmaerts, B.; Grodent, D. C.; Radioti, K.; Krupp, N.; Yao, Z.

    2017-12-01

    The main component of the ultraviolet auroral emissions at Saturn consists in a ring of emission around each pole of the planet. This main ring of emission has been revealed to oscillate by a few degrees in the prenoon-premidnight direction with a period of 10.8h. This auroral oscillation is thought to be induced by a rotating external magnetospheric current system associated with the planetary period oscillations. Here we report, by means of auroral imaging sequences obtained with the Ultraviolet Imaging Spectrograph (UVIS) on board the Cassini spacecraft, the first direct observation of an additional motion of the main emission superimposed to this oscillation. The whole main emission ring exhibits step-like displacements in latitude mainly towards dayside, decoupled from the 10.8h oscillation. These latitude shifts recur around every hour, which is a typical short periodicity at Saturn previously identified in the aurora intensity, in the charged particle fluxes and in the magnetic field. This unique observation directly demonstrates what has been inferred from past in-situ and remote measurements: the 1-hour periodicities reveal a global and fundamental magnetospheric oscillation mode that acts independently of the local magnetospheric conditions. However, the magnetospheric mechanism responsible for these 1-hour auroral shifts is still unknown. It is possible that Alfvén waves inducing hourly magnetic fluctuations might also modify the place where the field-aligned electrons precipitate in the ionosphere and produce the main emission.

  1. Cassini ISS Observation of Saturn from Grand Finale Orbits

    Science.gov (United States)

    Blalock, J. J.; Sayanagi, K. M.; Ingersoll, A. P.; Dyudina, U.; Ewald, S. P.; McCabe, R. M.; Garland, J.; Gunnarson, J.; Gallego, A.

    2017-12-01

    We present images captured during Cassini's Grand Finale orbits, and their preliminary analyses. During the final 22 orbits of the mission, the spacecraft is in orbits that have 6.5 day period at an inclination of 62 degrees, apoapsis altitude of about 1,272,000 km, and periapsis altitudes of about 2,500 km. Images captured during periapsis passes show Saturn's atmosphere at unprecedented spatial resolution. We present preliminary analyses of these images, including the final images captured before the end of the mission when the spacecraft enters Saturn's atmosphere on September 15th, 2017. Prominent features captured during the final orbits include the north polar vortex and other vortices as well as very detailed views of the "popcorn clouds" that reside between the Hexagon and the north pole. In the cloud field between zonal jets, clouds either resemble linear streaks suggestive of cirrus-like clouds or round shapes suggestive of vortices or cumulus anvil. The presence of linear streaks that follow lines of constant latitudes suggests that meridional mixing is inhibited at those latitudes. The size of vortices may reflect latitudinal variation in the atmospheric deformation radius. We also compare the new images to those captured earlier in the Cassini mission to characterize the temporal evolution such as changes in the zonal jet speeds, and prevalence and colors of vortices. A particular focus of our interest is the long-term change in the color of the hexagon, the evolution of the wind speeds in the jetstream that blows eastward at the boundary of the hexagon, and the morphology of the north polar vortex. Our work has been supported by NASA PATM NNX14AK07G, NSF AAG 1212216, and NASA NESSF NNX15AQ70H.

  2. Saturn - lord of the rings. [Pioneer II investigation of Saturn reviewed

    Energy Technology Data Exchange (ETDEWEB)

    Hunt, G [University Coll., London (UK); Burgess, E

    1979-12-13

    Much new information has been obtained about Saturn and its system of rings by the spacecraft Pioneer II. One of the major discoveries was that Saturn has a magnetic field whose axis was found to correspond almost exactly with the axis of rotation of the planet. The planet was also found to be surrounded by belts of trapped energetic particles (radiation belts) which are effected by the planet's rings. It was not only discovered that Saturn has at least 10 satellites but also new information was provided by Pioneer about the Planet's ring system that would have been impossible to obtain from Earth-based observations. Analysis of Saturn's gravitational field, coupled with a temperature profile calculated from infrared measurements of the heat emitted by the clouds in excess of that received from the Sun, has allowed a new view of the interior of the planet to be developed.

  3. Diagram of the Saturn V Launch Vehicle in Metric

    Science.gov (United States)

    1971-01-01

    This is a good cutaway diagram of the Saturn V launch vehicle showing the three stages, the instrument unit, and the Apollo spacecraft. The chart on the right presents the basic technical data in clear metric detail. The Saturn V is the largest and most powerful launch vehicle in the United States. The towering, 111 meter, Saturn V was a multistage, multiengine launch vehicle standing taller than the Statue of Liberty. Altogether, the Saturn V engines produced as much power as 85 Hoover Dams. Development of the Saturn V was the responsibility of the Marshall Space Flight Center at Huntsville, Alabama, directed by Dr. Wernher von Braun.

  4. Self-gravitation in Saturn's rings

    International Nuclear Information System (INIS)

    Salo, H.; Lukkari, J.

    1982-01-01

    In a ring-shaped collisional system self-gravitation reduces the equilibrium values of the geometric and optical thickness. In Saturn's rings both effects are appreciable. The previously found discrepancy between the calculated profile and the observed profile of the rings is chiefly caused by the omission of self-gravitation. (Auth.)

  5. Origin and evolution of Jupiter and Saturn

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, S S [Virginia Univ., Charlottesville (USA)

    1977-07-01

    Arguments are presented which make it very unlikely that Jupiter and Saturn were formed by contraction from initially extended gaseous states. Formation of these and other planets (in the solar system) by the mechanism of accretion does not appear to present any difficulties.

  6. Apollo Image Atlas

    Data.gov (United States)

    National Aeronautics and Space Administration — The Apollo Image Atlas is a comprehensive collection of Apollo-Saturn mission photography. Included are almost 25,000 lunar images, both from orbit and from the...

  7. Bimodality and the formation of Saturn's ring particles

    International Nuclear Information System (INIS)

    Gehrels, T.

    1980-01-01

    The F ring appears to have an outer and an inner rim, with only the latter observed by the imaging photopolarimeter (IPP) on the Pioneer Saturn spacecraft. The inside of the G ring, near 2.49 R/sub S/, may also be seen in the optical data. 1979S1 is red as well as dark. The light scattered through the B ring is noticeably red. The A ring has a dense outer rim. The Cassini Division and the French Division (Dollfus Division) have a dark gap near their centers. The C ring becomes weaker toward the center such that outer, middle, and inner C rings can be recognized. The Pioneer and earth-based observations are explained with a model for the B and A rings to some extent of a bimodal size distributions of particles; the larger ones may be original accretions, while small debris diffuses inward through the Cassini Division and the C ring. During the formation of the ring system, differential gravitation allowed only silicaceous grains of higher density (rho> or approx. =3 g cm -3 ) to coagulate. These serve as interstitial cores for snowy carbonaceous grains, between the times of accretion from interplanetary cometary grains and liberation by collision followed by diffusion inward to Saturn and final evaporation

  8. Cassini MIMI Close-Up of Saturn Energetic Particles: Low Altitude Trapped Radiation, Auroral Ion Acceleration, and Interchange Flow Channels

    Science.gov (United States)

    Mitchell, D. G.; Krimigis, S. M.; Krupp, N.; Paranicas, C.; Roussos, E.; Kollmann, P.

    2017-12-01

    We present observations from the final orbits of the Cassini Mission at Saturn by the Magnetospheric Imaging Instrument (MIMI). Crossing inside the D-Ring at the equator and just above Saturn's atmosphere, these orbits covered regions never visited previously in the mission. Highlights include the confirmation of an inner radiation belt analogous to the inner radiation belt at Earth by the Low Energy Magnetospheric Measurement System (LEMMS), with surprising twists—Saturn's D-ring material appears to be a source for these particles. Details will be presented in another session. The Grand Finale orbits also afforded a close-up view of the auroral ion acceleration regions by the Ion and Neutral Camera (INCA). Ionospheric ions at the base of auroral field lines are accelerated perpendicular to the magnetic field to 10's and 100's of keV, and charge exchange with exospheric neutrals to be emitted as energetic neutral atoms and images by INCA. We show that this acceleration region lies at about 0.1 Rs. Another feature seen previously in the mission but imaged with greater resolution is a flow channel associated with interchange motion in the middle magnetosphere. We show this feature to extend over several Saturn radii in the radial direction, and over about 2 Saturn radii azimuthally. Additional data have been received since the writing of this abstract and before Cassini's plunge into the atmosphere on September 15, so additional features may be presented.

  9. A Saturn Ring Observer Mission Using Multi-Mission Radioisotope Power Systems

    International Nuclear Information System (INIS)

    Abelson, Robert D.; Spilker, Thomas R.; Shirley, James H.

    2006-01-01

    Saturn remains one of the most fascinating planets within the solar system. To better understand the complex ring structure of this planet, a conceptual Saturn Ring Observer (SRO) mission is presented that would spend one year in close proximity to Saturn's A and B rings, and perform detailed observations and measurements of the ring particles and electric and magnetic fields. The primary objective of the mission would be to understand ring dynamics, including the microphysics of individual particles and small scale (meters to a few kilometers) phenomena such as particle agglomeration behavior. This would be accomplished by multispectral imaging of the rings at multiple key locations within the A and B rings, and by ring-particle imaging at an unprecedented resolution of 0.5 cm/pixel. The SRO spacecraft would use a Venus-Earth-Earth-Jupiter Gravity Assist (VEEJGA) and be aerocaptured into Saturn orbit using an advanced aeroshell design to minimize propellant mass. Once in orbit, the SRO would stand off from the ring plane 1 to 1.4 km using chemical thrusters to provide short propulsive maneuvers four times per revolution, effectively causing the SRO vehicle to 'hop' above the ring plane. The conceptual SRO spacecraft would be enabled by the use of a new generation of multi-mission Radioisotope Power Systems (RPSs) currently being developed by NASA and DOE. These RPSs include the Multi-Mission Radioisotope Thermoelectric Generator (MMRTG) and Stirling Radioisotope Generator (SRG). The RPSs would generate all necessary electrical power (≥330 We at beginning of life) during the 10-year cruise and 1-year science mission (∼11 years total). The RPS heat would be used to maintain the vehicle's operating and survival temperatures, minimizing the need for electrical heaters. Such a mission could potentially launch in the 2015-2020 timeframe, with operations at Saturn commencing in approximately 2030

  10. Cassini-Huygens Nears Saturn Orbit Insertion

    Science.gov (United States)

    Showstack, Randy

    2004-06-01

    After nearly 7 years and a 3.5-billion-km, circuitous journey from Earth, the $3-billion Cassini-Huygens mission to Saturn and Titan-an international effort by NASA, the European Space Agency, and the Italian Space Agency-now is just days away from its critical Saturn orbit insertion. Scheduled for 30 June, this will begin the 4-years part of the mission to study the Saturnian system. At a 3 June briefing at NASA headquarters in Washington, D.C., Robert Mitchell, the Cassini program manager with the Jet Propulsion Laboratory in Pasadena, California, said that scientists involved with the program are feeling excited, relieved, and also a bit anxious as the Cassini-Huygens spacecraft draws near to the ringed planet and its system.

  11. Profiling Saturn's rings by radio occultation

    International Nuclear Information System (INIS)

    Marouf, E.A.; Tyler, G.L.; Rosen, P.A.

    1986-01-01

    The development of reconstruction algorithms that correct for diffraction effects in radio occultation measurements is described. The reciprocal Fresnel transform relationship between the complex amplitude of the observed coherent signal and the complex microwave transmittance of the rings is derived using the Huygens-Fresnel formulation of the diffraction problem. The effects of the finite data segment width, the uncertainties in the Fresnel scale, systematic phase errors in the kernel of the inverse transform, reference oscillator instabilities, and random noise measurements on the resolution of the reconstructed transmittance are analyzed. Examples of reconstructed opacity profiles for some regions of Saturn's rings derived by applying the reconstruction theory to Voyager 1 at Saturn data are presented. 35 references

  12. Evidence of Accretion in Saturn's F Ring (Invited)

    Science.gov (United States)

    Agnor, C. B.; Buerle, K.; Murray, C. D.; Evans, M. W.; Cooper, N. J.; Williams, G. W.

    2010-12-01

    Lying slightly outside the classical Roche radius and being strongly perturbed by the adjacent moons Prometheus and Pandora, Saturn's F ring represents a unique astrophysical laboratory for examining the processes of mass accretion and moonlet formation. Recent images from the Cassini spacecraft reveal optically thick clumps, capable of casting shadows, and associated structures in regions of the F ring following close passage by Prometheus. Here we examine the accretion environment of the F ring and Prometheus' role in moonlet formation and evolution. Using the observed structures adjacent to these clumps and dynamical arguments we estimate the masses of these clumps and find them comparable to that of ~10-20-km contiguous moonlets. Further, we show that Prometheus' perturbations on the F ring create regions of enhanced density and low relative velocity that may accelerate the accretion of clumps and moonlets.

  13. Experimental results and modeling of a dynamic hohlraum on SATURN

    International Nuclear Information System (INIS)

    Derzon, M.S.; Allshouse, G.O.; Deeney, C.; Leeper, R.J.; Nash, T.J.; Matuska, W.; Peterson, D.L.; MacFarlane, J.J.; Ryutov, D.D.

    1998-06-01

    Experiments were performed at SATURN, a high current z-pinch, to explore the feasibility of creating a hohlraum by imploding a tungsten wire array onto a low-density foam. Emission measurements in the 200--280 eV energy band were consistent with a 110--135 eV Planckian before the target shock heated, or stagnated, on-axis. Peak pinch radiation temperatures of nominally 160 eV were obtained. Measured early time x-ray emission histories and temperature estimates agree well with modeled performance in the 200--280 eV band using a 2D radiation magneto-hydrodynamics code. However, significant differences are observed in comparisons of the x-ray images and 2D simulations

  14. Modeling Saturn's Inner Plasmasphere: Cassini's Closest Approach

    Science.gov (United States)

    Moore, L.; Mendillo, M.

    2005-05-01

    Ion densities from the three-dimensional Saturn-Thermosphere-Ionosphere-Model (STIM, Moore et al., 2004) are extended above the plasma exobase using the formalism of Pierrard and Lemaire (1996, 1998), which evaluates the balance of gravitational, centrifugal and electric forces on the plasma. The parameter space of low-energy ionospheric contributions to Saturn's plasmasphere is explored by comparing results that span the observed extremes of plasma temperature, 650 K to 1700 K, and a range of velocity distributions, Lorentzian (or Kappa) to Maxwellian. Calculations are made for plasma densities along the path of the Cassini spacecraft's orbital insertion on 1 July 2004. These calculations neglect any ring or satellite sources of plasma, which are most likely minor contributors at 1.3 Saturn radii. Modeled densities will be compared with Cassini measurements as they become available. Moore, L.E., M. Mendillo, I.C.F. Mueller-Wodarg, and D.L. Murr, Icarus, 172, 503-520, 2004. Pierrard, V. and J. Lemaire, J. Geophys. Res., 101, 7923-7934, 1996. Pierrard, V. and J. Lemaire, J. Geophys. Res., 103, 4117, 1998.

  15. Comparison of the Cloud Morphology Spatial Structure Between Jupiter and Saturn Using JunoCam and Cassini ISS

    Science.gov (United States)

    Garland, Justin; Sayanagi, Kunio M.; Blalock, John J.; Gunnarson, Jacob; McCabe, Ryan M.; Gallego, Angelina; Hansen, Candice; Orton, Glenn S.

    2017-10-01

    We present an analysis of the spatial-scales contained in the cloud morphology of Jupiter’s southern high latitudes using images captured by JunoCam in 2016 and 2017, and compare them to those on Saturn using images captured using the Imaging Science Subsystem (ISS) on board the Cassini orbiter. For Jupiter, the characteristic spatial scale of cloud morphology as a function of latitude is calculated from images taken in three visual (600-800, 500-600, 420-520 nm) bands and a near-infrared (880- 900 nm) band. In particular, we analyze the transition from the banded structure characteristic of Jupiter’s mid-latitudes to the chaotic structure of the polar region. We apply similar analysis to Saturn using images captured using Cassini ISS. In contrast to Jupiter, Saturn maintains its zonally organized cloud morphology from low latitudes up to the poles, culminating in the cyclonic polar vortices centered at each of the poles. By quantifying the differences in the spatial scales contained in the cloud morphology, our analysis will shed light on the processes that control the banded structures on Jupiter and Saturn. Our work has been supported by the following grants: NASA PATM NNX14AK07G, NASA MUREP NNX15AQ03A, and NSF AAG 1212216.

  16. Saturn's Internal Magnetic Field Revealed by Cassini Grand Finale

    Science.gov (United States)

    Cao, H.; Dougherty, M. K.; Khurana, K. K.; Hunt, G. J.; Provan, G.; Kellock, S.; Burton, M. E.; Burk, T. A.

    2017-12-01

    Saturn's internal magnetic field has been puzzling since the first in-situ measurements during the Pioneer 11 Saturn flyby. Cassini magnetometer measurements prior to the Grand Finale phase established 1) the highly axisymmetric nature of Saturn's internal magnetic field with a dipole tilt smaller than 0.06 degrees, 2) at least an order of magnitude slower secular variation rate compared to that of the current geomagnetic field, and 3) expulsion of magnetic fluxes from the equatorial region towards high latitude. The highly axisymmetric nature of Saturn's intrinsic magnetic field not only challenges dynamo theory but also makes an accurate determination of the interior rotation rate of Saturn extremely difficult. The Cassini spacecraft entered the Grand Finale phase in April 2017, during which time the spacecraft dived through the gap between Saturn's atmosphere and the inner edge of the D-ring 22 times before descending into the deep atmosphere of Saturn. The unprecedented proximity to Saturn (reaching 2500 km above the cloud deck) and the highly inclined nature of the Grand Finale orbits provided an ideal opportunity to decode Saturn's internal magnetic field. The fluxgate magnetometer onboard Cassini made precise vector measurements during the Grand Finale phase. Magnetic signals from the interior of the planet, the magnetospheric ring current, the high-latitude field-aligned current (FAC) modulated by the 10.7 hour planetary period oscillation, and low-latitude FACs were observed during the Grand Finale phase. Here we report the magnetometer measurements during the Cassini Grand Finale phase, new features of Saturn's internal magnetic field revealed by these measurements (e.g., the high degree magnetic moments of Saturn, the level of axisymmetry beyond dipole), and implications for the deep interior of Saturn.

  17. Saturn V First Stage S-1C LOX Fuel Tanks

    Science.gov (United States)

    1960-01-01

    This photograph shows the Saturn V assembled LOX (Liquid Oxygen) and fuel tanks ready for transport from the Manufacturing Engineering Laboratory at Marshall Space Flight Center in Huntsville, Alabama. The tanks were then shipped to the launch site at Kennedy Space Center for a flight. The towering 363-foot Saturn V was a multi-stage, multi-engine launch vehicle standing taller than the Statue of Liberty. Altogether, the Saturn V engines produced as much power as 85 Hoover Dams.

  18. Saturn V First Stage Leaves the Dynamic Test Stand

    Science.gov (United States)

    1967-01-01

    This photo shows the Saturn V first stage being lowered to the ground following a successful test to determine the effects of continual vibrations simulating the effects of an actual launch. The towering 363-foot Saturn V was a multi-stage, multi-engine launch vehicle standing taller than the Statue of Liberty. Altogether, the Saturn V engines produced as much power as 85 Hoover Dams.

  19. Saturn V First Stage (S-1C) At MSFC

    Science.gov (United States)

    1960-01-01

    This small group of unidentified officials is dwarfed by the gigantic size of the Saturn V first stage (S-1C) at the shipping area of the Manufacturing Engineering Laboratory at Marshall Space Flight Center in Huntsville, Alabama. The towering 363-foot Saturn V was a multi-stage, multi-engine launch vehicle standing taller than the Statue of Liberty. Altogether, the Saturn V engines produced as much power as 85 Hoover Dams.

  20. Aft View of Saturn V Third Stage (S-IVB)

    Science.gov (United States)

    1960-01-01

    The powerful J-2 engine is prominent in this photograph of a Saturn V Third Stage (S-IVB) resting on a transporter in the Manufacturing Facility at Marshall Space Flight Center in Huntsville, Alabama. The towering 363-foot Saturn V was a multi-stage, multi-engine launch vehicle standing taller than the Statue of Liberty. Altogether, the Saturn V engines produced as much power as 85 Hoover Dams.

  1. F-1 Engine for Saturn V Undergoing a Static Test

    Science.gov (United States)

    1964-01-01

    The flame and exhaust from the test firing of an F-1 engine blast out from the Saturn S-IB Static Test Stand in the east test area of the Marshall Space Flight Center. A Cluster of five F-1 engines, located in the S-IC (first) stage of the Saturn V vehicle, provided over 7,500,000 pounds of thrust to launch the giant rocket. The towering 363-foot Saturn V was a multistage, multiengine launch vehicle standing taller than the Statue of Liberty. Altogether, the Saturn V engines produced as much power as 85 Hoover Dams.

  2. A Long-lived Cyclone In Saturn's Atmosphere: Observations And Models

    Science.gov (United States)

    Del Rio Gaztelurrutia, Teresa; Legarreta, J.; Hueso, R.; Pérez-Hoyos, S.; Sánchez-Lavega, A.

    2009-09-01

    The atmospheres of the Giant Planets Jupiter and Saturn possess large numbers of atmospheric vortices. On Jupiter, anticyclones are generally long-lived structures while cyclones survive a much shorter time. A long term survey of images of Saturn atmosphere obtained by the Cassini ISS camera has revealed the presence of a long-lived cyclone in Saturn's southern hemisphere during at least four years, making this vortex the longest lived cyclone on either Jupiter or Saturn. We find that the vortex drifts following the wind profile, with changes in velocity following changes of latitude. During the four years of our survey its size remained essentially constant, and there was no other structure of comparable size at its latitude. Internal circulation is cyclonic, with a maximum velocity of 20±5 m/s and an average vorticity of 4·10-5 s-1, an order of magnitude lower than planetary vorticity, but only slightly higher than the ambient vorticity. Photometric analysis shows that the vortex is located at a slightly lower altitude than its surroundings, at an average of 10-20 mbar below adjacent clouds. Finally, EPIC simulations of the vortex that reproduce its behavior imply a Rossby deformation radius of 2000 km in the weather layer (1 - 10 bar), consistent with the size of the cyclone. The long-lifetime of this cyclonic spot is surprising in view of its low tangential velocity and it suggests that low dissipation conditions prevail at mid-latitudes in Saturn's upper troposphere. Acknowledgements This work has been funded by Spanish MEC AYA2006-07735 with FEDER support and Grupos Gobierno Vasco IT-464-07. RH acknowledges a "Ramón y Cajal” contract from MEC.

  3. The 2010 Saturn's Great White Spot: Observations and models

    Science.gov (United States)

    Sanchez-Lavega, A.

    2011-12-01

    On December 5, 2010, a major storm erupted in Saturn's northern hemisphere at a planetographic latitude of 37.7 deg [1]. These phenomena are known as "Great White Spots" (GWS) and they have been observed once per Saturn year since the first case confidently reported in 1876. The last event occurred at Saturn's Equator in 1990 [2]. A GWS differs from similar smaller-scale storms in that it generates a planetary-scale disturbance that spreads zonally spanning the whole latitude band. We report on the evolution and motions of the 2010 GWS and its associated disturbance during the months following the outbreak, based mainly on high quality images obtained in the visual range submitted to the International Outer Planet Watch PVOL database [3], with the 1m telescope at Pic-du-Midi Observatory and the 2.2 m telescope at Calar Alto Observatory. The GWS "head source" extinguished by June 2011 implying that it survived about 6 months. Since this source is assumed to be produced by water moist convection, a reservoir of water vapor must exist at a depth of 10 bar and at the same time a disturbance producing the necessary convergence to trigger the ascending motions. The high temporal sampling and coverage allowed us to study the dynamics of the GWS in detail and the multi-wavelength observations provide information on its cloud top structure. We present non-linear simulations using the EPIC code of the evolution of the potential vorticity generated by a continuous Gaussian heat source extending from 10 bar to about 1 bar, that compare extraordinary well to the observed cloud field evolution. Acknowledgements: This work has been funded by Spanish MICIIN AYA2009-10701 with FEDER support and Grupos Gobierno Vasco IT-464-07. The presentation is done on behalf of the team listed in Reference [1]. [1]Sánchez-Lavega A., et al., Nature, 475, 71-74 (2011) [2]Sánchez-Lavega A., et al., Nature, 353, 397-401 (1991) [3]Hueso R., et al., Planet. Space Sci., 58, 1152-1159 (2010).

  4. Cassini Radio Occultations of Saturn's Ionosphere: Modeling a Variable Influx of Water into Saturn's Atmosphere

    Science.gov (United States)

    Moore, L.; Mendillo, M.

    2006-12-01

    The Saturn-Thermosphere-Ionosphere-Model (STIM), a global circulation model (GCM) of Saturn's upper atmosphere, is used to investigate a range of possible parameters that could lead to the profiles measured recently by the Radio Science Subsystem (RSS) aboard Cassini. Specifically, electron density observations of Saturn's equatorial ionosphere demonstrate a dawn/dusk asymmetry, a possible double peak, and a high degree of vertical structure and variability. On average, peak electron densities are larger at dusk than dawn (5400 cm-3 vs. 1700 cm-3) and the peak altitudes are lower at dusk than dawn (1880 km vs. 2360 km). Self-consistent, time-dependent 1D water diffusion calculations have been combined with the GCM in order to examine the possibility that a topside flux of neutral water into Saturn's atmosphere may provide a loss mechanism -- via charge exchange with protons -- that is sufficient to reproduce the observed ionosphere. Our previous modeling results indicated that a constant background influx of (0.5 -- 1.0) x 107 H2O cm-2 sec-1 was adequate in reproducing Cassini measurements on average [Moore et al., 2006], however the large observed variations in the vertical electron density profiles require additional complexities in the modeling. In this study we show that one possible source of the structuring observed in the electron density profiles could be from brief surges and/or reductions in the background water flux, which ultimately may be linked to geysers near Enceladus' southern pole. Moore, L., A.F. Nagy, A.J. Kliore, I. Mueller-Wodarg, J.D. Richardson, M. Mendillo (2006), Cassini radio occultations of Saturn's ionopshere: I. model comparisons using a constant water flux, submitted to GRL.

  5. Developments and new performance of Saturne II

    International Nuclear Information System (INIS)

    Ciret, J.C.

    1979-01-01

    The development of Saturne II aims to improve the quality, diversity and reliability of the beams which are or will be delivered to physicists. The significant development projects (polarized ions, heavy ions, Mimas, SPES II, etc.) are dealt with separately and specifically by other authors. Only the new performance and qualities of the beam delivered to physicists in the future are described here. The purpose of these developments is to meet the short and long term requirements expressed by the physicists and concern the Machine and the Areas [fr

  6. The Interiors of Jupiter and Saturn

    Science.gov (United States)

    Helled, Ravit

    2018-05-01

    Probing the interiors of the giant planets in our Solar System is not an easy task. This requires a set of observations combined with theoretical models that are used to infer the planetary composition and its depth dependence. The masses of Jupiter and Saturn are 318 and 96 Earth masses, respectively, and since a few decades, we know that they mostly consist of hydrogen and helium. It is the mass of heavy elements (all elements heavier than helium) that is not well determined, as well as its distribution within the planets. While the heavy elements are not the dominating materials in Jupiter and Saturn, they are the key for our understanding of their formation and evolution histories. The planetary internal structure is inferred to fit the available observational constraints including the planetary masses, radii, 1-bar temperatures, rotation rates, and gravitational fields. Then, using theoretical equations of states (EOSs) for hydrogen, helium, their mixtures, and heavier elements (typically rocks and/or ices), a structure model is developed. However, there is no unique solution for the planetary structure, and the results depend on the used EOSs and the model assumptions imposed by the modeler. Standard interior models of Jupiter and Saturn include three main regions: (1) the central region (core) that consists of heavy elements, (2) an inner metallic hydrogen envelope that is helium rich, and (3) an outer molecular hydrogen envelope depleted with helium. The distribution of heavy elements can be either homogenous or discontinuous between the two envelopes. Major model assumptions that can affect the derived internal structure include the number of layers, the heat transport mechanism within the planet (and its entropy), the nature of the core (compact vs. diluted), and the location/pressure where the envelopes are divided. Alternative structure models assume a less distinct division between the layers and/or a less non-homogenous distribution of the heavy

  7. Cassini at Saturn: The Final Two Years

    Science.gov (United States)

    Spilker, L.; Edgington, S.; Altobelli, N.

    2015-10-01

    After 11 years in orbit, the Cassini-Huygens Mission to Saturn, a collaboration of NASA, ESA, and ASI, continues to wow the imagination and reveal unprecedented findings. Every year Cassini produces answers to questions raised by the Voyager flybys, while at the same time posing new questions that can only be answered with a long duration mission using a flagship-class spacecraft. Here we sample a few of Cassini's discoveries from the past year and give an overview of Cassini's final two years.

  8. Spallation neutron spectra measured at Saturne

    International Nuclear Information System (INIS)

    Boyard, J.L.; Bouyer, P.; Brochard, F.; Duchazeaubeneix, J.C.; Durand, J.M.; Leray, S.; Milleret, G.; Plouin, F.; Uematsu, M.; Whittal, D.M.; Martinez, E.; Beau, M.; Boue, F.; Crespin, S.; Drake, D.; Frehaut, J.; Lochard, J.P.; Patin, Y.; Petibon, E.; Legrain, R.; Terrien, Y.

    1995-01-01

    Good knowledge of spallation reactions is necessary to design accelerator-based transmutation systems. An extensive program has begun at Saturne to measure energy and angular distributions of neutrons produced by incident protons or deuterons of up to 2 GeV on several thin targets. Our measurements will extend the available data to higher energies than the present limit of 800 MeV enabling improvements to the codes which are sometimes in poor agreement with the data. (Authors). 7 refs., 7 figs

  9. Apollo Saturn V Height Comparison to Statue of Liberty

    Science.gov (United States)

    1967-01-01

    This 1967 illustration compares the Apollo Saturn V Spacecraft of the Moon Landing era to the Statue of Liberty located on Ellis Island in New York City. The Apollo Saturn V, at 363 feet towers above Lady Liberty, as the statue is called, standing at 305 feet.

  10. The Second Stage of a Saturn V Ready For Test

    Science.gov (United States)

    1970-01-01

    This Saturn V S-II (second) stage is being lifted into position for a test at the Vehicle Assembly Building at the Kennedy Space Center. When the Saturn V booster stage (S-IC) burned out and dropped away, power for the Saturn was provided by the 82-foot-long and 33-foot-diameter S-II stage. Developed by the Space Division of North American Aviation under the direction of the Marshall Space Flight Center, the stage utilized five J-2 engines, each producing 200,000 pounds of thrust. The engines used liquid oxygen and liquid hydrogen as propellants. The towering 363-foot Saturn V was a multi-stage, multi-engine launch vehicle standing taller than the Statue of Liberty. Altogether, the Saturn V engines produced as much power as 85 Hoover Dams.

  11. Source mechanism of Saturn narrowband emission

    Directory of Open Access Journals (Sweden)

    J. D. Menietti

    2010-04-01

    Full Text Available Narrowband emission (NB is observed at Saturn centered near 5 kHz and 20 kHz and harmonics. This emission appears similar in many ways to Jovian kilometric narrowband emission observed at higher frequencies, and therefore may have a similar source mechanism. Source regions of NB near 20 kHz are believed to be located near density gradients in the inner magnetosphere and the emission appears to be correlated with the occurrence of large neutral plasma clouds observed in the Saturn magnetotail. In this work we present the results of a growth rate analysis of NB emission (~20 kHz near or within a probable source region. This is made possible by the sampling of in-situ wave and particle data. The results indicate waves are likely to be generated by the mode-conversion of directly generated Z-mode emission to O-mode near a density gradient. When the local hybrid frequency is close n fce (n is an integer and fce is the electron cyclotron frequency with n=4, 5 or 6 in our case, electromagnetic Z-mode and weak ordinary (O-mode emission can be directly generated by the cyclotron maser instability.

  12. The DISTO data acquisition system at SATURNE

    International Nuclear Information System (INIS)

    Balestra, F.; Bedfer, Y.; Bertini, R.

    1998-01-01

    The DISTO collaboration has built a large-acceptance magnetic spectrometer designed to provide broad kinematic coverage of multiparticle final states produced in pp scattering. The spectrometer has been installed in the polarized proton beam of the Saturne accelerator in Saclay to study polarization observables in the rvec pp → pK + rvec Y (Y = Λ, Σ 0 or Y * ) reaction and vector meson production (ψ, ω and ρ) in pp collisions. The data acquisition system is based on a VME 68030 CPU running the OS/9 operating system, housed in a single VME crate together with the CAMAC interface, the triple port ECL memories, and four RISC R3000 CPU. The digitization of signals from the detectors is made by PCOS III and FERA front-end electronics. Data of several events belonging to a single Saturne extraction are stored in VME triple-port ECL memories using a hardwired fast sequencer. The buffer, optionally filtered by the RISC R3000 CPU, is recorded on a DLT cassette by DAQ CPU using the on-board SCSI interface during the acceleration cycle. Two UNIX workstations are connected to the VME CPUs through a fast parallel bus and the Local Area Network. They analyze a subset of events for on-line monitoring. The data acquisition system is able to read and record 3,500 ev/burst in the present configuration with a dead time of 15%

  13. New `Moons' of Saturn May Be Transient Objects

    Science.gov (United States)

    1996-01-01

    ring plane crossings (RPX) . At the corresponding times, the Sun illuminates the thin Saturnian rings exactly from the side. Due to its own orbital motion around the Sun, the Earth will cross the ring plane either once or three times, just before and/or after a solar RPX event. In 1995, this happened on May 22 and August 10, and there will be a third Earth RPX event on February 11, 1996. RPX Events Offer Improved Possibilities to Discover Faint Moons The apparent brightness of Saturn's rings decreases dramatically around the time of a solar RPX event. It is then much easier to detect faint moons which would otherwise be lost in the strong glare of Saturn's ring system. Also, the edge-on view improves the chances of detecting faint and dilute rings [3]. Moreover, numerous `mutual events' (eclipses and occultations) occur between the moons during this period; exact timing of these events allows highly improved determination of the motions and orbits around Saturn of these objects. The most recent Earth RPX event took place on August 10, 1995. At this time, Saturn was situated nearly opposite the Sun (in `opposition'), as seen from the Earth, and conditions were very favourable for astronomical observations from both hemispheres. However, because of the longer nights during the southern winter, observing possibilities were particularly good in the south and thus at the ESO La Silla Observatory. The ADONIS Observations Here, a team of astronomers (Jean-Luc Beuzit, Bruno Sicardy and Francois Poulet of the Paris Observatory; Pablo Prado from ESO) followed this rare event during 6 half-nights around August 10, 1995, with the advanced ADONIS adaptive optics camera at the ESO 3.6-m telescope. This instrument neutralizes the image-smearing effects of the atmospheric turbulence and records very sharp images on an infrared-sensitive 256 x 256 pixel detector with a scale of 0.05 arcsec/pixel. Most of the Saturn images were taken through the `short K' filter with a central

  14. A statistical analysis of the location and width of Saturn's southern auroras

    Directory of Open Access Journals (Sweden)

    S. V. Badman

    2006-12-01

    Full Text Available A selection of twenty-two Hubble Space Telescope images of Saturn's ultraviolet auroras obtained during 1997–2004 has been analysed to determine the median location and width of the auroral oval, and their variability. Limitations of coverage restrict the analysis to the southern hemisphere, and to local times from the post-midnight sector to just past dusk, via dawn and noon. It is found that the overall median location of the poleward and equatorward boundaries of the oval with respect to the southern pole are at ~14° and ~16° co-latitude, respectively, with a median latitudinal width of ~2°. These median values vary only modestly with local time around the oval, though the poleward boundary moves closer to the pole near noon (~12.5° such that the oval is wider in that sector (median width ~3.5° than it is at both dawn and dusk (~1.5°. It is also shown that the position of the auroral boundaries at Saturn are extremely variable, the poleward boundary being located between 2° and 20° co-latitude, and the equatorward boundary between 6° and 23°, this variability contrasting sharply with the essentially fixed location of the main oval at Jupiter. Comparison with Voyager plasma angular velocity data mapped magnetically from the equatorial magnetosphere into the southern ionosphere indicates that the dayside aurora lie poleward of the main upward-directed field-aligned current region associated with corotation enforcement, which maps to ~20°–24° co-latitude, while agreeing reasonably with the position of the open-closed field line boundary based on estimates of the open flux in Saturn's tail, located between ~11° and ~15°. In this case, the variability in location can be understood in terms of changes in the open flux present in the system, the changes implied by the Saturn data then matching those observed at Earth as fractions of the total planetary flux. We infer that the broad (few degrees diffuse auroral emissions

  15. Interaction of Titan's atmosphere with Saturn's magnetosphere

    International Nuclear Information System (INIS)

    Hartle, R.E.

    1985-01-01

    The Voyager 1 measurements made during the Titan flyby reveal that Saturn's rotating magnetospheric plasma interacts directly with Titan's neutral atmosphere and ionosphere. This results from the lack of an intrinsic magnetic field at Titan. The interaction induces a magnetosphere which deflects the flowing plasma around Titan and forms a plasma wake downstream. Within the tail of the induced magnetosphere, ions of ionospheric origin flow away from Titan. Just outside Titan's magnetosphere, a substantial ion-exosphere forms from an extensive hydrogen-nitrogen exosphere. The exospheric ions are picked up and carried downstream into the wake by the plasma flowing around Titan. Mass loading produced by the addition of exospheric ions slows the wake plasma down considerably in the vicinity of the magnetopause. 36 references

  16. The Diogene 4π detector at Saturne

    International Nuclear Information System (INIS)

    Alard, J.P.; Arnold, J.; Augerat, J.; Bastid, N.; Costilhes, J.P.; Crouau, M.; Dupieux, P.; Fraysse, L.; Montarou, G.; Parizet, M.J.; Tamain, J.C.; Valero, J.; Babinet, R.; Marco, N. de; Drouet, M.; Fanet, H.; Fodor, Z.; Girard, J.; Gosset, J.; Laspalles, C.; Lemaire, M.C.; L'Hote, D.; Lucas, B.; Papineau, A.; Poitou, J.; Schimmerling, W.; Terrien, Y.; Valette, O.; Brochard, F.; Gorodetzky, P.; Racca, C.

    1987-01-01

    Diogene, an electronic 4π detector, has been built and installed at the Saturne synchrotron in Saclay. The forward angular range (0 0 -6 0 ) is covered by 48 time-of-flight scintillator telescopes that provide charge identification. The trajectories of fragments emitted at larger angles are recorded in a cylindrical 0.4 m 3 Pictorial Drift Chamber (PDC) surrounding the target. The PDC is inside a 1-T magnetic field; the axis of the PDC cylinder and the magnetic field are parallel to the beam. Good identification has been obtained for both positive and negative π mesons and for hydrogen and helium isotopes. Multiplicities in relativistic nucleus-nucleus reactions up to 40 have been detected, limited mainly by the present electronics. (orig.)

  17. The Saturn Probe Interior and aTmosphere Explorer (SPRITE) Mission

    Science.gov (United States)

    Simon, Amy; Banfield, Donald; Atkinson, David; SPRITE Science Team

    2018-01-01

    A key question in planetary science is how the planets formed in our Solar System, and, by extension, in exoplanet systems. The abundances of the noble gases (He, Ne, Ar, Kr, Xe), heavy elements (C, N, O, S), and their isotopes provide important forensic clues as to location and time of formation in the early Solar System. Jupiter and Saturn contain most of the planetary mass in our solar system, and their chemical fingerprints will distinguish between competing models of the formation of all the planets. After the end of the Cassini mission, some of these elements have only ambiguous values above the cloud tops, while others (particularly the noble gases) have not been measured at all. Resolving this requires direct in situ measurements. The proposed NASA New Frontiers Saturn PRobe Interior and aTmosphere Explorer (SPRITE) mission delivers an instrumented entry probe from a carrier relay spacecraft that also provides context imaging. The powerful probe instrument suite is comprised of a Quadrupole Mass Spectrometer, a Tunable Laser Spectrometer, and an Atmospheric Structure Instrument including a Doppler Wind Experiment and a simple backscatter nephelometer. These instruments measure the elemental and isotopic abundances of helium, the heavier noble gases, and the major elements, as well as constraining cloud properties, 3-D atmospheric dynamics, and disequilibrium chemistry to at least 10 bars in Saturn's troposphere. In situ measurements of Saturn's atmosphere by SPRITE will provide a significantly improved context for interpreting the results from the Galileo probe, Juno, and Cassini missions. SPRITE will revolutionize our understanding of the formation and evolution of the gas giant planets, and ultimately the present-day structure of the Solar System.

  18. Noncircular features in Saturn's rings IV: Absolute radius scale and Saturn's pole direction

    Science.gov (United States)

    French, Richard G.; McGhee-French, Colleen A.; Lonergan, Katherine; Sepersky, Talia; Jacobson, Robert A.; Nicholson, Philip D.; Hedman, Mathew M.; Marouf, Essam A.; Colwell, Joshua E.

    2017-07-01

    We present a comprehensive solution for the geometry of Saturn's ring system, based on orbital fits to an extensive set of occultation observations of 122 individual ring edges and gaps. We begin with a restricted set of very high quality Cassini VIMS, UVIS, and RSS measurements for quasi-circular features in the C and B rings and the Cassini Division, and then successively add suitably weighted additional Cassini and historical occultation measurements (from Voyager, HST and the widely-observed 28 Sgr occultation of 3 Jul 1989) for additional non-circular features, to derive an absolute radius scale applicable across the entire classical ring system. As part of our adopted solution, we determine first-order corrections to the spacecraft trajectories used to determine the geometry of individual occultation chords. We adopt a simple linear model for Saturn's precession, and our favored solution yields a precession rate on the sky n^˙P = 0.207 ± 0 .006‧‧yr-1 , equivalent to an angular rate of polar motion ΩP = 0.451 ± 0 .014‧‧yr-1 . The 3% formal uncertainty in the fitted precession rate is approaching the point where it can provide a useful constraint on models of Saturn's interior, although realistic errors are likely to be larger, given the linear approximation of the precession model and possible unmodeled systematic errors in the spacecraft ephemerides. Our results are largely consistent with independent estimates of the precession rate based on historical RPX times (Nicholson et al., 1999 AAS/Division for Planetary Sciences Meeting Abstracts #31 31, 44.01) and from theoretical expectations that account for Titan's 700-yr precession period (Vienne and Duriez 1992, Astronomy and Astrophysics 257, 331-352). The fitted precession rate based on Cassini data only is somewhat lower, which may be an indication of unmodeled shorter term contributions to Saturn's polar motion from other satellites, or perhaps the result of inconsistencies in the assumed

  19. Saturn's north polar cyclone and hexagon at depth revealed by Cassini/VIMS

    Science.gov (United States)

    Baines, K.H.; Momary, T.W.; Fletcher, L.N.; Showman, A.P.; Roos-Serote, M.; Brown, R.H.; Buratti, B.J.; Clark, R.N.; Nicholson, P.D.

    2009-01-01

    A high-speed cyclonic vortex centered on the north pole of Saturn has been revealed by the visual-infrared mapping spectrometer (VIMS) onboard the Cassini-Huygens Orbiter, thus showing that the tropospheres of both poles of Saturn are occupied by cyclonic vortices with winds exceeding 135 m/s. High-spatial-resolution (~200 km per pixel) images acquired predominantly under night-time conditions during Saturn's polar winter-using a thermal wavelength of 5.1 ??m to obtain time-lapsed imagery of discrete, deep-seated (>2.1-bar) cloud features viewed in silhouette against Saturn's internally generated thermal glow-show a classic cyclonic structure, with prograde winds exceeding 135 m/s at its maximum near 88.3?? (planetocentric) latitude, and decreasing to conditions as the polar winter wanes shows the hexagon is still visible in reflected sunlight nearly 28 years since its discovery, that a similar 3-lane structure is observed in reflected and thermal light, and that the cloudtops may be typically lower in the hexagon than in nearby discrete cloud features outside of it. Clouds are well-correlated in visible and 5.1 ??m images, indicating little windshear above the ~2-bar level. The polar cyclone is similar in size and shape to its counterpart at the south pole; a primary difference is the presence of a small (<600 km in diameter) nearly pole-centered cloud, perhaps indicative of localized upwelling. Many dozens of discrete, circular cloud features dot the polar region, with typical diameters of 300-700 km. Equatorward of 87.8??N, their compact nature in the high-wind polar environment suggests that vertical shear in horizontal winds may be modest on 1000 km scales. These circular clouds may be anticyclonic vortices produced by baroclinic instabilities, barotropic instabilities, moist convection or other processes. The existence of cyclones at both poles of Saturn indicates that cyclonic circulation may be an important dynamical style in planets with significant

  20. VOYAGER 1 SATURN POSITION RESAMPLED DATA 48.0 SECONDS

    Data.gov (United States)

    National Aeronautics and Space Administration — This data set includes Voyager 1 Saturn encounter position data that have been generated at a 48.0 second sample rate using the NAIF SPICE kernals. The data set is...

  1. VOYAGER 2 SATURN POSITION RESAMPLED DATA 48.0 SECONDS

    Data.gov (United States)

    National Aeronautics and Space Administration — This data set includes Voyager 2 Saturn encounter position data that have been generated at a 48.0 second sample rate using the NAIF SPICE kernals. The data set is...

  2. Saturn radio emission and the solar wind - Voyager-2 studies

    International Nuclear Information System (INIS)

    Desch, M.D.; Rucker, H.O.; Observatorium Lustbuhel, Graz, Austria)

    1985-01-01

    Voyager 2 data from the Plasma Science experiment, the Magnetometer experiment and the Planetary Radio Astronomy experiment were used to analyze the relationship between parameters of the solar wind/interplanetary medium and the nonthermal Saturn radiation. Solar wind and interplanetary magnetic field properties were combined to form quantities known to be important in controlling terrestrial magnetospheric processes. The Voyager 2 data set used in this investigation consists of 237 days of Saturn preencounter measurements. However, due to the immersion of Saturn and the Voyager 2 spacecraft into the extended Jupiter magnetic tail, substantial periods of the time series were lacking solar wind data. To cope with this problem a superposed epoch method (CHREE analysis) was used. The results indicate the superiority of the quantities containing the solar wind density in stimulating the radio emission of Saturn - a result found earlier using Voyager 1 data - and the minor importance of quantities incorporating the interplanetary magnetic field. 10 references

  3. VOYAGER 1 SATURN MAGNETOMETER RESAMPLED DATA 9.60 SEC

    Data.gov (United States)

    National Aeronautics and Space Administration — This data set includes Voyager 1 Saturn encounter magnetometer data that have been resampled at a 9.6 second sample rate. The data set is composed of 6 columns: 1)...

  4. Shock mitigation for the PFLs at the SATURN accelerator

    International Nuclear Information System (INIS)

    Craven, R.E.

    1997-06-01

    Accelerometer measurements were made on the SATURN pulse forming lines (PFL) to determine the mechanism responsible for severe metal deformation around the water switch openings and cracking of welded seams. A reason for this problem and a solution were established. A simple shock mitigating pad under the support stand for the PFL provides more than adequate protection from shock damage and will greatly extend the useful life of the power flow sections of SATURN

  5. SATURN-S - a program system for the description of the thermomechanical behaviour of reactor fuel pins under irradiation

    International Nuclear Information System (INIS)

    Pesl, R.; Freund, D.; Gaertner, H.; Steiner, H.

    1987-07-01

    On the basis of post irradiation examination results of various irradiation experiments with different fuel types real case calculations showed many of the existing models to be applicable to a restricted extent only. Therefore a re- and partially new formulation of models was necessary. Furthermore, the data base had been actualized and numerical procedures had been improved. This, together with the capabilities of modern computer systems, conducted the development of the program system SATURN-S with a strictly modular structure, specified by the requirements of the determination of the superposition of effects. In the present report the program SATURN-S as well as some analysis results are presented. (orig./HP) [de

  6. Non-Linear Dynamics of Saturn's Rings

    Science.gov (United States)

    Esposito, L. W.

    2016-12-01

    Non-linear processes can explain why Saturn's rings are so active and dynamic. Ring systems differ from simple linear systems in two significant ways: 1. They are systems of granular material: where particle-to-particle collisions dominate; thus a kinetic, not a fluid description needed. Stresses are strikingly inhomogeneous and fluctuations are large compared to equilibrium. 2. They are strongly forced by resonances: which drive a non-linear response, that push the system across thresholds that lead to persistent states. Some of this non-linearity is captured in a simple Predator-Prey Model: Periodic forcing from the moon causes streamline crowding; This damps the relative velocity. About a quarter phase later, the aggregates stir the system to higher relative velocity and the limit cycle repeats each orbit, with relative velocity ranging from nearly zero to a multiple of the orbit average. Summary of Halo Results: A predator-prey model for ring dynamics produces transient structures like `straw' that can explain the halo morphology and spectroscopy: Cyclic velocity changes cause perturbed regions to reach higher collision speeds at some orbital phases, which preferentially removes small regolith particles; surrounding particles diffuse back too slowly to erase the effect: this gives the halo morphology; this requires energetic collisions (v ≈ 10m/sec, with throw distances about 200km, implying objects of scale R ≈ 20km).Transform to Duffing Eqn : With the coordinate transformation, z = M2/3, the Predator-Prey equations can be combined to form a single second-order differential equation with harmonic resonance forcing.Ring dynamics and history implications: Moon-triggered clumping explains both small and large particles at resonances. We calculate the stationary size distribution using a cell-to-cell mapping procedure that converts the phase-plane trajectories to a Markov chain. Approximating it as an asymmetric random walk with reflecting boundaries

  7. Energetic Nitrogen Ions within the Inner Magnetosphere of Saturn

    Science.gov (United States)

    Sittler, E. C.; Johnson, R. E.; Richardson, J. D.; Jurac, S.; Moore, M.; Cooper, J. F.; Mauk, B. H.; Smith, H. T.; Michael, M.; Paranicus, C.; Armstrong, T. P.; Tsurutani, B.; Connerney, J. E. P.

    2003-05-01

    Titan's interaction with Saturn's magnetosphere will result in the energetic ejection of atomic nitrogen atoms into Saturn's magnetosphere due to dissociation of N2 by electrons, ions, and UV photons. The ejection of N atoms into Saturn's magnetosphere will form a nitrogen torus around Saturn with mean density of about 4 atoms/cm3 with source strength of 4.5x1025 atoms/sec. These nitrogen atoms are ionized by photoionization, electron impact ionization and charge exchange reactions producing an N+ torus of 1-4 keV suprathermal ions centered on Titan's orbital position. We will show Voyager plasma observations that demonstrate presence of a suprathermal ion component within Saturn's outer magnetosphere. The Voyager LECP data also reported the presence of inward diffusing energetic ions from the outer magnetosphere of Saturn, which could have an N+ contribution. If so, when one conserves the first and second adiabatic invariant the N+ ions will have energies in excess of 100 keV at Dione's L shell and greater than 400 keV at Enceladus' L shell. Energetic charged particle radial diffusion coefficients are also used to constrain the model results. But, one must also consider the solar wind as another important source of keV ions, in the form of protons and alpha particles, for Saturn's outer magnetosphere. Initial estimates indicate that a solar wind source could dominate in the outer magnetosphere, but various required parameters for this estimate are highly uncertain and will have to await Cassini results for confirmation. We show that satellite sweeping and charged particle precipitation within the middle and outer magnetosphere will tend to enrich N+ ions relative to protons within Saturn's inner magnetosphere as they diffuse radially inward for radial diffusion coefficients that do not violate observations. Charge exchange reactions within the inner magnetosphere can be an important loss mechanism for O+ ions, but to a lesser degree for N+ ions. Initial LECP

  8. [Biochemical principles of early saturnism recognition].

    Science.gov (United States)

    Tsimakuridze, M P; Mansuradze, E A; Zurashvili, D G; Tsimakuridze, M P

    2009-03-01

    The aim of the work is to determine the major sensitive criteria of biochemical indicators that allow timely discovery of negative influence of lead on organism and assist in early diagnosis of primary stages of saturnism. The workers of Georgian typographies, performing technological processes of letterpress printing were observed. Professional groups having contact with lead aerosols (main group of 66 people) and the workers of the same typography not being in touch with the poison (control group of 24 people) were studied. It was distinguished that, protracted professional contact with lead causes moderate increase of lead, coproporphyrin and DALA in daily urine in most cases; it is more clearly evidenced in the professional groups of lead smelters and lino operators and less clearly among typesetter and printers. Upon the checkup of people, having a direct contact with lead, biochemical analysis of urine should be given a preference, especially the determination of quantitative content of lead and coproporphyrin in urine with the aim of revealing the lead carrier, which is one of the first signals for occupational lookout and medical monitoring of the similar contingent.

  9. Magnetic fields of Jupiter and Saturn

    International Nuclear Information System (INIS)

    Ness, N.F.

    1981-01-01

    The magnetic fields of Jupiter and Saturn and the characteristics of their magnetospheres, formed by interaction with the solar wind, are discussed. The origins of both magnetic fields are associated with a dynamo process deep in the planetary interior. The Jovian magnetosphere is analogous to that of a pulsar magnetosphere: a massive central body with a rapid rotation and an associated intense magnetic field. Its most distinctive feature is its magnetodisk of concentrated plasma and particle flux, and reduced magnetic field intensity. The magnetopause near the subsolar point has been observed at radial distances ranging over 50 to 100 Jovian radii, implying a relatively compressible obstacle to solar wind flow. The composition of an embedded current sheet within the magnetic tail is believed to be influenced by volcanic eruptions and emissions from Io. Spectral troughs of the Jovian radiation belts have been interpreted as possible ring particles. The Saturnian magnetosphere appears to be more like the earth in its topology. It is mainly characterized by a dipole axis parallel to the rotational axis of the planet and a magnetic field intensity much less than expected

  10. The atmospheres of Saturn and Titan in the near-infrared: First results of Cassini/Vims

    Science.gov (United States)

    Baines, K.H.; Momary, T.W.; Buratti, B.J.; Matson, D.L.; Nelson, R.M.; Drossart, P.; Sicardy, B.; Formisano, V.; Bellucci, G.; Coradini, A.; Griffith, C.; Brown, R.H.; Bibring, J.-P.; Langevin, Y.; Capaccioni, F.; Cerroni, P.; Clark, R.N.; Combes, M.; Cruikshank, D.P.; Jaumann, R.; McCordt, T.B.; Mennella, V.; Nicholson, P.D.; Sotin, Christophe

    2006-01-01

    The wide spectral coverage and extensive spatial, temporal, and phase-angle mapping capabilities of the Visual Infrared Mapping Spectrometer (VIMS) onboard the Cassini-Huygens Orbiter are producing fundamental new insights into the nature of the atmospheres of Saturn and Titan. For both bodies, VIMS maps over time and solar phase angles provide information for a multitude of atmospheric constituents and aerosol layers, providing new insights into atmospheric structure and dynamical and chemical processes. For Saturn, salient early results include evidence for phosphine depletion in relatively dark and less cloudy belts at temperate and mid-latitudes compared to the relatively bright and cloudier Equatorial Region, consistent with traditional theories of belts being regions of relative downwelling. Additional Saturn results include (1) the mapping of enhanced trace gas absorptions at the south pole, and (2) the first high phase-angle, high-spatial-resolution imagery of CH4 fluorescence. An additional fundamental new result is the first nighttime near-infrared mapping of Saturn, clearly showing discrete meteorological features relatively deep in the atmosphere beneath the planet's sunlit haze and cloud layers, thus revealing a new dynamical regime at depth where vertical dynamics is relatively more important than zonal dynamics in determining cloud morphology. Zonal wind measurements at deeper levels than previously available are achieved by tracking these features over multiple days, thereby providing measurements of zonal wind shears within Saturn's troposphere when compared to cloudtop movements measured in reflected sunlight. For Titan, initial results include (1) the first detection and mapping of thermal emission spectra of CO, CO2, and CH3D on Titan's nightside limb, (2) the mapping of CH4 fluorescence over the dayside bright limb, extending to ??? 750 km altitude, (3) wind measurements of ???0.5 ms-1, favoring prograde, from the movement of a persistent

  11. A View into Saturn through its Natural Seismograph

    Science.gov (United States)

    Mankovich, Christopher

    2018-04-01

    Saturn's nonradial oscillations perturb the orbits of ring particles. The C ring is fortuitous in that it spans several resonances with Saturn's fundamental acoustic (f-) modes, and its moderate optical depth allows the characterization of wave features using stellar occultations. The growing set of C-ring waves with precise pattern frequencies and azimuthal order m measured from Cassini stellar occultations (Hedman & Nicholson 2013, 2014; French et al. 2016) provides new constraints on Saturn's internal structure, with the potential to aid in resolving long-standing questions about the planet's distribution of helium and heavier elements, its means of internal energy transport, and its rotation state.We construct Saturn interior models and calculate mode eigenfrequencies, mapping the planet mode frequencies to resonant locations in the rings to compare with the locations of observed spiral density and vertical bending waves in the C ring. While spiral density waves at low azimuthal order (m=2-3) appear strongly affected by resonant coupling between f-modes and deep g-modes (Fuller 2014), the locations of waves with higher azimuthal order can be fit with a spectrum of pure f-modes for Saturn models with adiabatic envelopes and realistic equations of state. Notably, several newly observed density waves and bending waves (Nicholson et al., in preparation) align with outer Lindblad and outer vertical resonances for non-sectoral (m!=l) Saturn f-modes of relatively high angular degree, and we present normal mode identifications for these waves. We assess the range of resonance locations in the C and D rings allowed for the spectrum of f-modes given gravity field constraints, point to other resonance locations that should experience strong forcing, and use the full set of observed waves to estimate Saturn's bulk rotation rate.

  12. Mapping Ring Particle Cooling across Saturn's Rings with Cassini CIRS

    Science.gov (United States)

    Brooks, Shawn M.; Spilker, L. J.; Edgington, S. G.; Pilorz, S. H.; Deau, E.

    2010-10-01

    Previous studies have shown that the rings' thermal inertia, a measure of their response to changes in the thermal environment, varies from ring to ring. Thermal inertia can provide insight into the physical structure of Saturn's ring particles and their regoliths. Low thermal inertia and quick temperature responses are suggestive of ring particles that have more porous or fluffy regoliths or that are riddled with cracks. Solid, coherent particles can be expected to have higher thermal inertias (Ferrari et al. 2005). Cassini's Composite Infrared Spectrometer has recorded millions of spectra of Saturn's rings since its arrival at Saturn in 2004 (personal communication, M. Segura). CIRS records far infrared radiation between 10 and 600 cm-1 (16.7 and 1000 µm) at focal plane 1 (FP1), which has a field of view of 3.9 mrad. Thermal emission from Saturn's rings peaks in this wavelength range. FP1 spectra can be used to infer ring temperatures. By tracking how ring temperatures vary, we can determine the thermal inertia of the rings. In this work we focus on CIRS observations of the shadowed portion of Saturn's rings. The thermal budget of the rings is dominated by the solar radiation absorbed by its constituent particles. When ring particles enter Saturn's shadow this source of energy is abruptly cut off. As a result, ring particles cool as they traverse Saturn's shadow. From these shadow observations we can create cooling curves at specific locations across the rings. We will show that the rings' cooling curves and thus their thermal inertia vary not only from ring to ring, but by location within the individual rings. This research was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under contract with NASA. Copyright 2010 California Institute of Technology. Government sponsorship acknowledged.

  13. REFLECTED LIGHT CURVES, SPHERICAL AND BOND ALBEDOS OF JUPITER- AND SATURN-LIKE EXOPLANETS

    Energy Technology Data Exchange (ETDEWEB)

    Dyudina, Ulyana; Kopparla, Pushkar; Ingersoll, Andrew P.; Yung, Yuk L. [Division of Geological and Planetary Sciences, 150-21 California Institute of Technology, Pasadena, CA 91125 (United States); Zhang, Xi [University of California Santa Cruz 1156 High Street, Santa Cruz, CA 95064 (United States); Li, Liming [Department of Physics, University of Houston, Houston, TX 77204 (United States); Dones, Luke [Southwest Research Institute, 1050 Walnut Street, Suite 300, Boulder CO 80302 (United States); Verbiscer, Anne, E-mail: ulyana@gps.caltech.edu [Department of Astronomy, University of Virginia, Charlottesville, VA 22904-4325 (United States)

    2016-05-10

    Reflected light curves observed for exoplanets indicate that a few of them host bright clouds. We estimate how the light curve and total stellar heating of a planet depends on forward and backward scattering in the clouds based on Pioneer and Cassini spacecraft images of Jupiter and Saturn. We fit analytical functions to the local reflected brightnesses of Jupiter and Saturn depending on the planet’s phase. These observations cover broadbands at 0.59–0.72 and 0.39–0.5 μ m, and narrowbands at 0.938 (atmospheric window), 0.889 (CH4 absorption band), and 0.24–0.28 μ m. We simulate the images of the planets with a ray-tracing model, and disk-integrate them to produce the full-orbit light curves. For Jupiter, we also fit the modeled light curves to the observed full-disk brightness. We derive spherical albedos for Jupiter and Saturn, and for planets with Lambertian and Rayleigh-scattering atmospheres. Jupiter-like atmospheres can produce light curves that are a factor of two fainter at half-phase than the Lambertian planet, given the same geometric albedo at transit. The spherical albedo is typically lower than for a Lambertian planet by up to a factor of ∼1.5. The Lambertian assumption will underestimate the absorption of the stellar light and the equilibrium temperature of the planetary atmosphere. We also compare our light curves with the light curves of solid bodies: the moons Enceladus and Callisto. Their strong backscattering peak within a few degrees of opposition (secondary eclipse) can lead to an even stronger underestimate of the stellar heating.

  14. Examining the Combined Saturn and Ring Exosphere/Ionosphere using Cassini's Proximal orbits

    Science.gov (United States)

    Tucker, O. J.; Tseng, W. L.; Johnson, R. E.; Perry, M. E.

    2017-12-01

    Neutral molecules that are emitted from Saturn's exobase (i.e., H2) and the main rings (i.e., H2, O2, H) are a source of material for both the Saturn and ring ionospheres as well as Saturn's magnetosphere (Tseng et al., 2013 [PSS 85 164 - 167]). However, the density gradient of H2 produced from the main rings is very different than that produced by Saturn's exospheric flux due to its emission from the ring plane and distance from Saturn. Cassini measurements obtained during the proximal orbits can likely be used to identify contributions from Saturn and the rings. Here we present results obtained from Monte Carlo models of the Saturn and ring exosphere used to analyze INMS data of neutrals and ions measured along the trajectories of the Proximal orbits. Understanding the sources of neutrals and the concomitant ions can help provide insight about the dynamics occurring in the Saturn system.

  15. Dynamical variability in Saturn Equatorial Atmosphere

    Science.gov (United States)

    Sánchez-Lavega, A.; Pérez-Hoyos, S.; Hueso, R.; Rojas, J. F.; French, R. G.; Grupo Ciencias Planetarias Team

    2003-05-01

    Historical ground-based and recent HST observations show that Saturn's Equatorial Atmosphere is the region where the most intense large-scale dynamical variability took place at cloud level in the planet. Large-scale convective storms (nicknamed the ``Great White Spots") occurred in 1876, 1933 and 1990. The best studied case (the 1990 storm), produced a dramatic change in the cloud aspect in the years following the outburst of September 1990. Subsequently, a new large storm formed in 1994 and from 1996 to 2002 our HST observations showed periods of unusual cloud activity in the southern part of the Equator. This contrast with the aspect observed during the Voyager 1 and 2 encounters in 1980 and 1981 when the Equator was calm, except for some mid-scale plume-like features seen in 1981. Cloud-tracking of the features have revealed a dramatic slow down in the equatorial winds from maximum velocities of ˜ 475 m/s in 1980-1981 to ˜ 275 m/s during 1996-2002, as we have recently reported in Nature, Vol. 423, 623 (2003). We discuss the possibility that seasonal and ring-shadowing effects are involved in generating this activity and variability. Acknowledgements: This work was supported by the Spanish MCYT PNAYA 2000-0932. SPH acknowledges a PhD fellowship from the Spanish MECD and RH a post-doc fellowship from Gobierno Vasco. RGF was supported in part by NASA's Planetary Geology and Geophysics Program NAG5-10197 and STSCI Grant GO-08660.01A.

  16. Improved Radio Emissivities for Satellites of Saturn

    Science.gov (United States)

    Ries, Paul

    2010-10-01

    The size distribution of TNOs is one of the most important constraints on the history of the early solar system. However, while TNOs are most detectable in the visible and near-IR wavelengths, their albedos vary substantially, thus creating uncertainty in their sizes when determined from reflected light alone. One way of determining the size distribution for a large number of TNOs is to measure their thermal emission, such as has been done with Spitzer and Herschel. However, in just a few year's time, ALMA will be coming online, and will be able to detect thermal emission from even more TNOs. However, thermal emission from Solar System bodies in the millimeter and submillimeter, such as that which ALMA will detect, is not that of a pure blackbody. Pluto, the Gallillean satellites, and Vesta have all shown deviations from unity emissivity. However, the cause of this variation is not well understood. Here we re-analayze data from the Cassini RADAR instrument at 2.5 cm. Cassini RADAR measured the brightness temperature and emissivity of several of Saturn's icy satellites, at least one of which, Phoebe, is thought to be a captured TNO. Previous emissivity determinations relied on relatively simple thermal models. We recalculate emissivities using thermal models based on recent data obtained with the CIRS (infrared) instrument on Cassini which account for, among other things, diurnal effects and the rotation during the RADAR observations. For one important result, we demonstrate that deviation from unity emissivity on Iapetus is due solely to surface depth effects at long wavelengths when RADAR data at 2.5 cm is combined with data obtained at 3.3 mm on the Green Bank Telescope (GBT). This research is supported by a grant under the NRAO Student Observing Support program.

  17. Hydrocarbons on Saturn's satellites Iapetus and Phoebe

    Science.gov (United States)

    Cruikshank, D.P.; Wegryn, E.; Dalle, Ore C.M.; Brown, R.H.; Bibring, J.-P.; Buratti, B.J.; Clark, R.N.; McCord, T.B.; Nicholson, P.D.; Pendleton, Y.J.; Owen, T.C.; Filacchione, G.; Coradini, A.; Cerroni, P.; Capaccioni, F.; Jaumann, R.; Nelson, R.M.; Baines, K.H.; Sotin, Christophe; Bellucci, G.; Combes, M.; Langevin, Y.; Sicardy, B.; Matson, D.L.; Formisano, V.; Drossart, P.; Mennella, V.

    2008-01-01

    Material of low geometric albedo (pV ??? 0.1) is found on many objects in the outer Solar System, but its distribution in the saturnian satellite system is of special interest because of its juxtaposition with high-albedo ice. In the absence of clear, diagnostic spectral features, the composition of this low-albedo (or "dark") material is generally inferred to be carbon-rich, but the form(s) of the carbon is unknown. Near-infrared spectra of the low-albedo hemisphere of Saturn's satellite Iapetus were obtained with the Visible-Infrared Mapping Spectrometer (VIMS) on the Cassini spacecraft at the fly-by of that satellite of 31 December 2004, yielding a maximum spatial resolution on the satellite's surface of ???65 km. The spectral region 3-3.6 ??m reveals a broad absorption band, centered at 3.29 ??m, and concentrated in a region comprising about 15% of the low-albedo surface area. This is identified as the C{single bond}H stretching mode vibration in polycyclic aromatic hydrocarbon (PAH) molecules. Two weaker bands attributed to {single bond}CH2{single bond} stretching modes in aliphatic hydrocarbons are found in association with the aromatic band. The bands most likely arise from aromatic and aliphatic units in complex macromolecular carbonaceous material with a kerogen- or coal-like structure, similar to that in carbonaceous meteorites. VIMS spectra of Phoebe, encountered by Cassini on 11 June 2004, also show the aromatic hydrocarbon band, although somewhat weaker than on Iapetus. The origin of the PAH molecular material on these two satellites is unknown, but PAHs are found in carbonaceous meteorites, cometary dust particles, circumstellar dust, and interstellar dust. ?? 2007 Elsevier Inc. All rights reserved.

  18. Tungsten Z-Pinch Long Implosions on the Saturn Generator

    International Nuclear Information System (INIS)

    DOUGLAS, MELISSA R.; DEENEY, Christopher; SPIELMAN, RICK B.; COVERDALE, CHRISTINE A.; RODERICK, N.F.; HAINES, M.G.

    1999-01-01

    Recent success on the Saturn and Z accelerators at Sandia National Laboratories have demonstrated the ability to scale z-pinch parameters to increasingly larger current pulsed power facilities. Next generation machines will require even larger currents (>20 MA), placing further demands on pulsed power technology. To this end, experiments have been carried out on Saturn operating in a long pulse mode, investigating the potential of lower voltages and longer implosion times while still maintaining pinch fidelity. High wire number, 25 mm diameter tungsten arrays were imploded with implosion times ranging from 130 to 240 ns. The results were comparable to those observed in the Saturn short pulse mode, with risetimes on the order of 4.5 to 6.5 ns. Experimental data will be presented, along with two dimensional radiation magnetohydrodynamic simulations used to explain and reproduce the experiment

  19. Possible origin of Saturn's newly discovered outer ring

    International Nuclear Information System (INIS)

    Moehlmann, D.

    1986-01-01

    Within a planetogonic model the self-gravitationally caused formation of pre-planetary and pre-satellite rings from an earlier thin disk is reported. The theoretically derived orbital radii of these rings are compared with the orbital levels in the planetary system and the satellite systems of Jupiter, Saturn and Uranus. From this comparison it is concluded that at the radial position of Saturn's newly discovered outer ring an early pre-satellite ring of more or less evolved satellites could have existed. These satellites should have been disturbed in their evolution by the gravitation of the neighbouring massive satellite Titan. The comparison also may indicate similarities between the asteroidal belt and the newly discovered outer ring of Saturn

  20. Saturn's Internal Structure: A View through its Natural Seismograph

    Science.gov (United States)

    Mankovich, Christopher; Marley, Mark S.; Fortney, Jonathan J.; Movshovitz, Naor

    2017-10-01

    Saturn's nonradial oscillations perturb the orbits of ring particles. The C ring is fortuitous in that it spans several resonances with Saturn's fundamental acoustic (f-) modes, and its moderate optical depth allows the characterization of wave features using stellar occultations. The growing set of C-ring waves with precise pattern frequencies and azimuthal order m measured from Cassini stellar occultations (Hedman & Nicholson 2013, 2014; French et al. 2016) provides new constraints on Saturn's internal structure, with the potential to resolve long-standing questions about the planet's distribution of helium and heavier elements, its means of internal energy transport, and its rotation state.We construct Saturn interior models and calculate mode eigenfrequencies, mapping the planet mode frequencies to resonant locations in the rings to compare with the locations of observed spiral density and vertical bending waves in the C ring. While spiral density waves at low azimuthal order (m=2-3) appear strongly affected by resonant coupling between f-modes and deep g-modes (Fuller 2014), the locations of waves with higher azimuthal order can be fit reasonably well with a spectrum of pure f-modes for Saturn models with adiabatic envelopes and realistic equations of state. In particular, four observed bending waves (Nicholson et al., DPS 2016) align with outer vertical resonances for non-sectoral (m≠l) Saturn f-modes of relatively high angular degree, and we present preliminary identifications of these. We assess the range of resonance locations in the C and D rings allowed for the spectrum of f-modes given gravity field constraints and discuss what role a realistic helium distribution in the planet might play.

  1. Saturn V First Stage (S-1C) Ready for Assembly AT KSC

    Science.gov (United States)

    1968-01-01

    This photograph shows the Saturn V first stage (S-1C) in the Vehicle Assembly Building at Kennedy Space Center ready to be mated with the second and third stages to complete the assembly of a Saturn V launch vehicle. This particular Saturn V was used for Apollo 6, which was a systems test flight. The towering 363-foot Saturn V was a multi-stage, multi-engine launch vehicle standing taller than the Statue of Liberty. Altogether, the Saturn V engines produced as much power as 85 Hoover Dams.

  2. IMF dependence of the open-closed field line boundary in Saturn's ionosphere, and its relation to the UV auroral oval observed by the Hubble Space Telescope

    Directory of Open Access Journals (Sweden)

    E. S. Belenkaya

    2007-06-01

    Full Text Available We study the dependence of Saturn's magnetospheric magnetic field structure on the interplanetary magnetic field (IMF, together with the corresponding variations of the open-closed field line boundary in the ionosphere. Specifically we investigate the interval from 8 to 30 January 2004, when UV images of Saturn's southern aurora were obtained by the Hubble Space Telescope (HST, and simultaneous interplanetary measurements were provided by the Cassini spacecraft located near the ecliptic ~0.2 AU upstream of Saturn and ~0.5 AU off the planet-Sun line towards dawn. Using the paraboloid model of Saturn's magnetosphere, we calculate the magnetospheric magnetic field structure for several values of the IMF vector representative of interplanetary compression regions. Variations in the magnetic structure lead to different shapes and areas of the open field line region in the ionosphere. Comparison with the HST auroral images shows that the area of the computed open flux region is generally comparable to that enclosed by the auroral oval, and sometimes agrees in detail with its poleward boundary, though more typically being displaced by a few degrees in the tailward direction.

  3. New results from optical polarimetry of Saturn's rings

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, P E; Kemp, J C; King, R; Parker, T E; Barbour, M S [Oregon Univ., Eugene (USA). Dept. of Physics

    1980-01-10

    Linear polarimetry of Saturn's rings, obtained through the period of the 1979 opposition, is presented. The polarisation clearly correlates in direction with the plane containing the Sun, planet and Earth, but not the ring plane. The results are consistent with local scattering on the surface of individual ring bodies, covered with frost.

  4. Spallation neutron production on thick target at saturne

    International Nuclear Information System (INIS)

    David, J.C.; David, J.C.; Varignon, C.; Borne, F.; Boudard, A.; Brochard, F.; Crespin, S.; Duchazeaubeneix, J.C.; Durand, D.; Durand, J.M.; Frehaut, J.; Hannappe, F.; Lebrun, C.; Lecolley, J.F.; Ledoux, X.; Lefebvres, F.; Legrain, R.; Leray, S.; Louvel, M.; Martinez, E.; Menard, S.; Milleret, G.; Patin, Y.; Petitbon, E.; Plouin, F.; Schapira, J.P.; Stugge, L.; Terrien, Y.; Thun, J.; Volant, C.; Whittal, D.M.

    2003-01-01

    In view of the new spallation neutron source projects, we discuss the characteristics of the neutron spectra on thick targets measured at SATURNE. Some comparisons to spallation models, and especially INCL4/ABLA implemented in the LAHET code, are done. (orig.)

  5. Heavy meson production at Saturne: the role of baryon resonances

    International Nuclear Information System (INIS)

    Le Bornec, Y.

    1991-01-01

    A selection of experiments performed at SATURNE which demonstrate the role played by N* resonances is presented. Nucleon-nucleon and proton-deuteron reactions are discussed and analyzed. Recent theoretical interpretations are also briefly described. (R.P.) 27 refs., 20 figs

  6. Cassini at Saturn Proximal Orbits - Attitude Control Challenges

    Science.gov (United States)

    Burk, Thomas A.

    2013-01-01

    The Cassini mission at Saturn will come to an end in the spring and summer of 2017 with a series of 22 orbits that will dip inside the rings of Saturn. These are called proximal orbits and will conclude with spacecraft disposal into the atmosphere of the ringed world on September 15, 2017. These unique orbits that cross the ring plane only a few thousand kilometers above the cloud tops of the planet present new attitude control challenges for the Cassini operations team. Crossing the ring plane so close to the inner edge of the rings means that the Cassini orientation during the crossing will be tailored to protect the sensitive electronics bus of the spacecraft. This orientation will put the sun sensors at some extra risk so this paper discusses how the team prepares for dust hazards. Periapsis is so close to the planet that spacecraft controllability with RCS thrusters needs to be evaluated because of the predicted atmospheric torque near closest approach to Saturn. Radiation during the ring plane crossings will likely trigger single event transients in some attitude control sensors. This paper discusses how the attitude control team deals with radiation hazards. The angular size and unique geometry of the rings and Saturn near periapsis means that star identification will be interrupted and this paper discusses how the safe mode attitude is selected to best deal with these large bright bodies during the proximal orbits.

  7. Quasar Host Galaxies/Neptune Rotation/Galaxy Building Blocks/Hubble Deep Field/Saturn Storm

    Science.gov (United States)

    2001-01-01

    Computerized animations simulate a quasar erupting in the core of a normal spiral galaxy, the collision of two interacting galaxies, and the evolution of the universe. Hubble Space Telescope (HST) images show six quasars' host galaxies (including spirals, ellipticals, and colliding galaxies) and six clumps of galaxies approximately 11 billion light years away. A false color time lapse movie of Neptune displays the planet's 16-hour rotation, and the evolution of a storm on Saturn is seen though a video of the planet's rotation. A zoom sequence starts with a ground-based image of the constellation Ursa major and ends with the Hubble Deep Field through progressively narrower and deeper views.

  8. Modeling x-ray data for the Saturn z-pinch machine

    International Nuclear Information System (INIS)

    Matuska, W.; Peterson, D.; Deeney, C.; Derzon, M.

    1997-01-01

    A wealth of XRD and time dependent x-ray imaging data exist for the Saturn z-pinch machine, where the load is either a tungsten wire array or a tungsten wire array which implodes onto a SiO 2 foam. Also, these pinches have been modeled with a 2-D RMHD Eulerian computer code. In this paper the authors start with the 2-D Eulerian results to calculate time and spatially dependent spectra using both LTE and NLTE models. Then using response functions, these spectra are converted to XRD currents and camera images, which are quantitatively compared with the data. Through these comparisons, areas of good and lesser quality agreement are determined, and areas are identified where the 2-D Eulerian code should be improved

  9. Mechanisms for the Production of Fast HI from Dissociation of H2 on Saturn

    Science.gov (United States)

    Liu, Xianming; Johnson, Paul; Malone, Charles; Young, Jason; Kanik, Isik; Shemansky, Donald

    2010-05-01

    Images of the Saturn system obtained by the Cassini UVIS at a pixel resolution of 0.1 × 0.1 Saturn radii (Rs) reveal atomic hydrogen in ballistic and escaping trajectories sourced at the top of the thermosphere, primarily in the southern sunlit hemisphere. The main feature in the image is a distinctive H Lyman-α plume structure with FWHM of 0.56 Rs at the exobase sub-solar limb at ~ -13.5° latitude constituting the core of the distributed outward flow of atomic hydrogen from the sunlit hemisphere, with a counterpart on the anti-solar side peaking near the equator above the exobase limb. The structure of the image indicates that part of the out-flowing population is sub-orbital and re-enters the thermosphere in ~ 5 hour time scale. A larger and more broadly distributed component fills the magnetosphere to beyond 45 Rs in the orbital plane and 20 Rs latitudinally above and below the plane in an asymmetric distribution in local time. Molecular hydrogen emission in extreme and far ultraviolet regions collected with the H Lyman-α into the image mosaic reveals a distinctive resonance property correlated with the atomic hydrogen plume and shows a strong deviation of H2 X 1Σg+ from local thermodynamic equilibrium in the main source region. The inferred approximate globally averaged energy deposition at the top of the thermosphere from the production of the hot atomic hydrogen accounts for the measured atmospheric temperature. Possible processes for the fast atomic hydrogen formation from dissociation of H2 include the excitation of singlet-ungerade states and doubly excited states by photons and electrons, and the excitation of the singlet-gerade and triplet states by electrons, and chemical reactions involving the formation and dissociative recombination of H3+. Based on the available laboratory measurements and quantum mechanics calculations, the assessment of various mechanisms for H2 - H production, especially those producing H atoms with sufficient energy to

  10. On the long-term variability of Jupiter and Saturn zonal winds

    Science.gov (United States)

    Sanchez-Lavega, A.; Garcia-Melendo, E.; Hueso, R.; Barrado-Izagirre, N.; Legarreta, J.; Rojas, J. F.

    2012-12-01

    We present an analysis of the long-term variability of Jupiter and Saturn zonal wind profiles at their upper cloud level as retrieved from cloud motion tracking on images obtained at ground-based observatories and with different spacecraft missions since 1979, encompassing about three Jovian and one Saturn years. We study the sensitivity and variability of the zonal wind profile in both planets to major planetary-scale disturbances and to seasonal forcing. We finally discuss the implications that these results have for current model efforts to explain the global tropospheric circulation in these planets. Acknowledgements: This work has been funded by Spanish MICIIN AYA2009-10701 with FEDER support, Grupos Gobierno Vasco IT-464-07 and UPV/EHU UFI11/55. [1] Sánchez-Lavega A., et al., Icarus, 147, 405-420 (2000). [2] García-Melendo E., Sánchez LavegaA., Icarus, 152, 316-330 (2001) [3] Sánchez-Lavega A., et al., Nature, 423, 623-625 (2003). [4] García-Melendo E., et al., Geophysical Research Letters, 37, L22204 (2010).

  11. An Enduring Rapidly Moving Storm as a Guide to Saturn's Equatorial Jet's Complex Structure

    Science.gov (United States)

    Sanchez-Lavega, A.; Garcia-Melendo, E.; Perez-Hoyos, S.; Hueso, R.; Wong, M. H.; Simon, A.; Sanz-Requena, J. F.; Antunano, A.; Barrado-Izagirre, N.; Garate-Lopez, I.; hide

    2016-01-01

    Saturn has an intense and broad eastward equatorial jet with a complex three-dimensional structure mixed with time variability. The equatorial region experiences strong seasonal insolation variations enhanced by ring shadowing, and three of the six known giant planetary-scale storms have developed in it. These factors make Saturn's equator a natural laboratory to test models of jets in giant planets. Here we report on a bright equatorial atmospheric feature imaged in 2015 that moved steadily at a high speed of 450/ms not measured since 1980-1981 with other equatorial clouds moving within an ample range of velocities. Radiative transfer models show that these motions occur at three altitude levels within the upper haze and clouds. We find that the peak of the jet (latitudes 10degN to 10degS) suffers intense vertical shears reaching + 2.5/ms/km, two orders of magnitude higher than meridional shears, and temporal variability above 1 bar altitude level.

  12. The Periodic Flapping and Breathing of Saturn's Magnetodisk During Equinox

    Science.gov (United States)

    Sorba, A. M.; Achilleos, N.; Guio, P.; Arridge, C. S.; Dougherty, M. K.; Sergis, N.

    2017-12-01

    Periodic variations have been observed in many field and particle properties in Saturn's magnetosphere, modulated at a period close to the planetary rotation rate. Magnetic field observations by Cassini's magnetometer instrument suggest that in the outer magnetosphere (beyond 12 Saturn radii) Saturn's current sheet is periodically displaced with respect to the rotational equator, to a first approximation acting as a rotating, tilted disk. This manifests as a `flapping' mode when observed by the spacecraft. Recent studies suggest the magnetosphere also has a `breathing' mode, expanding and contracting with a period close to the planetary rotation rate. We model these two modes in tandem by combining a global, geometrical model of a tilted and rippled current sheet with a local, force-balance model of Saturn's magnetodisk, accounting for the magnetospheric size and hot plasma content. We simulate the breathing behavior by introducing an azimuthal dependence of the system size. We fit Cassini magnetometer data acquired on equatorial orbits from 23 Oct - 17 Dec 2009 (Revs 120-122), close to Saturn equinox, in order that seasonal effects on the current sheet are minimised. We find that our model characterises well the amplitude and phase of the oscillations in the data, for those passes that show clear periodic signatures in the field. In particular, the Bθ (meridional) component can only be characterised when the breathing mode is included. This study introduces calculations for an oscillating boundary under conditions of constant solar wind dynamic pressure, which provide a good basis for understanding the complex relationship between current sheet dynamics and the periodic field perturbations.

  13. INMS measures an influx of molecules from Saturn's rings

    Science.gov (United States)

    Perry, M. E.

    2017-12-01

    In 1984, Connerney and Waite proposed water influx from Saturn's rings to explain the low electron densities measured during Pioneer and Voyager radio occultation experiments. Charge exchange with this minor species depleted the H+ ions and provided a faster path to electron recombination. With ice the primary constituent of the rings, water was the most likely in-falling molecule. During the Grand Finale orbits, Cassini's Ion and Neutral Mass Spectrometer (INMS) detected and quantified an influx from the rings. Unexpectedly, the primary influx molecules are CH4 and a heavier carbon-bearing species. Water was detected, but quantities were factors of ten lower than these other species. Distribution in both altitude and latitude are consistent with a ring influx. The concentration of the minor species in Saturn's atmosphere shows that they enter Saturn's atmosphere from the top. Both molecules have their highest concentrations at the highest altitudes, with concentrations >0.4% at 3,500 km altitude and only 0.02% at 2,700 km. Molecules from the rings deorbit to Saturn's atmosphere at altitudes near 4,000 km, consistent with the INMS measurements. The latitudinal dependence of the minor species indicates that their source is near the equatorial plane. At high altitudes, the minor species were observed primarily at zero latitude, where the 28u species was six times more concentrated than at 5° latitude. At lower altitudes, the peaking ratio was 1, indicating that the species had diffused and was fully mixed into Saturn's H2 atmosphere. The lighter molecule, CH4, diffuses more rapidly than the 28u species. INMS also detected both of these species during the earlier F-ring passes, finding that the neutrals were centered at the ring plane and extended 3,000 km (half width, half max) north and south.

  14. Open and partially closed models of the solar wind interaction with outer planet magnetospheres. The case of Saturn

    Energy Technology Data Exchange (ETDEWEB)

    Belenkaya, Elena S.; Alexeev, Igor I.; Kalegaev, Vladimir V.; Pensionerov, Ivan A.; Blokhina, Marina S.; Parunakian, David A. [Federal State Budget Educational Institution of Higher Education M.V. Lomonosov Moscow State Univ., Moscow (Russian Federation). Skobeltsyn Inst. of Nuclear Physics (SINP MSU); Cowley, Stanley W. H. [Leicester Univ. (United Kingdom). Dept. of Physics and Astronomy

    2017-07-01

    A wide variety of interactions take place between the magnetized solar wind plasma outflow from the Sun and celestial bodies within the solar system. Magnetized planets form magnetospheres in the solar wind, with the planetary field creating an obstacle in the flow. The reconnection efficiency of the solar-wind-magnetized planet interaction depends on the conditions in the magnetized plasma flow passing the planet. When the reconnection efficiency is very low, the interplanetary magnetic field (IMF) does not penetrate the magnetosphere, a condition that has been widely discussed in the recent literature for the case of Saturn. In the present paper, we study this issue for Saturn using Cassini magnetometer data, images of Saturn's ultraviolet aurora obtained by the HST, and the paraboloid model of Saturn's magnetospheric magnetic field. Two models are considered: first, an open model in which the IMF penetrates the magnetosphere, and second, a partially closed model in which field lines from the ionosphere go to the distant tail and interact with the solar wind at its end. We conclude that the open model is preferable, which is more obvious for southward IMF. For northward IMF, the model calculations do not allow us to reach definite conclusions. However, analysis of the observations available in the literature provides evidence in favor of the open model in this case too. The difference in magnetospheric structure for these two IMF orientations is due to the fact that the reconnection topology and location depend on the relative orientation of the IMF vector and the planetary dipole magnetic moment. When these vectors are parallel, two-dimensional reconnection occurs at the low-latitude neutral line. When they are antiparallel, three-dimensional reconnection takes place in the cusp regions. Different magnetospheric topologies determine different mapping of the open-closed boundary in the ionosphere, which can be considered as a proxy for the poleward edge

  15. A study of the outermost ring of Saturn

    International Nuclear Information System (INIS)

    Bobrov, M.S.

    1974-01-01

    The attention is called to the fact that the discovery by Feibelman (1967) of the rarefied outer ring of Saturn is confirmed by the observations of Kuiper (1972). It is proposed to designate this object as E-ring (exterior) in order to avoid confusion with the innermost, also rarefied, D-ring observed by Guerin (1970) and earlier by Barabashov and Semejkin (1933). The effects of the interaction of E-ring with inner Saturn's satellites are briefly discussed. The conclusion is drawn that in cosmogonic time scale these effects are small. It is also shown that the optical thickness of E-ring is lower than 1/20000; the available photometric estimations of the geometric thickness of A- and B-rings need not be corrected for the light scattering and absorption by E-ring. (Auth.)

  16. Possible concepts for an in situ Saturn probe mission

    Science.gov (United States)

    Coustenis, Athena; Lebreton, Jean-Pierre; Mousis, Olivier; Atkinson, David H.; Lunine, Jonathan I.; Reh, Kim R.; Fletcher, Leigh N.; Simon-Miller, Amy A.; Atreya, Sushil; Brinckerhoff, William B.; Cavalie, Thibault; Colaprete, Anthony; Gautier, Daniel; Guillot, Tristan; Mahaffy, Paul R.; Marty, Bernard; Morse, Andy; Sims, Jon; Spilker, Tom; Spilker, Linda

    2014-05-01

    In situ exploration of Saturn's atmosphere would bring insights in two broad themes: the formation history of our solar system and the processes at play in planetary atmospheres. The science case for in situ measurements at Saturn are developed in [1] and two companion abstracts (see Mousis et al., and Atkinson et al.). They are summarized here. Measurements of Saturn's bulk chemical and isotopic composition would place important constraints on the volatile reservoirs in the protosolar nebula and hence on the formation mechanisms. An in situ probe, penetrating from the upper atmosphere (μbar level) into the convective weather layer to a minimum depth of 10 bar, would also contribute to our knowledge of Saturn's atmospheric structure, dynamics, composition, chemistry and cloud-forming processes. Different mission architectures are envisaged, all based on an entry probe that would descend through Saturn's stratosphere and troposphere under parachute down to a minimum of 10 bars [1]. Future studies will focus on the trade-offs between science return and the added design complexity of a probe that could operate at pressures larger than 10 bars. Accelerometry measurements may also be performed during the entry phase in the higher part of the stratosphere prior to starting measurements under parachute. A carrier system would be required to deliver the probe along its interplanetary trajectory to the desired atmospheric entry point at Saturn. The entry site would be carefully selected. Three possible mission configurations are currently under study (with different risk/cost trades): • Configuration 1: Probe + Carrier. After probe delivery, the carrier would follow its path and be destroyed during atmospheric entry, but could perform pre-entry science. The carrier would not be used as a radio relay, but the probe would transmit its data to the ground system via a direct-to-Earth (DTE) RF link; • Configuration 2: Probe + Carrier/Relay. The probe would detach from the

  17. Detection of a strongly negative surface potential at Saturn's moon Hyperion.

    Science.gov (United States)

    Nordheim, T A; Jones, G H; Roussos, E; Leisner, J S; Coates, A J; Kurth, W S; Khurana, K K; Krupp, N; Dougherty, M K; Waite, J H

    2014-10-28

    On 26 September 2005, Cassini conducted its only close targeted flyby of Saturn's small, irregularly shaped moon Hyperion. Approximately 6 min before the closest approach, the electron spectrometer (ELS), part of the Cassini Plasma Spectrometer (CAPS) detected a field-aligned electron population originating from the direction of the moon's surface. Plasma wave activity detected by the Radio and Plasma Wave instrument suggests electron beam activity. A dropout in energetic electrons was observed by both CAPS-ELS and the Magnetospheric Imaging Instrument Low-Energy Magnetospheric Measurement System, indicating that the moon and the spacecraft were magnetically connected when the field-aligned electron population was observed. We show that this constitutes a remote detection of a strongly negative (∼ -200 V) surface potential on Hyperion, consistent with the predicted surface potential in regions near the solar terminator.

  18. METER-SIZED MOONLET POPULATION IN SATURN'S C RING AND CASSINI DIVISION

    International Nuclear Information System (INIS)

    Baillié, Kévin; Colwell, Joshua E.; Esposito, Larry W.; Lewis, Mark C.

    2013-01-01

    Stellar occultations observed by the Cassini Ultraviolet Imaging Spectrograph reveal the presence of transparent holes a few meters to a few tens of meters in radial extent in otherwise optically thick regions of the C ring and the Cassini Division. We attribute the holes to gravitational disturbances generated by a population of ∼10 m boulders in the rings that is intermediate in size between the background ring particle size distribution and the previously observed ∼100 m propeller moonlets in the A ring. The size distribution of these boulders is described by a shallower power-law than the one that describes the ring particle size distribution. The number and size distribution of these boulders could be explained by limited accretion processes deep within Saturn's Roche zone.

  19. Tilting Saturn without Tilting Jupiter: Constraints on Giant Planet Migration

    Science.gov (United States)

    Brasser, R.; Lee, Man Hoi

    2015-11-01

    The migration and encounter histories of the giant planets in our solar system can be constrained by the obliquities of Jupiter and Saturn. We have performed secular simulations with imposed migration and N-body simulations with planetesimals to study the expected obliquity distribution of migrating planets with initial conditions resembling those of the smooth migration model, the resonant Nice model and two models with five giant planets initially in resonance (one compact and one loose configuration). For smooth migration, the secular spin-orbit resonance mechanism can tilt Saturn’s spin axis to the current obliquity if the product of the migration timescale and the orbital inclinations is sufficiently large (exceeding 30 Myr deg). For the resonant Nice model with imposed migration, it is difficult to reproduce today’s obliquity values, because the compactness of the initial system raises the frequency that tilts Saturn above the spin precession frequency of Jupiter, causing a Jupiter spin-orbit resonance crossing. Migration timescales sufficiently long to tilt Saturn generally suffice to tilt Jupiter more than is observed. The full N-body simulations tell a somewhat different story, with Jupiter generally being tilted as often as Saturn, but on average having a higher obliquity. The main obstacle is the final orbital spacing of the giant planets, coupled with the tail of Neptune’s migration. The resonant Nice case is barely able to simultaneously reproduce the orbital and spin properties of the giant planets, with a probability ˜ 0.15%. The loose five planet model is unable to match all our constraints (probability <0.08%). The compact five planet model has the highest chance of matching the orbital and obliquity constraints simultaneously (probability ˜0.3%).

  20. MeV proton flux predictions near Saturn's D ring.

    Science.gov (United States)

    Kollmann, P; Roussos, E; Kotova, A; Cooper, J F; Mitchell, D G; Krupp, N; Paranicas, C

    2015-10-01

    Radiation belts of MeV protons have been observed just outward of Saturn's main rings. During the final stages of the mission, the Cassini spacecraft will pass through the gap between the main rings and the planet. Based on how the known radiation belts of Saturn are formed, it is expected that MeV protons will be present in this gap and also bounce through the tenuous D ring right outside the gap. At least one model has suggested that the intensity of MeV protons near the planet could be much larger than in the known belts. We model this inner radiation belt using a technique developed earlier to understand Saturn's known radiation belts. We find that the inner belt is very different from the outer belts in the sense that its intensity is limited by the densities of the D ring and Saturn's upper atmosphere, not by radial diffusion and satellite absorption. The atmospheric density is relatively well constrained by EUV occultations. Based on that we predict an intensity in the gap region that is well below that of the known belts. It is more difficult to do the same for the region magnetically connected to the D ring since its density is poorly constrained. We find that the intensity in this region can be comparable to the known belts. Such intensities pose no hazard to the mission since Cassini would only experience these fluxes on timescales of minutes but might affect scientific measurements by decreasing the signal-to-contamination ratio of instruments.

  1. Resistive Heating and Ion Drag in Saturn's Thermosphere

    Science.gov (United States)

    Vriesema, Jess William; Koskinen, Tommi; Yelle, Roger V.

    2017-10-01

    One of the most puzzling observations of the jovian planets is that the thermospheres of Jupiter, Saturn, Uranus and Neptune are all several times hotter than solar heating can account for (Strobel and Smith 1973; Yelle and Miller 2004; Muller-Wodarg et al. 2006). On Saturn, resistive heating appears sufficient to explain these temperatures in auroral regions, but the particular mechanism(s) responsible for heating the lower latitudes remains unclear. The most commonly proposed heating mechanisms are breaking gravity waves and auroral heating at the poles followed by redistribution of energy to mid-and low latitudes. Both of these energy sources are potentially important but also come with significant problems. Wave heating would have to be continuous and global to produce consistently elevated temperatures and the strong Coriolis forces coupled with polar ion drag appear to hinder redistribution of auroral energy (see Strobel et al. 2016 for review). Here we explore an alternative: wind-driven electrodynamics that can alter circulation and produce substantial heating outside of the auroral region. Smith (2013) showed this in-situ mechanism to be potentially significant in Jupiter’s thermosphere. We present new results from an axisymmetric, steady-state model that calculates resistive (Joule) heating rates through rigorous solutions of the electrodynamic equations for the coupled neutral atmosphere and ionosphere of Saturn. At present, we assume a dipole magnetic field and neglect any contributions from the magnetosphere. We use ion mixing ratios from the model of Kim et al. (2014) and the observed temperature-pressure profile from Koskinen et al. (2015) to calculate the generalized conductivity tensor as described by Koskinen et al. (2014). We calculate the current density under the assumption that it has no divergence and use it to calculate the resistive heating rates and ion drag. Our results suggest that resistive heating and ion drag at low latitudes likely

  2. 10 Years at Saturn, and More Excitement to Come!

    Science.gov (United States)

    Edgington, S. G.; Spilker, L. J.; Altobelli, N.

    2014-04-01

    After 10 years in orbit, the Cassini-Huygens Mission to Saturn, a collaboration of NASA, ESA, and ASI, continues to wow the imagination. Every year Cassini produces answers to questions raised by the Voyager flybys, while at the same time posing new questions that can only be answered with a long duration mission using a flagship-class spacecraft. In this talk, we sample a few of Cassini's discoveries from the past decade and give an overview of what comes next.

  3. Extracted-beam-detection system around synchrotron saturne

    International Nuclear Information System (INIS)

    Anne, Remy; Milleret, Gerard; Giuliani, Arlette; Lefol, Andre; Perret, Robert; Poupard, Joseph; Trogno, Andre; Van den Bossche, Maurice; N'Guyen Sieu Viet.

    1977-07-01

    The extracted-beam-detection system working around the synchrotron Saturne is presented. The whole system is composed of about forty multiwire chambers used for beam tuning and providing beams profiles. Optic beam parameters such as position, divergence, dimension, emittance can be easily measured, or calculated with a program running on a computer. They are working in large range intensity beams (10 2 to 5.10 11 p/cm 2 /s of protons, alpha particles, deutons, pions, tritons and electrons [fr

  4. A model of Saturn inferred from its measured gravitational field

    Science.gov (United States)

    Kong, Dali; Zhang, Keke; Schubert, Gerald; Anderson, John D.

    2018-04-01

    We present an interior model of Saturn with an ice-rock core, a metallic region, an outer molecular envelope and a thin transition layer between the metallic and molecular regions. The shape of Saturn’s 1 bar surface is irregular and determined fully self-consistently by the required equilibrium condition. While the ice-rock core is assumed to have a uniform density, three different equations of state are adopted for the metallic, molecular and transition regions. The Saturnian model is constrained by its known mass, its known equatorial and polar radii, and its known zonal gravitational coefficients, J 2n , n = 1, 2, 3. The model produces an ice-rock core with equatorial radius 0.203 R S, where R S is the equatorial radius of Saturn at the 1-bar pressure surface; the core density ρ c = 10388.1 kgm‑3 corresponding to 13.06 Earth masses; and an analytical expression describing the Saturnian irregular shape of the 1-bar pressure level. The model also predicts the values of the higher-order gravitational coefficients, J 8, J 10 and J 12, for the hydrostatic Saturn and suggests that Saturn’s convective dynamo operates in the metallic region approximately defined by 0.2 R S < r e < 0.7 R S, where r e denotes the equatorial radial distance from the Saturnian center of figure.

  5. Magnetotail Reconnection and Flux Circulation: Jupiter and Saturn Compared

    Science.gov (United States)

    Jackman, C. M.; Vogt, M. F.; Slavin, J. A.; Cowley, S. W. H.; Boardsen, S. A.

    2011-01-01

    The Jovian magnetosphere has been visited by eight spacecraft, and the magnetometer data have been used to identify dozens of plasmoids and 250 field dipolarizations associated with magnetic reconnection in the tail [e.g. Vogt et al., 2010]. Since the arrival of the Cassini spacecraft at Saturn in 2004, the magnetometer instrument has also been used to identify reconnection signatures. The deepest magnetotail orbits were in 2006, and during this time 34 signatures of plasmoids were identified. In this study we compare the statistical properties of plasmoids at Jupiter and Saturn such as duration, size, location, and recurrence period. Such parameters can be influenced by many factors, including the different Dungey cycle timescales and cross-magnetospheric potential drops at the two planets. We present superposed epoch analyses of plasmoids at the two planets to determine their average properties and to infer their role in the reconfiguration of the nightside of the magnetosphere. We examine the contributions of plasmoids to the magnetic flux transfer cycle at both planets. At Jupiter, there is evidence of an extended interval after reconnection where the field remains northward (analogous to the terrestrial post-plasmoid plasma sheet). At Saturn we see a similar feature, and calculate the amount of flux closed on average in reconnection events, leading us to an estimation of the recurrence rate of plasmoid release.

  6. 3-Dimensional simulations of storm dynamics on Saturn

    Science.gov (United States)

    Hueso, R.; Sanchez-Lavega, A.

    2000-10-01

    The formation and evolution of convective clouds in the atmosphere of Saturn is investigated using an anelastic three-dimensional time-dependent model with parameterized microphysics. The model is designed to study the development of moist convection on any of the four giant planets and has been previously used to investigate the formation of water convective storms in the jovian atmosphere. The role of water and ammonia in moist convection is investigated with varying deep concentrations. Results imply that most of the convective activity observed at Saturn may occur at the ammonia cloud deck while the formation of water moist convection may happen only when very strong constraints on the lower troposphere are met. Ammonia storms can ascend to the 300 mb level with vertical velocities around 30 ms-1. The seasonal effect on the thermal profile at the upper troposphere may have important effects on the development of ammonia storms. In the cases where water storms can develop they span many scale heights with peak vertical velocities around 160 ms-1 and cloud particles can be transported up to the 150 mb level. These predicted characteristics are similar to the Great White Spots observed in Saturn which, therefore, could be originated at the water cloud base level. This work has been supported by Gobierno Vasco PI 1997-34. R. Hueso acknowledges a PhD fellowship from Gobierno Vasco.

  7. Saturn's Magnetic Field from the Cassini Grand Finale orbits

    Science.gov (United States)

    Dougherty, M. K.; Cao, H.; Khurana, K. K.; Hunt, G. J.; Provan, G.; Kellock, S.; Burton, M. E.; Burk, T. A.

    2017-12-01

    The fundamental aims of the Cassini magnetometer investigation during the Cassini Grand Finale orbits were determination of Saturn's internal planetary magnetic field and the rotation rate of the deep interior. The unique geometry of the orbits provided an unprecedented opportunity to measure the intrinsic magnetic field at close distances never before encountered. The surprising close alignment of Saturn's magnetic axis with its spin axis, known about since the days of Pioneer 11, has been a focus of the team's analysis since Cassini Saturn Orbit Insertion. However, the varying northern and southern magnetospheric planetary period oscillations, which fill the magnetosphere, has been a factor in masking the field signals from the interior. Here we describe an overview of the magnetometer results from the Grand Finale orbits, including confirmation of the extreme axisymmetric nature of the planetary magnetic field, implications for knowledge of the rotation rate and the behaviour of external magnetic fields (arising from the ring current, field aligned currents both at high and low latitudes and the modulating effect of the planetary period oscillations).

  8. Quasiperiodic ULF-pulsations in Saturn's magnetosphere

    Directory of Open Access Journals (Sweden)

    G. Kleindienst

    2009-02-01

    Full Text Available Recent magnetic field investigations made onboard the Cassini spacecraft in the magnetosphere of Saturn show the existence of a variety of ultra low frequency plasma waves. Their frequencies suggest that they are presumably not eigenoscillations of the entire magnetospheric system, but excitations confined to selected regions of the magnetosphere. While the main magnetic field of Saturn shows a distinct large scale modulation of approximately 2 nT with a periodicity close to Saturn's rotation period, these ULF pulsations are less obvious superimposed oscillations with an amplitude generally not larger than 3 nT and show a package-like structure. We have analyzed these wave packages and found that they are correlated to a certain extent with the large scale modulation of the main magnetic field. The spatial localization of the ULF wave activity is represented with respect to local time and Kronographic coordinates. For this purpose we introduce a method to correct the Kronographic longitude with respect to a rotation period different from its IAU definition. The observed wave packages occur in all magnetospheric regions independent of local time, elevation, or radial distance. Independent of the longitude correction applied the wave packages do not occur in an accentuated Kronographic longitude range, which implies that the waves are not excited or confined in the same selected longitude ranges at all times or that their lifetime leads to a variable phase with respect to the longitudes where they have been exited.

  9. Catalog of Astronomical Positions of Saturn's Moons Obtained by Photographic Observations at the Mao Nasu in 1961-1991

    Science.gov (United States)

    Yizhakevych, O. M.; Andruk, V. M.; Pakuliak, L. K.

    In the framework of UkrVO national project the new methods of plate digital image processing are developed. The photographic material of the UkrVO Joint Digital Archive (JDA, http://194.44.35.19/vo-mao/DB/ archivespecial.php) is used for the solution of classic astrometric problem - positional and photometric determinations of objects registered on the plates including Saturn's moons. The results of tested methods show that the positional RMS errors are better than ±150 mas for both coordinates and photometric ones are better than ±0.20m with the Tycho-2 catalogue as reference.

  10. Planar wire array dynamics and radiation scaling at multi-MA levels on the Saturn pulsed power generator

    International Nuclear Information System (INIS)

    Chuvatin, Alexander S.; Vesey, Roger Alan; Waisman, Eduardo Mario; Esaulov, Andrey A.; Ampleford, David J.; Kantsyrev, Victor Leonidovich; Cuneo, Michael Edward; Rudakov, Leonid I.; Coverdale, Christine Anne; Jones, Brent Manley; Safronova, Alla S.; Jones, Michael C.

    2008-01-01

    Planar wire arrays are studied at 3-6 MA on the Saturn pulsed power generator as potential drivers of compact hohlraums for inertial confinement fusion studies. Comparison with zero-dimensional modeling suggests that there is significant trailing mass. The modeled energy coupled from the generator cannot generally explain the energy in the main x-ray pulse. Preliminary comparison at 1-6 MA indicates sub-quadratic scaling of x-ray power in a manner similar to compact cylindrical wire arrays. Time-resolved pinhole images are used to study the implosion dynamics

  11. Lunar occultation of Saturn. IV - Astrometric results from observations of the satellites

    Science.gov (United States)

    Dunham, D. W.; Elliot, J. L.

    1978-01-01

    The method of determining local lunar limb slopes, and the consequent time scale needed for diameter studies, from accurate occultation timings at two nearby telescopes is described. Results for photoelectric observations made at Mauna Kea Observatory during the occultation of Saturn's satellites on March 30, 1974, are discussed. Analysis of all observations of occultations of Saturn's satellites during 1974 indicates possible errors in the ephemerides of Saturn and its satellites.

  12. Saturn V First Stage Lowered to the Ground After Static Test

    Science.gov (United States)

    1966-01-01

    This vintage photograph shows the 138-foot long first stage of the Saturn V being lowered to the ground following a successful static test firing at Marshall Space flight Center's S-1C test stand. The firing provided NASA engineers information on the booster's systems. The towering 363-foot Saturn V was a multi-stage, multi-engine launch vehicle standing taller than the Statue of Liberty. Altogether, the Saturn V engines produced as much power as 85 Hoover Dams.

  13. Second stage of Saturn V being assembled with the first stage.

    Science.gov (United States)

    1965-01-01

    The hydrogen-powered second stage is being lowered into place during the final phase of fabrication of the Saturn V moon rocket at North American's Seal Beach, California facility. The towering 363-foot Saturn V was a multi-stage, multi-engine launch vehicle standing taller than the Statue of Liberty. Altogether, the Saturn V engines produced as much power as 85 Hoover Dams.

  14. Gravity Field and Interior Structure of Saturn from Cassini Observations

    Science.gov (United States)

    Anderson, J. D.; Schubert, G.

    2007-05-01

    We discuss the sources for a determination of Saturn's external gravitational potential, beginning with a Pioneer 11 flyby in September 1979, two Voyager flybys in November 1980 for Voyager 1 and August 1981 for Voyager 2, four useful close approaches by the Cassini orbiter in May and June 2005, and culminating in an extraordinary close approach for Radio Science in September 2006. Results from the 2006 data are not yet available, but even without them, Cassini offers improvements in accuracy over Pioneer and Voyager by a factor of 37 in the zonal coefficient J2, a factor of 14 in J4, and a factor of 5 in J6. These improvements are important to our understanding of the internal structure of Saturn in particular, and to solar and extrasolar giant planets in general. Basically, Saturn can be modeled as a rapidly rotating planet in hydrostatic equilibrium. Consistent with the limited data available, we express the density distribution as a polynomial of fifth degree in the normalized mean radius β = r/R over the real interval zero to one, where R is the radius of a sphere with density equal to the mean density of Saturn. Then the six coefficients of the polynomial are adjusted by nonlinear least squares until they match the measured even zonal gravity coefficients J2,J4,J6 within a fraction of a standard deviation. The gravity coefficients are computed from the density distribution by the method of level surfaces to the third order in the rotational smallness parameter. Two degrees of freedom are removed by applying the constraints that (1)~the derivative of the density distribution is zero at the center, and (2)~the density is zero at the surface. Further, a unique density distribution is obtained by the method of singular value decomposition truncated at rank three. Given this unique density distribution, the internal pressure can be obtained by numerical integration of the equation of hydrostatic equilibrium, expressed in terms of the single independent parameter

  15. From Data to Equations: Inferring the Laws governing Saturn's Ring Temperature

    Science.gov (United States)

    Altobelli, N.; Lopez-Paz, D.; Spilker, L.; Pilorz, S.

    2011-10-01

    Six years after Saturn Orbit Insertion (SOI), the Composite Infrared Spectrometer (CIRS) on-board the Cassini Spacecraft has been performing a thermal mapping of Saturn's main rings, by measuring the thermal radiance in the far-infrared ( [10-600] cm-1 ) for different viewing geometries. So far, more than 2.5 millions individual spectra have been recorded, from Saturn's northern winter solstice till Saturn's northern spring. We present a first attempt of treating the data set globally by applying numerical data mining techniques inherited from the field of artificial intelligence, such as neural networks and genetic programing.

  16. Magnetospheric magnetic field modelling for the 2011 and 2012 HST Saturn aurora campaigns – implications for auroral source regions

    Directory of Open Access Journals (Sweden)

    E. S. Belenkaya

    2014-06-01

    Full Text Available A unique set of images of Saturn's northern polar UV aurora was obtained by the Hubble Space Telescope in 2011 and 2012 at times when the Cassini spacecraft was located in the solar wind just upstream of Saturn's bow shock. This rare situation provides an opportunity to use the Kronian paraboloid magnetic field model to examine source locations of the bright auroral features by mapping them along field lines into the magnetosphere, taking account of the interplanetary magnetic field (IMF measured near simultaneously by Cassini. It is found that the persistent dawn arc maps to closed field lines in the dawn to noon sector, with an equatorward edge generally located in the inner part of the ring current, typically at ~ 7 Saturn radii (RS near dawn, and a poleward edge that maps variously between the centre of the ring current and beyond its outer edge at ~ 15 RS, depending on the latitudinal width of the arc. This location, together with a lack of response in properties to the concurrent IMF, suggests a principal connection with ring-current and nightside processes. The higher-latitude patchy auroras observed intermittently near to noon and at later local times extending towards dusk are instead found to straddle the model open–closed field boundary, thus mapping along field lines to the dayside outer magnetosphere and magnetopause. These emissions, which occur preferentially for northward IMF directions, are thus likely associated with reconnection and open-flux production at the magnetopause. One image for southward IMF also exhibits a prominent patch of very high latitude emissions extending poleward of patchy dawn arc emissions in the pre-noon sector. This is found to lie centrally within the region of open model field lines, suggesting an origin in the current system associated with lobe reconnection, similar to that observed in the terrestrial magnetosphere for northward IMF.

  17. Impact of lightning on the lower ionosphere of Saturn and possible generation of Transient Luminous Events (TLEs)

    Science.gov (United States)

    Luque, Alejandro; Dubrovin, Daria; José Gordillo-Vázquez, Francisco; Ebert, Ute; Yair, Yoav; Price, Colin

    2013-04-01

    Radio observations [1] and, more recently, optical images from the Cassini spacecraft [2] have clearly established the existence of electrical storms in Saturn and constrained the possible altitude range and total dissipated energy of lightning strokes. Based on these observations, we here investigate the physical effects of lightning on the upper layers of Saturn's atmosphere. We first study the relevance of the conductivity profile of the lower Saturnian ionosphere and how the Maxwell relaxation time limits the amplitude and duration of the reduced electric fields. We implemented a simple, zero-dimensional model [3] that considers only the most relevant ionization reactions; we then applied this model to two conductivity profiles proposed in the literature [4, 5] and a range of possible amplitudes and durations of the driving stroke. Then we investigate the possibility that the lightning-induced ionization results in a field that is locally strong enough to ignite streamer discharges and thus form a sprite. A sprite would lead to localized but very intense fields potentially resulting in detectable optical emissions [6]. We model the possible sprite inception with a self-consistent, cylindrically symmetrical 3d transport code [7]. Finally we discuss the chemical impact of lightning-induced electric fields in the upper Saturnian atmosphere. We use a kinetic model where we implemented the most important reactions induced by energized electrons in a H2/He atmosphere. We thus investigate what species densities are significantly enhanced and what are the expected spectroscopical signatures of upper-atmospheric electricity in Saturn. [1] G. Fischer, M.D. Desch, P. Zarka, M.L. Kaiser, D.A. Gurnett, W.S. Kurth, W. Macher, HO Rucker, A. Lecacheux, W.M. Farrell, et al., Saturn lightning recorded by cassini/rpws in 2004. Icarus, 183(1):135, 2006. [2] U.A. Dyudina, A.P. Ingersoll, S.P. Ewald, C.C. Porco, G. Fischer, W.S. Kurth, and R.A. West, Detection of visible lightning

  18. The Evolution and Fate of Saturn's Stratospheric Vortex: Infrared Spectroscopy from Cassini

    Science.gov (United States)

    Fletcher, Leigh N.; Hesman, B. E.; Arhterberg, R. K.; Bjoraker, G.; Irwin, P. G. J.; Hurley, J.; Sinclair, J.; Gorius, N.; Orton, G. S.; Read, P. L.; hide

    2012-01-01

    The planet-encircling springtime storm in Saturn's troposphere (December 2010-July 2011) produced dramatic perturbations to stratospheric temperatures, winds and composition at mbar pressures that persisted long after the tropospheric disturbance had abated. Observations from the Cassini Composite Infrared Spectrometer (CIRS), supported by ground-based imaging from the VISIR instrument on the Very Large Telescope,is used to track the evolution of a large, hot stratospheric anticyclone between January 2011 and the present day. The evolutionary sequence can be divided into three phases: (I) the formation and intensification of two distinct warm airmasses near 0.5 mbar between 25 and 35N (one residing directly above the convective storm head) between January-April 2011, moving westward with different zonal velocities; (II) the merging of the warm airmasses to form the large single 'stratospheric beacon' near 40N between April and June 2011, dissociated from the storm head and at a higher pressure (2 mbar) than the original beacons; and (III) the mature phase characterized by slow cooling and longitudinal shrinkage of the anticyclone since July 2011, moving west with a near-constant velocity of 2.70+/-0.04 deg/day (-24.5+/-0.4 m/s at 40N). Peak temperatures of 220 K at 2 mbar were measured on May 5th 2011 immediately after the merger, some 80 K warmer than the quiescent surroundings. Thermal winds hear calculations in August 2011 suggest clockwise peripheral velocities of 200400 mls at 2 mbar, defining a peripheral collar with a width of 65 degrees longitude (50,000 km in diameter) and 25 degrees latitude. Stratospheric acetylene (C2H2) was uniformly enhanced by a factor of three within the vortex, whereas ethane (C2H6) remained unaffected. We will discuss the thermal and chemical characteristics of Saturn's beacon in its mature phase, and implications for stratospheric vortices on other giant planets.

  19. Evidence for Break-Up of Clumps in Dynamically Stirred Regions of Saturn's Rings

    Science.gov (United States)

    Colwell, J. E.; Sega, D. N.; Jerousek, R. G.; Cooney, J. H.; Esposito, L. W.

    2017-12-01

    Stellar occultations of Saturn's rings observed by the Cassini Ultraviolet Imaging Spectrograph (UVIS) High Speed Photometer (HSP) record stellar brightness seen through the rings as photon counts that are described by Poisson counting statistics in the absence of intervening ring material. The variance in the data increases above counting statistics due to the discrete sizes of the ring particles, with larger particles leading to a larger variance at a given optical depth. We take advantage of the high spatial resolution and multiple viewing geometries of the UVIS occultations to study variations in particle size near and within strongly perturbed regions of Saturn's A ring, in particular the strong first order Lindblad resonances with Janus and the Mimas 5:3 Lindblad resonance and inner vertical resonance. The variance shows changes in the area-weighted particle size between peaks and troughs in the density waves as well as an overall decrease in particle size in the broad "halo" regions that bracket the strong Janus Lindblad resonances in the A ring. In addition we see a decrease in particle size at the location of the Mimas 5:3 bending wave wavetrain itself, and an increase in optical depth at the location of the wave when viewed from high elevation angles out of the ring plane. Taken together, these observations suggest that clumps of particles, perhaps the ubiquitous A ring self-gravity wakes, are disaggregated in the bending wave, even though standard bending wave theory does not predict enhanced collision velocities. We also examine the skewness, a higher order moment of the occultation data, that is diagnostic of asymmetries in the particle size distribution. We use Monte Carlo simulations of occultations to match the first three moments of the data (the signal mean, or equivalently the optical depth, the variance, and the skewness) to illustrate differences in ring particle size in these perturbed regions.

  20. The near-surface electron radiation environment of Saturn's moon Mimas

    Science.gov (United States)

    Nordheim, T. A.; Hand, K. P.; Paranicas, C.; Howett, C. J. A.; Hendrix, A. R.; Jones, G. H.; Coates, A. J.

    2017-04-01

    Saturn's inner mid-size moons are exposed to a number of external weathering processes, including charged particle bombardment and UV photolysis, as well as deposition of E-ring grains and interplanetary dust. While optical remote sensing observations by several instruments onboard the Cassini spacecraft have revealed a number of weathering patterns across the surfaces of these moons, it is not entirely clear which external process is responsible for which observed weathering pattern. Here we focus on Saturn's moon Mimas and model the effect of energetic electron bombardment across its surface. By using a combination of a guiding center, bounce-averaged charged particle tracing approach and a particle physics code, we investigate how the radiation dose due to energetic electrons is deposited with depth at different locations. We predict a lens-shaped electron energy deposition pattern that extends down to ∼cm depths at low latitudes centered around the apex of the leading hemisphere (90° W). These results are consistent with previous remote sensing observations of a lens-shaped color anomaly observed by the Imaging Science Subsystem (ISS) instrument as well as a thermal inertia anomaly observed by the Visual and Infrared Mapping Spectrometer (VIMS) and the Composite Infrared Spectrometer (CIRS). Our results confirm that these features are produced by MeV electrons that have a penetration depth into the surface comparable to the effective sampling depths of these instruments. On the trailing hemisphere we predict a similar lens-shaped electron energy deposition pattern, whose effects have to date not been observed by the Cassini remote sensing instruments. We suggest that no corresponding lens-shaped weathering pattern has been observed on the trailing hemisphere because of the comparatively short range of lower energy (<1 MeV) electrons into surface ice, as well as competing effects from cold plasma, neutral, and dust bombardment.

  1. CONSTRAINING SATURN'S CORE PROPERTIES BY A MEASUREMENT OF ITS MOMENT OF INERTIA-IMPLICATIONS TO THE CASSINI SOLSTICE MISSION

    International Nuclear Information System (INIS)

    Helled, R.

    2011-01-01

    Knowledge of Saturn's axial moment of inertia can provide valuable information on its internal structure. We suggest that Saturn's angular momentum may be determined by the Solstice Mission (Cassini XXM) by measuring Saturn's pole precession rate and the Lense-Thirring acceleration on the spacecraft, and therefore put constraints on Saturn's moment of inertia. It is shown that Saturn's moment of inertia can change up to ∼2% due to different core properties. However, a determination of Saturn's rotation rate is required to constrain its axial moment of inertia. A change of about seven minutes in rotation period leads to a similar uncertainty in the moment of inertia value as different core properties (mass, radius). A determination of Saturn's angular momentum and rotation period by the Solstice Mission could reveal important information on Saturn's internal structure, in particular, its core properties.

  2. The Case for Massive and Ancient Rings of Saturn

    Science.gov (United States)

    Esposito, Larry W.

    2016-04-01

    Analysis of Voyager and Pioneer 11 results give a mass for Saturn's rings, M = 5 x 10-8 Msat. This is about the mass of Saturn's small moon Mimas. This has been interpreted as a lower limit to the ring mass (Esposito et al 1983), since the thickest parts of the rings were not penetrated by the stellar occultstion, and this calculation assumes an unvarying particle size throughout the rings. Because the rings are constantly bombarded by micrometeroids, their current composition of nearly pure water ice implies such low mass rings must have formed recently. The case is par-ticularly strong for Saturn's A ring, where the data are the best, implying the A ring is less than 10% of the age of the Saturn (Esposito 1986). Cassini results com-pound this problem. UVIS spectra are consistent with either young rings or rings about 10x as massive as the Voyager estimate (Elliott and Esposito (2011). CDA confirms the impacting mass flux is similar to that as-sumed for the pollution calculations (Kempf etal 2015). VIMS analysis of density wave signatures in the B ring gives a value of about 1/3 the Voyager value (Hedmann etal 2016). This VIMS result implies the rings are even younger! The problem is that young rings are very unlikely to be formed recently, meaning that we live in a very special epoch, following some unlikely recent origin… like disruption of a medium sized moon or capture of the fragments of a disrupted comet. This paradox (Charnoz etal 2009) is unre-solved. Alternative interpretations: To take the VIMS results at face value, Saturn's low mass rings must be very young. The optically thick B ring must be made of small, porous or fractal particles. This is hard to understand, since the particles are continually colliding every few hours and temporary aggregates will stir the collision velocities to higher values. An alternative is that we accept the higher mass interpretation of the Pioneer 11 results (Esposito etal 2008) using the granola bar model of Colwell

  3. SUPRATHERMAL ELECTRONS AT SATURN'S BOW SHOCK

    Energy Technology Data Exchange (ETDEWEB)

    Masters, A.; Dougherty, M. K. [The Blackett Laboratory, Imperial College London, Prince Consort Road, London, SW7 2AZ (United Kingdom); Sulaiman, A. H. [Department of Physics and Astronomy, University of Iowa, Iowa City, IA 52242 (United States); Sergis, N. [Office of Space Research and Technology, Academy of Athens, Soranou Efesiou 4, 11527 Athens (Greece); Stawarz, L. [Astronomical Observatory, Jagiellonian University, ul. Orla 171, 30-244 Krakow (Poland); Fujimoto, M. [Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, 3-1-1 Yoshinodai, Chuo-ku, Sagamihara, Kanagawa 252-5210 (Japan); Coates, A. J., E-mail: a.masters@imperial.ac.uk [Mullard Space Science Laboratory, Department of Space and Climate Physics, University College London, Holmbury St. Mary, Dorking RH5 6NT (United Kingdom)

    2016-07-20

    The leading explanation for the origin of galactic cosmic rays is particle acceleration at the shocks surrounding young supernova remnants (SNRs), although crucial aspects of the acceleration process are unclear. The similar collisionless plasma shocks frequently encountered by spacecraft in the solar wind are generally far weaker (lower Mach number) than these SNR shocks. However, the Cassini spacecraft has shown that the shock standing in the solar wind sunward of Saturn (Saturn's bow shock) can occasionally reach this high-Mach number astrophysical regime. In this regime Cassini has provided the first in situ evidence for electron acceleration under quasi-parallel upstream magnetic conditions. Here we present the full picture of suprathermal electrons at Saturn's bow shock revealed by Cassini . The downstream thermal electron distribution is resolved in all data taken by the low-energy electron detector (CAPS-ELS, <28 keV) during shock crossings, but the higher energy channels were at (or close to) background. The high-energy electron detector (MIMI-LEMMS, >18 keV) measured a suprathermal electron signature at 31 of 508 crossings, where typically only the lowest energy channels (<100 keV) were above background. We show that these results are consistent with the theory in which the “injection” of thermal electrons into an acceleration process involves interaction with whistler waves at the shock front, and becomes possible for all upstream magnetic field orientations at high Mach numbers like those of the strong shocks around young SNRs. A future dedicated study will analyze the rare crossings with evidence for relativistic electrons (up to ∼1 MeV).

  4. SUPRATHERMAL ELECTRONS AT SATURN'S BOW SHOCK

    International Nuclear Information System (INIS)

    Masters, A.; Dougherty, M. K.; Sulaiman, A. H.; Sergis, N.; Stawarz, L.; Fujimoto, M.; Coates, A. J.

    2016-01-01

    The leading explanation for the origin of galactic cosmic rays is particle acceleration at the shocks surrounding young supernova remnants (SNRs), although crucial aspects of the acceleration process are unclear. The similar collisionless plasma shocks frequently encountered by spacecraft in the solar wind are generally far weaker (lower Mach number) than these SNR shocks. However, the Cassini spacecraft has shown that the shock standing in the solar wind sunward of Saturn (Saturn's bow shock) can occasionally reach this high-Mach number astrophysical regime. In this regime Cassini has provided the first in situ evidence for electron acceleration under quasi-parallel upstream magnetic conditions. Here we present the full picture of suprathermal electrons at Saturn's bow shock revealed by Cassini . The downstream thermal electron distribution is resolved in all data taken by the low-energy electron detector (CAPS-ELS, <28 keV) during shock crossings, but the higher energy channels were at (or close to) background. The high-energy electron detector (MIMI-LEMMS, >18 keV) measured a suprathermal electron signature at 31 of 508 crossings, where typically only the lowest energy channels (<100 keV) were above background. We show that these results are consistent with the theory in which the “injection” of thermal electrons into an acceleration process involves interaction with whistler waves at the shock front, and becomes possible for all upstream magnetic field orientations at high Mach numbers like those of the strong shocks around young SNRs. A future dedicated study will analyze the rare crossings with evidence for relativistic electrons (up to ∼1 MeV).

  5. Interstellar Organics, the Solar Nebula, and Saturn's Satellite Phoebe

    Science.gov (United States)

    Pendleton, Y. J.; Cruikshank, D. P.

    2014-01-01

    The diffuse interstellar medium inventory of organic material (Pendleton et al. 1994, Pendleton & Allamandola 2002) was likely incorporated into the molecular cloud in which the solar nebula condensed. This provided the feedstock for the formation of the Sun, major planets, and the smaller icy bodies in the region outside Neptune's orbit (transneptunian objects, or TNOs). Saturn's satellites Phoebe, Iapetus, and Hyperion open a window to the composition of one class of TNO as revealed by the near-infrared mapping spectrometer (VIMS) on the Cassini spacecraft at Saturn. Phoebe (mean diameter 213 km) is a former TNO now orbiting Saurn. VIMS spaectral maps of PHoebe's surface reveal a complex organic spectral signature consisting of prominent aromatic (CH) and alophatic hydrocarbon (CH2, CH3) absorption bands (3.2-3.6 micrometers). Phoebe is the source of a huge debris ring encircling Saturn, and from which particles (approximately 5-20 micrometer size) spiral inward toward Saturn. They encounter Iapetus and Hperion where they mix with and blanket the native H2O ice of those two bodies. Quantitative analysis of the hydrocarbon bands on Iapetus demonstrates that aromatic CH is approximately 10 times as abundant as aliphatic CH2+CH3, significantly exceeding the strength of the aromatic signature in interplanetary dust particles, comet particles, ad in carbonaceous meteorites (Cruikshank et al. 2013). A similar excess of aromatics over aliphatics is seen in the qualitative analysis of Hyperion and Phoebe itself (Dalle Ore et al. 2012). The Iapetus aliphatic hydrocarbons show CH2/CH3 approximately 4, which is larger than the value found in the diffuse ISM (approximately 2-2.5). In so far as Phoebe is a primitive body that formed in the outer regions of the solar nebula and has preserved some of the original nebula inventory, it can be key to understanding the content and degree of procesing of the nebular material. There are other Phoebe-like TNOs that are presently

  6. Galaxies and Saturn's rings: Gravitational analogues of nonneutral plasmas

    International Nuclear Information System (INIS)

    Mark, J.W.K.

    1985-01-01

    Orbit and collective dynamics in disk galaxies and in Saturn's rings are gravitational analogues of those occurring in nonneutral plasmas. The interesting problems for such ''gravitational plasmas'' are analogous to single-disk studies of transverse dynamics in particle beams. Of particular interest are various orbit-resonances with spiral density and bending waves in these disks which are analogous to electrostatic waves in nonneutral beam plasmas. The background physics, terminology and results of astrophysical investigations in these fields are surveyed in this paper. 53 refs., 19 figs., 1 tab

  7. First Observation of Lion Roar Emission in Saturn's Magnetosheath

    Czech Academy of Sciences Publication Activity Database

    Píša, David; Sulaiman, A. H.; Santolík, Ondřej; Hospodarsky, G. B.; Kurth, W. S.; Gurnett, D. A.

    2018-01-01

    Roč. 45, č. 2 (2018), s. 486-492 ISSN 0094-8276 R&D Projects: GA ČR GA17-08772S; GA ČR GJ16-16050Y Grant - others:AV ČR(CZ) AP1401 Program:Akademická prémie - Praemium Academiae Institutional support: RVO:68378289 Keywords : Cassini spacecraft * Magnetosheath * Saturn * lion roar emissions * bow shock * propagation * particle * plasma * waves Subject RIV: BL - Plasma and Gas Discharge Physics OBOR OECD: Fluids and plasma physics (including surface physics ) Impact factor: 4.253, year: 2016 http://onlinelibrary.wiley.com/doi/10.1002/2017GL075919/abstract

  8. Hydrogen-Helium shock Radiation tests for Saturn Entry Probes

    Science.gov (United States)

    Cruden, Brett A.

    2016-01-01

    This paper describes the measurement of shock layer radiation in Hydrogen/Helium mixtures representative of that encountered by probes entering the Saturn atmosphere. Normal shock waves are measured in Hydrogen-Helium mixtures (89:11% by volume) at freestream pressures between 13-66 Pa (0.1-0.5 Torr) and velocities from 20-30 km/s. Radiance is quantified from the Vacuum Ultraviolet through Near Infrared. An induction time of several centimeters is observed where electron density and radiance remain well below equilibrium. Radiance is observed in front of the shock layer, the characteristics of which match the expected diffusion length of Hydrogen.

  9. JANNAF Lessons Learned Panel: Selected Saturn V History

    Science.gov (United States)

    Urquhart, Skip

    2010-01-01

    Pogo occurs when the natural frequency of a propellant feed line comes close to a readily excited rocket longitudinal structural vibration natural frequency. Maximum Pogo response corresponds to close tuning of the structural and hydraulic frequencies. On Saturn V, accelerations up to 17 g's (Zero To Peak) at the Launch Vehicle/Payload Interface and up to 34 g's at an Engine have been observed. Nicknamed Pogo because it causes the Rocket to stretch and compress like a Pogo stick. First recognized with the Titan II in 1962, Pogo remains a prime consideration in design of launch vehicles today

  10. Scientific Value of a Saturn Atmospheric Probe Mission

    Science.gov (United States)

    Simon-Miller, A. A.; Lunine, J. I.; Atreya, S. K.; Spilker, T. R.; Coustenis, A.; Atkinson, D. H.

    2012-01-01

    Atmospheric entry probe mISSions to the giant planets can uniquely discriminate between competing theories of solar system formation and the origin and evolution of the giant planets and their atmospheres. This provides for important comparative studies of the gas and ice giants, and to provide a laboratory for studying the atmospheric chemistries, dynamics, and interiors of all the planets including Earth. The giant planets also represent a valuable link to extrasolar planetary systems. As outlined in the recent Planetary Decadal Survey, a Saturn Probe mission - with a shallow probe - ranks as a high priority for a New Frontiers class mission [1].

  11. The isolated non-circular ringlets of Saturn

    International Nuclear Information System (INIS)

    Hill, J.R.; Mendis, D.A.

    1982-01-01

    It is shown that the combined effect of electrodynamic and gravitational forces can account for a number of features observed by Voyagers 1 and 2 in the isolated fine dust rings of Saturn. These include (a) the appearance and disappearance of the braids in the F-ring, (b) the eccentricities of the F-ring and the ringlets within the Encke and Cassine divisions and a gap in the C-ring, and (c) the kinks in the eccentric Encke ring. They may also account for the very existence of these rings. (Auth.)

  12. Hyperion II: a heavy ion pre-injector for Saturne

    International Nuclear Information System (INIS)

    Olivier, M.; Auclair, J.P.; Courtois, A.

    1983-01-01

    Since 1978, the 3GeV synchrotron Saturne is routinely operated with proton, deuteron, helium beams and, since 1981 with polarized protons and deuterons. Heavy ions are expected in 1983 by using a new pre-injector presently under construction. The marriage of an EBIS and an RFQ can be looked upon generally as a very good means of production of heavy ion beams at low energy. In the first paragraph, the cryogenic version of EBIS, called CRYEBIS, is described, while the RFQ design is studied in detail in paragraph two. The construction status is given in a third paragraph

  13. The Pole Orientation, Pole Precession, and Moment of Inertia Factor of Saturn

    Science.gov (United States)

    Jacobson, R. A.; French, R. G.; Nicholson, P. D.; Hedman, M.; Colwell, J. E.; Marouf, E.; Rappaport, N.; McGhee, C.; Sepersky, T.; Lonergan, K.

    2011-01-01

    This paper discusses our determination of the Saturn's pole orientation and precession using a combination of Earthbased and spacecraft based observational data. From our model of the polar motion and the observed precession rate we obtain a value for Saturn's polar moment of inertia

  14. Seasonal variation of the radial brightness contrast of Saturn's rings viewed in mid-infrared by Subaru/COMICS

    Science.gov (United States)

    Fujiwara, Hideaki; Morishima, Ryuji; Fujiyoshi, Takuya; Yamashita, Takuya

    2017-03-01

    Aims: This paper investigates the mid-infrared (MIR) characteristics of Saturn's rings. Methods: We collected and analyzed MIR high spatial resolution images of Saturn's rings obtained in January 2008 and April 2005 with the COoled Mid-Infrared Camera and Spectrometer (COMICS) mounted on the Subaru Telescope, and investigated the spatial variation in the surface brightness of the rings in multiple bands in the MIR. We also composed the spectral energy distributions (SEDs) of the C, B, and A rings and the Cassini Division, and estimated the temperatures of the rings from the SEDs assuming the optical depths. Results: We found that the C ring and the Cassini Division were warmer than the B and A rings in 2008, which could be accounted for by their lower albedos, lower optical depths, and smaller self-shadowing effect. We also fonud that the C ring and the Cassini Division were considerably brighter than the B and A rings in the MIR in 2008 and the radial contrast of the ring brightness is the inverse of that in 2005, which is interpreted as a result of a seasonal effect with changing elevations of the Sun and observer above the ring plane. The reduced images (FITS files) are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (http://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/599/A29

  15. Elusive Ethylene Detected in Saturns Northern Storm Region

    Science.gov (United States)

    Hesman, B. E.; Bjoraker, G. L.; Sada, P. V.; Achterberg, R. K.; Jennings, D. E.; Romani, P. N.; Lunsford, A. W.; Fletcher, L. N.; Boyle, R. J.; Simon-Miller, A. A.; hide

    2013-01-01

    The massive eruption at 40 deg. N (planetographic latitude) on Saturn in 2010 December has produced significant and lasting effects in the northern hemisphere on temperature and species abundances. The northern storm region was observed on many occasions in 2011 by Cassini's Composite Infrared Spectrometer (CIRS). In 2011 May, temperatures in the stratosphere greater than 200 K were derived from CIRS spectra in the regions referred to as "beacons" (warm regions in the stratosphere). Ethylene has been detected in the beacon region in Saturn's northern storm region using CIRS. Ground-based observations using the high-resolution spectrometer Celeste on the McMath-Pierce Telescope on 2011 May 15 were used to confirm the detection and improve the altitude resolution in the retrieved profile. The derived ethylene profile from the CIRS data gives a C2H4 mole fraction of 5.9 +/- 4.5 x 10(exp -7) at 0.5 mbar, and from Celeste data it gives 2.7 +/- 0.45 x 10(exp -6) at 0.1 mbar. This is two orders of magnitude higher than the amount measured in the ultraviolet at other latitudes prior to the storm. It is also much higher than predicted by photochemical models, indicating that perhaps another production mechanism is required or a loss mechanism is being inhibited.

  16. Predicted radiation environment of the Saturn baseline diode

    International Nuclear Information System (INIS)

    Halbleib, J.A.; Lee, J.R.

    1987-09-01

    Coupled electron/photon Monte Carlo radiation transport was used to predict the radiation environment of the Saturn accelerator for the baseline diode design. The x-ray output has been calculated, as well as energy deposition in CaF 2 thermoluminescent dosimetry and silicon. It is found that the design criteria for the radiation environment will be met and that approximately 10 kJ of x rays will be available for simulation experiments, if the diode provides a nominal beam of 2.0-MeV electrons for 20 ns with a peak current of 12.5 MA. The penalty in dose and x-ray output for operating below the nominal energy in order to obtain a softer spectrum is quantified. The penalty for using excessive electron equilibration in the standard packaging of the thermoluminescent dosimeters is shown to be negligible. An intrinsic lack of electron equilibration for silicon elements of components and subsystems is verified for Saturn environments, demonstrating the ambiguity of design criteria based on silicon deposition. Validation of an efficient next-event-estimator method for predicting energy deposition in equilibrated detectors/dosimetry is confirmed. Finally, direct-electron depositions in excess of 1 kJ/g are shown to be easily achievable. 34 refs., 30 figs

  17. Developments of STIM, the Saturn Thermosphere Ionosphere Model

    Science.gov (United States)

    Aylward, A. D.; Smith, C. G.; Miller, S.; Millward, G.

    2005-05-01

    The STIM (Saturn Thermosphere Ionosphere Model) model is a joint venture betwen University College London, Imperial College London, Boston University and the University of Arizona to develop a 3-d global circulation model of the Saturnian system - the primary aim being to use this as a tool for interpretation and testing of Cassini data. After initial work producing a basic thermosphere model (Muller-Wodarg et al 2005), examining issues to do with the ionosphere (Moore et al 2005) and examining auroral heating effects (Smith et al 2005), a global coupled ionosphere-plasmasphere has been added to the model. At low latitudes the model calculates ion densities on closed flux tubes passing through the ring plane. At high latitudes it performs self-consistent calculations of Joule heating and ion drag based on the calculated thermospheric and ionospheric parameters. The plasmasphere is complicated for Saturn by the strength of the centrifugal force which can dominate the forces in the outer flux tubes. Studies initially used H+ and H3+ as the principle ions but for the future it will be necessary to look at the consequences of the rings supplying OH or oxygen from ring ice particles. The high-latitude morphology is being refined as Cassini data constrains it. Long-term plans for the STIM development will be discussed.

  18. IMF dependence of the open-closed field line boundary in Saturn's ionosphere, and its relation to the UV auroral oval observed by the Hubble Space Telescope

    Directory of Open Access Journals (Sweden)

    E. S. Belenkaya

    2007-06-01

    Full Text Available We study the dependence of Saturn's magnetospheric magnetic field structure on the interplanetary magnetic field (IMF, together with the corresponding variations of the open-closed field line boundary in the ionosphere. Specifically we investigate the interval from 8 to 30 January 2004, when UV images of Saturn's southern aurora were obtained by the Hubble Space Telescope (HST, and simultaneous interplanetary measurements were provided by the Cassini spacecraft located near the ecliptic ~0.2 AU upstream of Saturn and ~0.5 AU off the planet-Sun line towards dawn. Using the paraboloid model of Saturn's magnetosphere, we calculate the magnetospheric magnetic field structure for several values of the IMF vector representative of interplanetary compression regions. Variations in the magnetic structure lead to different shapes and areas of the open field line region in the ionosphere. Comparison with the HST auroral images shows that the area of the computed open flux region is generally comparable to that enclosed by the auroral oval, and sometimes agrees in detail with its poleward boundary, though more typically being displaced by a few degrees in the tailward direction.

  19. Cloud and Wind Variability in Saturn's Equatorial Jet prior to the Cassini orbital tour

    Science.gov (United States)

    Sánchez-Lavega, A.; Pérez-Hoyos, S.; Hueso, R.; Rojas, J. F.; French, R. G.

    2004-11-01

    We use ground-based observations (going back to 1876), Pioneer-11 data (1979), Voyager 1 and 2 encounter images in 1980 and 1981, and HST 1990-2004 images, to study the changes that occurred in the vertical cloud structure and morphology and motions, in Saturn's Equatorial Region (approximately the band between latitudes 40 deg North and South). We compare ``calm periods" with ``stormy periods" i. e. those that occur during the development of the phenomenon known as the ``Great White Spots." We discuss different interpretations of the mechanisms that can be involved in the observed changes: vertical wind shears, waves, storm - mean flow interaction and changes in atmospheric angular momentum. Acknowledgements: This work was supported by the Spanish MCYT AYA 2003-03216. SPH acknowledges a PhD fellowship from the Spanish MECD and RH a post-doc fellowship from Gobierno Vasco. RGF was supported in part by NASA's Planetary Geology and Geophysics Program NAG5-10197 and STSCI Grant GO-08660.01A.

  20. Near equality of ion phase space densities at earth, Jupiter, and Saturn

    Science.gov (United States)

    Cheng, A. F.; Krimigis, S. M.; Armstrong, T. P.

    1985-01-01

    Energetic-ion phase-space density profiles are strikingly similar in the inner magnetospheres of earth, Jupiter, and Saturn for ions of first adiabatic invariant near 100 MeV/G and small mirror latitudes. Losses occur inside L approximately equal to 7 for Jupiter and Saturn and inside L approximately equal to 5 at earth. At these L values there exist steep plasma-density gradients at all three planets, associated with the Io plasma torus at Jupiter, the Rhea-Dione-Tethys torus at Saturn, and the plasmasphere at earth. Measurements of ion flux-tube contents at Jupiter and Saturn by the low-energy charged-particle experiment show that these are similar (for O ions at L = 5-9) to those at earth (for protons at L = 2-6). Furthermore, the thermal-ion flux-tube contents from Voyager plasma-science data at Jupiter and Saturn are also very nearly equal, and again similar to those at earth, differing by less than a factor of 3 at the respective L values. The near equality of energetic and thermal ion flux-tube contents at earth, Jupiter, and Saturn suggests the possibility of strong physical analogies in the interaction between plasma and energetic particles at the plasma tori/plasma sheets of Jupiter and Saturn and the plasmasphere of earth.

  1. The evolution of Saturn's radiation belts modulated by changes in radial diffusion

    Science.gov (United States)

    Kollmann, P.; Roussos, E.; Kotova, A.; Paranicas, C.; Krupp, N.

    2017-12-01

    Globally magnetized planets, such as the Earth1 and Saturn2, are surrounded by radiation belts of protons and electrons with kinetic energies well into the million electronvolt range. The Earth's proton belt is supplied locally from galactic cosmic rays interacting with the atmosphere3, as well as from slow inward radial transport4. Its intensity shows a relationship with the solar cycle4,5 and abrupt dropouts due to geomagnetic storms6,7. Saturn's proton belts are simpler than the Earth's because cosmic rays are the principal source of energetic protons8 with virtually no contribution from inward transport, and these belts can therefore act as a prototype to understand more complex radiation belts. However, the time dependence of Saturn's proton belts had not been observed over sufficiently long timescales to test the driving mechanisms unambiguously. Here we analyse the evolution of Saturn's proton belts over a solar cycle using in-situ measurements from the Cassini Saturn orbiter and a numerical model. We find that the intensity in Saturn's proton radiation belts usually rises over time, interrupted by periods that last over a year for which the intensity is gradually dropping. These observations are inconsistent with predictions based on a modulation in the cosmic-ray source, as could be expected4,9 based on the evolution of the Earth's proton belts. We demonstrate that Saturn's intensity dropouts result instead from losses due to abrupt changes in magnetospheric radial diffusion.

  2. Statistical eclipses of close-in Kepler sub-Saturns

    Energy Technology Data Exchange (ETDEWEB)

    Sheets, Holly A.; Deming, Drake, E-mail: hsheets@astro.umd.edu [Department of Astronomy, University of Maryland, College Park, MD 20742-2421 (United States)

    2014-10-20

    We present a method to detect small atmospheric signals in Kepler's planet candidate light curves by averaging light curves for multiple candidates with similar orbital and physical characteristics. Our statistical method allows us to measure unbiased physical properties of Kepler's planet candidates, even for candidates whose individual signal-to-noise precludes the detection of their secondary eclipse. We detect a secondary eclipse depth of 3.83{sub −1.11}{sup +1.10} ppm for a group of 31 sub-Saturn (R < 6 R {sub ⊕}) planet candidates with the greatest potential for a reflected light signature ((R{sub p} /a){sup 2} > 10 ppm). Including Kepler-10b in this group increases the depth to 5.08{sub −0.72}{sup +0.71} ppm. For a control group with (R{sub p} /a){sup 2} < 1 ppm, we find a depth of 0.36 ± 0.37 ppm, consistent with no detection. We also analyze the light curve of Kepler-10b and find an eclipse depth of 7.08 ± 1.06 ppm. If the eclipses are due solely to reflected light, this corresponds to a geometric albedo of 0.22 ± 0.06 for our group of close-in sub-Saturns, 0.37 ± 0.05 if including Kepler-10b in the group, and 0.60 ± 0.09 for Kepler-10b alone. Including a thermal emission model does not change the geometric albedo appreciably, assuming A{sub B} = (3/2)*A{sub g} . Our result for Kepler-10b is consistent with previous works. Our result for close-in sub-Saturns shows that Kepler-10b is unusually reflective, but our analysis is consistent with the results of Demory for super-Earths. Our results also indicate that hot Neptunes are typically more reflective than hot Jupiters.

  3. The Hera Saturn Entry Probe Mission: a Proposal in Response to the ESA M5 Call

    Science.gov (United States)

    Mousis, Olivier; Atkinson, David; Amato, Michael; Aslam, Shahid; Atreya, Sushil; Blanc, Michel; Bolton, Scott; Brugger, Bastien; Calcutt, Simon; Cavalié, Thibault; Charnoz, Sébastien; Coustenis, Athena; Deleuil, Magali; Dobrijevic, Michel; Ferri, Francesca; Fletcher, Leigh; Gautier, Daniel; Guillot, Tristan; Hartogh, Paul; Holland, Andrew

    2017-04-01

    The Hera Saturn entry probe mission is proposed as an ESA M-class mission to be piggybacked on a NASA spacecraft sent to or past the Saturn system. Hera consists of an atmospheric probe built by ESA and released into the atmosphere of Saturn by its NASA companion Saturn Carrier-Relay spacecraft. Hera will perform in situ measurements of the chemical and isotopic composition as well as the structure and dynamics of Saturn's atmosphere using a single probe, with the goal of improving our understanding of the origin, formation, and evolution of Saturn, the giant planets and their satellite systems, with extrapolation to extrasolar planets. Hera will probe well into and possibly beneath the cloud-forming region of the troposphere, below the region accessible to remote sensing, to locations where certain cosmogenically abundant species are expected to be well mixed. The Hera probe will be designed from ESA elements with possible contributions from NASA, and the Saturn/Carrier-Relay Spacecraft will be supplied by NASA through its selection via the New Frontier 2016 call or in the form of a flagship mission selected by the NASA "Roadmaps to Ocean Worlds" (ROW) program. The Hera probe will be powered by batteries, and we therefore anticipate only one major subsystems to be possibly supplied by the United States, either by direct procurement by ESA or by contribution from NASA: the thermal protection system of the probe. Following the highly successful example of the Cassini-Huygens mission, Hera will carry European and American instruments, with scientists and engineers from both agencies and many affiliates participating in all aspects of mission development and implementation. A Saturn probe is one of the six identified desired themes by the Planetary Science Decadal Survey committee on the NASA New Frontier's list, providing additional indication that a Saturn probe is of extremely high interest and a very high priority for the international community.

  4. Saturn V Second Stage (S-II) Ready for Static Test

    Science.gov (United States)

    1965-01-01

    Two workers are dwarfed by the five J-2 engines of the Saturn V second stage (S-II) as they make final inspections prior to a static test firing by North American Space Division. These five hydrogen -fueled engines produced one million pounds of thrust, and placed the Apollo spacecraft into earth orbit before departing for the moon. The towering 363-foot Saturn V was a multi-stage, multi-engine launch vehicle standing taller than the Statue of Liberty. Altogether, the Saturn V engines produced as much power as 85 Hoover Dams.

  5. Study and realisation of cabled interfaces for the control and command of the Saturne cyclotron

    International Nuclear Information System (INIS)

    Devailly, Jean

    1975-01-01

    This research thesis addressed the assessment of needs, design and realisation of some hardware used by the Saturne cyclotron to solve problems of command and control while using connections developed for the Saturne's computer. After some generalities (description of Saturne, requirements and constraints, general statements about acquisitions and commands, selection of the acquisition and command system, codes), the author presents the different hardware for analog acquisitions, digital acquisitions, analog commands, digital commands, all-or-none control, simulators, amplifiers and memories. He reports some examples: magnetic measurements, control of ejection currents, programs. He finally presents the developed hardware

  6. Works about the Saturne synchrotron during the third quarter 1961

    International Nuclear Information System (INIS)

    1961-11-01

    This report first gives an overview of works performed by the Saturne maintenance and operation department (works on magnet supply rectifiers, vessel inspection and detected defects and corrective measures), of the annual maintenance (dismounting, cleaning and control of different elements, installation of new components), of works and adjustments performed on the machine, and of miscellaneous studies (dynamic filtering of the magnetic field, target propellers). The next part briefly reports the various works performed by the department of maintenance and development physics apparatuses: works performed in the hall, underground measurement rooms, building extension, protection of the control room. It also presents newly installed equipment: particle selector, electric supply device, cooling. The third part indicates subcontracted scientific and industrial activities

  7. Analysis of Electric Propulsion System for Exploration of Saturn

    Directory of Open Access Journals (Sweden)

    Carlos Renato Huaura Solórzano

    2009-01-01

    Full Text Available Exploration of the outer planets has experienced new interest with the launch of the Cassini and the New Horizons Missions. At the present time, new technologies are under study for the better use of electric propulsion system in deep space missions. In the present paper, the method of the transporting trajectory is used to study this problem. This approximated method for the flight optimization with power-limited low thrust is based on the linearization of the motion of a spacecraft near a keplerian orbit that is close to the transfer trajectory. With the goal of maximizing the mass to be delivered in Saturn, several transfers were studied using nuclear, radioisotopic and solar electric propulsion systems.

  8. Saturn's polar ionospheric flows and their relation to the main auroral oval

    Directory of Open Access Journals (Sweden)

    S. W. H. Cowley

    2004-04-01

    current bounding the region of open and closed field lines. Estimates indicate that auroras of brightness from a few kR to a few tens of kR can be produced by precipitating accelerated magnetospheric electrons of a few keV to a few tens of keV energy, if the current flows in a region which is sufficiently narrow, of the order of or less than ~1000 km (~1° latitude wide. Arguments are also given which indicate that the auroras should typically be significantly brighter on the dawn side of the oval than at dusk, by roughly an order of magnitude, and should be displaced somewhat towards dawn by the down-tail outflow at dusk associated with the Vasyliunas cycle. Model estimates are found to be in good agreement with data derived from high quality images newly obtained using the Space Telescope Imaging Spectrograph on the Hubble Space Telescope, both in regard to physical parameters, as well as local time effects. The implication of this picture is that the form, position, and brightness of Saturn's main auroral oval provide remote diagnostics of the magnetospheric interaction with the solar wind, including dynamics associated with magnetopause and tail plasma interaction processes. Key words. Magnetospheric physics (auroral phenomena, magnetosphere-ionosphere interactions, solar windmagnetosphere interactions

  9. Saturn's polar ionospheric flows and their relation to the main auroral oval

    Directory of Open Access Journals (Sweden)

    S. W. H. Cowley

    2004-04-01

    upward current bounding the region of open and closed field lines. Estimates indicate that auroras of brightness from a few kR to a few tens of kR can be produced by precipitating accelerated magnetospheric electrons of a few keV to a few tens of keV energy, if the current flows in a region which is sufficiently narrow, of the order of or less than ~1000 km (~1° latitude wide. Arguments are also given which indicate that the auroras should typically be significantly brighter on the dawn side of the oval than at dusk, by roughly an order of magnitude, and should be displaced somewhat towards dawn by the down-tail outflow at dusk associated with the Vasyliunas cycle. Model estimates are found to be in good agreement with data derived from high quality images newly obtained using the Space Telescope Imaging Spectrograph on the Hubble Space Telescope, both in regard to physical parameters, as well as local time effects. The implication of this picture is that the form, position, and brightness of Saturn's main auroral oval provide remote diagnostics of the magnetospheric interaction with the solar wind, including dynamics associated with magnetopause and tail plasma interaction processes.

    Key words. Magnetospheric physics (auroral phenomena, magnetosphere-ionosphere interactions, solar windmagnetosphere interactions

  10. Lightning-produced Carbon Species in the Atmosphere of Saturn

    Science.gov (United States)

    Delitsky, Mona; Baines, K. H.

    2010-10-01

    Recent studies by Baines et al (2009) indicate that thunderstorm-associated clouds on Saturn are spectrally dark from 0.7 to 4 um, darker than regular clouds. This darkening is found to be consistent with the presence of particles of elemental carbon, such as in the form of soot particles mixed in with spectrally bright condensates. This carbon is thought to be generated by lightning-induced dissociation of methane. Lightning on Saturn will input large amounts of energy to a narrow column of atmosphere and generate products at high energies such as radicals and ions. After the column cools down, the new chemical species recombine and are frozen into a new chemical equilibrium. Experimental studies in the literature of reactions of methane and other gases in plasma discharges (which simulate lightning) indicate that, even with high ratios of hydrogen/methane, the elemental carbon obtained will form solid dark particles that persist and have a very high C/H ratio. Basically, they are mostly pure carbon, in the form of soot, amorphous carbon, graphite, graphene, polycyclic aromatic hydrocarbons, carbon black, carbon onions, etc. Hydrogen will act as a sealant onto the particles and attach to dangling bonds on their growing surfaces. Even in experiments to form the most crystalline allotrope of carbon, that is, diamond, the presence of hydrogen does not inhibit diamond formation, even at the low pressures in the atmospheres of the Jovian planets or in the interstellar medium (Allamandola et al 1991). Therefore, some form of elemental carbon is likely produced in Saturnian storm clouds and may occur as dark particles of either amorphous carbon, PAHs or crystalline carbon in a form such as graphite. ..Refs: Baines et al., PSS 57, 1650-1658 (2009) ; Allamandola et al., Meteoritics 26, 313 (1991).

  11. Stochastic orbital migration of small bodies in Saturn's rings

    Science.gov (United States)

    Rein, H.; Papaloizou, J. C. B.

    2010-12-01

    Many small moonlets that create propeller structures have been found in Saturn's rings by the Cassini spacecraft. We study the dynamical evolution of such 20-50 m sized bodies, which are embedded in Saturn's rings. We estimate the importance of various interaction processes with the ring particles on the moonlet's eccentricity and semi-major axis analytically. For low ring surface densities, the main effects on the evolution of the eccentricity and the semi-major axis are found to be caused by collisions and the gravitational interaction with particles in the vicinity of the moonlet. For high surface densities, the gravitational interaction with self-gravity wakes becomes important. We also perform realistic three-dimensional, collisional N-body simulations with up to a quarter of a million particles. A new set of pseudo shear periodic boundary conditions is used, which reduces the computational costs by an order of magnitude compared to previous studies. Our analytic estimates are confirmed to within a factor of two. On short timescales the evolution is always dominated by stochastic effects caused by collisions and gravitational interaction with self-gravitating ring particles. These result in a random walk of the moonlet's semi-major axis. The eccentricity of the moonlet quickly reaches an equilibrium value owing to collisional damping. The average change in semi-major axis of the moonlet after 100 orbital periods is 10-100m. This translates to an offset in the azimuthal direction of several hundred kilometres. We expect that such a shift is easily observable. Two movies are only available in electronic form at http://www.aanda.org

  12. Waves in Saturn's rings probed by radio occultation

    International Nuclear Information System (INIS)

    Rosen, P.A.

    1989-01-01

    Thirty wave features, observed in 3.6 and 13 cm-wavelength optical depth profiles of Saturn's rings obtained by Voyager 1 radio occultation, are analyzed individually and comparatively. Many are the signature of spiral density waves and bending waves excited by gravitational resonances with Saturn's satellites. A new technique for locating waveform extrema, which fits a sinusoid to each half cycle of wave data, quantifies the wavelength variation across a feature. Fitting dispersion models to the derived wavelengths provides new estimates of ambient surface mass density σ in each wave region. For fourteen weak density waves in Ring A, modelling of the waveform near resonance with linear density wave theory gives independent estimates of σ, as well as reliable estimates of resonance location. Measurements of wave amplitude damping give an upper bound for ring thickness 2H, where H is the ring scale height. In the wave regions studied, Rings A, B, and C have 30 approx-lt σ approx-lt 70, σ approx-gt 65, and σ ∼ 1 g/cm 2 , respectively. Mass loading estimates from waveform modelling are 20 to 40% larger than dispersion-derived values, suggesting accumulation of mass in the wave regions. The average offset of derived wave location from theoretical resonance is about 1 km. Model waveforms of overlapping waves excited by the satellites Janus and Epimethenus agree well with observed morphologies in the linear region near resonance. In Ring C, dispersion analysis indicates that the most prominent wave feature, previously unidentified, is a one-armed spiral wave

  13. The Plasma Proton Environment within Saturn's inner magnetosphere as Observed by the Cassini Plasma Spectrometer (CAPS) during Saturn Orbit Insertion

    Science.gov (United States)

    Sittler, E. C., Jr.; Elrod, M. K.; Johnson, R. E.; Cooper, J. F.; Tseng, W. L.; Smith, H. T.; Chornay, D. J.; Shappirio, M.; Simpson, D. G.

    2017-12-01

    In analyzing the Cassini data between Saturn's A-ring outer edge and Mimas' L shell numerous inconsistencies have been reported in estimates of total ionic charge and electron density. The primary focus of our work is to understand these inconsistencies. We present our recent discovery of plasma protons during Saturn Orbit Insertion (SOI) outbound pass of the magnetospheric region between the F and G rings. We also searched for H2+ ions but no such events were found. The discovery of protons was made possible by a recent analysis of the CAPS Ion Mass Spectrometer's (IMS's) time-of-flight (TOF) composition data in a mode of reduced post-acceleration voltage at 6 kV instead of the usual 14.6 kV. All previous work for this region had not considered the TOF data. The new proton analysis was enabled by minimum scattering of 6 kV protons in the instrument's ultrathin carbon foils (CF), in comparison to larger scattering for the heavier ions such as for O+ and O2+. We use a SIMION model of the CAPS IMS including the effects of energy straggling and scattering by the instrument's CFs in an attempt to understand the TOF composition data for the heavier ions. This analysis within the uncertainties of the instrument allows us to estimate the relative abundances of the heavier ions and thus run our 2D velocity ion moments code to get ion densities, temperatures and velocities during the SOI outbound pass through the F-ring and G-ring gap. Comparisons with other data sets will be made.

  14. Analysis of the structure of Saturn's magnetic field using charged particle absorption signatures

    International Nuclear Information System (INIS)

    Chenette, D.L.; Davis, L. Jr.

    1982-01-01

    A new technique is derived for determining the structure of Saturn's magnetic field. This technique uses the observed positions of charged particle absorption signatures due to the satellites and rings of Saturn to determine the parameters of an axially symmetric, spherical harmonic model of the magnetic field using the method of least squares. Absorption signatures observed along the Pioneer 11, Voyager 1, and Voyager 2 spacecraft trajectories are used to derive values for the orientation of the magnetic symmetry axis relative to Saturn's axis of rotation, the axial displacement of the center of the magnetic dipole from the center of Saturn, and the magnitude of the external field component. Comparing these results with the magnetic field model parameters deduced from analyses of magnetometer data leads us to prefer models that incorporate a northward offset of the dipole center by about 0.05 R/sub s/

  15. Magnetic field orientations in Saturn's upper ionosphere inferred from Voyager radio occultations

    Science.gov (United States)

    Hinson, D. P.

    1984-01-01

    The radio scintillations observed during occultations of Voyagers 1 and 2 by Saturn are analyzed to determine the morphology of plasma irregularities and hence the magnetic field orientation in Saturn's upper atmosphere. The measurement techniques, the weak scattering theory, and the method used to relate the observed radio scintillations to physical properties of the ionospheric irregularities are briefly described. Results on the spatial characteristics of the irregularities are presented, and the magnetic field orientation in Saturn's ionosphere is inferred. Although the occultation measurements generally confirm the accuracy of the Saturnian magnetic field model of Connerney et al. (1982), it is found that a small adjustment of the coefficients in that model's zonal harmonic expansion would remove the discrepancy between the model predictions and the measurements. A strategy for obtaining improved measurements of Saturn's magnetic field from radio occultation observations of scintillations and Faraday rotation using an orbiting spacecraft is briefly discussed.

  16. Cassini Attitude and Articulation Control Subsystem Fault Protection Challenges During Saturn Proximal Orbits

    Science.gov (United States)

    Bates, David M.

    2015-01-01

    NASA's Cassini Spacecraft, launched on October 15th, 1997 arrived at Saturn on June 30th, 2004, is the largest and most ambitious interplanetary spacecraft in history. As the first spacecraft to achieve orbit at Saturn, Cassini has collected science data throughout its four-year prime mission (2004-08), and has since been approved for a first and second extended mission through 2017. As part of the final extended mission, Cassini will begin an aggressive and exciting campaign of high inclination low altitude flybys within the inner most rings of Saturn, skimming Saturn's outer atmosphere, until the spacecraft is finally disposed of via planned impact with the planet. This final campaign, known as the proximal orbits, presents unique fault protection related challenges, the details of which are discussed in this paper.

  17. Atmospheric structure and helium abundance on Saturn from Cassini/UVIS and CIRS observations

    Science.gov (United States)

    Koskinen, T. T.; Guerlet, S.

    2018-06-01

    We combine measurements from stellar occultations observed by the Cassini Ultraviolet Imaging Spectrograph (UVIS) and limb scans observed by the Composite Infrared Spectrometer (CIRS) to create empirical atmospheric structure models for Saturn corresponding to the locations probed by the occultations. The results cover multiple locations at low to mid-latitudes between the spring of 2005 and the fall of 2015. We connect the temperature-pressure (T-P) profiles retrieved from the CIRS limb scans in the stratosphere to the T-P profiles in the thermosphere retrieved from the UVIS occultations. We calculate the altitudes corresponding to the pressure levels in each case based on our best fit composition model that includes H2, He, CH4 and upper limits on H. We match the altitude structure to the density profile in the thermosphere that is retrieved from the occultations. Our models depend on the abundance of helium and we derive a volume mixing ratio of 11 ± 2% for helium in the lower atmosphere based on a statistical analysis of the values derived for 32 different occultation locations. We also derive the mean temperature and methane profiles in the upper atmosphere and constrain their variability. Our results are consistent with enhanced heating at the polar auroral region and a dynamically active upper atmosphere.

  18. Spatially and temporally resolved EUV emissions from SATURN z-pinches

    International Nuclear Information System (INIS)

    Nash, T.J.; Breeze, S.; Mock, R.; Jobe, D.

    1995-01-01

    EUV emissions can be used to measure several z-pinch parameters. The authors have measured implosion velocity from Doppler splitting of lines and estimated electron temperature during run-in from the mean ionization state of line emissions. In an argon pinch they measure an electron temperature of 100 eV before stagnation. To date Doppler split lines have measured implosion velocities less than 40 cm/microsecond. They are presently attempting to measure magnetic field or load current from Zeeman splitting and it may be possible to measure electron density from a Stark-broadened line. Opacity and ion thermal broadening may also contribute to line width information. The spectrometer utilizes a variable line space grating to give a flat focal field. Spectral resolution with a 60 micron detector resolution is up to 3,000 and generally increases with wavelength. This is sufficient to detect several plasma line broadening mechanisms. The spectrometer may detect lines above 100 angstrom and below 1,400 angstrom. Spectral range across a microchannel plate stripline detector decreases with increasing wavelength setting. The authors may gate two striplines with 1 to 12 nsec gates at any time during the pinch discharge. Each stripline spatially images the pinch diameter perpendicular to the direction of dispersion. Spatial resolution in the pinch diameter is 1 mm. Spatial acquisition along the z axis is also 1 mm. Data are presented from argon, krypton, and aluminum z-pinch discharges on the SATURN accelerator

  19. The beam-kicker system of the synchrotron Saturne. Magnetic field and particle orbit computations. Experimental results (1963); Le percuteur de faisceau de Saturne. Calcul du champ magnetique et des trajectoires. Verifications experimentales (1963)

    Energy Technology Data Exchange (ETDEWEB)

    Gouttefangeas, M; Katz, A; Rastoix, G [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1963-07-01

    In this report is briefly described the beam-kicker system of the synchrotron Saturne. An analysis of its operation based on the sampling method is given, as well as two methods for computing toe magnetic field produced by a set of endless conductors in the neighbourhood of a conducting shield where eddy currents are circulating. The first method leads to the resolution of a bi-dimensional Laplace equation with first kind boundary conditions (Dirichlet problem); the second one translates to electromagnetism the electrical images method currently used in electrostatics and yields the magnetic field as the sum of a triple series expansion in the general case of a set of conductors located in a parallelepipedal box. Finally are given the results obtained in computing on IBM 7090 the perturbation of the particle motion due to the beam-kicker. These results are compared with the experimental data. (authors) [French] Ce rapport decrit brievement le dispositif percuteur de faisceau mis en place sur le synchrotron Saturne. On y trouvera une analyse de se fonctionnement a partir de la theorie des echantillonnages. On indique egalment deux methodes de calcul du champ magnetique produit par un system de conducteurs indefinis en presence d'un blindage conducteur parcouru par des courants de Foucault: la premiere se ramene a la resolution d'une equation de Laplace a deux dimensions avec des conditions aux limites de premiere espece (probleme de Dirichlet), la seconde transpose en electromagnetisme la methode des images electriques classique en electrostatique et permet d'exprimer le champ magnetique sous la forme de la somme d'une serie triple dans le cas general d'un systeme de conducteurs contenus dans un blindage parallelepipedique. Pour terminer, on mentionne les resultats du calcul numerique de la perturbation de la trajectoire des particules sous l'effet du percuteur et on compare ces resultats aux resultats experimentaux. (auteurs)

  20. H/He demixing and the cooling behavior of Saturn

    Science.gov (United States)

    Püstow, Robert; Nettelmann, Nadine; Lorenzen, Winfried; Redmer, Ronald

    2016-03-01

    The description of the interior structure and evolution of the Solar System giant planets continues to be a serious challenge. The most prominent example is Saturn for which simple homogeneous evolution models yield ages between 2 and 3 billion years (Gyr), i.e. much shorter than the age of the Solar System of τ⊙ = 4.56 Gyr. It has long been suggested that H/He demixing might occur in the interior of Saturn after the planet has cooled off sufficiently. This incident would mark the begin of an inhomogeneous evolution period in which He droplets sink down and accumulate above the planetary core. The corresponding release of gravitational energy contributes to the intrinsic luminosity of the planet, thereby prolonging its cooling time, perhaps towards the correct value. Such scenarios have been studied in the past on the basis of rather approximate assumptions for the H-He phase diagram. Recently, various ab initio simulations have revealed details of the H-He phase diagram but also of remaining uncertainties (Morales, M.A. et al. [2009]. Proc. Nat. Acad. Sci. USA 106, 1324; Morales, M.A. et al. [2013a]. Phys. Rev. B 87, 174105; Lorenzen, W. et al. [2011]. Phys. Rev. B 84, 235109). In this paper we use the new predictions by Lorenzen et al. and modifications thereof to study the inhomogeneous evolution period of Saturn, with resulting values for the onset of H/He phase separation ts , the cooling time τ , and the atmospheric helium abundance y1 . For the planetary interior during the inhomogeneous evolution we assume adiabatic, convective envelopes. We find ts = 1 Gyr, τ = 5.8 Gyr, and y1 = 0.18 , while ts ≊ 2 Gyr for the Morales et al. data, for which we also estimate τ ≈ 5.1 Gyr. On the other hand, reasonable cooling times τ ≈τ⊙ are obtained for shifts of the Lorenzen et al. phase diagram by respectively -1300 K and +500 K, yielding y1 = 0.22 and y1 = 0.06 . More accurate knowledge of H-He phase diagram is necessary to understand cool gas giant

  1. Deciphering the embedded wave in Saturn's Maxwell ringlet

    Science.gov (United States)

    French, Richard G.; Nicholson, Philip D.; Hedman, Mathew M.; Hahn, Joseph M.; McGhee-French, Colleen A.; Colwell, Joshua E.; Marouf, Essam A.; Rappaport, Nicole J.

    2016-11-01

    The eccentric Maxwell ringlet in Saturn's C ring is home to a prominent wavelike structure that varies strongly and systematically with true anomaly, as revealed by nearly a decade of high-SNR Cassini occultation observations. Using a simple linear "accordion" model to compensate for the compression and expansion of the ringlet and the wave, we derive a mean optical depth profile for the ringlet and a set of rescaled, background-subtracted radial wave profiles. We use wavelet analysis to identify the wave as a 2-armed trailing spiral, consistent with a density wave driven by an m = 2 outer Lindblad resonance (OLR), with a pattern speed Ωp = 1769.17° d-1 and a corresponding resonance radius ares = 87530.0 km. Estimates of the surface mass density of the Maxwell ringlet range from a mean value of 11g cm-2 derived from the self-gravity model to 5 - 12gcm-2 , as inferred from the wave's phase profile and a theoretical dispersion relation. The corresponding opacity is about 0.12 cm2 g-1, comparable to several plateaus in the outer C ring (Hedman, M.N., Nicholson, P.D. [2014]. Mont. Not. Roy. Astron. Soc. 444, 1369-1388). A linear density wave model using the derived wave phase profile nicely matches the wave's amplitude, wavelength, and phase in most of our observations, confirming the accuracy of the pattern speed and demonstrating the wave's coherence over a period of 8 years. However, the linear model fails to reproduce the narrow, spike-like structures that are prominent in the observed optical depth profiles. Using a symplectic N-body streamline-based dynamical code (Hahn, J.M., Spitale, J.N. [2013]. Astrophys. J. 772, 122), we simulate analogs of the Maxwell ringlet, modeled as an eccentric ringlet with an embedded wave driven by a fictitious satellite with an OLR located within the ring. The simulations reproduce many of the features of the actual observations, including strongly asymmetric peaks and troughs in the inward-propagating density wave. We argue that

  2. Rotation Rate of Saturn's Magnetosphere using CAPS Plasma Measurements

    Science.gov (United States)

    Sittler, E.; Cooper, J.; Simpson, D.; Paterson, W.

    2012-01-01

    We present the present status of an investigation of the rotation rate of Saturn 's magnetosphere using a 3D velocity moment technique being developed at Goddard which is similar to the 2D version used by Sittler et al. (2005) [1] for SOI and similar to that used by Thomsen et al. (2010). This technique allows one to nearly cover the full energy range of the CAPS IMS from 1 V less than or equal to E/Q less than 50 kV. Since our technique maps the observations into a local inertial frame, it does work during roll manoeuvres. We have made comparisons with Wilson et al. (2008) [2] (2005-358 and 2005-284) who performs a bi-Maxwellian fit to the ion singles data and our results are nearly identical. We will also make comparisons with results by Thomsen et al. (2010) [3]. Our analysis uses ion composition data to weight the non-compositional data, referred to as singles data, to separate H+, H2+ and water group ions (W+) from each other. The ion data set is especially valuable for measuring flow velocities for protons, which are more difficult to derive using singles data within the inner magnetosphere, where the signal is dominated by heavy ions (i.e., proton peak merges with W+ peak as low energy shoulder). Our technique uses a flux function, which is zero in the proper plasma flow frame, to estimate fluid parameter uncertainties. The comparisons investigate the experimental errors and potential for systematic errors in the analyses, including ours. The rolls provide the best data set when it comes to getting 4PI coverage of the plasma but are more susceptible to time aliasing effects. Since our analysis is a velocity moments technique it will work within the inner magnetosphere where pickup ions are important and velocity distributions are non-Maxwellian. So, we will present results inside Enceladus' L shell and determine if mass loading is important. In the future we plan to make comparisons with magnetic field observations, use Saturn ionosphere conductivities as

  3. NASA Helps Keep the Light Burning for the Saturn Car Company

    Science.gov (United States)

    2003-01-01

    The Saturn Electronics & Engineering, Inc. (Saturn) facility in Marks, Miss., that produces lamp assemblies was experiencing itermittent problems with its automotive under the hood lamps. After numerous testing and engineering efforts, technicians could not pin down the root of the problem. So Saturn contacted the NASA Technology Assistance Program (TAP) at Stennis Space Center. The Marks production facility had been experiencing intermittent problems with under the hood lamp assemblies for some time. The failure rate, at 2 percent, was unacceptable. Every effort was made to identify the problem so that corrective action could be put in place. The problem was investigated and researched by Saturn's engineering department. In addition, Saturn brought in several independent testing laboratories. Other measures included examining the switch component suppliers and auditing them for compliance to the design specifications and for surface contaminants. All attempts to identify the factors responsible for the failures were inconclusive. In an effort to get to the root of the problem, and at the recommendation of the Mississippi Department of Economic Development, Saturn contacted the NASA TAP at Stennis. The NASA Materials and Contamination Laboratory, with assistance from the Stennis Prototype Laboratory, conducted a materials evaluation study on the switch components. The laboratory findings showed the failures were caused by a build-up of carbon-based contaminants on the switch components. Saturn Electronics & Engineering, Inc., is a minority-owned provider of contract manufacturing services to a diverse global marketplace. Saturn operates manufacturing facilities globally serving the North American, European, and Asian markets. Saturn's production facility in Marks, Mississippi, produces more than 1,000,000 lamps and switches monthly. "Since the NASA recommendations were implemented, our internal failure rate for intermittency has dropped to less than .02 percent

  4. Modelling of the ring current in Saturn's magnetosphere

    Directory of Open Access Journals (Sweden)

    G. Giampieri

    2004-01-01

    Full Text Available The existence of a ring current inside Saturn's magnetosphere was first suggested by Smith et al. (1980 and Ness et al. (1981, 1982, in order to explain various features in the magnetic field observations from the Pioneer 11 and Voyager 1 and 2 spacecraft. Connerney et al. (1983 formalized the equatorial current model, based on previous modelling work of Jupiter's current sheet and estimated its parameters from the two Voyager data sets. Here, we investigate the model further, by reconsidering the data from the two Voyager spacecraft, as well as including the Pioneer 11 flyby data set. First, we obtain, in closed form, an analytic expression for the magnetic field produced by the ring current. We then fit the model to the external field, that is the difference between the observed field and the internal magnetic field, considering all the available data. In general, through our global fit we obtain more accurate parameters, compared to previous models. We point out differences between the model's parameters for the three flybys, and also investigate possible deviations from the axial and planar symmetries assumed in the model. We conclude that an accurate modelling of the Saturnian disk current will require taking into account both of the temporal variations related to the condition of the magnetosphere, as well as non-axisymmetric contributions due to local time effects. Key words. Magnetospheric physics (current systems; planetary magnetospheres; plasma sheet

  5. First Observation of Lion Roar Emission in Saturn's Magnetosheath

    Science.gov (United States)

    Píša, D.; Sulaiman, A. H.; Santolík, O.; Hospodarsky, G. B.; Kurth, W. S.; Gurnett, D. A.

    2018-01-01

    We present an observation of intense emissions in Saturn's magnetosheath as detected by the Cassini spacecraft. The emissions are observed in the dawn sector (magnetic local time ˜06:45) of the magnetosheath over a time period of 11 h before the spacecraft crossed the bow shock and entered the unshocked solar wind. They are found to be narrow-banded with a peak frequency of about 0.16 fce, where fce is the local electron gyrofrequency. Using plane wave propagation analysis, we show that the waves are right hand circularly polarized in the spacecraft frame and propagate at small wave normal angles (lion roars" have been reported by numerous missions in the terrestrial magnetosheath. Here we show the first evidence such emission outside the terrestrial environment. Our observations suggest that lion roars are a solar-system-wide phenomenon and capable of existing in a broad range of parameter space. This also includes 1 order of magnitude difference in frequencies. We anticipate our result to provide new insight into such emissions in a new parameter regime characterized by a higher plasma beta (owing to the substantially higher Mach number bow shock) compared to Earth.

  6. Polar heating in Saturn's thermosphere

    Directory of Open Access Journals (Sweden)

    C. G. A. Smith

    2005-10-01

    Full Text Available A 3-D numerical global circulation model of the Kronian thermosphere has been used to investigate the influence of polar heating. The distributions of temperature and winds resulting from a general heat source in the polar regions are described. We show that both the total energy input and its vertical distribution are important to the resulting thermal structure. We find that the form of the topside heating profile is particularly important in determining exospheric temperatures. We compare our results to exospheric temperatures from Voyager occultation measurements (Smith et al., 1983; Festou and Atreya, 1982 and auroral H3+ temperatures from ground-based spectroscopic observations (e.g. Miller et al., 2000. We find that a polar heat source is consistent with both the Smith et al. determination of T~400 K at ~30° N and auroral temperatures. The required heat source is also consistent with recent estimates of the Joule heating rate at Saturn (Cowley et al., 2004. However, our results show that a polar heat source can probably not explain the Festou and Atreya determination of T~800 K at ~4° N and the auroral temperatures simultaneously.

    Keywords. Ionosphere (Planetary ionosphere – Magnetospherica physics (Planetary magnetospheres – Meterology and atmospheric dynamics (Thermospheric dynamics

  7. Discovery of a Jupiter/Saturn analog with gravitational microlensing.

    Science.gov (United States)

    Gaudi, B S; Bennett, D P; Udalski, A; Gould, A; Christie, G W; Maoz, D; Dong, S; McCormick, J; Szymanski, M K; Tristram, P J; Nikolaev, S; Paczynski, B; Kubiak, M; Pietrzynski, G; Soszynski, I; Szewczyk, O; Ulaczyk, K; Wyrzykowski, L; Depoy, D L; Han, C; Kaspi, S; Lee, C-U; Mallia, F; Natusch, T; Pogge, R W; Park, B-G; Abe, F; Bond, I A; Botzler, C S; Fukui, A; Hearnshaw, J B; Itow, Y; Kamiya, K; Korpela, A V; Kilmartin, P M; Lin, W; Masuda, K; Matsubara, Y; Motomura, M; Muraki, Y; Nakamura, S; Okumura, T; Ohnishi, K; Rattenbury, N J; Sako, T; Saito, To; Sato, S; Skuljan, L; Sullivan, D J; Sumi, T; Sweatman, W L; Yock, P C M; Albrow, M D; Allan, A; Beaulieu, J-P; Burgdorf, M J; Cook, K H; Coutures, C; Dominik, M; Dieters, S; Fouqué, P; Greenhill, J; Horne, K; Steele, I; Tsapras, Y; Chaboyer, B; Crocker, A; Frank, S; Macintosh, B

    2008-02-15

    Searches for extrasolar planets have uncovered an astonishing diversity of planetary systems, yet the frequency of solar system analogs remains unknown. The gravitational microlensing planet search method is potentially sensitive to multiple-planet systems containing analogs of all the solar system planets except Mercury. We report the detection of a multiple-planet system with microlensing. We identify two planets with masses of approximately 0.71 and approximately 0.27 times the mass of Jupiter and orbital separations of approximately 2.3 and approximately 4.6 astronomical units orbiting a primary star of mass approximately 0.50 solar mass at a distance of approximately 1.5 kiloparsecs. This system resembles a scaled version of our solar system in that the mass ratio, separation ratio, and equilibrium temperatures of the planets are similar to those of Jupiter and Saturn. These planets could not have been detected with other techniques; their discovery from only six confirmed microlensing planet detections suggests that solar system analogs may be common.

  8. Cassini’s Discoveries at Saturn and the Proposed Cassini Solstice Mission

    Science.gov (United States)

    Pappalardo, R. T.; Spilker, L. J.; Mitchell, R. T.; Cuzzi, J.; Gombosi, T. I.; Ingersoll, A. P.; Lunine, J. I.

    2009-12-01

    Understanding of the Saturn system has been greatly enhanced by the Cassini-Huygens mission. Fundamental discoveries have altered our views of Saturn, Titan and the other icy satellites, the rings, and magnetosphere of the system. Key discoveries include: water-rich plumes emanating from the south pole of Enceladus; hints of possible activity on Dione and of rings around Rhea; a methane hydrological cycle on Titan complete with fluvial erosion, lakes, and seas of liquid methane and ethane; non-axisymmetric ring microstructure in all moderate optical depth rings; south polar vortices on Saturn; and a unique magnetosphere that shares characteristics with both Earth’s and Jupiter’s magnetospheres. These new discoveries are directly relevant to current Solar System science goals including: planet and satellite formation processes, formation of gas giants, the nature of organic material, the history of volatiles, habitable zones and processes for life, processes that shape planetary bodies, and evolution of exoplanets. The proposed 7-year Cassini Solstice Mission would address new questions that have arisen during the Cassini Prime and Equinox Missions, and would observe seasonal and temporal change in the Saturn system to prepare for future missions to Saturn, Titan, and Enceladus. The proposed Cassini Solstice Mission would provide new science in three ways. First, it would observe seasonally and temporally dependent processes on Saturn, Titan and other icy satellites, and within the rings and magnetosphere, in a hitherto unobserved seasonal phase from equinox to solstice. Second, it would address new questions that have arisen during the mission thus far, providing qualitatively new measurements (e.g. of Enceladus and Titan) which could not be accommodated in the earlier mission phases. Tthird, it would conduct a close-in mission phase at Saturn that would provide unique science including comparison to the Juno observations at Jupiter.

  9. The Age of Saturn's Rings Constrained by the Meteoroid Flux Into the System

    Science.gov (United States)

    Kempf, S.; Altobelli, N.; Srama, R.; Cuzzi, J. N.; Estrada, P. R.

    2017-12-01

    The origin of Saturn's ring is still not known. There is an ongoing argument whether Saturn's ring are rather young or have been formed shortly after Saturn together with its satellites. The water-ice rings contain about 5% rocky material resulting from continuous meteoroid bombardment of the ring material with interplanetary micrometeoroids. Knowledge of the incoming mass flux would allow to estimate the ring's exposure time. Model calculations suggest exposure times of 108 years implying a late ring formation. This scenario is problematic because the tidal disruption of a Mimas-sized moon or of a comet within the planet's Roche zone would lead to a much larger rock content as observed today. Here we report on the measurement of the meteoroid mass flux into the Saturnian system obtained by the charge-sensitive entrance grid system (QP) of the Cosmic Dust Analyser (CDA) on the Cassini spacecraft. Interplanetary dust particles (IDPs) entering Saturn's sphere of gravitational influence are identified through the measurements of their speed vectors. We analyzed the full CDA data set acquired after Cassini's arrival at Saturn in 2004, identified the impact speed vectors of 128 extrinsic micrometeoroids ≥ 2 μm, and determined their orbital elements. On the basis of these measurements we determined the mass flux into the Saturnian system. Our preliminary findings are in support of an old ring. The knowledge of the meteoroids orbital elements allows us for the first time to characterize the meteoroid environment in the outer solar system based on direct measurements.

  10. Periods, poles, and shapes of Saturn's irregular moons

    Science.gov (United States)

    Denk, Tilmann; Mottola, Stefano

    2016-10-01

    We report rotational-lightcurve observations of irregular moons of Saturn based on disk-integrated observations with the Narrow-Angle Camera of the Cassini spacecraft. From 24 measured rotation periods, 20 are now known with an accuracy of ~2% or better. The numbers are as follows (in hours; an '*' marks the less reliable periods): Hati 5.42; Mundilfari 6.74; Loge 6.94*; Skoll 7.26; Kari 7.70; Suttungr 7.82*, Bergelmir 8.13; Phoebe 9.274; Siarnaq 10.188; Narvi 10.21; Tarvos 10.69; Skathi 11.30; Ymir 11.922; Hyrrokkin 12.76; Greip 12.79*; Ijiraq 13.03; Albiorix 13.32; Bestla 14.624; Bebhionn 16.40; Paaliaq 18.75; Kiviuq 21.96; Erriapus 28.15; Thrymr 35 or >45* Tarqeq 76.8.More recent data strengthen the notion that objects in orbits with an inclination supplemental angle i' > 27° have significantly slower spin rates than those at i' 27°, Siarnaq, stands opposed to at least eight objects with faster spins and i' 27° bin contains all nine known prograde moons and four retrograde objects.A total of 25 out of 38 known outer moons has been observed with Cassini, and there is no chance to observe the 13 missing objects until end-of-mission. However, all unobserved objects are part of the i' 27° are known, and none of them is a fast rotator, with no exception.Several objects were observed repeatedly to determine pole directions, sidereal periods, and convex shapes. A few lightcurves have been observed to show three maxima and three minima even at low phase angles, suggesting objects with a triangular equatorial cross-section. Some objects with 2 maxima/ 2 minima are probably quite elongated. One moon even shows lightcurves with 4 maxima/ 4 minima.

  11. Slicing The 2010 Saturn's Storm: Upper Clouds And Hazes

    Science.gov (United States)

    Perez-Hoyos, Santiago; Sanz-Requena, J. F.; Sanchez-Lavega, A.; Hueso, R.

    2012-10-01

    At the end of 2010 a small storm erupted in Saturn's northern mid-latitudes. Starting from a localized perturbation, it grew up to be a global-scale disturbance and cover the whole latitude band by February, 2011 (Fletcher et al. 2011, Science 332; Sánchez-Lavega et al. 2011, Nature 475; Fischer et al. 2011, Nature 475). By June, 2011 the storm was facing its end and gradually disappeared (Sánchez-Lavega et al. 2012, Icarus 220). In this work we use the observations acquired by the Cassini ISS instrument during the whole process to investigate the vertical cloud and haze structure above the ammonia condensation level (roughly 1 bar). Cassini ISS observations cover visual wavelengths from the blue to the near-infrared including two methane absorption bands. Such observations have been modeled using a radiative transfer code which reproduces the atmospheric reflectivity as a function of observation/illumination geometry and wavelength together with a retrieval technique to find maximum likelihood atmospheric models. This allows to investigate some atmospheric parameters: cloud-top pressures, aerosol optical thickness and particle absorption, among others. We will focus on two aspects: (1) maximum likelihood models for the undisturbed reference atmosphere in the 15°N to 45°N band before and after the disturbance; (2) models for particular structures during the development of the global-scale phenomenon. Our results show a general increase of particle density and single-scattering albedo inside the storm. However, some discrete features showing anomalous structure and related to the storm peculiar dynamics will also be discussed. Acknowledgments: This work was supported by the Spanish MICIIN project AYA2009-10701 with FEDER funds, by Grupos Gobierno Vasco IT-464-07 and by Universidad País Vasco UPV/EHU through program UFI11/55.

  12. MIGRATION OF SMALL MOONS IN SATURN's RINGS

    Energy Technology Data Exchange (ETDEWEB)

    Bromley, Benjamin C. [Department of Physics and Astronomy, University of Utah, 115 S 1400 E, Rm 201, Salt Lake City, UT 84112 (United States); Kenyon, Scott J., E-mail: bromley@physics.utah.edu, E-mail: skenyon@cfa.harvard.edu [Smithsonian Astrophysical Observatory, 60 Garden Street, Cambridge, MA 02138 (United States)

    2013-02-20

    The motions of small moons through Saturn's rings provide excellent tests of radial migration models. In theory, torque exchange between these moons and ring particles leads to radial drift. We predict that moons with Hill radii r {sub H} {approx} 2-24 km should migrate through the A ring in 1000 yr. In this size range, moons orbiting in an empty gap or in a full ring eventually migrate at the same rate. Smaller moons or moonlets-such as the propellers-are trapped by diffusion of disk material into corotating orbits, creating inertial drag. Larger moons-such as Pan or Atlas-do not migrate because of their own inertia. Fast migration of 2-24 km moons should eliminate intermediate-size bodies from the A ring and may be responsible for the observed large-radius cutoff of r {sub H} {approx} 1-2 km in the size distribution of the A ring's propeller moonlets. Although the presence of Daphnis (r {sub H} Almost-Equal-To 5 km) inside the Keeler gap challenges this scenario, numerical simulations demonstrate that orbital resonances and stirring by distant, larger moons (e.g., Mimas) may be important factors. For Daphnis, stirring by distant moons seems the most promising mechanism to halt fast migration. Alternatively, Daphnis may be a recent addition to the ring that is settling into a low inclination orbit in {approx}10{sup 3} yr prior to a phase of rapid migration. We provide predictions of observational constraints required to discriminate among possible scenarios for Daphnis.

  13. Cassini Operational Sun Sensor Risk Management During Proximal Orbit Saturn Ring Plane Crossings

    Science.gov (United States)

    Bates, David M.

    2016-01-01

    NASA's Cassini Spacecraft, launched on October 15th, 1997 which arrived at Saturn on June 30th, 2004, is the largest and most ambitious interplanetary spacecraft in history. As the first spacecraft to achieve orbit at Saturn, Cassini has collected science data throughout its four-year prime mission (2004–08), and has since been approved for a first and second extended mission through 2017. As part of the final extended missions, Cassini will begin an aggressive and exciting campaign of high inclination, low altitude flybys within the inner most rings of Saturn, skimming Saturn’s outer atmosphere, until the spacecraft is finally disposed of via planned impact with the planet. This final campaign, known as the proximal orbits, requires a strategy for managing the Sun Sensor Assembly (SSA) health, the details of which are presented in this paper.

  14. Ogle-2012-blg-0724lb: A Saturn Mass Planet Around an M-dwarf

    Science.gov (United States)

    Hirao, Y.; Sumi, T.; Bennett, D. P.; Bond, I. A.; Rattenbury, N.; Suzuki, D.; Koshimoto, N.; Abe, F.; Asakura, Y.; Bhattacharya, A.

    2016-01-01

    We report the discovery of a planet by the microlensing method, OGLE-2012-BLG-0724Lb. Although the duration of the planetary signal for this event was one of the shortest seen for a planetary event, the anomaly was well covered thanks to high-cadence observations taken by the survey groups OGLE and MOA. By analyzing the light curve, this planetary system is found to have a mass ratio q = (1.58 +/- 0.15) x 10(exp -3). By conducting a Bayesian analysis, we estimate that the host star is an M dwarf with a mass of M(sub L) = 0.29(+0.33/-0.16) solar mass located at D(sub L) = 6.7(+1.1/-1.2) kpc away from the Earth and the companion's mass is m(sub P) = 0.47(+0.54/-0.26) M(Jup). The projected planet- host separation is a falsum = 1.6(+0.4/-0.3) AU. Because the lens-source relative proper motion is relatively high, future highresolution images would detect the lens host star and determine the lens properties uniquely. This system is likely a Saturn-mass exoplanet around an M dwarf, and such systems are commonly detected by gravitational microlensing. This adds another example of a possible pileup of sub-Jupiters (0.2 less than m(sub P)/M(sub Jup) less than 1) in contrast to a lack of Jupiters (approximately 1-2 M(sub Jup)) around M dwarfs, supporting the prediction by core accretion models that Jupiter-mass or more massive planets are unlikely to form around M dwarfs.

  15. HST HOT-JUPITER TRANSMISSION SPECTRAL SURVEY: CLEAR SKIES FOR COOL SATURN WASP-39b

    Energy Technology Data Exchange (ETDEWEB)

    Fischer, Patrick D.; Knutson, Heather A. [Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA 91125 (United States); Sing, David K.; Kataria, Tiffany; Nikolov, Nikolay [Astrophysics Group, School of Physics, University of Exeter, Stocker Road, Exeter, EX4 4QL (United Kingdom); Henry, Gregory W.; Williamson, Michael W. [Center of Excellence in Information Systems, Tennessee State University, Nashville, TN 37209 (United States); Fortney, Jonathan J. [Department of Astronomy and Astrophysics, University of California Santa Cruz, CA 95064 (United States); Burrows, Adam S. [Department of Astrophysical Sciences, Peyton Hall, Princeton University, Princeton, NJ 08544 (United States); Showman, Adam P.; Ballester, Gilda E. [Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ 85721 (United States); Désert, Jean-Michel [CASA, Department of Astrophysical and Planetary Sciences, University of Colorado, 389-UCB, Boulder, CO 80309 (United States); Aigrain, Suzanne [Department of Physics, University of Oxford, Denys Wilkinson Building, Keble Road, Oxford OX1 3RH (United Kingdom); Deming, Drake [Department of Astronomy, University of Maryland, College Park, MD 20742 (United States); Etangs, Alain Lecavelier des; Vidal-Madjar, Alfred [CNRS, Institut dAstrophysique de Paris, UMR 7095, 98bis boulevard Arago, F-75014 Paris (France)

    2016-08-10

    We present the Hubble Space Telescope (HST) Space Telescope Imaging Spectrograph (STIS) optical transmission spectroscopy of the cool Saturn-mass exoplanet WASP-39b from 0.29-1.025 μ m, along with complementary transit observations from Spitzer IRAC at 3.6 and 4.5 μ m. The low density and large atmospheric pressure scale height of WASP-39b make it particularly amenable to atmospheric characterization using this technique. We detect a Rayleigh scattering slope as well as sodium and potassium absorption features; this is the first exoplanet in which both alkali features are clearly detected with the extended wings predicted by cloud-free atmosphere models. The full transmission spectrum is well matched by a clear H{sub 2}-dominated atmosphere, or one containing a weak contribution from haze, in good agreement with the preliminary reduction of these data presented in Sing et al. WASP-39b is predicted to have a pressure-temperature profile comparable to that of HD 189733b and WASP-6b, making it one of the coolest transiting gas giants observed in our HST STIS survey. Despite this similarity, WASP-39b appears to be largely cloud-free, while the transmission spectra of HD 189733b and WASP-6b both indicate the presence of high altitude clouds or hazes. These observations further emphasize the surprising diversity of cloudy and cloud-free gas giant planets in short-period orbits and the corresponding challenges associated with developing predictive cloud models for these atmospheres.

  16. On Radiative Factors in Planetary Rings: New Insight Derived from Cassini CIRS Observations at Saturn Equinox

    Science.gov (United States)

    Brooks, S. M.; Spilker, L. J.; Pilorz, S.; Edgington, S. G.; Deau, E.; Morishima, R.

    2012-12-01

    Since arriving at Saturn in 2004, Cassini's Composite Infrared Spectrometer has recorded tens of millions of spectra of Saturn's rings (personal communication, M. Segura). CIRS records far infrared radiation (16.7-1000 microns) at focal plane 1 (FP1). Thermal emission from Saturn's rings peaks at FP1 wavelengths. CIRS spectra are well characterized as blackbody emission at an effective temperature Te, multiplied by a scalar factor related to ring emissivity (Spilker et al. [2005, 2006]). CIRS can therefore characterize the rings' temperature and study the thermal environment to which the ring particles are subject. We focus on CIRS data from the 2009 Saturnian equinox. As the Sun's disk crossed the ring plane, CIRS obtained several radial scans of the rings at a variety of phase angles, local hour angles and distances. With the Sun's rays striking the rings at an incidence angle of zero, solar heating is virtually absent, and thermal radiation from Saturn and sunlight reflected by Saturn dominate the thermal environment. These observations appear to present a paradox. Equinox data show that the flux of thermal energy radiated by the rings can even exceed the energy incident upon them as prescribed by thermal models, particularly in the C ring and Cassini Division (Ferrari and Leyrat [2006], Morishima et al. [2009, 2010]). Conservation principles suggest that such models underestimate heating of the rings in these cases, as it is clearly unphysical for the rings to radiate significantly more energy than is incident upon them. In this presentation, we will describe our efforts to resolve this paradox and determine what doing so can teach us about Saturn's rings. This research was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under contract with NASA. Copyright 2012 California Institute of Technology. Government sponsorship acknowledged.

  17. Memory testing with Saturne synchrotron beams. Experiments with protons and deuterons

    International Nuclear Information System (INIS)

    Buisson, J.

    1989-01-01

    For simulate light ions of the cosmic rays CEA will use facilities used in fundamental physic research. SATURNE is a synchrotron especially designed to accelerate light particles, for example protons with energy up to 2.9 GeV. Two experiments are made on SATURNE to specify the beam characteristics (energy and intensity) and to adapt the beam for irradiation of electronic components. During these preliminary experimentation memories and microprocessors was tested. The results of the tests (cross-section) are given in this paper [fr

  18. Long-lived particulate or gaseous structure in Saturn's outer magnetosphere

    Science.gov (United States)

    Lazarus, A. J.; Hasegawa, T.; Bagenal, F.

    1983-01-01

    Voyager 1 and 2 and Pioneer 11 data on the variations in the number density of low-energy plasma ions in the outer Saturn magnetosphere are discussed. Low and high latitude observations are compared in reference to the position of the spacecraft crossing of the field line. Abrupt decreases in the number density interrupted the tendancy for the number density to increase with spacecraft approach to Saturn. All three spacecraft are concluded to have encountered the same magnetospheric structure in the field line, with absorbers being present in the equatorial plane. The absorbers are suggested to be either gas or debris, which may be detectable visibly or with occultation techniques.

  19. Loading the Saturn I S-IV Stage into Pregnant Guppy

    Science.gov (United States)

    1965-01-01

    The photograph shows the loading operation of the Saturn I S-IV stage (second stage) into the Pregnant Guppy at the Redstone Airfield, Huntsville, Alabama. The Pregnant Guppy was a Boeing B-377 Stratocruiser modified to transport various stages of Saturn launch vehicles. The modification project called for lengthening the fuselage to accommodate the S-IV stage. After the flight test of that modification, phase two called for the enlargement of the plane's cabin section to approximately double its normal volume. The fuselage separated just aft of the wing's trailing edge to load and unload the S-IV and other cargoes.

  20. Saturn Orbits Car Making into the Twenty-First Century. A Case Study

    Science.gov (United States)

    1993-04-01

    are adding a new automotive operating unit--Saturn--to our passenger car lines....Not since 1918, when Chevrolet joined the General Motors family, have...34landmark" for a U.S.-made car. In its comparison test with the Nissan NX 2000, the Mazda MX-3, and the Toyota Paseo, Saturn SC (sports coupe) ended in a dead...every year. 2 2 The Goliath of the group is General Motors , the world’s largest corporation. GM employs 715,000 people in 35 countries (368,000 in the

  1. Mission Techniques for Exploring Saturn's icy moons Titan and Enceladus

    Science.gov (United States)

    Reh, Kim; Coustenis, Athena; Lunine, Jonathan; Matson, Dennis; Lebreton, Jean-Pierre; Vargas, Andre; Beauchamp, Pat; Spilker, Tom; Strange, Nathan; Elliott, John

    2010-05-01

    The future exploration of Titan is of high priority for the solar system exploration community as recommended by the 2003 National Research Council (NRC) Decadal Survey [1] and ESA's Cosmic Vision Program themes. Cassini-Huygens discoveries continue to emphasize that Titan is a complex world with very many Earth-like features. Titan has a dense, nitrogen atmosphere, an active climate and meteorological cycles where conditions are such that the working fluid, methane, plays the role that water does on Earth. Titan's surface, with lakes and seas, broad river valleys, sand dunes and mountains was formed by processes like those that have shaped the Earth. Supporting this panoply of Earth-like processes is an ice crust that floats atop what might be a liquid water ocean. Furthermore, Titan is rich in very many different organic compounds—more so than any place in the solar system, except Earth. The Titan Saturn System Mission (TSSM) concept that followed the 2007 TandEM ESA CV proposal [2] and the 2007 Titan Explorer NASA Flagship study [3], was examined [4,5] and prioritized by NASA and ESA in February 2009 as a mission to follow the Europa Jupiter System Mission. The TSSM study, like others before it, again concluded that an orbiter, a montgolfiѐre hot-air balloon and a surface package (e.g. lake lander, Geosaucer (instrumented heat shield), …) are very high priority elements for any future mission to Titan. Such missions could be conceived as Flagship/Cosmic Vision L-Class or as individual smaller missions that could possibly fit within NASA's New Frontiers or ESA's Cosmic Vision M-Class budgets. As a result of a multitude of Titan mission studies, several mission concepts have been developed that potentially fit within various cost classes. Also, a clear blueprint has been laid out for early efforts critical toward reducing the risks inherent in such missions. The purpose of this paper is to provide a brief overview of potential Titan (and Enceladus) mission

  2. The exploitation of the Saturne synchrotron during the forth quarter of 1960; L'exploitation du synchrotron Saturne pendant le 4eme trimestre 1960

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1961-01-15

    This document reports information and data regarding the operation of the Saturne synchrotron during the fourth quarter of 1960. It addresses the machine operation (acceleration cycles, beam intensity, technical incidents, time table), hardware studies (corrector circuit under high fields, intensity increase), physics experiments (on counters, in bubble chambers, target irradiation), measures and measurements regarding the protection against radiations (comparison of irradiation levels in different areas of the synchrotron, annual evolution), the liquefactor activity (nitrogen and hydrogen consumption and production data)

  3. The exploitation of the Saturne synchrotron during the first quarter of 1959; L'exploitation du synchrotron Saturne pendant le 1er trimestre 1959

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1959-05-15

    After having recalled some important events which occurred in 1958 regarding the operation of the Saturne synchrotron, this document first reports facts concerning the operation of the synchrotron (technical incidents are mentioned), experiments performed on the equipment (trajectory anomalies), physics experiments (use of fixed targets and of a target with radial projection, experiments in a bubble chamber), measures and measurements regarding protection against radiations during the first quarter of 1959.

  4. The Changing Surface of Saturn's Titan: Cassini Observations Suggest Active Cryovolcanism

    Science.gov (United States)

    Nelson, R. M.

    2008-12-01

    R. M. Nelson(1), L. Kamp(1), R. M. C. Lopes(1), D. L. Matson(1), S. D. Wall(1), R. L. Kirk(2), K. L Mitchell(1), G. Mitri(1), B. W. Hapke(3), M. D. Boryta(4), F. E. Leader(1) , W. D. Smythe(1), K. H. Baines(1), R. Jauman(5), C. Sotin(1), R. N. Clark(6), D. P. Cruikshank(7) , P. Drossart(9), B. J. Buratti(1) , J.Lunine(8), M. Combes(9), G. Bellucci(10), J.-P. Bibring(11), F. Capaccioni(10), P. Cerroni(10), A. Coradini(10), V. Formisano(10), G Filacchione(10), R. Y. Langevin(11), T. B. McCord(12), V. Mennella(13), P. D. Nicholson(14) , B. Sicardy(8) 1-JPL, 4800 Oak Grove Drive, Pasadena CA 91109, 2-USGS, Flagstaff, 3-U Pittsburgh, 4-Mt. Sac Col, 5- DLR, Berlin, 6-USGS Denver, 7-NASA AMES, 8-U Paris-Meudon, 9-Obs de Paris, 10-ISFI-CNR Rome, 11-U Paris -Sud. Orsay, 12-Bear Flt Cntr Winthrop WA, 13-Obs Capodimonte Naples, 14-Cornell U. Several Instruments on the Cassini Saturn Orbiter have been observing the surface of Saturn's moon Titan since mid 2004. The Visual and Infrared Mapping Spectrometer (VIMS) reports that regions near 26oS, 78oW (region 1) and 7oS, 138oW (region 2) exhibit photometric changes consistent with on-going surface activity. These regions are photometrically variable with time(1). Cassini Synthetic Aperture Rader (SAR) has investigated these regions and reports that both of these regions exhibit morphologies consistent with cryovolcanism (2). VIMS observed region 1 eight times and reported that on two occasions the region brightened two-fold and then decreased again on timescales of several weeks. Region 2 was observed on four occasions (Tb-Dec13/2004 ,T8-Oct27/2005, T10-Jan15/2006, T12-Mar18/2006) and exhibited a pronounced change in I/F betweenT8 and T10. Our photometric analysis finds that both regions do not exhibit photometric properties consistent with atmospheric phenomena such as tropospheric clouds. These changes must be at or very near the surface. Radar images of these regions reveal morphology that is consistent with cryovolcanoes. We

  5. Habitability potential of satellites around Jupiter and Saturn

    Science.gov (United States)

    Coustenis, Athena; Raulin, Francois; Encrenaz, Therese; Grasset, Olivier; Solomonidou, Anezina

    2016-07-01

    In looking for habitable conditions in the outer solar system recent research focuses on the natural satellites rather than the planets themselves. Indeed, the habitable zone as traditionally defined may be larger than originally conceived. The outer solar system satellites provide a conceptual basis within which new theories for understanding habitability can be constructed. Measurements from the ground but also by the Voyager, Galileo and the Cassini spacecrafts revealed the potential of these satellites in this context, and our understanding of habitability in the solar system and beyond can be greatly enhanced by investigating several of these bodies together [1]. Their environments seem to satisfy many of the "classical" criteria for habitability (liquid water, energy sources to sustain metabolism and chemical compounds that can be used as nutrients over a period of time long enough to allow the development of life). Indeed, several of the moons show promising conditions for habitability and the development and/or maintenance of life. The strong gravitational pull caused by the giant planets may produce enough energy to sufficiently heat the cores of orbiting icy moons. Europa and Ganymede may be hiding, under their icy crust, putative undersurface liquid water oceans [2] which, in the case of Europa [3], may be in direct contact with a silicate mantle floor and kept warm by tidally generated heat [4]. Titan and Enceladus, Saturn's satellites, were found by the Cassini-Huygens mission to possess active organic chemistries with seasonal variations, unique geological features and possibly internal liquid water oceans. Titan's rigid crust and the probable existence of a subsurface ocean create an analogy with terrestrial-type plate tectonics, at least surficial [5], while Enceladus' plumes find an analogue in geysers. As revealed by Cassini the liquid hydrocarbon lakes [6] distributed mainly at polar latitudes on Titan are ideal isolated environments to look for

  6. The deuterium abundance in Jupiter and Saturn from ISO-SWS observations

    NARCIS (Netherlands)

    Lellouch, E; Bezard, B; Fouchet, T; Feuchtgruber, H; Encrenaz, T; de Graauw, T

    Observations with the Short Wavelength Spectrometer (SWS) onboard the Infrared Space Observatory (ISO) are used to determine the D/H ratio in Jupiter's and Saturn's atmospheres. The D/H ratio is measured independently in hydrogen (i.e. from the HD/H-2 ratio) and methane (from CH3D/CH4). Observations

  7. Solar System Exploration Augmented by In-Situ Resource Utilization: Mercury and Saturn Propulsion Investigations

    Science.gov (United States)

    Palaszewski, Bryan

    2016-01-01

    Human and robotic missions to Mercury and Saturn are presented and analyzed with a range of propulsion options. Historical studies of space exploration, in-situ resource utilization (ISRU), and industrialization all point to the vastness of natural resources in the solar system. Advanced propulsion benefitted from these resources in many ways. While advanced propulsion systems were proposed in these historical studies, further investigation of nuclear options using high power nuclear thermal and nuclear pulse propulsion as well as advanced chemical propulsion can significantly enhance these scenarios. Updated analyses based on these historical visions will be presented. Nuclear thermal propulsion and ISRU enhanced chemical propulsion landers are assessed for Mercury missions. At Saturn, nuclear pulse propulsion with alternate propellant feed systems and Titan exploration with chemical propulsion options are discussed. In-situ resource utilization was found to be critical in making Mercury missions more amenable for human visits. At Saturn, refueling using local atmospheric mining was found to be difficult to impractical, while refueling the Saturn missions from Uranus was more practical and less complex.

  8. Observations of chorus at Saturn using the Cassini Radio and Plasma Wave Science Instrument

    Czech Academy of Sciences Publication Activity Database

    Hospodarsky, G. B.; Averkamp, T. F.; Kurth, W. S.; Gurnett, D. A.; Menietti, J. D.; Santolík, Ondřej; Dougherty, M. K.

    2008-01-01

    Roč. 113, č. 12 (2008), A12206/1-A12206/13 ISSN 0148-0227 Grant - others:National Aeronautics and Space Administration (US) 1279973 Institutional research plan: CEZ:AV0Z30420517 Keywords : Saturn * chorus Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 3.147, year: 2008

  9. High and medium high energy lines in France. The SATURNE case

    International Nuclear Information System (INIS)

    Milleret, G.

    1994-01-01

    Located in the Paris area, the SATURNE accelerator produces high energy charged particles: protons, deuterons, helium 3, helium 4, neutrons. The beams, with very flexible characteristics (linear energy transfer, flexible environment, dimension and intensity) for simulation of cosmic particles or high energy accelerator environments, allow for testing various individual or complete components. The various commercial offers and prices are presented. 5 fig., 2 ref

  10. Evolution of electron pitch angle distributions across Saturn's middle magnetospheric region from MIMI/LEMMS

    Science.gov (United States)

    Clark, G.; Paranicas, C.; Santos-Costa, D.; Livi, S.; Krupp, N.; Mitchell, D. G.; Roussos, E.; Tseng, W.-L.

    2014-12-01

    We provide a global view of ~20 to 800 keV electron pitch angle distributions (PADs) close to Saturn's current sheet using observations from the Cassini MIMI/LEMMS instrument. Previous work indicated that the nature of pitch angle distributions in Saturn's inner to middle magnetosphere changes near the radial distance of 10RS. This work confirms the existence of a PAD transition region. Here we go further and develop a new technique to statistically quantify the spatial profile of butterfly PADs as well as present new spatial trends on the isotropic PAD. Additionally, we perform a case study analysis and show the PADs exhibit strong energy dependent features throughout this transition region. We also present a diffusion theory model based on adiabatic transport, Coulomb interactions with Saturn's neutral gas torus, and an energy dependent radial diffusion coefficient. A data-model comparison reveals that adiabatic transport is the dominant transport mechanism between ~8 to 12RS, however interactions with Saturn's neutral gas torus become dominant inside ~7RS and govern the flux level of ~20 to 800 keV electrons. We have also found that field-aligned fluxes were not well reproduced by our modeling approach. We suggest that wave-particle interactions and/or a polar source of the energetic particles needs further investigation.

  11. Saturne II: characteristics of the proton beam, field qualities and corrections, acceleration of the polarized protons

    International Nuclear Information System (INIS)

    Laclare, J.-L.

    1978-01-01

    Indicated specifications of Saturne II are summed up: performance of the injection system, quality of the guidance field (magnetic measurements and multipolar corrections), transverse and longitudinal instabilities, characteristics of the beam stored in the machine and of the extracted beam. The problem of depolarization along the acceleration cycle is briefly discussed (1 or 2% between injection and 3 GeV) [fr

  12. Analysis of Saturn's Thermal Emission at 2.2-cm Wavelength: Spatial Distribution of Ammonia Vapor

    Science.gov (United States)

    Laraia, A. L.; Ingersoll, A. P.; Janssen, Michael A.; Gulkis, Samuel; Oyafuso, Fabiano A.; Allison, Michael D.

    2013-01-01

    This work focuses on determining the latitudinal structure of ammonia vapor in Saturn's cloud layer near 1.5 bars using the brightness temperature maps derived from the Cassini RADAR (Elachi et al., 2004) instrument, which works in a passive mode to measure thermal emission from Saturn at 2.2-cm wavelength. We perform an analysis of five brightness temperature maps that span epochs from 2005 to 2011, which are presented in a companion paper by Janssen et al. (2013a, this issue). The brightness temperature maps are representative of the spatial distribution of ammonia vapor, since ammonia gas is the only effective opacity source in Saturn's atmosphere at 2.2-cm wavelength. Relatively high brightness temperatures indicate relatively low ammonia relative humidity (RH), and vice versa. We compare the observed brightness temperatures to brightness temperatures computed using the Juno atmospheric microwave radiative transfer (JAMRT) program which includes both the means to calculate a tropospheric atmosphere model for Saturn and the means to carry out radiative transfer calculations at microwave frequencies. The reference atmosphere to which we compare has a 3x solar deep mixing ratio of ammonia (we use 1.352x10(exp -4) for the solar mixing ratio of ammonia vapor relative to H2; see Atreya, 2010) and is fully saturated above its cloud base. The maps are comprised of residual brightness temperatures-observed brightness temperature minus the model brightness temperature of the saturated atmosphere.

  13. CONVECTIVE BURSTS AND THE COUPLING OF SATURN'S EQUATORIAL STORMS AND INTERIOR ROTATION

    International Nuclear Information System (INIS)

    Heimpel, Moritz; Aurnou, Jonathan M.

    2012-01-01

    Temporal variations of Saturn's equatorial jet and magnetic field hint at rich dynamics coupling the atmosphere and the deep interior. However, it has been assumed that rotation of the interior dynamo must be steady over tens of years of modern observations. Here we use a numerical convection model and scaling estimates to show how equatorial convective bursts can transfer angular momentum to the deeper interior. The numerical model allows angular momentum transfer between a fluid outer spherical shell and a rigid inner sphere. Convection drives a prograde equatorial jet exhibiting quasiperiodic bursts that fill the equatorial volume outside the tangent cylinder. For each burst strong changes in the equatorial surface velocity are associated with retrograde torque on the inner sphere. Our results suggest that Saturn's Great White Spot, a giant storm that was observed to fill the equatorial region in 1990, could mobilize a volume of fluid carrying roughly 15% of Saturn's moment of inertia. Conservation of angular momentum then implies that a 20% change in the equatorial jet angular velocity could change the average interior rotation rate by about 0.1%—roughly an order of magnitude less than the apparent rotation rate changes associated with Saturn's kilometric radio (SKR) signal. However, if the SKR signal originates outside the liquid metal core in a 'planetary tachocline' that separates the layer of fast zonal flow from the magnetically controlled and slowly convecting deep interior, then convective bursts can provide a possible mechanism for the observed ∼1% SKR changes.

  14. Improvement in the 20 MeV beam brightness at Saturne

    International Nuclear Information System (INIS)

    Chamouard, P.A.; Olivier, M.

    1976-01-01

    Theoretical and experimental results are given for a program launched to improve beam brightness at Saturne. The low energy beam line located between the preinjector and linac was modified to give a reduction of beam size in the buncher and more flexible beam emittance matching with the linac acceptance, taking into account space charge effects. (E.C.B.)

  15. SUB-SATURN PLANET MOA-2008-BLG-310Lb: LIKELY TO BE IN THE GALACTIC BULGE

    International Nuclear Information System (INIS)

    Janczak, Julia; Dong, Subo; Kozlowski, Szymon

    2010-01-01

    We report the detection of sub-Saturn-mass planet MOA-2008-BLG-310Lb and argue that it is the strongest candidate yet for a bulge planet. Deviations from the single-lens fit are smoothed out by finite-source effects and therefore are not immediately apparent from the light curve. Nevertheless, we find that a model in which the primary has a planetary companion is favored over the single-lens model by Δχ 2 ∼ 880 for an additional 3 degrees of freedom. Detailed analysis yields a planet/star mass ratio q = (3.3 ± 0.3) x 10 -4 and an angular separation between the planet and star within 10% of the angular Einstein radius. The small angular Einstein radius, θ E = 0.155 ± 0.011 mas, constrains the distance to the lens to be D L >6.0 kpc if it is a star (M L >0.08 M sun ). This is the only microlensing exoplanet host discovered so far that must be in the bulge if it is a star. By analyzing VLT NACO adaptive optics images taken near the baseline of the event, we detect additional blended light that is aligned to within 130 mas of the lensed source. This light is plausibly from the lens, but could also be due to a companion to the lens or source, or possibly an unassociated star. If the blended light is indeed due to the lens, we can estimate the mass of the lens, M L = 0.67 ± 0.14 M sun , planet mass m = 74 ± 17 M + , and projected separation between the planet and host, 1.25 ± 0.10 AU, putting it right on the 'snow line'. If not, then the planet has lower mass, is closer to its host and is colder. To distinguish among these possibilities on reasonable timescales would require obtaining Hubble Space Telescope images almost immediately, before the source-lens relative motion of μ= 5 mas yr -1 causes them to separate substantially.

  16. STRONG TIDAL DISSIPATION IN SATURN AND CONSTRAINTS ON ENCELADUS' THERMAL STATE FROM ASTROMETRY

    International Nuclear Information System (INIS)

    Lainey, Valéry; Desmars, Josselin; Arlot, Jean-Eudes; Emelyanov, Nicolai; Remus, Françoise; Karatekin, Özgür; Charnoz, Sébastien; Mathis, Stéphane; Le Poncin-Lafitte, Christophe; Tobie, Gabriel; Zahn, Jean-Paul

    2012-01-01

    Tidal interactions between Saturn and its satellites play a crucial role in both the orbital migration of the satellites and the heating of their interiors. Therefore, constraining the tidal dissipation of Saturn (here the ratio k 2 /Q) opens the door to the past evolution of the whole system. If Saturn's tidal ratio can be determined at different frequencies, it may also be possible to constrain the giant planet's interior structure, which is still uncertain. Here, we try to determine Saturn's tidal ratio through its current effect on the orbits of the main moons, using astrometric data spanning more than a century. We find an intense tidal dissipation (k 2 /Q = (2.3 ± 0.7) × 10 –4 ), which is about 10 times higher than the usual value estimated from theoretical arguments. As a consequence, eccentricity equilibrium for Enceladus can now account for the huge heat emitted from Enceladus' south pole. Moreover, the measured k 2 /Q is found to be poorly sensitive to the tidal frequency, on the short frequency interval considered. This suggests that Saturn's dissipation may not be controlled by turbulent friction in the fluid envelope as commonly believed. If correct, the large tidal expansion of the moon orbits due to this strong Saturnian dissipation would be inconsistent with the moon formations 4.5 Byr ago above the synchronous orbit in the Saturnian subnebulae. But it would be compatible with a new model of satellite formation in which the Saturnian satellites formed possibly over a longer timescale at the outer edge of the main rings. In an attempt to take into account possible significant torques exerted by the rings on Mimas, we fitted a constant rate da/dt on Mimas' semi-major axis as well. We obtained an unexpected large acceleration related to a negative value of da/dt = –(15.7 ± 4.4) × 10 –15 AU day –1 . Such acceleration is about an order of magnitude larger than the tidal deceleration rates observed for the other moons. If not coming from an

  17. Photochemistry in Saturn's Ring-Shadowed Atmosphere: Modulation of Hydrocarbons and Observations of Dust Content

    Science.gov (United States)

    Edgington, S. G.; Atreya, S. K.; Wilson, E. H.; Baines, K. H.; West, R. A.; Bjoraker, G. L.; Fletcher, L. N.; Momary, T.

    2016-12-01

    Cassini has been orbiting Saturn for over twelve years now. During this epoch, the ring shadow has moved from covering much of the northern hemisphere with solar inclination of 24 degrees to covering a large swath south of the equator and it continues to move southward. At Saturn Orbit Insertion in 2004, the projection of the A-ring onto Saturn reached as far as 40N along the central meridian (52N at the terminator). At its maximum extent, the ring shadow can reach as far as 48N/S (58N/S at the terminator). The net effect is that the intensity of both ultraviolet and visible sunlight penetrating through the rings to any particular latitude will vary depending on both Saturn's axis relative to the Sun and the optical thickness of each ring system. In essence, the rings act like semi-transparent venetian blinds.Previous work examined the variation of the solar flux as a function of solar inclination, i.e. for each 7.25-year season at Saturn. Here, we report on the impact of the oscillating ring shadow on the photolysis and production rates of hydrocarbons (acetylene, ethane, propane, and benzene) and phosphine in Saturn's stratosphere and upper troposphere. The impact of these production and loss rates on the abundance of long-lived photochemical products leading to haze formation are explored. We assess their impact on phosphine abundance, a disequilibrium species whose presence in the upper troposphere can be used as a tracer of convective processes in the deeper atmosphere.We will also present our ongoing analysis of Cassini's CIRS, UVIS, and VIMS datasets that provide an estimate of the evolving haze content of the northern hemisphere and we will begin to assess the implications for dynamical mixing. In particular, we will examine how the now famous hexagonal jet stream acts like a barrier to transport, isolating Saturn's north polar region from outside transport of photochemically-generated molecules and haze.The research described in this paper was carried out

  18. Variations in Ring Particle Cooling across Saturn's Rings with Cassini CIRS

    Science.gov (United States)

    Brooks, S. M.; Spilker, L. J.; Pilorz, S.; Edgington, S. G.; Déau, E.; Altobelli, N.

    2010-12-01

    Cassini's Composite Infrared Spectrometer has recorded over two million of spectra of Saturn's rings in the far infrared since arriving at Saturn in 2004. CIRS records far infrared radiation between 10 and 600 cm-1 ( 16.7 and 1000 μ {m} ) at focal plane 1 (FP1), which has a field of view of 3.9 mrad. Thermal emission from Saturn’s rings peaks in this wavelength range. Ring temperatures can be inferred from FP1 data. By tracking how ring temperatures vary, we can determine the thermal inertia of the rings. Previous studies have shown that the rings' thermal inertia, a measure of their response to changes in the thermal environment, varies from ring to ring. Thermal inertia can provide insight into the physical structure of Saturn's ring particles and their regoliths. Low thermal inertia and rapidly changing temperatures are suggestive of ring particles that have more porous or fluffy regoliths or that are riddled with cracks. Solid particles can be expected to have higher thermal inertias. Ferrari et al. (2005) fit thermal inertia values of 5218 {Jm)-2 {K}-1 {s}-1/2 to their B ring data and 6412 {Jm)-2 {K}-1 {s}-1/2 to their C ring data. In this work we focus on CIRS observations of the shadowed portion of Saturn's rings. The rings’ thermal budget is dominated by its absorption of solar radiation. As a result, ring particles abruptly cool as they traverse Saturn's shadow. From these shadow observations we can create cooling curves at specific locations across the rings. We will show that the rings' cooling curves and thus their thermal inertia vary not only from ring to ring, but by location within the individual rings. This research was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under contract with NASA. Copyright 2010 California Institute of Technology. Government sponsorship acknowledged.

  19. Sizes of the Smallest Particles at Saturn Ring Edges from Diffraction in UVIS Stellar Occultations

    Science.gov (United States)

    Eckert, S.; Colwell, J. E.; Becker, T. M.; Esposito, L. W.

    2017-12-01

    Cassini's Ultraviolet Imaging Spectrograph (UVIS) has observed more than 150 ring stellar occultations since its arrival at Saturn in 2004. We use stellar occultation data from the UVIS High Speed Photometer (HSP) to identify diffraction signals at ring edges caused by small particles diffracting light into the detector and consequently increasing the signal above that of the unocculted star. The shape of a diffraction signal is indicative of the particle size distribution at the ring edge, which may be a dynamically perturbed region. Becker et al. (2015 Icarus doi:10.1016/j.icarus.2015.11.001) analyzed diffraction signals at the outer edge of the A Ring and the edges of the Encke Gap. We apply the Becker et al. (2015) model to the outer edge of the B Ring as well as the edges of ringlets within the C Ring and Cassini Division. In addition, we analyze diffraction signatures at the A Ring outer edge in 2 new occultations. The best-fit model signals to these occultations are consistent with the findings of Becker et al. (2015) who found an average minimum particle size amin =4.5 mm and average power law slope q=3.2. At the B Ring outer edge, we detect a diffraction signal in 10 of 28 occultations in which the diffraction signal would be observable according to our criteria for star brightness and observation geometry. We find a mean amin =11 mm and a mean q=3.0. At both edges of the so-called "Strange" ringlet (R6) we find a mean amin = 20 mm and mean q values of 3.0 and 2.8 at the inner and outer edges, respectively. In contrast, we do not observe any clear diffraction signals at either edge of the wider Huygens ringlet. This could imply an absence of cm-scale or smaller particles and indicates that collisions here may be less vigorous than at the other ring edges analyzed in this study. We detect diffraction in a small fraction ( 10%) of occultations at 3 ringlets within the Cassini Division: the Herschel ringlet, the Laplace ringlet, and the Barnard ringlet. We

  20. PAHs in the Ices of Saturn's Satellites: Connections to the Solar Nebula and the Interstellar Medium

    Science.gov (United States)

    Cruikshank, Dale P.; Pendleton, Yvonne J.

    2015-01-01

    Aliphatic hydrocarbons and PAHs have been observed in the interstellar medium (e.g., Allamandola et al. 1985, Pendleton et al. 1994, Pendleton & Allamandola 2002, Tielens 2013, Kwok 2008, Chiar & Pendleton 2008) The inventory of organic material in the ISM was likely incorporated into the molecular cloud in which the solar nebula condensed, contributing to the feedstock for the formation of the Sun, major planets, and the smaller icy bodies in the region outside Neptune's orbit (transneptunian objects, or TNOs). Additional organic synthesis occurred in the solar nebula (Ciesla & Sandford 2012). Saturn's satellites Phoebe, Iapetus, and Hyperion open a window to the composition of one class of TNO as revealed by the near-infrared mapping spectrometer (VIMS) on the Cassini spacecraft at Saturn. Phoebe (mean diameter 213 km) is a former TNO now orbiting Saturn (Johnson & Lunine 2005). VIMS spectral maps of Phoebe's surface reveal a complex organic spectral signature consisting of prominent aromatic (CH) and aliphatic hydrocarbon (=CH2, -CH3) absorption bands (3.2-3.6 micrometers). Phoebe is the source of a huge debris ring encircling Saturn, and from which particles ((is) approximately 5-20 micrometers size) spiral inward toward Saturn (Verbiscer et al. 2009). They encounter Iapetus and Hyperion where they mix with and blanket the native H2O ice of those two bodies. Quantitative analysis of the hydrocarbon bands on Iapetus demonstrates that aromatic CH is approximately 10 times as abundant as aliphatic CH2+CH3, significantly exceeding the strength of the aromatic signature in interplanetary dust particles, comet particles, and in carbonaceous meteorites (Cruikshank et al. 2014). A similar excess of aromatics over aliphatics is seen in the qualitative analysis of Hyperion and Phoebe itself (Dalle Ore et al. 2012). The Iapetus aliphatic hydrocarbons show CH2/CH3 (is) approximately 4, which is larger than the value found in the diffuse ISM ((is) approximately 2

  1. Synergism of Saturn, Enceladus and Titan and Formation of HCNO Prebiotic Molecules

    Science.gov (United States)

    Sittler, Edward C.; Cooper, John F.

    2011-01-01

    Saturn as a system has two very exotic moons Titan and Enceladus. Titan, taking in energy from Saturn's magnetosphere, solar UV irradiation, and cosmic rays, can make HCN based molecules as discussed in earlier paper by Raulin and Owen. Space radiation effects at both moons, and as coupled by the Saturn magnetosphere, could cause an unexpected series of events potentially leading to prebiotic chemical evolution at Titan with HCNO from magnetospheric oxygen as the new ingredient. The "Old Faithful" model suggests that Enceladus, highly irradiated by Saturn magnetospheric electrons and thus having a source of chemical energy from radiolytic gas production, has episodic ejections of water vapor, carbon dioxide, and various hydrocarbons into Saturn's magnetosphere. The hydrocarbons do not survive transport through the plasma environment, but oxygen ions from Enceladus water molecules become the dominant ion species in the outer magnetosphere. At Titan, Cassini discovered that 1) keV oxygen ions, evidently from Enceladus, are bombarding Titan's upper atmosphere and 2) heavy positive and negative ions exist in significant abundances within Titan's upper atmosphere. Initial models of heavy ion formation in Titan's upper atmosphere invoked polymerization of aromatics such as benzenes and their radicals to make polycyclic aromatic hydrocarbons (PAH) , while a more recent model by Sittler et al., has raised the possibility of carbon chains forming from the polymerization of acetylene and its radicals to make fullerenes. Laboratory measurements indicate that fullerenes, which are hollow carbon shells, can trap keV oxygen ions. Clustering of the fullerenes with aerosol mixtures from PAHs and the dominant nitrogen molecules could form larger aerosols enriched in trapped oxygen. Aerosol precipitation could then convey these chemically complex structures deeper into the atmosphere and to the moon surface. Ionizing solar UV, magnetospheric electron, and galactic cosmic ray

  2. Changes to Saturn's zonal-mean tropospheric thermal structure after the 2010-2011 northern hemisphere storm

    Energy Technology Data Exchange (ETDEWEB)

    Achterberg, R. K.; Hesman, B. E. [Department of Astronomy, University of Maryland, College Park, MD 20742 (United States); Gierasch, P. J.; Conrath, B. J. [Department of Astronomy, Cornell University, Ithaca, NY 14853 (United States); Fletcher, L. N. [Atmospheric Oceanic and Planetary Physics, University of Oxford, Clarenden Laboratory, Parks Road, Oxford OX1 3PU (United Kingdom); Bjoraker, G. L.; Flasar, F. M., E-mail: Richard.K.Achterberg@nasa.gov [Planetary Systems Laboratory NASA/GSFC, Greenbelt, MD 20771 (United States)

    2014-05-10

    We use far-infrared (20-200 μm) data from the Composite Infrared Spectrometer on the Cassini spacecraft to determine the zonal-mean temperature and hydrogen para-fraction in Saturn's upper troposphere from observations taken before and after the large northern hemisphere storm in 2010-2011. During the storm, zonal mean temperatures in the latitude band between approximately 25°N and 45°N (planetographic latitude) increased by about 3 K, while the zonal mean hydrogen para-fraction decreased by about 0.04 over the same latitudes, at pressures greater than about 300 mbar. These changes occurred over the same latitude range as the disturbed cloud band seen in visible images. The observations are consistent with low para-fraction gas being brought up from the level of the water cloud by the strong convective plume associated with the storm, while being heated by condensation of water vapor, and then advected zonally by the winds near the plume tops in the upper troposphere.

  3. Solar System Exploration Augmented by In-Situ Resource Utilization: Human Mercury and Saturn Exploration

    Science.gov (United States)

    Palaszewski, Bryan

    2015-01-01

    Human and robotic missions to Mercury and Saturn are presented and analyzed. Unique elements of the local planetary environments are discussed and included in the analyses and assessments. Using historical studies of space exploration, in-situ resource utilization (ISRU), and industrialization all point to the vastness of natural resources in the solar system. Advanced propulsion benefitted from these resources in many way. While advanced propulsion systems were proposed in these historical studies, further investigation of nuclear options using high power nuclear thermal and nuclear pulse propulsion as well as advanced chemical propulsion can significantly enhance these scenarios. Updated analyses based on these historical visions will be presented. Nuclear thermal propulsion and ISRU enhanced chemical propulsion landers are assessed for Mercury missions. At Saturn, nuclear pulse propulsion with alternate propellant feed systems and Titan exploration with chemical propulsion options are discussed.

  4. First observation of lion roar-like emissions in Saturn's magnetosheath

    Science.gov (United States)

    Pisa, David; Sulaiman, Ali H.; Santolik, Ondrej; Hospodarsky, George B.; Kurth, William S.; Gurnett, Donald A.

    2017-04-01

    Electromagnetic whistler mode waves known as "lion roars" have been reported by many missions inside the terrestrial magnetosheath. We show the observation of similar intense emissions in Saturn's magnetosheath as detected by the Cassini spacecraft. The emissions were observed inside the dawn sector (MLT˜0730) of the magnetosheath over a time period of nine hours before the satellite crossed the bow shock and entered the solar wind. The emissions were narrow-banded with a typical frequency of about 15 Hz well below the local electron cyclotron frequency (fce ˜100 Hz). Using the minimum variance analysis method, we show that the waves are right hand circularly polarized and propagate at small wave normal angles with respect to the ambient magnetic field. Here, for the first time, we report the evidence of lion roar-like emissions in Saturn's magnetosheath which represents a new and unique parameter regime.

  5. Photochemistry Saturn's Atmosphere. 2; Effects of an Influx of External Oxygen

    Science.gov (United States)

    Moses, Julianne I.; Lellouch, Emmanuel; Bezard, Bruno; Gladstone, G. Randall; Allen, Mark

    2000-01-01

    We use a one-dimensional diurnally averaged model of photochemistry and diffusion in Saturn's stratosphere to investigate the influence of extraplanetary debris on atmospheric chemistry. In particular, we consider the effects of an influx of oxygen from micrometeoroid ablation or from ring-particle diffusion; the contribution from cometary impacts, satellite debris, or ring vapor is deemed to be less important. The photochemical model results are compared directly with Infrared Space Observatory (ISO) observations to constrain the influx of extraplanetary oxygen to Saturn. From the ISO observations, we determine that the column densities of CO2 and H2O above 10 mbar in Saturn's atmosphere are (6.3 +/- 1) x 10(exp 14) and (1.4 +/- 0.4) x 10(exp 15)/ square cm, respectively; our models indicate that a globally averaged oxygen influx of (4+/-2) x 10(exp 6) O atoms /sq cm/s is required to explain these observations. Models with a locally enhanced influx of H20 operating over a small fraction of the projected area do not provide as good a fit to the ISO H2O observations. If volatile oxygen compounds comprise one-third to one-half of the exogenic source by mass, then Saturn is currently being bombarded with (3 +/- 2) x 10(exp -16) g/square cm/s of extraplanetary material. To reproduce the observed CO2/H2O ratio in Saturn's stratosphere, some of the exogenic oxygen must arrive in the form of a carbon-oxygen bonded species such as CO or CO2. An influx consistent with the composition of cometary ices fails to reproduce the high observed CO2/H2O ratio, suggesting that (i) the material has ices that are slightly more carbon-rich than is typical for comets, (ii) a contribution from an organic-rich component is required, or (iii) some of the hydrogen-oxygen bonded material is converted to carbon-oxygen bonded material without photochemistry (e.g., during the ablation process). We have also reanalyzed the 5-micron CO observations of Noll and Larson and determine that the CO

  6. Dynamic auroral storms on Saturn as observed by the Hubble Space Telescope.

    Science.gov (United States)

    Nichols, J D; Badman, S V; Baines, K H; Brown, R H; Bunce, E J; Clarke, J T; Cowley, S W H; Crary, F J; Dougherty, M K; Gérard, J-C; Grocott, A; Grodent, D; Kurth, W S; Melin, H; Mitchell, D G; Pryor, W R; Stallard, T S

    2014-05-28

    We present observations of significant dynamics within two UV auroral storms observed on Saturn using the Hubble Space Telescope in April/May 2013. Specifically, we discuss bursts of auroral emission observed at the poleward boundary of a solar wind-induced auroral storm, propagating at ∼330% rigid corotation from near ∼01 h LT toward ∼08 h LT. We suggest that these are indicative of ongoing, bursty reconnection of lobe flux in the magnetotail, providing strong evidence that Saturn's auroral storms are caused by large-scale flux closure. We also discuss the later evolution of a similar storm and show that the emission maps to the trailing region of an energetic neutral atom enhancement. We thus identify the auroral form with the upward field-aligned continuity currents flowing into the associated partial ring current.

  7. Spatial distribution of Langmuir waves observed upstream of Saturn's bow shock by Cassini

    Czech Academy of Sciences Publication Activity Database

    Píša, David; Santolík, Ondřej; Hospodarsky, G. B.; Kurth, W. S.; Gurnett, D. A.; Souček, Jan

    2016-01-01

    Roč. 121, č. 8 (2016), s. 7771-7784 ISSN 2169-9380 R&D Projects: GA ČR GJ16-16050Y; GA ČR(CZ) GAP209/12/2394 Institutional support: RVO:68378289 Keywords : Langmuir waves * Cassini * foreshock * Saturn Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 2.733, year: 2016 http://onlinelibrary.wiley.com/doi/10.1002/2016JA022912/abstract

  8. Flameless atomic absorption determination of ruthenium using a ''Saturn-1'' spectrophotometer

    International Nuclear Information System (INIS)

    Pichkov, V.N.; Sinitsyn, N.M.; Sadikova, F.G.; Govorova, M.I.; Yakshinskij, A.I.

    1980-01-01

    A flameless atomic absorption method is suggested for determining ruthenium in samples of complicated composition using a ''Saturn-1'' spectrophotometer with a L'vov graphite cuvette. The method was used for determining ruthenium in a copper-based sample (10 -3 % Ru) and in electrolyte slurries (10 -3 -10 -2 %). The limit of detection Csub(min, 0.95) = 3.0x10 -3 μg Ru/ml. Other platinum metals do not interfere [ru

  9. Selection of K+ mesons in a secondary beam of Saturne (1961)

    International Nuclear Information System (INIS)

    Van Rossum, L.

    1961-01-01

    The electronic device is described which permitted the determination of the number of K + mesons produced in a secondary beam of the 'Saturne' proton synchrotron. The selective criteria and the tests which allowed the identification of the K + mesons, are analysed in detail. For the ratio π + / K + = 400, and with a momentum of 600 MeV/c, less than 5 p. 100 of the detected particles corresponded to spurious events. (authors) [fr

  10. Density Structures, Dynamics, and Seasonal and Solar Cycle Modulations of Saturn's Inner Plasma Disk

    Science.gov (United States)

    Holmberg, M. K. G.; Shebanits, O.; Wahlund, J.-E.; Morooka, M. W.; Vigren, E.; André, N.; Garnier, P.; Persoon, A. M.; Génot, V.; Gilbert, L. K.

    2017-12-01

    We present statistical results from the Cassini Radio and Plasma Wave Science (RPWS) Langmuir probe measurements recorded during the time interval from orbit 3 (1 February 2005) to 237 (29 June 2016). A new and improved data analysis method to obtain ion density from the Cassini LP measurements is used to study the asymmetries and modulations found in the inner plasma disk of Saturn, between 2.5 and 12 Saturn radii (1 RS=60,268 km). The structure of Saturn's plasma disk is mapped, and the plasma density peak, nmax, is shown to be located at ˜4.6 RS and not at the main neutral source region at 3.95 RS. The shift in the location of nmax is due to that the hot electron impact ionization rate peaks at ˜4.6 RS. Cassini RPWS plasma disk measurements show a solar cycle modulation. However, estimates of the change in ion density due to varying EUV flux is not large enough to describe the detected dependency, which implies that an additional mechanism, still unknown, is also affecting the plasma density in the studied region. We also present a dayside/nightside ion density asymmetry, with nightside densities up to a factor of 2 larger than on the dayside. The largest density difference is found in the radial region 4 to 5 RS. The dynamic variation in ion density increases toward Saturn, indicating an internal origin of the large density variability in the plasma disk rather than being caused by an external source origin in the outer magnetosphere.

  11. [An epidemiological survey on saturnism among children due to lead pollution released from township enterprise].

    Science.gov (United States)

    Li, Heng-xin; Song, Ya-li; Li, Hong-guang; Yuan, Yong-xin; Xu, Qing; Liu, En-xu; Li, Jin-song

    2008-03-01

    To understand the current situations of saturnism and blood lead levels of children resided in village and circumjacent areas, and to know its relations with sex, age and other factors on children' s health as to providing some evidences for prevention and control. An epidemiological survey was conducted for finding out the pollution sources and for a better understanding of the surrounding environment. All 221 children under 14 years old, from the lead pollution villages and surrounding establishments were enrolled, and their blood lead levels were detected by graphite atomizer absorption spectrophotometer method. Symptoms of the saturnism were investigated through a standardized questionnaire. SPSS13.0 software was administrated for data analysis. High blood lead level identification rate was 66.06% (146/221), and saturnism rate 32.13% (71/221). The children's blood lead levels among group 1, group 2, group 3 in this village and jade factory were (161.20 +/- 32.94), (176.60 +/- 43.62), (258.00 +/-106.08) and (238.01 +/- 55.20) microg/L respectively and the significant differences were observed through Kruskal-Wallis test (chi2 = 51.84, df= 3, Plead levels of children from group 3 in this village and the jade factory were higher than those of other two groups. No correlation was found between children's age and blood lead level (r = 0.10, P = 0.13). There was a significant difference in blood lead levels between boys and girls (t' = 3.83, Plead levels rising, the occurrence rate of main saturnism symptoms was significantly increased. This survey suggested that the pollution source was a coarse lead smelter. The blood lead level should ke overwhelmingly increased among children who live nearby the higher level of lead blood, that living nearby the lead smeltery,might result in stautnism and negative effect on children's healthy.

  12. Disruption of Saturn's quasi-periodic equatorial oscillation by the great northern storm

    Science.gov (United States)

    Fletcher, Leigh N.; Guerlet, Sandrine; Orton, Glenn S.; Cosentino, Richard G.; Fouchet, Thierry; Irwin, Patrick G. J.; Li, Liming; Flasar, F. Michael; Gorius, Nicolas; Morales-Juberías, Raúl

    2017-11-01

    The equatorial middle atmospheres of the Earth1, Jupiter2 and Saturn3,4 all exhibit a remarkably similar phenomenon—a vertical, cyclic pattern of alternating temperatures and zonal (east-west) wind regimes that propagate slowly downwards with a well-defined multi-year period. Earth's quasi-biennial oscillation (QBO) (observed in the lower stratospheric winds with an average period of 28 months) is one of the most regular, repeatable cycles exhibited by our climate system1,5,6, and yet recent work has shown that this regularity can be disrupted by events occurring far away from the equatorial region, an example of a phenomenon known as atmospheric teleconnection7,8. Here, we reveal that Saturn's equatorial quasi-periodic oscillation (QPO) (with an 15-year period3,9) can also be dramatically perturbed. An intense springtime storm erupted at Saturn's northern mid-latitudes in December 201010-12, spawning a gigantic hot vortex in the stratosphere at 40° N that persisted for three years13. Far from the storm, the Cassini temperature measurements showed a dramatic 10 K cooling in the 0.5-5 mbar range across the entire equatorial region, disrupting the regular QPO pattern and significantly altering the middle-atmospheric wind structure, suggesting an injection of westward momentum into the equatorial wind system from waves generated by the northern storm. Hence, as on Earth, meteorological activity at mid-latitudes can have a profound effect on the regular atmospheric cycles in Saturn's tropics, demonstrating that waves can provide horizontal teleconnections between the phenomena shaping the middle atmospheres of giant planets.

  13. Statistics of Langmuir wave amplitudes observed inside Saturn's foreshock by the Cassini spacecraft

    Czech Academy of Sciences Publication Activity Database

    Píša, David; Hospodarsky, G. B.; Kurth, W. S.; Santolík, Ondřej; Souček, Jan; Gurnett, D. A.; Masters, A.; Hill, M. E.

    2015-01-01

    Roč. 120, č. 4 (2015), s. 2531-2542 ISSN 2169-9380 R&D Projects: GA ČR GAP205/10/2279; GA ČR(CZ) GAP209/12/2394 Institutional support: RVO:68378289 Keywords : Langmuir waves * foreshock * Saturn * Cassini Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 3.318, year: 2015 http://onlinelibrary.wiley.com/doi/10.1002/2014JA020560/abstract

  14. A possible link between the rotation of Saturn and its ring structure

    International Nuclear Information System (INIS)

    Franklin, F.A.; Colombo, G.; Cook, A.F.

    1982-01-01

    Evidence is presented which indicates that two previously unidentified, yet conspicuous gaps in Saturn's rings lie at distances corresponding to 2/3 and 4/3 of the planet's rotation period. It is argued that gaps such as these can be produced in a ring of large bodies or small uncharged particles only by a non-axisymmetric gravitational field a fact that is relevant to models of planetary interiors. (U.K.)

  15. The Saturne beam measurement system for orbit corrections and high and low intensity beam acceleration

    International Nuclear Information System (INIS)

    Degueurce, L.; Nakach, A.; Sole, J.

    1980-07-01

    This paper summarizes the dipolar and multipolar correction system and the main beam diagnostics of Saturne II: wide-band RF electrostatic pick-up electrode for observation of bunches, beam position and tune measurement systems, special electrodes for observation of emittance blow-up when particles cross a resonance line. For low intensity beams, special electrodes and electronics have been developed. All this instrumentation is computer controlled

  16. Power spectrum of electrical discharges seen on Earth and at Saturn

    International Nuclear Information System (INIS)

    Warwick, J.W.

    1989-01-01

    The author presents a method for deriving the radio spectrum of electrical discharges from the properties of the time series of charges crossing the discharge gap. This result is applied to the observed spectra of both terrestrial lightning and Saturn electrical discharge(s) (SED). SED occurrence and power density are shown to have subtle, yet important, differences from these observables as they have been described in the last 5 years. It is demonstrated that throughout the episode of Voyager 1's (V1) closest approach to Saturn, SED probably occurred continuously in frequency upward at least from the upper limit of Saturn kilometric radiation at about 800 kHz. This is so despite the fact that in the dynamic spectra a strip in time and frequency in which SED do not occur extends in frequency from 1.3 MHz up to the oft-discussed lower limit of SED in the leading edge of the episode of closest approach. The greater power in SED that occurred after V1 closest approach is emphasized: it is shown to be consistent with the lower frequency of the maximum in their power spectra. The variable gap length factor is also invoked to explain the variable frequency cutoff in the range 5-15 MHz of the episodes before closest approach. The SED source moved along a single arc defining both preencounter and postencounter events. The discharge gap lengths were a continuous function of position along this arc, with the shortest gaps lying about 5 degree west (as seen from the spacecraft) of the noon meridian of Saturn and the longest gaps lying on the nightside of the planet

  17. Diogene, a 4π detector for the heavy ion physics with Saturne

    International Nuclear Information System (INIS)

    Alard, J.P.; Augerat, J.; Babinet, R.

    A 4π-detection set up is presently being built around the Saturne II facility, to study central collisions between high energy heavy ions. This set up is essentially composed of a cylindrical drift chamber, triggered by a 30-scintillators multiplicity filter. A schematic description of the detector is given first. Then the present status of the project is presented, at last some progresses on track reconstruction technique with simulated events are given [fr

  18. Comparing Jupiter and Saturn: dimensionless input rates from plasma sources within the magnetosphere

    Directory of Open Access Journals (Sweden)

    V. M. Vasyliūnas

    2008-06-01

    Full Text Available The quantitative significance for a planetary magnetosphere of plasma sources associated with a moon of the planet can be assessed only by expressing the plasma mass input rate in dimensionless form, as the ratio of the actual mass input to some reference value. Traditionally, the solar wind mass flux through an area equal to the cross-section of the magnetosphere has been used. Here I identify another reference value of mass input, independent of the solar wind and constructed from planetary parameters alone, which can be shown to represent a mass input sufficiently large to prevent corotation already at the source location. The source rate from Enceladus at Saturn has been reported to be an order of magnitude smaller (in absolute numbers than that from Io at Jupiter. Both reference values, however, are also smaller at Saturn than at Jupiter, by factors ~40 to 60; expressed in dimensionless form, the estimated mass input from Enceladus may be larger than that from Io by factors ~4 to 6. The magnetosphere of Saturn may thus, despite a lower mass input in kg s−1, intrinsically be more heavily mass-loaded than the magnetosphere of Jupiter.

  19. Dynamics Of Saturn'S Mid-scale Storms In The Cassini Era.

    Science.gov (United States)

    Del Rio Gaztelurrutia, Teresa; Hueso, R.; Sánchez-Lavega, A.

    2010-10-01

    Convective storms, similar to those in Earth, but of much larger scale, develop often in Saturn's atmosphere. During the Voyagers’ flybys of Saturn in 1981 mid-scale storms, with an horizontal extension of the order of 1000-3000 km were observed to occur mainly in a narrow tropical-latitude band in the Northern hemisphere at latitudes 38-40 deg North. Contrasting with the Voyagers’ era, since the starting of the Cassini mission in 2004, a similar mid-scale convective activity has concentrated in the so-called "storm alley", a narrow band at a symmetric Southern latitude of 38 deg.. In this work, we characterize this storm activity using available visual information provided by Cassini ISS cameras and the continuous survey from the Earth by the International Outer Planets Watch (IOPW) and its online database PVOL (Hueso et al., Planetary and Space Science, 2010). We study the frequency of appearance of storms with sizes above 2000 km, their characteristic size and life-time, as well as their interaction with surrounding dynamical features. In particular we examine the possibility that storms might provide a mechanism of injection of energy into Saturn's jets, the influence of storms in the generation of atmospheric vortices, and the analogies and differences of Voyagers’ and present day jet structure at the relevant latitudes. Acknowledgments: This work has been funded by the Spanish MICIIN AYA2009-10701 with FEDER support and Grupos Gobierno Vasco IT-464

  20. Comparing Jupiter and Saturn: dimensionless input rates from plasma sources within the magnetosphere

    Directory of Open Access Journals (Sweden)

    V. M. Vasyliūnas

    2008-06-01

    Full Text Available The quantitative significance for a planetary magnetosphere of plasma sources associated with a moon of the planet can be assessed only by expressing the plasma mass input rate in dimensionless form, as the ratio of the actual mass input to some reference value. Traditionally, the solar wind mass flux through an area equal to the cross-section of the magnetosphere has been used. Here I identify another reference value of mass input, independent of the solar wind and constructed from planetary parameters alone, which can be shown to represent a mass input sufficiently large to prevent corotation already at the source location. The source rate from Enceladus at Saturn has been reported to be an order of magnitude smaller (in absolute numbers than that from Io at Jupiter. Both reference values, however, are also smaller at Saturn than at Jupiter, by factors ~40 to 60; expressed in dimensionless form, the estimated mass input from Enceladus may be larger than that from Io by factors ~4 to 6. The magnetosphere of Saturn may thus, despite a lower mass input in kg s−1, intrinsically be more heavily mass-loaded than the magnetosphere of Jupiter.

  1. The Atacama Cosmology Telescope: Beam Measurements and the Microwave Brightness Temperatures of Uranus and Saturn

    Science.gov (United States)

    Hasselfield, Matthew; Moodley, Kavilan; Bond, J. Richard; Das, Sudeep; Devlin, Mark J.; Dunkley, Joanna; Dunner, Rolando; Fowler, Joseph W.; Gallardo, Patricio; Gralla, Megan B.; hide

    2013-01-01

    We describe the measurement of the beam profiles and window functions for the Atacama Cosmology Telescope (ACT), which operated from 2007 to 2010 with kilopixel bolometer arrays centered at 148, 218, and 277 GHz. Maps of Saturn are used to measure the beam shape in each array and for each season of observations. Radial profiles are transformed to Fourier space in a way that preserves the spatial correlations in the beam uncertainty to derive window functions relevant for angular power spectrum analysis. Several corrections are applied to the resulting beam transforms, including an empirical correction measured from the final cosmic microwave background (CMB) survey maps to account for the effects of mild pointing variation and alignment errors. Observations of Uranus made regularly throughout each observing season are used to measure the effects of atmospheric opacity and to monitor deviations in telescope focus over the season. Using the WMAP-based calibration of the ACT maps to the CMB blackbody, we obtain precise measurements of the brightness temperatures of the Uranus and Saturn disks at effective frequencies of 149 and 219 GHz. For Uranus we obtain thermodynamic brightness temperatures T(149/U) = 106.7 +/- 2.2 K and T(219/U) = 100.1 +/- 3.1 K. For Saturn, we model the effects of the ring opacity and emission using a simple model and obtain resulting (unobscured) disk temperatures of T(149/S) = 137.3 +/- 3.2 K and T(219/S) = 137.3 +/- 4.7 K.

  2. SATURN-FS 1: A computer code for thermo-mechanical fuel rod analysis

    International Nuclear Information System (INIS)

    Ritzhaupt-Kleissl, H.J.; Heck, M.

    1993-09-01

    The SATURN-FS code was written as a general revision of the SATURN-2 code. SATURN-FS is capable to perform a complete thermomechanical analysis of a fuel pin, with all thermal, mechanical and irradiation-based effects. Analysis is possible for LWR and for LMFBR fuel pins. The thermal analysis consists of calculations of the temperature profile in fuel, gap and in the cladding. Pore migration, stoichiometry change of oxide fuel, gas release and diffusion effects are taken into account. The mechanical modeling allows the non steady-state analysis of elastic and nonelastic fuel pin behaviour, such as creep, strain hardening, recovery and stress relaxation. Fuel cracking and healing is taken into account as well as contact and friction between fuel and cladding. The modeling of the irradiation effects comprises swelling and fission gas production, Pu-migration and irradiation induced creep. The code structure, the models and the requirements for running the code are described in the report. Recommendations for the application are given. Program runs for verification and typical examples of application are given in the last part of this report. (orig.) [de

  3. Quasi-periodic 1-hour pulsations in the Saturn's outer magnetosphere

    Science.gov (United States)

    Rusaitis, L.; Khurana, K. K.; Walker, R. J.; Kivelson, M.

    2017-12-01

    Pulsations in the Saturn's magnetic field and particle fluxes of approximately 1-hour periodicity have been frequently detected in the outer Saturnian magnetosphere by the Cassini spacecraft since 2004. These particle and magnetic field enhancements have been typically observed more often in the dusk sector of the planet, and mid to high latitudes. We investigate nearly 200 of these events as detected by the magnetometer and the Cassini Low-Energy Magnetospheric Measurement System detector (LEMMS) data during the 2004-2015 time frame to characterize these pulsations and suggest their origin. The mechanism needed to produce these observed enhancements needs to permit the acceleration of the energetic electrons to a few MeV and a variable periodicity of enhancements from 40 to 90 minutes. We examine the relation of the oscillations to the periodic power modulations in Saturn kilometric radiation (SKR), using the SKR phase model of Kurth et al. [2007] and Provan et al. [2011]. Finally, we show that similar pulsations can also be observed at 2.5-D MHD simulations of Saturn's magnetosphere.

  4. An Ionosphere/Magnetosphere Coupling Current System Located in the Gap Between Saturn and its Rings

    Science.gov (United States)

    Khurana, K. K.; Dougherty, M. K.; Cao, H.; Hunt, G. J.; Provan, G.

    2017-12-01

    The Grand Finale Orbits of the Cassini spacecraft traversed through Saturn's D ring and brought the spacecraft to within 3000 km of Saturn's cloud tops. The closest approaches (CA) were near the equatorial plane of Saturn and were distributed narrowly around the local noon. The difference field (observations - internal field - magnetospheric ring current field) obtained from the Grand Finale orbits show persistent residual fields centered around the CA which diminish at higher latitudes on field lines that connect to the ring. Modeling of this perturbation in terms of internal harmonics shows that the perturbation is not of internal origin but is produced by external currents that couple the ionosphere to the magnetosphere. The sense of the current system suggests that the southern feet of the field lines in the ionosphere lead their northern footprints. We show that the observed field perturbations are consistent with a meridional Pedersen current whose strength is 1 MA/radian, i.e. comparable in strength to the Planetary-period-oscillation related current systems observed in the auroral zone. We show that the implied Lorentz force in the ionosphere extracts momentum from the faster moving southern ionosphere and passes it on to the northern ionosphere. We discuss several ideas for generating this current system. In particular, we highlight a mechanism that involves shears in the neutral winds in the thermospheric region to generate the observed magnetic field.

  5. Lit and unlit side temperatures of the Main Rings of Saturn.

    Science.gov (United States)

    Flandes, A.; Garcia, A.; Deau, E.; Spilker, L. J.

    2017-12-01

    The differences in the temperatures of both the lit and unlit sides of the main rings of Saturn can reveal important information about their structure. In general, the temperature of the main rings strongly depends upon the distribution and the general structure of the ensembles of particles that compose them, mainly due to shadowing effects that modulate how much energy reaches the individual particles -granted that the direct solar energy is the main driver of the rings' temperature-. In order to reproduce the temperatures of both sides of the rings, we use a semi-analytical energy balance model (considering solar direct and Saturn reflected energy, Saturn thermal energy and particles' thermal energies), where the shadowed fractional areas of the rings are removed through a shadowing function. We obtain this function (dependent on the solar elevation angle) for 13 different regions (for the A, CD, B and C rings) along the radial direction that are simulated using arrays of lambertian spherical particles based on the average properties of the structure of these regions derived from the Cassini UVIS observations. The obtained synthetic temperatures are compared to the Cassini CIRS measured temperatures (from -22º to equinox) with good agreement.

  6. Imaging

    International Nuclear Information System (INIS)

    Kellum, C.D.; Fisher, L.M.; Tegtmeyer, C.J.

    1987-01-01

    This paper examines the advantages of the use of excretory urography for diagnosis. According to the authors, excretory urography remains the basic radiologic examination of the urinary tract and is the foundation for the evaluation of suspected urologic disease. Despite development of the newer diagnostic modalities such as isotope scanning, ultrasonography, CT, and magnetic resonsance imaging (MRI), excretory urography has maintained a prominent role in ruorradiology. Some indications have been altered and will continue to change with the newer imaging modalities, but the initial evaluation of suspected urinary tract structural abnormalities; hematuria, pyuria, and calculus disease is best performed with excretory urography. The examination is relatively inexpensive and simple to perform, with few contraindictions. Excretory urography, when properly performed, can provide valuable information about the renal parenchyma, pelvicalyceal system, ureters, and urinary bladder

  7. Revolutionary Climatology: Rings of Saturn, Ringed by Red Lightning

    Directory of Open Access Journals (Sweden)

    Sarah K. Stanley

    2016-05-01

    Full Text Available Walter Benjamin’s concept of historical materialism is considered as a practice of media archaeology invented through literary montage and photo philosophy. The Arcades Project that facilitated this new research methodology involving a mobile archive. The main case involving architectural theory considers how Benjamin redeployed Sigfried Giedion and Laszlo Moholy-Nagy’s Building in France as a media environment, drawing upon its layout design, photo illustrations and textual systems. In terms of his urban writing, a reading of ‘A Berlin Chronicle’ considers how the diagram contributes to Benjamin’s archaeological methods, as a theory to generate site writing. Benjamin’s mode of media archaeology is then employed to map the arcades architecture onto the train stations and libraries in Berlin and Paris, sites that informed The Arcades Project. The final section assembles a set of citations as ‘Revolutionary Climatology’, thought-images as flashes of red lightning.

  8. Cassini UVIS solar occultations by Saturn's F ring and the detection of collision-produced micron-sized dust

    Science.gov (United States)

    Becker, Tracy M.; Colwell, Joshua E.; Esposito, Larry W.; Attree, Nicholas O.; Murray, Carl D.

    2018-05-01

    We present an analysis of eleven solar occultations by Saturn's F ring observed by the Ultraviolet Imaging Spectrograph (UVIS) on the Cassini spacecraft. In four of the solar occultations we detect an unambiguous signal from diffracted sunlight that adds to the direct solar signal just before or after the occultations occur. The strongest detection was a 10% increase over the direct signal that was enabled by the accidental misalignment of the instrument's pointing. We compare the UVIS data with images of the F ring obtained by the Cassini Imaging Science Subsystem (ISS) and find that in each instance of an unambiguous diffraction signature in the UVIS data, the ISS data shows that there was a recent disturbance in that region of the F ring. Similarly, the ISS images show a quiescent region of the F ring for all solar occultations in which no diffraction signature was detected. We therefore conclude that collisions in the F ring produce a population of small ring particles that can produce a detectable diffraction signal immediately interior or exterior to the F ring. The clearest example of this connection comes from the strong detection of diffracted light in the 2007 solar occultation, when the portion of the F ring that occulted the Sun had suffered a large collisional event, likely with S/2004 S 6, several months prior. This collision was observed in a series of ISS images (Murray et al., 2008). Our spectral analysis of the data shows no significant spectral features in the F ring, indicating that the particles must be at least 0.2 μm in radius. We apply a forward model of the solar occultations, accounting for the effects of diffracted light and the attenuated direct solar signal, to model the observed solar occultation light curves. These models constrain the optical depth, radial width, and particle size distribution of the F ring. We find that when the diffraction signature is present, we can best reproduce the occultation data using a particle population

  9. The exploitation of the Saturne synchrotron during the second quarter of 1959; L'exploitation du synchrotron Saturne pendant le 2eme trimestre 1959

    Energy Technology Data Exchange (ETDEWEB)

    Detoeuf, J. F.; Falk-Vairant, P.; Van Rossum, L.; Valladas, G.; Yuan, L. C.L.

    1959-08-15

    The first part gives an overview of Saturne operation during a quarter, and indicates time distribution among starting up, adjustment and maintenance, physics experiments, constructor interventions. It also evokes some problems encountered and data obtained for beam intensity. The second part addresses studies performed on the equipment: studies and correction of trajectory anomalies. The third part briefly evokes physics experiments performed by different research teams (notably the measurement of the total cross section), and some quantitative data illustrating this activity. The fourth part discusses measurements of radiation intensity in different locations of the building, measurements of radiation doses, and the study of newly installed protections (measurement of radiation absorption, attenuation of the direct radiation from targets through the roof). The fifth part proposes a quantitative comparison of the activity between the two first quarters.

  10. Solar System Exploration Augmented by In-Situ Resource Utilization: Human Planetary Base Issues for Mercury and Saturn

    Science.gov (United States)

    Palaszewski, Bryan A.

    2017-01-01

    Human and robotic missions to Mercury and Saturn are presented and analyzed with a range of propulsion options. Historical studies of space exploration, planetary spacecraft, and astronomy, in-situ resource utilization (ISRU), and industrialization all point to the vastness of natural resources in the solar system. Advanced propulsion benefitted from these resources in many ways. While advanced propulsion systems were proposed in these historical studies, further investigation of nuclear options using high power nuclear thermal and nuclear pulse propulsion as well as advanced chemical propulsion can significantly enhance these scenarios. Updated analyses based on these historical visions are presented. Nuclear thermal propulsion and ISRU enhanced chemical propulsion landers are assessed for Mercury missions. At Saturn, nuclear pulse propulsion with alternate propellant feed systems and Saturn moon exploration with chemical propulsion and nuclear electric propulsion options are discussed. Issues with using in-situ resource utilization on Mercury missions are discussed. At Saturn, the best locations for exploration and the use of the moons Titan and Enceladus as central locations for Saturn moon exploration is assessed.

  11. Saturn Rings Origin: Quantum Trapping of Superconducting Iced Particles and Meissner Effect Lead to the Stable Rings System

    Science.gov (United States)

    Viktorovich Tchernyi, Vladimir

    2018-06-01

    Saturn Rings Origin: Quantum Trapping of Superconducting Iced Particles and Meissner Effect Lead to the Stable Rings System Vladimir V. Tchernyi (Cherny), Andrew Yu. Pospelov Modern Science Institute, SAIBR, Moscow, Russia. E-mail: chernyv@bk.ruAbstractIt is demonstrated how superconducting iced particles of the protoplanetary cloud of Saturn are coming to magnetic equator plane and create the stable enough rings disk. There are two steps. First, after appearance of the Saturn magnetic field due to Meissner phenomenon all particles orbits are moving to the magnetic equator plane. Finally they become distributed as rings and gaps like iron particles around magnet on laboratory table. And they are separated from each other by the magnetic field expelled from them. It takes up to few tens of thousands years with ten meters rings disk thickness. Second, due to their quantum trapping all particles become to be trapped within magnetic well at the magnetic equator plane due to Abrikosov vortex for superconductor. It works even when particles have small fraction of superconductor. During the rings evolution some contribution to the disk also could come from the collision-generated debris of the current moon and from the geysers like it happened due to magnetic coupling of Saturn and Enceladus. The rings are relict of the early days of the magnetic field of Saturn system.

  12. Response of Saturn's ionosphere to solar radiation: Testing parameterizations for thermal electron heating and secondary ionization processes

    Science.gov (United States)

    Moore, Luke; Galand, Marina; Mueller-Wodarg, Ingo; Mendillo, Michael

    2009-12-01

    We evaluate the effectiveness of two parameterizations in Saturn's ionosphere over a range of solar fluxes, seasons, and latitudes. First, the parameterization of the thermal electron heating rate, Q* e, introduced in [Moore, L., Galand, M., Mueller-Wodarg, I., Yelle, R.V., Mendillo, M., 2008. Plasma temperatures in Saturn's ionosphere. J. Geophys. Res. 113, A10306. doi:10.1029/2008JA013373.] for one specific set of conditions, is found to produce ion and electron temperatures that agree with self-consistent suprathermal electron calculations to within 2% on average under all conditions considered. Next, we develop a new parameterization of the secondary ion production rate at Saturn based on the calculations of [Galand, M., Moore, L., Mueller-Wodarg, I., Mendillo, M., 2009. Modeling the photoelectron secondary ionization process at Saturn. accepted. J. Geophys. Res.]; it is found to be accurate to within 4% on average. The demonstrated effectiveness of these two parameterizations over a wide range of input conditions makes them good candidates for inclusion in 3D Saturn thermosphere-ionosphere general circulation models (TIGCMs).

  13. Explorer of Enceladus and Titan (E2T): Investigating Ocean Worlds' Evolution and Habitability in the Saturn System

    Science.gov (United States)

    Mitri, Giuseppe

    2017-04-01

    The NASA-ESA Cassini-Huygens mission has revealed Titan and Enceladus to be two of the most interesting worlds in the Solar System. Titan, with its organically rich and dynamic atmosphere and geology, and Enceladus, with its active plumes, both harboring subsurface oceans, are prime environments in which to investigate the conditions for the emergence of life and the habitability of ocean worlds. Explorer of Enceladus and Titan (E2T) is dedicated to investigating the evolution and habitability of these Saturnian satellites and is proposed in response to ESA's M5 Call as a medium-class mission led by ESA in collaboration with NASA. E2T has a focused payload that will provide in-situ composition investigations and high-resolution imaging during multiple flybys of Enceladus and Titan using a solar-electric powered spacecraft in orbit around Saturn. The E2T mission will provide high-resolution mass spectroscopy of the plumes currently emanating from Enceladus's south polar terrain (SPT) and of Titan's changing upper atmosphere. In addition, high-resolution IR imaging will detail Titan's geomorphology at 50-100 m resolution and the source fractures on Enceladus's SPT at meter resolution. These combined measurements of both Titan and Enceladus will permit to achieve the two major scientific goals of the E2T mission: 1) Study the origin and evolution of volatile-rich ocean worlds; and 2) Explore the habitability and potential for life in ocean worlds. More in detail, these goals will be achieved by measuring the nature, abundance and isotopic properties of solid- and vapor-phase species in Enceladus's plume and Titan's upper atmosphere, and determining the processes that are transporting and transforming organic materials on the surface of Titan and the mechanisms controlling, and the energy dissipated by, Enceladus's plumes. E2T's two high-resolution time-of-flight mass spectrometers will enable us to resolve the ambiguities left by Cassini regarding the identification

  14. Transmission measurements for the photon collimator of a Saturne 20 MeV linear accelerator

    International Nuclear Information System (INIS)

    Van Dam, J.; Rijnders, A.; Van Den Bogaert, W.

    1981-01-01

    The dose at 5 cm outside the field limit for the 18 MV X ray beam of the linear accelerator Saturne of the Academic Hospital in Leuven (Belgium) has been measured for square fields in a flat polystyrene phantom with an ionization chamber at 5 cm, 10 cm and 17 cm depth. The measurements have been referred to the field center dose at the same depth. As an indication, for a 25 x 25 cm field at 5 cm depth, the relative dose at 5 cm outside the field is equal to 5.5% and to 2.5% respectively without and with the use of an additional 5 cm thick lead block shielding the chamber outside the field. From the decrease in relative dose outside the field observed with and without the additional shielding block, an important leakage component through the Saturne collimator has been detected. For a typical mantle field set-up thermoluminescent measurements indicate that the relative midline dose (9 cm depth) outside the inferior mediastinal field limit is higher for the 18 MV X ray - than for a 60 Co γ ray beam, when no additional shielding is used for the X ray beam. The relative dose at 5 cm outside the field limit is equal to 4% and 3% for the high energy X ray - and for the 60 Co γ ray beam respectively. So, due to the leakage component through the Saturne collimator, part of the therapeutical advantages of high energy X rays in the case of mantle field treatments are lost

  15. Five Fabulous Flybys of the Small Inner Moons of Saturn by the Cassini Spacecraft

    Science.gov (United States)

    Buratti, B. J.; Momary, T.; Clark, R. N.; Brown, R. H.; Filacchione, G.; Mosher, J. A.; Baines, K. H.; Nicholson, P. D.

    2017-12-01

    The Saturn system possesses a number of small unique moons, including the coorbitals Janus and Epimetheus; the ring moons Pan and Daphnis; and Prometheus, Pandora, and Atlas, which orbit near the edge of the main ring system. During the last phases of the Cassini mission, when the spacecraft executed close passes to the F-ring of Saturn, five "best-ever" flybys of these moons occurred. Pan, Daphnis, Atlas, Pandora, and Epimetheus were approached at distances ranging from 6000-40,000 km. The Visual Infrared Mapping Spectrometer (VIMS) captured data from the spectral range spanning 0.35-5.1 microns, as well as capturing solar phase angles not observed before. When combined with spectra from different regions of the moons obtained throughout the mission, the VIMS observations reveal substantial changes in the depth of water-ice absorption bands and color over the moons' surfaces. These measurements show the accretion of main-ring material onto the moons, with leading sides exhibiting stronger water-ice signatures in general. Atlas and Pandora have red visible spectra similar to the A-ring and unlike other icy moons, which are blue, further revealing accretion of main ring material onto the small inner moons. In general the visible spectra of the moons gets bluer with distance from Saturn until the surface of the moons is dominated by contamination from the E-ring, which is composed of fresh ice. There is a weak correlation between color and albedo, with lower-albedo moons being redder, suggesting the existence of a dark reddish contaminant from the main ring system. The solar phase curves of the moons are similar to those of larger icy moons (unfortunately no opposition surge data was gathered). 2017 California Institute of Technology. Government sponsorship acknowledged.

  16. The effect of the equatorially symmetric zonal winds of Saturn on its gravitational field

    Science.gov (United States)

    Kong, Dali; Zhang, Keke; Schubert, Gerald; Anderson, John D.

    2018-04-01

    The penetration depth of Saturn’s cloud-level winds into its interior is unknown. A possible way of estimating the depth is through measurement of the effect of the winds on the planet’s gravitational field. We use a self-consistent perturbation approach to study how the equatorially symmetric zonal winds of Saturn contribute to its gravitational field. An important advantage of this approach is that the variation of its gravitational field solely caused by the winds can be isolated and identified because the leading-order problem accounts exactly for rotational distortion, thereby determining the irregular shape and internal structure of the hydrostatic Saturn. We assume that (i) the zonal winds are maintained by thermal convection in the form of non-axisymmetric columnar rolls and (ii) the internal structure of the winds, because of the Taylor-Proundman theorem, can be uniquely determined by the observed cloud-level winds. We calculate both the variation ΔJn , n = 2, 4, 6 … of the axisymmetric gravitational coefficients Jn caused by the zonal winds and the non-axisymmetric gravitational coefficients ΔJnm produced by the columnar rolls, where m is the azimuthal wavenumber of the rolls. We consider three different cases characterized by the penetration depth 0.36, R S, 0.2, R S and 0.1, R S, where R S is the equatorial radius of Saturn at the 1-bar pressure level. We find that the high-degree gravitational coefficient (J 12 + ΔJ 12) is dominated, in all the three cases, by the effect of the zonal flow with |ΔJ 12/J 12| > 100% and that the size of the non-axisymmetric coefficients ΔJ mn directly reflects the depth and scale of the flow taking place in the Saturnian interior.

  17. THE ATACAMA COSMOLOGY TELESCOPE: BEAM MEASUREMENTS AND THE MICROWAVE BRIGHTNESS TEMPERATURES OF URANUS AND SATURN

    Energy Technology Data Exchange (ETDEWEB)

    Hasselfield, Matthew [Department of Astrophysical Sciences, Peyton Hall, Princeton University, Princeton, NJ 08544 (United States); Moodley, Kavilan [Astrophysics and Cosmology Research Unit, School of Mathematics, Statistics, and Computer Science, University of KwaZulu-Natal, Durban 4041 (South Africa); Bond, J. Richard; Hajian, Amir; Hincks, Adam D.; Nolta, Michael R. [Canadian Institute for Theoretical Astrophysics, University of Toronto, Toronto, ON M5S 3H8 (Canada); Das, Sudeep [High Energy Physics Division, Argonne National Laboratory, 9700 South Cass Avenue, Lemont, IL 60439 (United States); Devlin, Mark J.; Marsden, Danica; Schmitt, Benjamin L. [Department of Physics and Astronomy, University of Pennsylvania, 209 South 33rd Street, Philadelphia, PA 19104 (United States); Dunkley, Joanna [Department of Astrophysics, Oxford University, Oxford OX1 3RH (United Kingdom); Dünner, Rolando; Gallardo, Patricio [Departamento de Astronomía y Astrofísica, Facultad de Física, Pontificía Universidad Católica, Casilla 306, Santiago 22 (Chile); Fowler, Joseph W.; Niemack, Michael D. [NIST Quantum Devices Group, 325 Broadway Mailcode 817.03, Boulder, CO 80305 (United States); Gralla, Megan B.; Marriage, Tobias A. [Department of Physics and Astronomy, The Johns Hopkins University, 3400 North Charles Street, Baltimore, MD 21218-2686 (United States); Halpern, Mark [Department of Physics and Astronomy, University of British Columbia, Vancouver, BC V6T 1Z4 (Canada); Page, Lyman A. [Joseph Henry Laboratories of Physics, Jadwin Hall, Princeton University, Princeton, NJ 08544 (United States); Partridge, Bruce [Department of Physics and Astronomy, Haverford College, Haverford, PA 19041 (United States); and others

    2013-11-01

    We describe the measurement of the beam profiles and window functions for the Atacama Cosmology Telescope (ACT), which operated from 2007 to 2010 with kilopixel bolometer arrays centered at 148, 218, and 277 GHz. Maps of Saturn are used to measure the beam shape in each array and for each season of observations. Radial profiles are transformed to Fourier space in a way that preserves the spatial correlations in the beam uncertainty to derive window functions relevant for angular power spectrum analysis. Several corrections are applied to the resulting beam transforms, including an empirical correction measured from the final cosmic microwave background (CMB) survey maps to account for the effects of mild pointing variation and alignment errors. Observations of Uranus made regularly throughout each observing season are used to measure the effects of atmospheric opacity and to monitor deviations in telescope focus over the season. Using the WMAP-based calibration of the ACT maps to the CMB blackbody, we obtain precise measurements of the brightness temperatures of the Uranus and Saturn disks at effective frequencies of 149 and 219 GHz. For Uranus we obtain thermodynamic brightness temperatures T{sub U}{sup 149}= 106.7 ± 2.2 K and T{sub U}{sup 219}= 100.1 ± 3.1 K. For Saturn, we model the effects of the ring opacity and emission using a simple model and obtain resulting (unobscured) disk temperatures of T{sub S}{sup 149}= 137.3 ± 3.2 K and T{sub S}{sup 219}= 137.3 ± 4.7 K.

  18. Physical properties of the Saturn's rings with the opposition effect.

    Science.gov (United States)

    Deau, E.

    2012-04-01

    We use the Cassini/ISS images from the early prime mission to build lit phase curves data from 0.01 degrees to 155 degrees at a solar elevation of 23-20 degrees. All the main rings exhibit on their phase curves a prominent surge at small phase angles. We use various opposition effect models to explain the opposition surge of the rings, including the coherent backscattering, the shadow hiding and a combination of the two (Kawata & Irvine 1974 In: Exploration of the planetary system Book p441; Shkuratov et al. 1999, Icarus, 141, p132; Poulet et al. 2002 Icarus, 158, p224 ; Hapke et al. 2002 Icarus, 157, p523). Our results show that either the coherent backscattering alone or a combination of the shadow hiding and the coherent backscattering can explain the observations providing physical properties (albedo, filling factor, grain size) consistent with previous other studies. However, they disagree with the most recent work of Degiorgio et al. 2011 (EPSC-DPS Abstract #732). We think that their attempt to use the shadow hiding alone lead to unrealistic values of the filling factor of the ring particles layer. For example they found 10^-3 in one of the thickest regions of the C ring (a plateau at R=88439km with an optical depth tau=0.22). We totally disagree with their conclusions stating that these values are consistent for the C ring plateaux and did not found any references that are consistent with theirs, as they claimed. We believe that their unrealistic values originated from the assumptions of the models they used (Kawata & Irvine and Hapke), which are basically an uniform size distribution. Any model using an uniform size distribution force the medium to be very diluted to reproduce the opposition surge. Our modeling that uses a power law size distribution provides realistic values. All these results have been already published previously (http://adsabs.harvard.edu/abs/2007PhDT........25D) and are summarized in a forthcoming manuscript submitted to publication so

  19. CIRS High-Resolution Thermal Scans and the Structure of Saturn's B Ring

    Science.gov (United States)

    Brooks, S. M.; Spilker, L. J.; Showalter, M.; Pilorz, S.; Edgington, S. G.

    2017-12-01

    The flyby of Titan on November 29, 2016, sent the Cassini spacecraft on a trajectory that would take it within 10,000 kilometers of Saturn's F ring multiple times before a subsequent Titan encounter on April 22, 2017, would send it on ballistic trajectory carrying it between Saturn's cloud tops and the planet's D ring for several flybys. This geometry has proven beneficial for high-resolution studies of the rings, not just because of Cassini's proximity to the rings, but also because of the spacecraft's high elevation angle above the rings, which reduces the foreshortening that tends to degrade resolution in the ring plane. We will report on several observations of Saturn's main rings at the high spatial resolutions enabled by the end-of-mission geometry, particulary the B ring, with the Composite Infrared Spectrometer onboard Cassini during the F-ring and proximal orbits. CIRS' three infrared detectors cover a combined spectral range of 10 to 1400 cm-1 (1 mm down to 7 microns). We focus on data from Focal Plane 1, which covers the 10 to 600 cm-1 range (1 mm to 16 microns). The apodized spectral resolution of the instrument can be varied from 15 cm-1 to 0.5 cm-1 (Flasar et al. 2004). FP1's wavelength range makes it well-suited to sensing thermal emission from objects at temperatures typical of Saturn's rings. Correlating ring optical depth with temperatures retrieved from scans of the face of the rings exposed to direct solar illumination (the lit face) and the opposite (unlit) face suggests differences in ring structure or particle transport between the lit and unlit sides of the rings in different regions of the B ring. Lit side temperatures in the core of the B ring range between 82 and 87 K; temperatures on the unlit side of the core vary from 66 K up to 74 K. Ferrari and Reffet (2013) and Pilorz et al. (2015) published thorough analyses of the thermal throughput across this optically thick ring. We will discuss these recent CIRS rings observations and their

  20. Astrometric observations of Saturn's satellites from McDonald Observatory, 1972. [using reference stars

    Science.gov (United States)

    Abbot, R. I.; Mulholland, J. D.; Shelus, P. J.

    1974-01-01

    Observations of Saturn's satellites were reduced by means of secondary reference stars obtained by reduction of Palomar Sky Survey (PSS) plates. This involved the use of 39 SAO stars and plate overlap technique to determine the coordinates of 59 fainter stars in the satellite field. Fourteen plate constants were determined for each of the two PSS plates. Comparison of two plate measurement and reduction techniques on the satellite measurements demonstrate the existence of a serious background gradient effect and the utility of microdensitometry to eliminate this error source in positional determinations of close satellites.

  1. Conformal Ablative Thermal Protection Systems (CA-TPS) for Venus and Saturn Backshells

    Science.gov (United States)

    Beck, R.; Gasch, M.; Stackpoole, M.; Wilder, M.; Boghozian, T.; Chavez-Garcia, J.; Prabhu, Dinesh; Kazemba, Cole D.; Venkatapathy, E.

    2016-01-01

    This poster provides an overview of the work performed to date on the Conformal Ablative TPS (CA-TPS) element of the TPSM project out of GCDP. Under this element, NASA is developing improved ablative TPS materials based on flexible felt for reinforcement rather than rigid reinforcements. By replacing the reinforcements with felt, the resulting materials have much higher strain-to-failure and are much lower in thermal conductivity than their rigid counterparts. These characteristics should allow for larger tile sizes, direct bonding to aeroshells and even lower weight TPS. The conformal phenolic impregnated carbon felt (C-PICA) is a candidate for backshell TPS for both Venus and Saturn entry vehicles.

  2. New-particle formation events in a continental boundary layer: first results from the SATURN experiment

    Directory of Open Access Journals (Sweden)

    F. Stratmann

    2003-01-01

    Full Text Available During the SATURN experiment, which took place from 27 May to 14 June 2002, new particle formation in the continental boundary layer was investigated. Simultaneous ground-based and tethered-balloon-borne measurements were performed, including meteorological parameters, particle number concentrations and size distributions, gaseous precursor concentrations and SODAR and LIDAR observations. Newly formed particles were observed inside the residual layer, before the break-up process of the nocturnal inversion, and inside the mixing layer throughout the break-up of the nocturnal inversion and during the evolution of the planetary boundary layer.

  3. Astrometric observations of Saturn's satellites from McDonald Observatory, 1972

    Science.gov (United States)

    Abbot, R. I.; Mulholland, J. D.; Shelus, P. J.

    1975-01-01

    Observations of Saturn's satellites have been reduced by means of secondary reference stars obtained by reduction of Palomar Sky Survey plates. This involved the use of 29 SAO stars and plate overlap technique to determine the coordinates of 59 fainter stars in the satellite field. Fourteen plate constants were determined for each of the two PSS plates. Comparison of two plate measurement and reduction techniques on the satellite measures appears to demonstrate the existence of a serious background gradient effect and the utility of microdensitometry to eliminate this error source in positional determinations of close satellites.

  4. Witches and Indian Women, Daughters of Saturn: Arts, Witchcraft and Cannibalism

    Directory of Open Access Journals (Sweden)

    Yobenj Aucardo Chicangana-Bayona

    2009-01-01

    Full Text Available The article inquires into the representation of women in the paintings and engravings about witchcraft in the XVI-XVII centuries, trying to establish an iconographic typology and covering the construction of negative stigmas attributed to the feminine body and its natural degradation. Through the support of visual sources such as paintings and engravings, mainly from the German Renaissance, the text demonstrates how the Indian women of the New World were associated to the witches of Europe and with the classic god Saturn, through the myth of cannibalism.

  5. Spin-isospin excitations induced by heavy ions at Saturne energies

    International Nuclear Information System (INIS)

    Hennino, T.

    1989-01-01

    Our program on the Spin-Isospin excitations started with the ( 3 He, 3 H) and ( 2 H, 2 He) reactions was extended with the heavy ion beams available at Saturne ( 12 C, 16 0, 20 Ne and 40 Ar) to study systematically the Δ excitation energy region. Projectile-ejectile dependences were measured. The Δ peak shift appears as a common feature in all charge exchange reactions. The first cross section calculations for the ( 12 C, 12 N) reaction are in good quantitative agreement with the data [fr

  6. The Diogene detector and relativistic heavy ion collisions. First experiments at Saturne

    International Nuclear Information System (INIS)

    Alard, J.P.; Augerat, J.; Babinet, R.

    1983-01-01

    Relativistic heavy ion collisions are important for a study of nuclear matter properties, at high density temperature. The use of high multiplicity detectors, with a 4π solid angle, permit more exclusive experiments which are essential for an approach of collision mechanisms and for the observation of eventual exotic phenomena. Also, we present some preliminary results, obtained with a 800 MeV/nucl α particle beam and concerning the performances of the Diogene detector actually setted up at the Laboratoire National Saturne at Saclay [fr

  7. The EBIS-RFQ couple: a fully matched heavy ion 3rd pre-injector for Saturne

    International Nuclear Information System (INIS)

    Olivier, M.; Faure, J.; Laclare, J.L.; Lefebvre, J.M.; Leleux, G.; Ropert, A.; Tkatchenko, A.; Tkatchenko, M.

    1983-01-01

    Since 1978, the 3 GeV Synchrotron Saturne is routinely operated with proton, deuteron, helium beams and, since 1981 with polarized protons and deuterons. Heavy ions are expected in the Summer of 1983 by using a new pre-injector presently under construction. As already proposed by R.W.Hamm, the marriage of an EBIS and an RFQ can be looked upon generally as a very good means of production of heavy ion beams at low energy because it combines high charges states, therefore low voltage on the terminal, and low velocity acceleration. After the RFQ, the beam is injected into Saturne through 20 MeV Alvarez linac

  8. PUBLIC AFFAIRS DIRECTOR HUGH HARRIS SPEAKS AT THE APOLLO/SATURN V CENTER RIBBON-CUTTING CEREMONY

    Science.gov (United States)

    1996-01-01

    NASA/KSC Public Affairs Director Hugh W. Harris gives the welcome and introductions at the ribbon-cutting ceremony to officially open the new Apollo/Saturn V Center, part of the Kennedy Space Center Visitor Center. The 100,000- square-foot facility includes two theaters, various exhibits and an Apollo-era Saturn V rocket, which formerly was on display outside the Vehicle Assembly Building and is one of only three moon rockets remaining in existence. The new center is located off the Kennedy Parkway at the Banana Creek launch viewing site.

  9. MIGRATION OF A MOONLET IN A RING OF SOLID PARTICLES: THEORY AND APPLICATION TO SATURN'S PROPELLERS

    International Nuclear Information System (INIS)

    Crida, Aurelien; Papaloizou, John C. B.; Rein, Hanno; Charnoz, Sebastien; Salmon, Julien

    2010-01-01

    Hundred-meter-sized objects have been identified by the Cassini spacecraft in Saturn's A ring through the so-called propeller features they create in the ring. These moonlets should migrate due to their gravitational interaction with the ring; in fact, some orbital variations have been detected. The standard theory of type I migration of planets in protoplanetary disks cannot be applied to the ring system as it is pressureless. Thus, we compute the differential torque felt by a moonlet embedded in a two-dimensional disk of solid particles, with a flat surface density profile, both analytically and numerically. We find that the corresponding migration rate is too small to explain the observed variations of the propeller's orbit in Saturn's A ring. However, local density fluctuations (due to gravity wakes in the marginally gravitationally stable A ring) may exert a stochastic torque on a moonlet. Our simulations show that this torque can be large enough to account for the observations depending on the parameters of the rings. We find that on timescales of several years the migration of propellers is likely to be dominated by stochastic effects (while the former, non-stochastic migration dominates after ∼10 4 -10 5 years). In that case, the migration rates provided by observations so far suggest that the surface density of the A ring should be on the order of 700 kg m -2 . The age of the propellers should not exceed 1-100 million years depending on the dominant migration regime.

  10. A Comparative Examination of Plasmoid Structure and Dynamics at Mercury, Earth, Jupiter, and Saturn

    Science.gov (United States)

    Slavin, James A.

    2010-01-01

    The circulation of plasma and magnetic flux within planetary magnetospheres is governed by the solar wind-driven Dungey and planetary rotation-driven cycles. The Dungey cycle is responsible for all circulation at Mercury and Earth. Jupiter and Saturn's magnetospheres are dominated by the Vasyliunas cycle, but there is evidence for a small Dungey cycle contribution driven by the solar wind. Despite these fundamental differences, all well-observed magnetospheres eject relatively large parcels of the hot plasma, termed plasmoids, down their tails at high speeds. Plasmoids escape from the restraining force of the planetary magnetic field through reconnection in the equatorial current sheet separating the northern and southern hemispheres of the magnetosphere. The reconnection process gives the magnetic field threading plasmoids a helical or flux rope-type topology. In the Dungey cycle reconnection also provides the primary tailward force that accelerates plasmoids to high speeds as they move down the tail. We compare the available observations of plasmoids at Mercury, Earth, Jupiter, and Saturn for the purpose of determining the relative role of plasmoids and the reconnection process in the dynamics these planetary magnetic tails.

  11. ELUSIVE ETHYLENE DETECTED IN SATURN'S NORTHERN STORM REGION

    Energy Technology Data Exchange (ETDEWEB)

    Hesman, B. E.; Achterberg, R. K.; Nixon, C. A. [Department of Astronomy, University of Maryland, College Park, MD 20742 (United States); Bjoraker, G. L.; Romani, P. N. [NASA/GSFC Code 693, Greenbelt, MD 20771 (United States); Sada, P. V. [Departamento de Fisica y Matematicas, Universidad de Monterrey, Garza Garcia, NL 66238 (Mexico); Jennings, D. E. [NASA/GSFC Code 693 and Code 500, Greenbelt, MD 20771 (United States); Lunsford, A. W. [Department of Physics, Catholic University of America, Washington, DC 20064 (United States); Fletcher, L. N.; Irwin, P. G. J. [Atmospheric, Oceanic and Planetary Physics, Clarendon Laboratory, Parks Road, Oxford OX1 3PU (United Kingdom); Boyle, R. J. [Department of Physics and Astronomy, Dickinson College, Carlisle, PA 17013 (United States); Simon-Miller, A. A., E-mail: brigette.e.hesman@nasa.gov [NASA/GSFC Code 690, Greenbelt, MD 20771 (United States)

    2012-11-20

    The massive eruption at 40 Degree-Sign N (planetographic latitude) on Saturn in 2010 December has produced significant and lasting effects in the northern hemisphere on temperature and species abundances. The northern storm region was observed on many occasions in 2011 by Cassini's Composite Infrared Spectrometer (CIRS). In 2011 May, temperatures in the stratosphere greater than 200 K were derived from CIRS spectra in the regions referred to as 'beacons' (warm regions in the stratosphere). Ethylene has been detected in the beacon region in Saturn's northern storm region using CIRS. Ground-based observations using the high-resolution spectrometer Celeste on the McMath-Pierce Telescope on 2011 May 15 were used to confirm the detection and improve the altitude resolution in the retrieved profile. The derived ethylene profile from the CIRS data gives a C{sub 2}H{sub 4} mole fraction of 5.9 {+-} 4.5 Multiplication-Sign 10{sup -7} at 0.5 mbar, and from Celeste data it gives 2.7 {+-} 0.45 Multiplication-Sign 10{sup -6} at 0.1 mbar. This is two orders of magnitude higher than the amount measured in the ultraviolet at other latitudes prior to the storm. It is also much higher than predicted by photochemical models, indicating that perhaps another production mechanism is required or a loss mechanism is being inhibited.

  12. Pulling it all together: the self-consistent distribution of neutral tori in Saturn's Magnetosphere based on all Cassini observations

    Science.gov (United States)

    Smith, H. T.; Richardson, J. D.

    2017-12-01

    Saturn's magnetosphere is unique in that the plumes from the small icy moon, Enceladus, serve at the primary source for heavy particles in Saturn's magnetosphere. The resulting co-orbiting neutral particles interact with ions, electrons, photons and other neutral particles to generate separate H2O, OH and O tori. Characterization of these toroidal distributions is essential for understanding Saturn magnetospheric sources, composition and dynamics. Unfortunately, limited direct observations of these features are available so modeling is required. A significant modeling challenge involves ensuring that either the plasma and neutral particle populations are not simply input conditions but can provide feedback to each population (i.e. are self-consistent). Jurac and Richardson (2005) executed such a self-consistent model however this research was performed prior to the return of Cassini data. In a similar fashion, we have coupled a 3-D neutral particle model (Smith et al. 2004, 2005, 2006, 2007, 2009, 2010) with a plasma transport model (Richardson 1998; Richardson & Jurac 2004) to develop a self-consistent model which is constrained by all available Cassini observations and current findings on Saturn's magnetosphere and the Enceladus plume source resulting in much more accurate neutral particle distributions. We present a new self-consistent model of the distribution of the Enceladus-generated neutral tori that is validated by all available observations. We also discuss the implications for source rate and variability.

  13. Optimization of Saturn paraboloid magnetospheric field model parameters using Cassini equatorial magnetic field data

    Directory of Open Access Journals (Sweden)

    E. S. Belenkaya

    2016-07-01

    Full Text Available The paraboloid model of Saturn's magnetosphere describes the magnetic field as being due to the sum of contributions from the internal field of the planet, the ring current, and the tail current, all contained by surface currents inside a magnetopause boundary which is taken to be a paraboloid of revolution about the planet-Sun line. The parameters of the model have previously been determined by comparison with data from a few passes through Saturn's magnetosphere in compressed and expanded states, depending on the prevailing dynamic pressure of the solar wind. Here we significantly expand such comparisons through examination of Cassini magnetic field data from 18 near-equatorial passes that span wide ranges of local time, focusing on modelling the co-latitudinal field component that defines the magnetic flux passing through the equatorial plane. For 12 of these passes, spanning pre-dawn, via noon, to post-midnight, the spacecraft crossed the magnetopause during the pass, thus allowing an estimate of the concurrent subsolar radial distance of the magnetopause R1 to be made, considered to be the primary parameter defining the scale size of the system. The best-fit model parameters from these passes are then employed to determine how the parameters vary with R1, using least-squares linear fits, thus providing predictive model parameters for any value of R1 within the range. We show that the fits obtained using the linear approximation parameters are of the same order as those for the individually selected parameters. We also show that the magnetic flux mapping to the tail lobes in these models is generally in good accord with observations of the location of the open-closed field line boundary in Saturn's ionosphere, and the related position of the auroral oval. We then investigate the field data on six passes through the nightside magnetosphere, for which the spacecraft did not cross the magnetopause, such that in this case we compare the

  14. Hydrocarbons on Saturns Satellites: Relationship to Interstellar Dust and the Solar Nebula

    Science.gov (United States)

    Cruikshank, D. P.

    2012-01-01

    To understand the origin and evolution of our Solar System, and the basic components that led to life on Earth, we study interstellar and planetary spectroscopic signatures. The possible relationship of organic material detected in carbonaceous meteorites, interplanetary dust particles (IDPs), comets and the interstellar medium have been the source of speculation over the years as the composition and processes that governed the early solar nebula have been explored to understand the extent to which primitive material survived or became processed. The Cassini VIMS has provided new data relevant to this problem. Three of Saturn's satellites, Phoebe, Iapetus, and Hyperion, are found to have aromatic and aliphatic hydrocarbons on their surfaces. The aromatic hydrocarbon signature (C-H stretching mode at 3.28 micrometers) is proportionally significantly stronger (relative to the aliphatic bands) than that seen in other Solar System bodies (e.g., comets) and materials (Stardust samples, IDPs, meteorites) and the distinctive sub-features of the 3.4 micrometer aliphatic band (CH2 and CH3 groups) are reminiscent of those widely detected throughout the diffuse ISM. Phoebe may be a captured object that originated in the region beyond the present orbit of Neptune, where the solar nebula contained a large fraction of original interstellar ice and dust that was less processed than material closer to the Sun. Debris from Phoebe now resident on Iapetus and Hyperion, as well as o Phoebe itself, thus presents a unique blend of hydrocarbons, amenable to comparisons with interstellar hydrocarbons and other Solar System materials. The dust ring surrounding Saturn, in which Phoebe is embedded, probably originated from a collision with Phoebe. Dust ring particles are the likely source of the organic-bearing materials, and perhaps the recently identified small particles of Fe detected on Saturn's satellites. Lab measurements of the absolute band strengths of representative aliphatic and

  15. Proton and neutron polarized targets for nucleon-nucleon experiments at SATURNE II

    International Nuclear Information System (INIS)

    Ball, J.; Combet, M.; Sans, J.L.; Benda, B.; Chaumette, P.; Deregel, J.; Durand, G.; Dzyubak, A.P.; Gaudron, C.; Lehar, F.; Janout, Z.; Khachaturov, B.A.

    1996-01-01

    A SATURNE polarized target has been used for nucleon-nucleon elastic scattering and transmission experiments for 15 years. The polarized proton target is a 70 cm 3 cartridge loaded with Pentanol-2. For polarized neutron target, two cartridges loaded with 6 LiD and 6 LiH are set in the refrigerator and can be quickly inserted in the beam. First experiments using 6 Li products in quasielastic pp or pn analyzing power measurements are compared with the same observables measured in a free nucleon-nucleon scattering using polarized proton targets. Angular distribution as a function of a kinematically conjugate angle and coplanarity in nucleon-nucleon scattering is shown for different targets. (author)

  16. Effect of the tiger stripes on the deformation of Saturn's moon Enceladus

    Science.gov (United States)

    Souček, Ondřej; Hron, Jaroslav; Běhounková, Marie; Čadek, Ondřej

    2016-07-01

    Enceladus is a small icy moon of Saturn with active jets of water emanating from fractures around the south pole, informally called tiger stripes, which might be connected to a subsurface water ocean. The effect of these features on periodic tidal deformation of the moon has so far been neglected because of the difficulties associated with implementation of faults in continuum mechanics models. Here we estimate the maximum possible impact of the tiger stripes on tidal deformation and heat production within Enceladus's ice shell by representing them as narrow zones with negligible frictional and bulk resistance passing vertically through the whole ice shell. Assuming a uniform ice shell thickness of 25 km, consistent with the recent estimate of libration, we demonstrate that the faults can dramatically change the distribution of stress and strain in Enceladus's south polar region, leading to a significant increase of the heat production in this area.

  17. Exploitation of the Saturne synchrotron during the forth quarter of 1961

    International Nuclear Information System (INIS)

    1962-01-01

    This document reports data describing the availability and operation (maintenance, failures, operation, beam availability, repetition period), main incidents, experiments related to the machine itself (adjustment of the beam median plane, influence of pressure on the number of accelerated particles, influence of noise on the HF chain on the number of accelerated particles, oscillator test, phase servo-control, detection of the extracted beam), other studies (beam striker, ejection, target propulsion, field measurement), physics experiments (electronic experiments), measures and measurements regarding the protection against radiation, and the liquefier activity which occurred or took place during the exploitation of the Saturne synchrotron during the second three-month period of 1961. It also indicates external works performed in the CERN hydrogen bubble chamber

  18. 2D radiation-magnetohydrodynamic simulations of SATURN imploding Z-pinches

    International Nuclear Information System (INIS)

    Hammer, J.H.; Eddleman, J.L.; Springer, P.T.

    1995-01-01

    Z-pinch implosions driven by the SATURN device at Sandia National Laboratory are modeled with a 2D radiation magnetohydrodynamic (MHD) code, showing strong growth of magneto-Rayleigh Taylor (MRT) instability. Modeling of the linear and nonlinear development of MRT modes predicts growth of bubble-spike structures that increase the time span of stagnation and the resulting x-ray pulse width. Radiation is important in the pinch dynamics keeping the sheath relatively cool during the run-in and releasing most of the stagnation energy. The calculations give x-ray pulse widths and magnitudes in reasonable agreement with experiments, but predict a radiating region that is too dense and radially localized at stagnation. We also consider peaked initial density profiles with constant imploding sheath velocity that should reduce MRT instability and improve performance. 2D krypton simulations show an output x-ray power > 80 TW for the peaked profile

  19. Photometry of occultation candidate stars. I - Uranus 1985 and Saturn 1985-1991

    Science.gov (United States)

    French, L. M.; Morales, G.; Dalton, A. S.; Klavetter, J. J.; Conner, S. R.

    1985-01-01

    Photometric observations of five stars to be occulted by the rings around Uranus are presented. The four stars to be occulted by Saturn or its rings during the period 1985-1991 were also observed. The observations were carried out with a CCD detector attached to the Kitt Peak McGraw-Hill 1.30-m telescope. Landolt standards of widely ranging V-I color indices were used to determine the extinction coefficients, transformation coefficients, and zero points of the stars. Mean extinction coefficients are given for each night of observation. K magnitudes for each star were estimated on the basis of the results of Johnson (1967). The complete photometric data set is given in a series of tables.

  20. Conformal Ablative Thermal Protection Systems (CA-TPS) for Venus and Saturn Backshells

    Science.gov (United States)

    Beck, R.; Gasch, M.; Stackpoole, M.; Wilder, M.; Boghozian, T.; Chavez-Garcia, J.; Prabhu, D.; Kazemba, C.; Venkatapathy, E.

    2015-01-01

    The new conformal ablator C-PICA, which was developed under STMD GCD, is an optimal candidate for use on the backshells for high velocity entry vehicles at both Venus and Saturn. The material has been tested at heat fluxes up to 400 Wcm2 in shear and over 1800 Wcm2 and 1.5 atm in stagnation with good results. C-PICA has similar density to PICA, but shows half the thermal penetration and similar recession at the same conditions, allowing for a lighter weight TPS to be flown. This poster for VEXAG will show the progress made in the development of the material and why it should be considered for use.

  1. Detecting dust hits at Enceladus, Saturn and beyond using CAPS / ELS data from Cassini

    Science.gov (United States)

    Vandegriff, J. D.; Stoneberger, P. J.; Jones, G.; Waite, J. H., Jr.

    2016-12-01

    It has recently been shown (1) that the impact of hypervelocity dust grains on the Cassini spacecraft can be detected by the Cassini Plasma Spectrometer (CAPS) Electron Spectrometer (ELS) instrument. For multiple Enceladus flybys, fine scale features in the lower energy regime of ELS energy spectra can be explained as short-duration, isotropic plasma clouds due to dust impacts. We have developed an algorithm for detecting these hypervelocity dust impacts, and the list of such impacts during Enceladus flybys will be presented. We also present preliminary results obtained when using the algorithm to search for dust impacts in other regions of Saturn's magnetosphere as well as in the solar wind. (1) Jones, Geraint, Hypervelocity dust impact signatures detected by Cassini CAPS-ELS in the Enceladus plume, MOP Meeting, June 1-5, 2015, Atlanta, GA

  2. Nano-Saturn: Experimental Evidence of Complex Formation of an Anthracene Cyclic Ring with C60.

    Science.gov (United States)

    Yamamoto, Yuta; Tsurumaki, Eiji; Wakamatsu, Kan; Toyota, Shinji

    2018-05-30

    An anthracene cyclic hexamer was synthesized by the coupling reaction as a macrocyclic hydrocarbon host. This disk-shaped host included a C 60 guest in 1:1 ratio to form a Saturn-type supramolecular complex in solution and in crystals. X-ray analysis unambiguously revealed that the guest molecule was accommodated in the middle of the host cavity with several CH⋅⋅⋅π contacts. The association constant K a determined by NMR titration measurements was 2.3×10 3  L mol -1 at 298 K in toluene. The structural features and the role of CH⋅⋅⋅π interactions are discussed with the aid of DFT calculations. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. Designing the KNK II-TOAST irradiation experiment with the saturn-FS code

    International Nuclear Information System (INIS)

    Ritzhaupt-Kleissl, H.J.; Elbel, H.; Heck, M.

    1991-01-01

    In order to study the existing specification of FBR fuel with respect to allowable fabrication tolerances with the objective to reduce the expense of fabrication and quality control, the TOAST irradiation experiment will be carried out in the 3 rd core of the KNK II. This experiment shall investigate the influence of the following fuel specification parameters on the operational behaviour: - Fuel diameter - Stoichiometry - Sintering atmosphere - Fill gas in the fuel pin. The combination of these test parameters led to a fabrication of 6 types of fuel pellets, giving together with two fill gas mixtures a total of 9 fuel pin types. Design calculations in the frame of the standard licensing procedure have been performed with the SATURN-FS fuel pin behaviour code. These calculations have been done for the steady-state behaviour as well as for some defined design transients, such as startup procedures and overpower ramps

  4. A near-infrared transmission spectrum for the warm Saturn HAT-P-12b

    Energy Technology Data Exchange (ETDEWEB)

    Line, Michael R.; Knutson, Heather; Desert, Jean-Michel [Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA 91125 (United States); Deming, Drake; Wilkins, Ashlee, E-mail: mrl@gps.caltech.edu [Department of Astronomy, University of Maryland, College Park, MD 20742 (United States)

    2013-12-01

    We present a Hubble Space Telescope Wide Field Camera-3 (WFC3) transmission spectrum for the transiting exoplanet HAT-P-12b. This warm (1000 K) sub-Saturn-mass planet has a smaller mass and a lower temperature than the hot Jupiters that have been studied so far. We find that the planet's measured transmission spectrum lacks the expected water absorption feature for a hydrogen-dominated atmosphere and is instead best described by a model with high-altitude clouds. Using a frequentist hypothesis testing procedure, we can rule out a hydrogen-dominated cloud-free atmosphere to 4.9σ. When combined with other recent WFC3 studies, our observations suggest that clouds may be common in exoplanetary atmospheres.

  5. GRAVITATIONAL ACCRETION OF PARTICLES ONTO MOONLETS EMBEDDED IN SATURN's RINGS

    International Nuclear Information System (INIS)

    Yasui, Yuki; Ohtsuki, Keiji; Daisaka, Hiroshi

    2014-01-01

    Using a local N-body simulation, we examine gravitational accretion of ring particles onto moonlet cores in Saturn's rings. We find that gravitational accretion of particles onto moonlet cores is unlikely to occur in the C ring and probably difficult in the inner B ring as well provided that the cores are rigid water ice. Dependence of particle accretion on ring thickness changes when the radial distance from the planet and/or the density of particles is varied: the former determines the size of the core's Hill radius relative to its physical size, while the latter changes the effect of self-gravity of accreted particles. We find that particle accretion onto high-latitude regions of the core surface can occur even if the rings' vertical thickness is much smaller than the core radius, although redistribution of particles onto the high-latitude regions would not be perfectly efficient in outer regions of the rings such as the outer A ring, where the size of the core's Hill sphere in the vertical direction is significantly larger than the core's physical radius. Our results suggest that large boulders recently inferred from observations of transparent holes in the C ring are not formed locally by gravitational accretion, while propeller moonlets in the A ring would be gravitational aggregates formed by particle accretion onto dense cores. Our results also imply that the main bodies of small satellites near the outer edge of Saturn's rings may have been formed in rather thin rings

  6. IR reflectance spectroscopy of carbon dioxide clathrate hydrates. Implications for Saturn's icy moons.

    Science.gov (United States)

    Oancea, A.; Grasset, O.; Le Menn, E.; Bezacier, L.; Bollengier, O.; Le Mouélic, S.; Tobie, G.

    2012-04-01

    A CO2 spectral band was discovered by VIMS on the Saturn's satellites Dione, Hyperion, Iapetus and Phoebe [1]. The band position on the three first satellites corresponds to CO2 trapped in a complex material, but no indication exists whether this latter is water ice or some mineral or complex organic compound [1]. On Phoebe, the CO2 spectral band is consistent with solid CO2 or CO2 molecules trapped in the small cages of a clathrate hydrate structure [2]. It is thought that clathrate hydrates could play a significant role in the chemistry of the solar nebula [3] and in the physical evolution of astrophysical objects [4]. But so far, no clathrate hydrate structure has been observed in astrophysical environments. Moreover, identification of molecules trapped in a clathrate hydrate structure is extremely difficult because of the strong IR vibration modes of the water ice matrix. In this work, experimental IR reflectance spectra for CO2 clathrate hydrates are studied on grains and films. Clathrates are synthesized in a high pressure autoclave at low temperatures. IR spectral analysis is made with a low pressure and low temperature cryostat. These experimental conditions - 80 spectrum will be presented. A comparison between the absorption bands of CO2 clathrate hydrates obtained in our lab and CO2 absorption bands as detected by VIMS on the icy satellites of Saturn will be shown. This experimental work confirms that VIMS data are not consistent with the presence of structure I CO2 clathrate hydrates on the surface of the icy moons. Possibility of having metastable structure II still remains unsolved and will be discussed. [1] Dalton et al., Space Sci. Rev. 2010, 153 : 113-154. [2] Cruikshank D.P. et al, Icarus, 2010, 206: 561-572. [3] Mousis O. et al , Ap. J. 2009, 691: 1780-1786. [4] Choukroun M. et al, in Solar System Ices, edited by Castillo-Rogez, J. et al., 2011.

  7. A Venus/Saturn Mission Study: 45deg Sphere-Cone Rigid Aeroshells and Ballistic Entries

    Science.gov (United States)

    Prabhu, Dinesh K.; Allen, Gary A.; Cappuccio, Gelsomina

    2012-01-01

    The present study considers ballistic entries into the atmospheres of Saturn and Venus using a 45deg sphere-cone rigid aeroshell (a legacy shape that has been successfully used in the Pioneer Venus and Galileo missions). For a number of entry mass and diameter combinations (i.e., various entries ballistic coefficients), entry velocities, and heading angles, the trajectory space in terms of entry flight path angles between skip out and -30deg is explored with a 3DOF trajectory code, TRAJ. Assuming that the thermal protection material of choice is carbon phenolic of flight heritage, the entry flight path angle space is constrained a posteriori by the mechanical and thermal performance parameters of the material. For mechanical performance, a 200 g limit is place on the peak deceleration load and 10 bar is assumed as the spallation pressure threshold for the legacy material. It is shown that both constraints cannot be active simultaneously. For thermal performance, a minimum margined heat flux threshold of 2.5 kW/sq cm is assumed for the heritage material. Using these constraints, viable entry flight path angle corridors are determined. Analysis of the results also hints at the existence of a "critical" ballistic coefficient beyond which the steepest possible entries are determined by the spallation pressure threshold. The results are verified against known performance of the various probes used in the Galileo and Pioneer Venus missions. It is hoped that the results presented here will serve as a baseline in the development of a new class of ablative materials for Venus and Saturn missions being considered in a future New Frontiers class of NASA missions.

  8. Large-eddy simulation of stratified atmospheric flows with the CFD code Code-Saturne

    International Nuclear Information System (INIS)

    Dall'Ozzo, Cedric

    2013-01-01

    Large-eddy simulation (LES) of the physical processes in the atmospheric boundary layer (ABL) remains a complex subject. LES models have difficulties to capture the evolution of the turbulence in different conditions of stratification. Consequently, LES of the whole diurnal cycle of the ABL including convective situations in daytime and stable situations in the nighttime is seldom documented. The simulation of the stable atmospheric boundary layer which is characterized by small eddies and by weak and sporadic turbulence is especially difficult. Therefore The LES ability to well reproduce real meteorological conditions, particularly in stable situations, is studied with the CFD code developed by EDF R and D, Code-Saturne. The first study consist in validate LES on a quasi-steady state convective case with homogeneous terrain. The influence of the sub-grid-scale models (Smagorinsky model, Germano-Lilly model, Wong-Lilly model and Wall-Adapting Local Eddy-viscosity model) and the sensitivity to the parametrization method on the mean fields, flux and variances are discussed. In a second study, the diurnal cycle of the ABL during Wangara experiment is simulated. The deviation from the measurement is weak during the day, so this work is focused on the difficulties met during the night to simulate the stable atmospheric boundary layer. The impact of the different sub-grid-scale models and the sensitivity to the Smagorinsky constant are been analysed. By coupling radiative forcing with LES, the consequences of infra-red and solar radiation on the nocturnal low level jet and on thermal gradient, close to the surface, are exposed. More, enhancement of the domain resolution to the turbulence intensity and the strong atmospheric stability during the Wangara experiment are analysed. Finally, a study of the numerical oscillations inherent to Code-Saturne is realized in order to decrease their effects. (author) [fr

  9. Equatorial Oscillation and Planetary Wave Activity in Saturn's Stratosphere Through the Cassini Epoch

    Science.gov (United States)

    Guerlet, S.; Fouchet, T.; Spiga, A.; Flasar, F. M.; Fletcher, L. N.; Hesman, B. E.; Gorius, N.

    2018-01-01

    Thermal infrared spectra acquired by Cassini/Composite InfraRed Spectrometer (CIRS) in limb-viewing geometry in 2015 are used to derive 2-D latitude-pressure temperature and thermal wind maps. These maps are used to study the vertical structure and evolution of Saturn's equatorial oscillation (SEO), a dynamical phenomenon presenting similarities with the Earth's quasi-biennal oscillation (QBO) and semi-annual oscillation (SAO). We report that a new local wind maximum has appeared in 2015 in the upper stratosphere and derive the descent rates of other wind extrema through time. The phase of the oscillation observed in 2015, as compared to 2005 and 2010, remains consistent with a ˜15 year period. The SEO does not propagate downward at a regular rate but exhibits faster descent rate in the upper stratosphere, combined with a greater vertical wind shear, compared to the lower stratosphere. Within the framework of a QBO-type oscillation, we estimate the absorbed wave momentum flux in the stratosphere to be on the order of ˜7 × 10-6 N m-2. On Earth, interactions between vertically propagating waves (both planetary and mesoscale) and the mean zonal flow drive the QBO and SAO. To broaden our knowledge on waves potentially driving Saturn's equatorial oscillation, we searched for thermal signatures of planetary waves in the tropical stratosphere using CIRS nadir spectra. Temperature anomalies of amplitude 1-4 K and zonal wave numbers 1 to 9 are frequently observed, and an equatorial Rossby (n = 1) wave of zonal wave number 3 is tentatively identified in November 2009.

  10. GRAVITATIONAL ACCRETION OF PARTICLES ONTO MOONLETS EMBEDDED IN SATURN's RINGS

    Energy Technology Data Exchange (ETDEWEB)

    Yasui, Yuki; Ohtsuki, Keiji [Department of Earth and Planetary Sciences, Kobe University, Kobe 657-8501 (Japan); Daisaka, Hiroshi, E-mail: y.yasui@whale.kobe-u.ac.jp, E-mail: ohtsuki@tiger.kobe-u.ac.jp [Graduate School of Commerce and Management, Hitotsubashi University, Tokyo 186-8601 (Japan)

    2014-12-20

    Using a local N-body simulation, we examine gravitational accretion of ring particles onto moonlet cores in Saturn's rings. We find that gravitational accretion of particles onto moonlet cores is unlikely to occur in the C ring and probably difficult in the inner B ring as well provided that the cores are rigid water ice. Dependence of particle accretion on ring thickness changes when the radial distance from the planet and/or the density of particles is varied: the former determines the size of the core's Hill radius relative to its physical size, while the latter changes the effect of self-gravity of accreted particles. We find that particle accretion onto high-latitude regions of the core surface can occur even if the rings' vertical thickness is much smaller than the core radius, although redistribution of particles onto the high-latitude regions would not be perfectly efficient in outer regions of the rings such as the outer A ring, where the size of the core's Hill sphere in the vertical direction is significantly larger than the core's physical radius. Our results suggest that large boulders recently inferred from observations of transparent holes in the C ring are not formed locally by gravitational accretion, while propeller moonlets in the A ring would be gravitational aggregates formed by particle accretion onto dense cores. Our results also imply that the main bodies of small satellites near the outer edge of Saturn's rings may have been formed in rather thin rings.

  11. Using the tools of the trade to understand plasma interactions at Jupiter and Saturn

    Science.gov (United States)

    Kivelson, Margaret G.

    2017-10-01

    For more than half a century, we have been learning how magnetospheres work. Fluid motions and electromagnetic interactions combine to produce the plasma and field environment of a planet. Kinetic responses often control the dynamics. Initial descriptions of the terrestrial magnetosphere were often theoretical (e.g., Chapman and Ferraro, Dungey) before an explosion of spacecraft data provided an atlas of the system and its temporal variations. The basic structure and dynamics of the terrestrial magnetosphere are now largely understood. A different situation exists for the magnetospheres of Jupiter, Saturn, and their moons. Data acquired from spacecraft flybys or from orbit have characterized many aspects of these systems, but measurements are far more limited than at Earth both in space and in time. Even after Cassini’s mission to Saturn and Juno’s prime mission at Jupiter have ended, large regions in the plasma environments of these planets will remain unexplored. No monitors are available to characterize the upstream solar wind. Theory is challenged by the complexity introduced by dynamical effects of the planets’ rapid rotation and the unfamiliar parameter regimes governing interactions with their large moons. Simulation has come to the rescue, providing computational models designed to incorporate the effects of rotation or to describe moon-magnetosphere interactions. Yet simulations must be viewed with appropriate skepticism as they invariably require some compromise with reality. This talk will describe a symbiotic approach to understanding the dynamics of giant planet magnetospheres and the plasma interactions between magnetospheric plasma and large moons. Data acquired along a spacecraft trajectory are compared with values extracted from a virtual spacecraft moving through the same path in the simulation. If results are similar, we use the simulation to identify the processes responsible for puzzling aspects of the signatures. If results differ

  12. The Composition and Chemistry of the Deep Tropospheres of Saturn and Uranus from Ground-Based Radio Observations

    Science.gov (United States)

    Hofstadter, M. D.; Adumitroaie, V.; Atreya, S. K.; Butler, B.

    2017-12-01

    Ground-based radio observations of the giant planets at wavelengths from 1 millimeter to 1 meter have long been the primary means to study the deep tropospheres of both gas- and ice-giant planets (e.g. de Pater and Massie 1985, Icarus 62; Hofstadter and Butler 2003, Icarus 165). Most recently, radiometers aboard the Cassini and Juno spacecraft at Saturn and Jupiter, respectively, have demonstrated the ability of spaceborne systems to study composition and weather beneath the visible cloud tops with high spatial resolution (Janssen et al. 2013, Icarus 226; Bolton et al. 2016, this meeting). Ground-based observations remain, however, an excellent way to study the tropospheres of the ice giants, particularly the temporal and spatial distribution of condensible species, and to study the deep troposphere of Saturn in the region of the water cloud. This presentation focuses on two ground-based data sets, one for Uranus and one for Saturn. The Uranus data were all collected near the 2007 equinox, and span wavelengths from 0.1 to 20 cm. These data provide a snapshot of atmospheric composition at a single season. The Saturn observations were recently made with the EVLA observatory at wavelengths from 3 to 90 cm, augmented by published observations at shorter and longer wavelengths. It is expected that these data will allow us to constrain conditions in the water cloud region on Saturn. At the time of this writing, both data sets are being analyzed using an optimal estimation retrieval algorithm fed with the latest published information on the chemical and electrical properties of relevant atmospheric species (primarily H2O, NH3, H2S, PH3, and free electrons). At Uranus, we find that—consistent with previously published work—ammonia in the 1 to 50-bar range is strongly depleted from solar values. The relative volume mixing ratios of the above species satisfy PH3 < NH3 < H2S < H2O, which is interesting because based on cosmic abundances one would expect H2S < NH3. At the

  13. Fast neutron dosimetry for radioprotection near large accelerators. Application to the proton synchrotron Saturne; Dosimetrie des neutrons rapides en vue de la radioprotection aupres des grands accelerateurs. Application au synchrotron a protons Saturne

    Energy Technology Data Exchange (ETDEWEB)

    Tardy-Joubert, P

    1963-07-01

    Methods are described that are used for the measurement of a neutron flux, and of the corresponding energy flux and dose absorbed. The methods are checked experimentally by the use of neutron sources of known energy distribution. The conditions of use of a proportional counter for recoil protons are described. The experimental results obtained with the synchrotron SATURNE at Saclay are described. (author) [French] L'auteur presente les methodes utilisables pour la mesure d'un flux de neutrons, du flux d'energie et de la dose absorbee correspondants. Les methodes sont verifiees experimentalement au moyen de sources de neutrons de spectre connu. Les conditions d'emploi d'un compteur proportionnel a protons de recul sont definies. Les resultats experimentaux obtenus aupres du synchrotron Saturne de Saclay sont presentes. (auteur)

  14. A critical review of charged particle astronomy at Saturn: The evidence for co-orbiting material in the inner satellite system

    Science.gov (United States)

    Wefel, John P.; Cooper, John F.

    1990-01-01

    The charged particle observations from Pioneer and Voyager at Saturn were reassessed with a view towards providing limits on the amount of unseen dust and debris that may exist in the Saturnian system. Such estimates are crucial for planning the Cassini tour of Saturn. The data from Pioneer 11 and Voyager were reviewed, intercompared, and correlated with model predictions to set limits on the matter distribution.

  15. A DETAILED MORPHO-KINEMATIC MODEL OF THE ESKIMO, NGC 2392: A UNIFYING VIEW WITH THE CAT'S EYE AND SATURN PLANETARY NEBULAE

    International Nuclear Information System (INIS)

    García-Díaz, Ma. T.; López, J. A.; Steffen, W.; Richer, M. G.

    2012-01-01

    The three-dimensional and kinematic structure of the Eskimo nebula, NGC 2392, has been notoriously difficult to interpret in detail given its complex morphology, multiple kinematic components and its nearly pole-on orientation along the line of sight. We present a comprehensive, spatially resolved, high-resolution, long-slit spectroscopic mapping of the Eskimo planetary nebula. The data consist of 21 spatially resolved, long-slit echelle spectra tightly spaced over the Eskimo and along its bipolar jets. This data set allows us to construct a velocity-resolved [N II] channel map of the nebula with a resolution of 10 km s –1 that disentangles its different kinematic components. The spectroscopic information is combined with Hubble Space Telescope images to construct a detailed three-dimensional morpho-kinematic model of the Eskimo using the code SHAPE. With this model we demonstrate that the Eskimo is a close analog to the Saturn and the Cat's Eye nebulae, but rotated 90° to the line of sight. Furthermore, we show that the main characteristics of our model apply to the general properties of the group of elliptical planetary nebulae with ansae or FLIERS, once the orientation is considered. We conclude that this kind of nebula belongs to a class with a complex common evolutionary sequence of events.

  16. Towards an Understanding of Radiative Factors on Planetary Rings: a Perspective from Cassini CIRS Observations at Saturn Equinox

    Science.gov (United States)

    Brooks, Shawn M.; Spilker, L.; Edgington, S. G.; Déau, E.; Pilorz, S. H.

    2012-10-01

    Since arriving at Saturn in 2004, Cassini's Composite Infrared Spectrometer has recorded tens of millions of spectra of Saturn’s rings (personal communication, M. Segura). CIRS records far infrared radiation (16.7-1000 microns) at focal plane 1 (FP1). Thermal emission from Saturn’s rings peaks at FP1 wavelengths. CIRS spectra are well characterized as blackbody emission at an effective temperature Te, multiplied by a scalar factor related to ring emissivity (Spilker et al. [2005, 2006]). CIRS can therefore characterize the rings' temperature and study the thermal environment to which the ring particles are subject. We focus on CIRS data from the 2009 Saturnian equinox. As the Sun's disk crossed the ring plane, CIRS obtained several radial scans of the rings at a variety of phase angles, local hour angles and distances. With the Sun's rays striking the rings at an incidence angle of zero, solar heating is virtually absent, and thermal radiation from Saturn and sunlight reflected by Saturn dominate the thermal environment. These observations present an apparent paradox. Equinox data show that the flux of thermal energy radiated by the rings is roughly equivalent to or even exceeds the energy incident upon them as prescribed by thermal models (Froidevaux [1981], Ferrari and Leyrat [2006], Morishima et al. [2009, 2010]). This apparent energy excess is largest in the C ring and Cassini Division. Conservation principles suggest that models underestimate heating of the rings, as it is clearly unphysical for the rings to radiate significantly more energy than is incident upon them. In this presentation, we will attempt to resolve this paradox and determine what this can teach us about Saturn's rings. This research was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under contract with NASA. Copyright 2012 California Institute of Technology. Government sponsorship acknowledged.

  17. Significance of Dungey-cycle flows in Jupiter's and Saturn's magnetospheres, and their identification on closed equatorial field lines

    Directory of Open Access Journals (Sweden)

    S. V. Badman

    2007-05-01

    Full Text Available We consider the contribution of the solar wind-driven Dungey-cycle to flux transport in Jupiter's and Saturn's magnetospheres, the associated voltages being based on estimates of the magnetopause reconnection rates recently derived from observations of the interplanetary medium in the vicinity of the corresponding planetary orbits. At Jupiter, the reconnection voltages are estimated to be ~150 kV during several-day weak-field rarefaction regions, increasing to ~1 MV during few-day strong-field compression regions. The corresponding values at Saturn are ~25 kV for rarefaction regions, increasing to ~150 kV for compressions. These values are compared with the voltages associated with the flows driven by planetary rotation. Estimates of the rotational flux transport in the "middle" and "outer" magnetosphere regions are shown to yield voltages of several MV and several hundred kV at Jupiter and Saturn respectively, thus being of the same order as the estimated peak Dungey-cycle voltages. We conclude that under such circumstances the Dungey-cycle "return" flow will make a significant contribution to the flux transport in the outer magnetospheric regions. The "return" Dungey-cycle flows are then expected to form layers which are a few planetary radii wide inside the dawn and morning magnetopause. In the absence of significant cross-field plasma diffusion, these layers will be characterized by the presence of hot light ions originating from either the planetary ionosphere or the solar wind, while the inner layers associated with the Vasyliunas-cycle and middle magnetosphere transport will be dominated by hot heavy ions originating from internal moon/ring plasma sources. The temperature of these ions is estimated to be of the order of a few keV at Saturn and a few tens of keV at Jupiter, in both layers.

  18. A dusty road connecting Saturn and its rings - preliminary results from Cassini Cosmic Dust Analyser during the Grand Finale Mission

    Science.gov (United States)

    Hsu, S.; Burton, M. E.; Horanyi, M.; Kempf, S.; Khawaja, N.; Moragas-Klostermeyer, G.; Postberg, F.; Schirdenwahn, D.; Seiss, M.; Schmidt, J.; Spahn, F.; Srama, R.

    2017-12-01

    The Cosmic Dust Analyzer observations during the Cassini Grand Finale Orbits were designed for the in situ characterization of Saturn's ring composition and to study their interaction with the host planet. It is found that the gap between the inner most D ring and Saturn is almost free of larger, micron-sized dust grains but rich in nanodust particles (radius smaller than 100 nm) that only become detectable by CDA because of the high spacecraft speed of 30 km/s through this region. Regarding the grain composition, while the majority of CDA mass spectra recorded during this phase are too faint to be individually calibrated, two types of mass spectra have been identified - water ice and silicates. These two types of grains were detected at different locations with respect to the ring plane, indicating that there are compositional differences across the rings. As for the dynamics, the observations confirm the transport of charged nanodust from the main rings along magnetic field lines to the planet, as previously proposed. The agreement between the simulated density profile and the observation strongly suggests nanodust as a pathway of ring-planet interaction associated with both exogenous (e.g., impactor ejecta) and endogenous (ionospheric plasma charging) processes. CDA measurements do not indicate significant temporal variation during the the Grand Finale orbits. The measured flux corresponds to a mass transport of < 0.1 kg/sec from the main rings to Saturn in the form of nanodust, with most of the deposition occurring near the equator.

  19. Constraining Saturn's interior density profile from precision gravity field measurement obtained during Grand Finale

    Science.gov (United States)

    Movshovitz, N.; Fortney, J. J.; Helled, R.; Hubbard, W. B.; Mankovich, C.; Thorngren, D.; Wahl, S. M.; Militzer, B.; Durante, D.

    2017-12-01

    The external gravity field of a planetary body is determined by the distribution of mass in its interior. Therefore, a measurement of the external field, properlyinterpreted, tells us about the interior density profile, ρ(r), which in turn can be used to constrain the composition in the interior and thereby learn about theformation mechanism of the planet. Recently, very high precision measurements of the gravity coefficients for Saturn have been made by the radio science instrument on the Cassini spacecraft during its Grand Finale orbits. The resulting coefficients come with an associated uncertainty. The task of matching a given density profile to a given set of gravity coefficients is relatively straightforward, but the question of how to best account for the uncertainty is not. In essentially all prior work on matching models to gravity field data inferences about planetary structure have rested on assumptions regarding the imperfectly known H/He equation of state and the assumption of an adiabatic interior. Here we wish to vastly expand the phase space of such calculations. We present a framework for describing all the possible interior density structures of a Jovian planet constrained by a given set of gravity coefficients and their associated uncertainties. Our approach is statistical. We produce a random sample of ρ(a) curves drawn from the underlying (and unknown) probability distribution of all curves, where ρ is the density on an interior level surface with equatorial radius a. Since the resulting set of density curves is a random sample, that is, curves appear with frequency proportional to the likelihood of their being consistent with the measured gravity, we can compute probability distributions for any quantity that is a function of ρ, such as central pressure, oblateness, core mass and radius, etc. Our approach is also Bayesian, in that it can utilize any prior assumptions about the planet's interior, as necessary, without being overly

  20. A new linear inductive voltage adder driver for the Saturn Accelerator

    International Nuclear Information System (INIS)

    Mazarakis, M.G.; Spielman, R.B.; Struve, K.W.; Long, F.W.

    2000-01-01

    Saturn is a dual-purpose accelerator. It can be operated as a large-area flash x-ray source for simulation testing or as a Z-pinch driver especially for K-line x-ray production. In the first mode, the accelerator is fitted with three concentric-ring 2-MV electron diodes, while in the Z-pinch mode the current of all the modules is combined via a post-hole convolute arrangement and driven through a cylindrical array of very fine wires. We present here a point design for a new Saturn class driver based on a number of linear inductive voltage adders connected in parallel. A technology recently implemented at the Institute of High Current Electronics in Tomsk (Russia) is being utilized. In the present design we eliminate Marx generators and pulse-forming networks. Each inductive voltage adder cavity is directly fed by a number of fast 100-kV small-size capacitors arranged in a circular array around each accelerating gap. The number of capacitors connected in parallel to each cavity defines the total maximum current. By selecting low inductance switches, voltage pulses as short as 30-50-ns FWHM can be directly achieved. The voltage of each stage is low (100-200 kv). Many stages are required to achieve multi-megavolt accelerator output. However, since the length of each stage is very short (4-10 cm), accelerating gradients of higher than 1 MV/m can easily be obtained. The proposed new driver will be capable of delivering pulses of 15-MA, 36-TW, 1.2-MJ to the diode load, with a peak voltage of -2.2 MV and FWHM of 40-ns. And although its performance will exceed the presently utilized driver, its size and cost could be much smaller (approximately1/3). In addition, no liquid dielectrics like oil or deionized water will be required. Even elimination of ferromagnetic material (by using air-core cavities) is a possibility

  1. Risk Assessment of Cassini Sun Sensor Integrity Due to Hypervelocity Impact of Saturn Dust Particles

    Science.gov (United States)

    Lee, Allan Y.

    2016-01-01

    A sophisticated interplanetary spacecraft, Cassini is one of the heaviest and most sophisticated interplanetary spacecraft humans have ever built and launched. Since achieving orbit at Saturn in 2004, Cassini has collected science data throughout its four-year prime mission (2004-08), and has since been approved for first and second extended missions through September 2017. In late 2016, the Cassini spacecraft will begin a daring set of ballistic orbits that will hop the rings and dive between the upper atmosphere of Saturn and its innermost D-ring twenty-two times. The "dusty" environment of the inner D-ring region the spacecraft must fly through is hazardous because of the possible damage that dust particles, travelling at speeds as high as 31.4 km/s, can do to spacecraft hardware. During hazardous proximal ring-plane crossings, the Cassini mission operation team plans to point the high-gain antenna to the RAM vector in order to protect most of spacecraft instruments from the incoming energetic ring dust particles. However, this particular spacecraft attitude will expose two Sun sensors (that are mounted on the antenna dish) to the incoming dust particles. High-velocity impacts on the Sun sensor cover glass might penetrate the 2.54-mm glass cover of the Sun sensor. Even without penetration damage, craters created by these impacts on the surface of the cover glass will degrade the transmissibility of light through it. Apart from being directly impacted by the dust particles, the Sun sensors are also threatened by some fraction of ricochet ejecta that are produced by dust particle impacts on the large antenna dish (made of graphite fiber epoxy composite material). Finally, the spacecraft attitude control system must cope with disturbances due to both the translational and angular impulses imparted on the large antenna dish and the long magnetometer boom by the incoming high-velocity projectiles. Analyses performed to quantify the risks the Sun sensors must contend

  2. Calculation of local flow conditions in the lower core of a PWR with code-Saturne

    International Nuclear Information System (INIS)

    Fournier, Y.

    2003-01-01

    In order to better understand the stresses to which fuel rods are subjected, we need to improve our knowledge of the fluid flow inside the core. A code specialized for calculations in tube bundles is used to calculate the flow inside the whole of the core, with a resolution at the assembly level. Still, it is necessary to obtain realistic entry conditions, and these depend on the flow in the downcomer and lower plenum. Also, the flow in the first stages of the core features 4 incoming jets per assembly, and requires a resolution much finer than that used for the whole core calculation. A series of calculations are thus run with our incompressible Navier-Stokes solver, Code-Saturne, using a classical Ranse turbulence model. The first calculations involve a detailed geometry, including part of the cold legs, downcomer, lower plenum, and lower core of a pressurized water reactor. The level of detail includes most obstacles below the core. The lower core plate, being pierced with close to 800 holes, cannot be realistically represented within a practical mesh size, so that a head loss model is used. The lower core itself requiring even more detail is also represented with head losses. We make full use of Code-Saturne's non conforming mesh possibilities to represent a complex geometry, being careful to retain a good mesh quality. Starting just under the lower core, the mesh is aligned with fuel rod assemblies, so that different types of assemblies can be represented through different head loss coefficients. These calculations yield steady-state or near steady-state results, which are compared to experimental data, and should be sufficient to yield realistic entry conditions for full core calculations at assembly width resolution, and beyond those mechanical strain calculations. We are also interested in more detailed flow conditions and fluctuations in the lower core area, so as to better quantify vibrational input. This requires a much higher resolution, which we limit

  3. The lead-poisoned genius: saturnism in famous artists across five centuries.

    Science.gov (United States)

    Montes-Santiago, Julio

    2013-01-01

    Lead poisoning (saturnism) has been present throughout the history of mankind. In addition to possible ingestion from contaminated food, one of the most important ways in which poisoning caused morbid processes was by occupational exposure. This exposition was pandemic in the Roman Empire, and it has been claimed that it contributed to its fall, but it also caused numerous epidemics in Western countries until the nineteenth century. In the case of artists, and since the Renaissance period, this toxicity has been called painter's colic or painter's madness. The latter term is partly due to the mental disorders displayed by some of the great masters, including Michelangelo and Caravaggio, although it was long recognized that even house and industrial painters were prone to the disorder. This chapter examines the historical evidence of recognition of such toxicity and discusses the controversies raised by the possibility of professional lead poisoning in great artists. In addition to those mentioned above, many other artists across several centuries will be discussed, some being Rubens, Goya, Fortuny, Van Gogh, Renoir, Dufy, Klee, Frida Kahlo, and Portinari. This chapter also briefly mentions the possibility of lead poisoning in two famous composers: Beethoven and Handel. Whether suffering from lead poisoning or not, about which we cannot always be sure, we should still highlight and admire such geniuses fighting their disorders to bequeath us their immortals works. © 2013 Elsevier B.V. All rights reserved.

  4. X-ray Power Increase from Symmetrized Wire-Array z-Pinch Implosions on Saturn.*

    Science.gov (United States)

    Sanford, T. W. L.; Allshouse, G. O.; Marder, B. M.; Nash, T. J.; Mock, R. C.; Douglas, M. R.; Spielman, R. B.; Seaman, J. F.; McGurn, J. S.; Jobe, D.; Gilliland, T. L.; Vargas, M.; Struve, K. W.; Stygar, W. A.; Hammer, J. H.; Degroot, J. S.; Eddleman, J. L.; Peterson, D. L.; Whitney, K. G.; Thornhill, J. W.; Pulsifer, P. E.; Apruzese, J. P.; Mosher, D.; Maron, Y.

    1996-11-01

    A systematic experimental study of annular aluminum wire z-pinches on the Saturn accelerator at Sandia National Laboratories shows that, for the first time, many of the measured spatial characteristics and x-ray powers can be correlated to 1D and 2D, radiation-magneto-hydrodynamic code (RMHC) simulations when large numbers of wires are used. Calculations show that the implosion begins to transition from that of individual wire plasmas to that of a continuous plasma shell when the circumferential gap between wires in the array is reduced below 1.4 +1.3/-0.7 mm. This calculated gap coincides with the measured transition of 1.4±0.4 mm between the observed regimes of slow and rapid improvement in power output with decreasing gap. In the plasma-shell regime, x-ray power has been more than tripled over that generated in the wire-plasma regime. In the full paper, measured characteristics in the plasma-shell regime are compared with 2D, 1- and 20-mm axial length simulations of the implosion using a multi-photon-group Lagrangian RMHC^1 and a three-temperature Eulerian RMHC,^2 respectively. ^1J.H. Hammer, et al., Phys. Plasmas 3, 2063 (1996). ^2D.L. Peterson, et al., Phys. Plasmas 3, 368 (1996). Work supported by U.S. DOE Contract No. DE-AC04-94AL85000.

  5. Comparative Examination of Plasmoid Ejection at Mercury, Earth, Jupiter, and Saturn

    Science.gov (United States)

    Slavin, James A.; Jackman, Caitriona M.; Vogt, Marissa F.

    2011-01-01

    The onset of magnetic reconnection in the near-tail of Earth, long known to herald the fast magnetospheric convection that leads to geomagnetic storms and substorms, is very closely associated with the formation and down-tail ejection of magnetic loops or flux ropes called plasmoids. Plasmoids form as a result of the fragmentation of preexisting cross-tail current sheet as a result of magnetic reconnection. Depending upon the number, location, and intensity of the individual reconnection X-lines and how they evolve, some of these loop-like or helical magnetic structures may also be carried sunward. At the inner edge of the tail they are expected to "re-reconnect' with the planetary magnetic field and dissipate. Plasmoid ejection has now been observed in the magnetotails of Mercury, Earth, Jupiter, and Saturn. These magnetic field and charged particle measurements have been taken by the MESSENGER, Voyager, Galileo, Cassini, and numerous Earth missions. Here we present a comparative examination of the structure and dynamics of plasmoids observed in the magnetotails of these 5 planets. The results are used to learn more about how these magnetic structures form and to assess similarities and differences in the nature of magnetotail reconnection at these planets.

  6. Production of iridium-alloy clad vent sets for the Cassini mission to Saturn

    International Nuclear Information System (INIS)

    Helle, K.J.; Moore, J.P.

    1995-01-01

    Martin Marietta Energy Systems, Inc., has successfully produced the iridium-alloy clad vent sets required for encapsulation of plutonia for the National Aeronautics and Space Administration Cassini mission to Saturn. Numerous improvements were made to the manufacturing process in various areas including dye-penetrant examination of cups, foil part stamping, chemical analysis, tungsten fixturing for laser welding, and enhanced inspections at high magnification. In addition, systems were initiated to ensure process control, and a detailed quality and technical surveillance program was prepared and followed to detect any incipient production problem early in the process so that corrective action could be taken immediately. The quality of the resulting iridium components has been high, and production yields have been above 90%. During the course of the production campaign for the Cassini mission, worker efficiencies lowered production costs, and further cost reductions are possible if operations are consolidated into a single area and bare-forming of the iridium alloys cups can be qualified for flight-quality clad vent sets

  7. Saturne II: a 3 GeV proton synchrotron for nuclear physics

    International Nuclear Information System (INIS)

    Faure, J.; Penicaud, J.P.

    1978-01-01

    A 3 GeV proton Synchrotron is now under completion at the Saclay Nuclear Research Center in France. This machine replaces the former Saturne Synchrotron built in 1958. The lattice type of the new machine is a strong focusing one, and the structure of the magnetic ring is made up of 16 bending magnets and 24 quadrupolar lenses. Due to the small injection energy (20 MeV), it has been necessary to design large aperture magnets. The two accelerating R.F. cavities need a wide range of tuning by ferrites from 0,86 to 8,3 MHz with a peak voltage of 18 kV. The performances of the new machine are better adaptated to the needs of Nuclear Physics. The main features of the extracted protons beam are an intensity of 2.10 12 protons per second at a variable energy from 0,5 to 3 GeV, an energy spread of a few 10 -4 and a small emittance (horizontal approximately 6 π mm.mrd, vertical 25 π mm.mrd). Heavy ions up to N 7+ and polarized particles (H + and D + ) will be accelerated too, around 10 9 per pulse on the target. On the experimental areas nine lines are fully equipped and four spectrometers will be set up. The first accelerated beam is expected in October 1978, and the physics experiments should start at the end of this year

  8. Saturne II: A 3 GeV proton synchrotron for nuclear physics

    Energy Technology Data Exchange (ETDEWEB)

    Faure, J; Penicaud, J P [Centre detude nucleaire de Saclay, Gif sur Yvette (France)

    1978-07-01

    A 3 GeV proton Synchrotron is now under completion at the Saclay Nuclear Research Center in France. This machine replaces the former Saturne Synchrotron built in 1958. The lattice type of the new machine is a strong focusing one, and the structure of the magnetic ring is made up to 16 bending magnets and 24 quadrupolar lenses. Due to the small injection energy (20 MeV), it has been necessary to design large aperture magnets. The two accelerating R.F. cavities need a wide range of tuning by ferrites from 0.86 to 8.3 MHz with a peak voltage 18 kV. The performances of the new machine are better adapted to the needs of Nuclear Physics. The main features of the extracted protons beam are an intensity of 2.10{sup 12} protons per second at a variable energy from 0.5 to 3 GeV, an energy spread of a few 10{sup -4} and a small emittance (horizontal {approx_equal} 6 {pi} mm.mrd, vertical 25 {pi} mm.mrad). Heavy ions up to N{sup 7+} and polarized particles (H{sup +} and D{sup +}) will be accelerated too, around 10{sup 9} per pulse on the target. On the experimental areas nine lines are fully equipped and four spectrometers will be set up. The first accelerated beam is expected in October 1978, and the physics experiments should start at the end of this year. (author)

  9. 3D modeling of lightning-induced electromagnetic pulses on Venus, Jupiter and Saturn

    Science.gov (United States)

    Pérez-Invernón, Francisco J.; Luque, Alejandro; Gordillo-Vázquez, Francisco J.

    2017-04-01

    Atmospheric electricity is a common phenomenon in some planets of The Solar System. We know that atmospheric discharges exist on Earth and gaseous planets; however, some characteristics of lightning on Saturn and Jupiter as well as their relevance on the effects of lightning in the atmospheres of these planets are still unknown. In the case of Venus, there exist some radio evidences of lightning, but the lack of optical observations suggests exploring indirect methods of detection, such as searching for lightning-induced transient optical emissions from the upper atmosphere. The Akatsuki probe, currently orbiting Venus, is equipped with a camera whose temporal resolution is high enough to detect optical emissions from lightning discharges and to measure nightglow enhancements. In this work, we extend previous models [1,2] to investigate the chemical impact and transient optical emissions produced by possible lightning-emitted electromagnetic pulses (EMP) in Venus, Saturn and Jupiter. Using a 3D FDTD ("Finite Differences Time Domain") model we solve the Maxwell equations coupled with the Langevin equation for electrons [3] and with a kinetic scheme, different for each planetary atmosphere. This method is useful to investigate the temporal and spatial impact of lightning-induced electromagnetic fields in the atmosphere of each planet for different lightning characteristics (e.g. energy released, orientation). This 3D FDTD model allows us to include the saturnian and jovian background magnetic field inclination and magnitude at different latitudes, and to determine the effects of different lightning channel inclinations. Results provide useful information to interpret lightning observations on giant gaseous planets and in the search for indirect optical signals from atmospheric discharge on Venus such as fast nightglow transient enhancements related to lightning as seen on Earth. Furthermore, we underline the observation of electrical discharges characteristics as a

  10. Qualification of code-Saturne for thermal-hydraulics single phase nuclear applications

    International Nuclear Information System (INIS)

    Archambeau, F.; Bechaud, C.; Gest, B.; Martin, A.; Sakiz, M.

    2003-01-01

    Code-Saturne is a general finite volume CFD (computational fluid dynamics) code developed by Electricite de France (EDF) under quality assurance for 2- and 3-dimensional simulations, laminar and turbulent flows, conjugate heat transfer (coupling with thermal code SYRTHES), including combustion modelling and a Lagrangian module. A very large range of meshes can be used. The solver relies on a finite volume method on arbitrary meshes (hybrid, with hanging nodes, any type of element). All variables are located at the cell centres. The solver is time marching, with a predictor-corrector scheme for Navier-Stokes equations. Standard Reynolds Average Navier-Stokes modelling (RANS) is included (k-epsilon, RSM). Code-Saturne is used by EDF in various industrial fields such as process engineering, aeraulics, combustion and nuclear applications. The present paper describes the qualification phase carried out during 2001 for single-phase nuclear applications. Indeed, once an industrial product has been released and validated, it is of major importance, especially in this particular field related to safety matters, to demonstrate the ability of the code to help engineers produce satisfactory conclusions to industrial problems. In coherence with analyses and best practice guidelines such as those published by the ERCOFTAC Special Interest Group, it seemed important to base the qualification phase on well defined and documented experimental facilities, sufficiently complex to be representative of industrial studies. Much attention has been devoted to evaluating sensitivity to numerical parameters such as grid refinement, time step... Moreover, the qualification studies have been carried out in real-life conditions, that is in limited time, with industrial limitations on the number of grid cells, and by the teams usually producing such studies, so as to integrate a real industrial process in the qualification phase. Two test cases chosen to assess certain types of flows in PWR

  11. THE 8 μm PHASE VARIATION OF THE HOT SATURN HD 149026b

    International Nuclear Information System (INIS)

    Knutson, Heather A.; Charbonneau, David; Cowan, Nicolas B.; Agol, Eric; Fortney, Jonathan J.; Showman, Adam P.; Henry, Gregory W.

    2009-01-01

    We monitor the star HD 149026 and its Saturn-mass planet at 8.0 μm over slightly more than half an orbit using the Infrared Array Camera on the Spitzer Space Telescope. We find an increase of 0.0227% ± 0.0066% (3.4σ significance) in the combined planet-star flux during this interval. The minimum flux from the planet is 45% ± 19% of the maximum planet flux, corresponding to a difference in brightness temperature of 480 ± 140 K between the two hemispheres. We derive a new secondary eclipse depth of 0.0411% ± 0.0076% in this band, corresponding to a dayside brightness temperature of 1440 ± 150 K. Our new secondary eclipse depth is half that of a previous measurement (3.0σ difference) in this same bandpass by Harrrington et al. We re-fit the Harrrington et al. data and obtain a comparably good fit with a smaller eclipse depth that is consistent with our new value. In contrast to earlier claims, our new eclipse depth suggests that this planet's dayside emission spectrum is relatively cool, with an 8 μm brightness temperature that is less than the maximum planet-wide equilibrium temperature. We measure the interval between the transit and secondary eclipse and find that that the secondary eclipse occurs 20.9 +7.2 -6.5 minutes earlier (2.9σ) than predicted for a circular orbit, a marginally significant result. This corresponds to ecos(ω) = -0.0079 +0.0027 -0.0025 , where e is the planet's orbital eccentricity and ω is the argument of pericenter.

  12. Plasma in Saturn's nightside magnetosphere and the implications for global circulation

    International Nuclear Information System (INIS)

    Mcandrews, Hazel J.; Thomsen, Michelle F.; Wilson, Robert J.; Henderson, Michael G.; Tokar, Robert L.; Arridge, Chris S.; Jackman, Caitriona M.; Khurana, Krishan K.; Sittler, Edward C.; Coates, Andrew J.; Dougherty, Michele K.

    2008-01-01

    We present a bulk ion flow map from the nightside, equatorial region of Saturn's magnetosphere derived from the Cassini CAPS ion mass spectrometer data. The map clearly demonstrates the dominance of corotation flow over radial flow and suggests that the flux tubes sampled are still closed and attached to the planet up to distances of 50 RS. The plasma characteristics in the near-midnight region are described and indicate a transition between the region of the magnetosphere containing plasma on closed drift paths and that containing flux tubes which may not complete a full rotation around the planet. Data from the electron spectrometer reveal two plasma states of high and low density. These are attributed either to the sampling of mass-loaded and depleted flux tubes, respectively, or to the latitudinal structure of the plasma sheet. Depleted, returning flux tubes are not, in general, directly observed in the ions, although the electron observations suggest that such a process must take place in order to produce the low density population. An example of such a low-density interval containing hot electrons with a dipolarised, swept-forward field configuration is described and strongly suggests that reconnection must have occurred planetward of Cassini. Flux tube content is conserved below a limit defined by the mass-loading and magnetic field strength and indicates that the flux tubes sampled may survive their passage through the tail. The conditions for mass release are evaluated using measured densities, angular velocities and magnetic field strength. The results suggest that for the relatively dense ion populations detectable by IMS, the condition for flux-tube breakage has not yet been exceeded. However, the low-density regimes observed in the electron data suggest that loaded flux tubes at greater distances do exceed the threshold for mass loss and subsequently return to the inner magnetosphere significantly depleted of plasma.

  13. Kappa distributions in Saturn's magnetosphere: energetic ion moments using Cassini/MIMI measurements

    Science.gov (United States)

    Dialynas, K.; Roussos, E.; Regoli, L.; Paranicas, C.; Krimigis, S. M.; Kane, M.; Mitchell, D. G.; Hamilton, D. C.

    2017-12-01

    Moments of the charged particle distribution function are a compact way of characterizing some of the properties of different magnetospheric regions. Following our previous analyses (Dialynas et al. 2009) and the techniques described in Dialynas et al. (2017), in the present study we use κ-Distribution fits to combine CHEMS (3 to 236 keV/e), LEMMS (0.024 220 keV) H+ and O+ energetic ion spectra covering measurements made in 2004-2016 to calculate the >20 keV energetic ion moments inside Saturn's magnetosphere. We use the Khurana et al. [2007] magnetic field model to map the ion measurements to the equatorial plane and produce the equatorial distributions of all ion integral moments, focusing on partial density (n), integral intensity (In), partial pressure (P), integral energy intensity (IE); as well as the characteristic energy (Ec=Ie/In), Temperature and κ-index of these ions as a function of Local Time (00:00 to 24:00 hrs) and L-Shell (5-20 Rs). The Roelof and Skinner [2000] model is then utilized to retrieve the equatorial H+ and O+ P, n and T in both local time and L-shell. We find that a) although the PH+ and PO+ are nearly comparable, H+ have higher IE and In at all radial distances (L>5) and local times; b) the 12Η+, ΓΟ+), are consistent with the Arridge et al. [2009] results. Dialynas K. et al. 2009, JGR, 114, A01212 Dialynas K. et al. 2017, Elsevier, ISBN: 9780128046388 Khurana K. K. et al. 2007, AGU, abstract #P44A-01 Roelof E. & A. Skinner 2000, SSR, 91, 437-459 Arridge C. S. et al. 2009, PSS, 57, 2032-2047

  14. Modelling of the ring current in Saturn's magnetosphere

    Directory of Open Access Journals (Sweden)

    G. Giampieri

    2004-01-01

    Full Text Available The existence of a ring current inside Saturn's magnetosphere was first suggested by Smith et al. (1980 and Ness et al. (1981, 1982, in order to explain various features in the magnetic field observations from the Pioneer 11 and Voyager 1 and 2 spacecraft. Connerney et al. (1983 formalized the equatorial current model, based on previous modelling work of Jupiter's current sheet and estimated its parameters from the two Voyager data sets. Here, we investigate the model further, by reconsidering the data from the two Voyager spacecraft, as well as including the Pioneer 11 flyby data set.

    First, we obtain, in closed form, an analytic expression for the magnetic field produced by the ring current. We then fit the model to the external field, that is the difference between the observed field and the internal magnetic field, considering all the available data. In general, through our global fit we obtain more accurate parameters, compared to previous models. We point out differences between the model's parameters for the three flybys, and also investigate possible deviations from the axial and planar symmetries assumed in the model. We conclude that an accurate modelling of the Saturnian disk current will require taking into account both of the temporal variations related to the condition of the magnetosphere, as well as non-axisymmetric contributions due to local time effects.

    Key words. Magnetospheric physics (current systems; planetary magnetospheres; plasma sheet

  15. The Ring System of Saturn as Seen by Cassini-VIMS (Invited)

    Science.gov (United States)

    Filacchione, G.; Ciarniello, M.; Capaccioni, F.

    2015-08-01

    Since 2004 the Visual and Infrared Mapping Spectrometer (VIMS) aboard Cassini has acquired numerous hyperspectral mosaics in the 0.35-5.1 μm spectral range of Saturn's main rings in very different illumination and viewing geometries. These observations have allowed us to infer the ring particles physical properties and composition: water ice abundance is estimated through the 1.25-1.5-2.0 μm band depths, chromophores distribution is derived from visible spectral slopes while organic material is traced by the aliphatic compounds signature at 3.42 μm which appears stronger on CD and C ring than on A-B rings (Filacchione et al., 2014). Observed reflectance spectra are fitted with a spectrophotometric model based on Montecarlo ray-tracing with the scope to infer particles composition while disentangling photometric effects (caused by multiple scattering, opposition surge and forward scattering) which depend on illumination/viewing geometries. Spectral bond albedo for different regions of the rings has been best-fitted using Hapke's radiative transfer modeling (Ciarniello et al, 2011) by choosing different mixtures of water ice, tholin, and amorphous carbon particles populations. While tholin distribution seems to be fairly constant across the rings, the amorphous carbon appears anti-correlated with optical depth. Moreover, dark material contamination is less effective on densest regions, where the more intense rejuvenation processes occur, in agreement with the ballistic transport theory (Cuzzi and Estrada,1998). Finally, the 3.6 μm continuum peak wavelength is used to infer particles temperature, which is anti-correlated with the albedo and the optical depth (tau): low-albedo/low-tau C ring and CD have higher temperatures than A-B rings where albedo and tau are high. This trend matches direct temperature measurements by CIRS (Spilker et al., 2013).

  16. Plasma in Saturn's nightside magnetosphere and the implications for global circulation

    Energy Technology Data Exchange (ETDEWEB)

    Mcandrews, Hazel J [Los Alamos National Laboratory; Wilson, R J [Los Alamos National Laboratory; Henderson, M G [Los Alamos National Laboratory; Tokar, R L [Los Alamos National Laboratory; Jackman, C M [IMPERIAL COLLEGE; Khurana, K K [UNIV OF CAL; Sittler, E C [NASA/GSFC; Coates, A J [MSSL; Dougherty, M K [IMPERIAL COLLEGE

    2009-01-01

    We present a bulk ion flow map from the nightside equatorial region of Saturn's magnetosphere derived from the Cassini CAPS ion mass spectrometer data. The map clearly demonstrates the dominance of corotation flow over radial flow and suggests that the flux tubes sampled are still closed and attached to the planet up to distances of 50 R{sub s}. The plasma characteristics in the near-midnight region are described and indicate a transition between the region of the magnetosphere containing plasma on closed drift paths and that containing flux tubes which may not complete a full rotation around the planet. Data from the electron spectrometer reveal two plasma states of high and low density. These are attributed either to the sampling of mass-loaded and depleted flux tubes, respectively, or to the latitudinal structure of the plasma sheet Depleted, returning flux tubes are not, in general, directly observed in the ions, although the electron observations suggest that such a process must take place in order to produce the low density population. Flux tube content is conserved below a limIt defined by the mass-loading and magnetic field strength and indicates that the flux tubes sampled may survive their passage through the tail. The conditions for mass release are evaluated using measured densities, angular velocities and magnetic field strength, The results suggest that for the relatively dense ion populations detectable by IMS, the condition for flux-tube breakage has not yet been exceeded, However, the low-density regimes observed in the electron data suggest that loaded flux tubes at greater distances do exceed the threshold for mass loss and subsequently return to the inner magnetosphere significantly depleted of plasma.

  17. Image, Image, Image

    Science.gov (United States)

    Howell, Robert T.

    2004-01-01

    With all the talk today about accountability, budget cuts, and the closing of programs in public education, teachers cannot overlook the importance of image in the field of industrial technology. It is very easy for administrators to cut ITE (industrial technology education) programs to save school money--money they might shift to teaching the…

  18. "Ring rain" on Saturn's ionosphere: densities and temperatures from 2011 observations and re-detection in 2013 observations

    Science.gov (United States)

    O'Donoghue, J.; Moore, L.; Melin, H.; Connerney, J. E. P.; Oliversen, R. J.

    2017-12-01

    In ground-based observations using the 10 meter W. M. Keck telescope in 2011, we discovered that the "ring rain" which falls on Saturn from the rings (along magnetic field lines) leaves an imprint on the upper-atmospheric H3+ ion. H3+ emissions were brightest where water products are expected to fall. Through subsequent modeling of the upper atmosphere, it became clear that an influx of water products (e.g. H2O+, O+, etc.) would act to soak up electrons - something that would otherwise destroy H3+ through recombination - and lead to a higher H3+ density and therefore emission. Here we present the first re-detections of the imprint of "ring rain" on Saturn's ionospheric H3+ from ground-based Keck telescope data from 2013. Observed intensities at low-latitudes decreased by an order of magnitude from 2011 to 2013, likely due to a decrease in upper atmospheric temperature by 100 K. A new analysis of 2011 observations revealed temperatures and densities as a function of latitude on Saturn for the first time. Where water influx is expected, H3+ column densities are high (as models predicted) and temperatures are low. While the latter was unexpected, the effect of ring rain on electron densities is stronger at lower altitudes. Therefore, as ring rain enhances density at lower altitudes where the temperature is lower, it should result in the emitting column of H3+ having a lower average temperature. These results come at a critical time as the Cassini spacecraft completes all orbits between planet and rings, with the opportunity to sample the forces and material fluxes related to ring rain.

  19. HD 89345: a bright oscillating star hosting a transiting warm Saturn-sized planet observed by K2

    Science.gov (United States)

    Van Eylen, V.; Dai, F.; Mathur, S.; Gandolfi, D.; Albrecht, S.; Fridlund, M.; García, R. A.; Guenther, E.; Hjorth, M.; Justesen, A. B.; Livingston, J.; Lund, M. N.; Pérez Hernández, F.; Prieto-Arranz, J.; Regulo, C.; Bugnet, L.; Everett, M. E.; Hirano, T.; Nespral, D.; Nowak, G.; Palle, E.; Silva Aguirre, V.; Trifonov, T.; Winn, J. N.; Barragán, O.; Beck, P. G.; Chaplin, W. J.; Cochran, W. D.; Csizmadia, S.; Deeg, H.; Endl, M.; Heeren, P.; Grziwa, S.; Hatzes, A. P.; Hidalgo, D.; Korth, J.; Mathis, S.; Montañes Rodriguez, P.; Narita, N.; Patzold, M.; Persson, C. M.; Rodler, F.; Smith, A. M. S.

    2018-05-01

    We report the discovery and characterization of HD 89345b (K2-234b; EPIC 248777106b), a Saturn-sized planet orbiting a slightly evolved star. HD 89345 is a bright star (V = 9.3 mag) observed by the K2 mission with one-minute time sampling. It exhibits solar-like oscillations. We conducted asteroseismology to determine the parameters of the star, finding the mass and radius to be 1.12^{+0.04}_{-0.01} M_⊙ and 1.657^{+0.020}_{-0.004} R_⊙, respectively. The star appears to have recently left the main sequence, based on the inferred age, 9.4^{+0.4}_{-1.3} Gyr, and the non-detection of mixed modes. The star hosts a "warm Saturn" (P = 11.8 days, Rp = 6.86 ± 0.14 R⊕). Radial-velocity follow-up observations performed with the FIES, HARPS, and HARPS-N spectrographs show that the planet has a mass of 35.7 ± 3.3 M⊕. The data also show that the planet's orbit is eccentric (e ≈ 0.2). An investigation of the rotational splitting of the oscillation frequencies of the star yields no conclusive evidence on the stellar inclination angle. We further obtained Rossiter-McLaughlin observations, which result in a broad posterior of the stellar obliquity. The planet seems to conform to the same patterns that have been observed for other sub-Saturns regarding planet mass and multiplicity, orbital eccentricity, and stellar metallicity.

  20. A Statistical Characterization of Reflection and Refraction in the Atmospheres of sub-Saturn Kepler Planet Candidates

    Science.gov (United States)

    Sheets, Holly A.; Deming, Drake; Arney, Giada; Meadows, Victoria

    2016-01-01

    We present the results of our method to detect small atmospheric signals in Kepler's close-in, sub-Saturn planet candidate light curves. We detect an average secondary eclipse for groups of super-Earth, Neptune-like, and other sub-Saturn-sized candidates by scaling and combining photometric data of the groups of candidates such that the eclipses add constructively. This greatly increases the signal-to-noise compared to combining eclipses for individual planets. We have modified our method for averaging short cadence light curves of multiple planet candidates (2014, ApJ, 794, 133), and have applied it to long cadence data, accounting for the broadening of the eclipse due to the 30 minute cadence. We then use the secondary eclipse depth to determine the average albedo for the group. In the short cadence data, we found that a group of close-in sub-Saturn candidates (1 to 6 Earth radii) was more reflective (geometric A ~ 0.22) than typical hot Jupiters (geometric A ~ 0.06 to 0.11: Demory 2014, ApJL, 789, L20). With the larger number of candidates available in long cadence, we improve the resolution in radius and consider groups of candidates with radii between 1 and 2, 2 and 4, and 4 and 6 Earth radii. We also modify our averaging technique to search for refracted light just before and after transit in the Kepler candidate light curves, as modelled by Misra and Meadows (2014, ApJL, 795, L14).

  1. The role of collective self-gravity in the nonlinear evolution of viscous overstability in Saturn's rings.

    Science.gov (United States)

    Lehmann, Marius; Schmidt, Jürgen; Salo, Heikki

    2017-06-01

    We investigate the influence of collective self-gravity forces on the nonlinear evolution of the viscous overstability in Saturn's dense rings. Local N-body simulations, incorporating vertical and radial collective self-gravity are performed. Vertical self-gravity is mimicked through an increased frequency of vertical oscillations, while radial self-gravity is approximated by solving the Poisson equation for a thin disk in Fourier space. Direct particle-particle forces are omitted, while the magnitude of radial self gravity is controlled by assigning a variable surface mass density to the system's homogeneous ground state. We compare our simulations with large-scale isothermal and non-isothermal hydrodynamic model calculations, including radial self-gravity and employing transport coefficients derived in Salo et al. (2001). We concentrate on optical depths τ=1.5-2, appropriate to model Saturn's dense rings. Our isothermal and non isothermal hydrodynamic results in the limit of vanishing self-gravity compare very well with the studies of Latter&Ogilvie (2010) and Rein&latter (2013), respectively.With non-vanishing radial self-gravity we find that the wavelengths of saturated overstable wave trains are located in close vicinity of the local minimum of the nonlinear dispersion relation for a particular surface density. Good agreement is found between non-isothermal hydrodynamics and N-body simulations for disks with strong radial self-gravity, while the largest deviations occur for a weak but non-vanishing self-gravity.The resulting saturation wavelengths of the viscous overstability for moderate and strong radial self-gravity (λ~ 200-300m) agree reasonably well with the length scale of periodic micro structure in Saturn's inner A and B ring, as found by Cassini.

  2. ON THE MIGRATION OF JUPITER AND SATURN: CONSTRAINTS FROM LINEAR MODELS OF SECULAR RESONANT COUPLING WITH THE TERRESTRIAL PLANETS

    International Nuclear Information System (INIS)

    Agnor, Craig B.; Lin, D. N. C.

    2012-01-01

    We examine how the late divergent migration of Jupiter and Saturn may have perturbed the terrestrial planets. Using a modified secular model we have identified six secular resonances between the ν 5 frequency of Jupiter and Saturn and the four apsidal eigenfrequencies of the terrestrial planets (g 1-4 ). We derive analytic upper limits on the eccentricity and orbital migration timescale of Jupiter and Saturn when these resonances were encountered to avoid perturbing the eccentricities of the terrestrial planets to values larger than the observed ones. Because of the small amplitudes of the j = 2, 3 terrestrial eigenmodes the g 2 – ν 5 and g 3 – ν 5 resonances provide the strongest constraints on giant planet migration. If Jupiter and Saturn migrated with eccentricities comparable to their present-day values, smooth migration with exponential timescales characteristic of planetesimal-driven migration (τ ∼ 5-10 Myr) would have perturbed the eccentricities of the terrestrial planets to values greatly exceeding the observed ones. This excitation may be mitigated if the eccentricity of Jupiter was small during the migration epoch, migration was very rapid (e.g., τ ∼< 0.5 Myr perhaps via planet-planet scattering or instability-driven migration) or the observed small eccentricity amplitudes of the j = 2, 3 terrestrial modes result from low probability cancellation of several large amplitude contributions. Results of orbital integrations show that very short migration timescales (τ < 0.5 Myr), characteristic of instability-driven migration, may also perturb the terrestrial planets' eccentricities by amounts comparable to their observed values. We discuss the implications of these constraints for the relative timing of terrestrial planet formation, giant planet migration, and the origin of the so-called Late Heavy Bombardment of the Moon 3.9 ± 0.1 Ga ago. We suggest that the simplest way to satisfy these dynamical constraints may be for the bulk of any giant

  3. Proton-proton correlations at small relative momentum in neon and argon collision with nuclei at Saturne

    International Nuclear Information System (INIS)

    Alard, J.P.; Dupieux, P.; Charmensat, P.; Augerat, J.; Babinet, R.; Cavaton, C.; Demoulins, M.; Lemaire, M.C.; Brochard, F.; Gorodetzky, P.; Racca, C.

    1990-01-01

    Proton proton correlations at small relative momentum have been studied using the Diogene 4π- Facility at Saturne. The incident energies vary from 200 to 1000 A.MeV for Ne and Ar projectiles on various targets. Experimental correlation functions are compared to theoretical calculations of S. Koonin, corrected for experimental biases. This paper gives the values of the source size as a function of incident energy, target-projectile system and centrality of the collisions. Extracted values of eh density of nuclear matter show that the method is mainly sensitive to the final stage of the interaction; nevertheless we have some indications of a highly compressed phase at the beginning collision

  4. The mysterious mid-latitude ionosphere of Saturn via ground-based observations of H3+: ring rain and other drivers

    Science.gov (United States)

    O'Donoghue, J.; Moore, L.; Stallard, T.; Melin, H.; Connerney, J. E. P.; Oliversen, R. J.

    2017-09-01

    In 2013, we discovered that the "ring rain" which falls on Saturn from the rings also leaves an imprint on the low-latitude upper-atmosphere. Specifically, the ionospheric-bound H3+ ion appeared to emit brightest where water products are known to fall. Here we show the first re-detections of the imprint of "ring rain" on Saturn's ionosphere, using ground-based Keck telescope data from 2013 and 2014. We have also found that the emission from low-latitudes decreases dramatically from 2011 to 2013, implying a planetary cooling over the time period, but we are unaware of the mechanism of this cooling at present.

  5. Planetary period oscillations in Saturn's magnetosphere: New results from the F-ring and proximal orbits

    Science.gov (United States)

    Provan, G.; Cowley, S. W. H.; Bunce, E. J.; Hunt, G. J.; Dougherty, M. K.

    2017-12-01

    We investigate planetary period oscillations (PPOs) in Saturn's magnetosphere using Cassini magnetic field data during the high cadence ( 7 days) F-ring and proximal orbits. Previous results have shown that there are two PPO systems, one in each hemisphere. Both PPO periods show seasonal dependence, and since mid-2014 the Northern PPO period has been 10.8 h and the Southern PPO period 10.7 h. The beat period of the two oscillations is 45 days. Previous results demonstrated that in the Northern (Southern) polar region only pure Northern (Southern) oscillations can be observed, whilst in the equatorial region both oscillations are present and constructively and destructively interfere over the beat-cycle of the two oscillations. The PPOs are believed to be driven by twin-cell convection patterns in the polar ionosphere/thermosphere regions, with two systems of field-aligned currents transmitting the PPO flows to the magnetospheric plasma.The F-ring and proximal orbits uniquely observe the PPOs over 6 orbits during each PPO beat cycle. This high-cadence data demonstrates that over a beat cycle both the periods and amplitudes of the PPO observed within the each polar region are modulated by the PPO system from the opposite hemisphere. When the two oscillations are in phase (anti-phase) the `drag' of one system on the other acts to decrease (increase) the amplitude of the oscillations and the two PPO periods diverge (converge). We present a theoretical model showing that this coupling is due to the PPO flows from one hemisphere not just being communicated to the magnetosphere as previously assumed, but also to the opposite hemisphere. The result is inter-hemispheric coupling of the PPO flow systems within the ionosphere/thermosphere system, so that the northern PPO system drives a northern twin-cell convection pattern in the southern hemisphere, and vice versa, thus leading to the observed polar modulations of the PPOs.We will also present PPO phase models determined

  6. A comparison of the consequences of thermospheric inertia on Saturn and Earth

    Science.gov (United States)

    Spain, T.; Achilleos, N.; Aruliah, A. L.

    2008-09-01

    ABSTRACT The ionosphere should react near-instantaneously to magnetospheric control via electric fields and particle precipitation. The neutral gas of the thermosphere becomes stirred up through collisions and momentum transfer with the ionospheric plasma, although with a time lag in response because of its much larger population mass [1]. The thermosphere thus responds to magnetospheric drivers with a modulating influence owing to its inertia. This study investigates the effect of thermospheric inertia on the energy drawn from the magnetosphere and redistributed as Joule heating and acceleration of the neutral gas. The decay of ionospheric currents and consequent magnetic perturbations are also studied. The UCL Saturn model [2] and CTIP Earth [3] model will each be used for 2 simulations: the first a steadystate 'quiet' simulation and the second including the representation of a geomagnetic storm lasting for an extended period that is then turned off. For each planet, comparisons will be made between these two simulations for the period immediately following the storm, when the electric field and particle precipitation drivers of the 'storm' simulations have returned to values in accordance with the 'quiet' models. The differences between the steady state and previously active simulations will be purely due to thermospheric inertia [4]. It is anticipated that the response of the Gas Giant will be very different from the Earth due to differences in the size, rotational speed, flow timescales [5] [6] and composition of the respective planetary environments. References [1] Schunk, R. W., 1987, Physica Scripta, T18, pp. 256- 275, doi: 10.1088/0031-8949/1987/T18/026. [2] Smith, C. G. A. and Aylward, A. D. and Millward, G. H. and Miller, S. and Moore, L. E., 2007, Nature, 445 (7126), pp. 399-401. [3] Millward, G. H. and Moffett, R. J. and Quegan, S. and Fuller-Rowell, T. J., 1996, in The STEP Handbook of Ionospheric Models, R.W. Schunk ed., Utah State University. [4

  7. The vertical structure of Jupiter and Saturn zonal winds from nonlinear simulations of major vortices and planetary-scale disturbances

    Science.gov (United States)

    Garcia-Melendo, E.; Legarreta, J.; Sanchez-Lavega, A.

    2012-12-01

    Direct measurements of the structure of the zonal winds of Jupiter and Saturn below the upper cloud layer are very difficult to retrieve. Except from the vertical profile at a Jupiter hot spot obtained from the Galileo probe in 1995 and measurements from cloud tracking by Cassini instruments just below the upper cloud, no other data are available. We present here our inferences of the vertical structure of Jupiter and Saturn zonal wind across the upper troposphere (deep down to about 10 bar level) obtained from nonlinear simulations using the EPIC code of the stability and interactions of large-scale vortices and planetary-scale disturbances in both planets. Acknowledgements: This work has been funded by Spanish MICIIN AYA2009-10701 with FEDER support, Grupos Gobierno Vasco IT-464-07 and UPV/EHU UFI11/55. [1] García-Melendo E., Sánchez-Lavega A., Dowling T.., Icarus, 176, 272-282 (2005). [2] García-Melendo E., Sánchez-Lavega A., Hueso R., Icarus, 191, 665-677 (2007). [3] Sánchez-Lavega A., et al., Nature, 451, 437- 440 (2008). [4] Sánchez-Lavega A., et al., Nature, 475, 71-74 (2011).

  8. Spectrophotometric study of Saturn's main rings by means of Monte Carlo ray-tracing and Hapke's theory

    Science.gov (United States)

    Ciarniello, Mauro; Filacchione, Gianrico; D'Aversa, Emiliano; Cuzzi, Jeffrey N.; Capaccioni, Fabrizio; Hedman, Matthew M.; Dalle Ore, Cristina M.; Nicholson, Philip D.; Clark, Roger Nelson; Brown, Robert H.; Cerroni, Priscilla; Spilker, Linda

    2017-10-01

    This work is devoted to the investigation of the spectrophotometric properties of Saturn's rings from Cassini-VIMS (Visible and Infrared Mapping Spectrometer) observations. The dataset used for this analysis is represented by ten radial spectrograms of the rings which have been derived in Filacchione et al. (2014) by radial mosaics produced by VIMS. Spectrograms report the measured radiance factor of the main Saturn's rings as a function of both radial distance (from 73.500 to 141.375 km) and wavelength (0.35-5.1 µm) for different observation geometries (phase angle ranging in the 1.9°-132.2° interval). We take advantage of a Monte Carlo ray-tracing routine to characterize the photometric behavior of the rings at each wavelength and derive the spectral Bond albedo of rings particles. This quantity is used to infer the composition of the regolith covering rings particles by applying Hapke's theory. Four different regions, characterized by different optical depths, and respectively located in the C ring, inner B ring, mid B ring and A ring, have been investigated. Results from spectral modeling indicate that rings spectrum can be described by water ice with minimal inclusion of organic materials (tholin, exogenous material, which is more effective in the less dense regions of the rings because of their lower content of pure water ice.

  9. Field dipolarization in Saturn's magnetotail with planetward ion flows and energetic particle flow bursts: Evidence of quasi-steady reconnection.

    Science.gov (United States)

    Jackman, C M; Thomsen, M F; Mitchell, D G; Sergis, N; Arridge, C S; Felici, M; Badman, S V; Paranicas, C; Jia, X; Hospodarksy, G B; Andriopoulou, M; Khurana, K K; Smith, A W; Dougherty, M K

    2015-05-01

    We present a case study of an event from 20 August (day 232) of 2006, when the Cassini spacecraft was sampling the region near 32 R S and 22 h LT in Saturn's magnetotail. Cassini observed a strong northward-to-southward turning of the magnetic field, which is interpreted as the signature of dipolarization of the field as seen by the spacecraft planetward of the reconnection X line. This event was accompanied by very rapid (up to ~1500 km s -1 ) thermal plasma flow toward the planet. At energies above 28 keV, energetic hydrogen and oxygen ion flow bursts were observed to stream planetward from a reconnection site downtail of the spacecraft. Meanwhile, a strong field-aligned beam of energetic hydrogen was also observed to stream tailward, likely from an ionospheric source. Saturn kilometric radiation emissions were stimulated shortly after the observation of the dipolarization. We discuss the field, plasma, energetic particle, and radio observations in the context of the impact this reconnection event had on global magnetospheric dynamics.

  10. Storm clouds on Saturn: Lightning-induced chemistry and associated materials consistent with Cassini/VIMS spectra

    Science.gov (United States)

    Baines, K.H.; Delitsky, M.L.; Momary, T.W.; Brown, R.H.; Buratti, B.J.; Clark, R.N.; Nicholson, P.D.

    2009-01-01

    Thunderstorm activity on Saturn is associated with optically detectable clouds that are atypically dark throughout the near-infrared. As observed by Cassini/VIMS, these clouds are ~20% less reflective than typical neighboring clouds throughout the spectral range from 0.8 ??m to at least 4.1 ??m. We propose that active thunderstorms originating in the 10-20 bar water-condensation region vertically transport dark materials at depth to the ~1 bar level where they can be observed. These materials in part may be produced by chemical processes associated with lightning, likely within the water clouds near the ~10 bar freezing level of water, as detected by the electrostatic discharge of lightning flashes observed by Cassini/RPWS (e.g., Fischer et al. 2008, Space Sci. Rev., 137, 271-285). We review lightning-induced pyrolytic chemistry involving a variety of Saturnian constituents, including hydrogen, methane, ammonia, hydrogen sulfide, phosphine, and water. We find that the lack of absorption in the 1-2 ??m spectral region by lightning-generated sulfuric and phosphorous condensates renders these constituents as minor players in determining the color of the dark storm clouds. Relatively small particulates of elemental carbon, formed by lightning-induced dissociation of methane and subsequently upwelled from depth - perhaps embedded within and on the surface of spectrally bright condensates such as ammonium hydrosulfide or ammonia - may be a dominant optical material within the dark thunderstorm-related clouds of Saturn. ?? 2009 Elsevier Ltd. All rights reserved.

  11. Constraints on the Mass and Location of Planet 9 set by Range and VLBI Observations of Spacecraft at Saturn

    Science.gov (United States)

    Jacobson, Robert A.; Folkner, William M.; Park, Ryan S.; Williams, James G.

    2017-06-01

    Batygin and Brown, 2016 AJ, found that all Kuiper belt objects (KBOs) with well determined orbits having periods greater than 4000 years share nearly the same orbital plane and are apsidally aligned. They attribute this orbital clustering to the existence of a distant planet, Planet 9, well beyond Neptune, with a mass roughly ten times that of Earth. If such a planet exists, it would affect the motion of the known solar system planets, in particular Saturn, which is well observed with radiometric ranging from the Voyager and Cassini spacecraft and VLBI observations of Cassini. The current planetary ephemerides do not account for the postulated Planet 9, yet their fit to the observational data shows no obvious effect that could be attributed to neglecting that planet. However, it is possible that the effect could be absorbed by the estimated parameters used to determine the ephemerides. Those parameters include the planetary orbital elements, mass of the Sun, and the masses of the asteroids that perturb the Martian orbit. We recently updated the Voyager and Cassini data sets and extended the latter through 2017 March. We analyze the sensitivity of these data to the tidal perturbations caused by Planet 9 for a range of positions on the sky and tidal parameters (the ratio of the mass of Planet 9 to the cube of its distance from Saturn). We determine an upper bound on the tidal parameter and the most probable directions consistent with the observational data.

  12. Recent developments at JPL in the application of digital image processing techniques to astronomical images

    Science.gov (United States)

    Lorre, J. J.; Lynn, D. J.; Benton, W. D.

    1976-01-01

    Several techniques of a digital image-processing nature are illustrated which have proved useful in visual analysis of astronomical pictorial data. Processed digital scans of photographic plates of Stephans Quintet and NGC 4151 are used as examples to show how faint nebulosity is enhanced by high-pass filtering, how foreground stars are suppressed by linear interpolation, and how relative color differences between two images recorded on plates with different spectral sensitivities can be revealed by generating ratio images. Analyses are outlined which are intended to compensate partially for the blurring effects of the atmosphere on images of Stephans Quintet and to obtain more detailed information about Saturn's ring structure from low- and high-resolution scans of the planet and its ring system. The employment of a correlation picture to determine the tilt angle of an average spectral line in a low-quality spectrum is demonstrated for a section of the spectrum of Uranus.

  13. Last Looks at the Eye of Saturn by Cassini/VIMS During the Grand Finale

    Science.gov (United States)

    Momary, Thomas W.; Baines, Kevin H.; Badman, Sarah; Brown, Robert H.; Buratti, Bonnie J.; Clark, Roger Nelson; Nicholson, Philip D.; Sotin, Christophe

    2017-10-01

    A lasting remnant of the Great Storm that erupted on Saturn in late 2010 has been a massive lone anticyclone persisting to the present time in a NH3-dry 5-µm-bright “desert” zone that spans the entire Saturnian globe at 34o N. We have been observing this oval storm with Cassini/VIMS since 2011 and, in 2017, as Cassini performs its Grand Finale orbits close to the planet, have captured it at our highest resolution since January 2012 at 260 km/pixel - enough to resolve spiral structure inside the oval at 5 µm. The spot drifts latitudinally in Saturn’s zonal currents: it was at 35.9o planetocentric latitude in May 2011, wandered northward to 37.8o in 2012, hovered near 37o through 2013, meandered as far south as 36.5o in 2014, drifted northward to 37o in 2015, and then returned back to about 36.3o in 2016, where it remains presently. It has also periodically bumped up against the dark band above it, spinning off material in 2013, 2015, and 2017. We measured a prograde zonal drift speed of 22 m/s in 2012, increasing as much as 60% through 2013, then relaxing to a more moderate 15 m/s in 2014 and 2015. It slowed considerably in 2016 to 4.7 m/s and is currently drifting slightly faster at 8.5 m/s. The spot has varied in size over time as it spins, spanning 4.9o x 3.2o in 2011, elongating to 7.3o x 2.9o by 2013, contracting to 5.5o x 2.9o in 2014, enlarging again to 9o x 4o in 2015, and contracting currently to 7.0o x 3.2o (6100 x 3200 km) in 2017, symmetrically oval in shape. It has varied in terms of cloudiness, being 90% 5-µm dark (obscured) in 2011, whereas by 2013 it was mostly bright (clear) with a thin dark edge. It was 90% dark in 2015, and in 2017 is about 65% obscured, with a bright central eye. Utilizing night observations to isolate thermal flux, we have found that the mean 5-µm flux coming from the anticyclone has diminished steadily by about 75% since 2013. The entire storm latitude of ~34o N itself has remained persistently 5-µm bright since 2011

  14. Saturn's Magnetosphere Interaction with Titan for T9 Encounter: 3D Hybrid Modeling and Comparison with CAPS Observations

    Science.gov (United States)

    Lipatov, A. S.; Sittler, E. C., Jr.; Hartle, R. E.; Cooper, J. F.; Simpson, D. G.

    2011-01-01

    Global dynamics of ionized and neutral gases in the environment of Titan plays an important role in the interaction of Saturn s magnetosphere with Titan. Several hybrid simulations of this problem have already been done (Brecht et al., 2000; Kallio et al., 2004; Modolo et al., 2007a; Simon et al., 2007a, 2007b; Modolo and Chanteur, 2008). Observational data from CAPS for the T9 encounter (Sittler et al., 2009) indicates an absence of O(+) heavy ions in the upstream that change the models of interaction which were discussed in current publications (Kallio et al., 2004; Modolo et al., 2007a; Simon et al., 2007a, 2007b; Ma et al., 2007; Szego et al., 2007). Further analysis of the CAPS data shows very low density or even an absence of H(+) ions in upstream. In this paper we discuss two models of the interaction of Saturn s magnetosphere with Titan: (A) high density of H(+) ions in the upstream flow (0.1/cu cm), and (B) low density of H(+) ions in the upstream flow (0.02/cu cm). The hybrid model employs a fluid description for electrons and neutrals, whereas a particle approach is used for ions. We also take into account charge-exchange and photoionization processes and solve self-consistently for electric and magnetic fields. The model atmosphere includes exospheric H(+), H(2+), N(2+)and CH(4+) pickup ion production as well as an immobile background ionosphere and a shell distribution for active ionospheric ions (M(sub i)=28 amu). The hybrid model allows us to account for the realistic anisotropic ion velocity distribution that cannot be done in fluid simulations with isotropic temperatures. Our simulation shows an asymmetry of the ion density distribution and the magnetic field, including the formation of Alfven wing-like structures. The results of the ion dynamics in Titan s environment are compared with Cassini T9 encounter data (CAPS).

  15. AN N-BODY INTEGRATOR FOR GRAVITATING PLANETARY RINGS, AND THE OUTER EDGE OF SATURN'S B RING

    International Nuclear Information System (INIS)

    Hahn, Joseph M.; Spitale, Joseph N.

    2013-01-01

    A new symplectic N-body integrator is introduced, one designed to calculate the global 360° evolution of a self-gravitating planetary ring that is in orbit about an oblate planet. This freely available code is called epi i nt, and it is distinct from other such codes in its use of streamlines to calculate the effects of ring self-gravity. The great advantage of this approach is that the perturbing forces arise from smooth wires of ring matter rather than discreet particles, so there is very little gravitational scattering and so only a modest number of particles are needed to simulate, say, the scalloped edge of a resonantly confined ring or the propagation of spiral density waves. The code is applied to the outer edge of Saturn's B ring, and a comparison of Cassini measurements of the ring's forced response to simulations of Mimas's resonant perturbations reveals that the B ring's surface density at its outer edge is σ 0 = 195 ± 60 g cm –2 , which, if the same everywhere across the ring, would mean that the B ring's mass is about 90% of Mimas's mass. Cassini observations show that the B ring-edge has several free normal modes, which are long-lived disturbances of the ring-edge that are not driven by any known satellite resonances. Although the mechanism that excites or sustains these normal modes is unknown, we can plant such a disturbance at a simulated ring's edge and find that these modes persist without any damping for more than ∼10 5 orbits or ∼100 yr despite the simulated ring's viscosity ν s = 100 cm 2 s –1 . These simulations also indicate that impulsive disturbances at a ring can excite long-lived normal modes, which suggests that an impact in the recent past by perhaps a cloud of cometary debris might have excited these disturbances, which are quite common to many of Saturn's sharp-edged rings

  16. Determination of the 20 MeV linear accelerator, new injector for the synchrotron Saturne. Choice of the electrical and dynamical particle parameters

    International Nuclear Information System (INIS)

    Prome, M.

    1968-12-01

    This report takes place in the general determination of the 20 MeV linear accelerator which will be the new Saturne injector; it deals with particle dynamics. Starting from beam requirements at the output of the linac, cells lengths with variable synchronous phase angle, buncher and de-buncher parameters, beam emittances at the output in several phase spaces are successively determined. (author) [fr

  17. Radio scintillations observed during atmospheric occultations of Voyager: Internal gravity waves at Titan and magnetic field orientations at Jupiter and Saturn. Ph.D. Thesis

    Science.gov (United States)

    Hinson, D. P.

    1983-01-01

    The refractive index of planetary atmospheres at microwave frequencies is discussed. Physical models proposed for the refractive irregularities in the ionosphere and neutral atmosphere serve to characterize the atmospheric scattering structures, and are used subsequently to compute theoretical scintillation spectra for comparison with the Voyager occultation measurements. A technique for systematically analyzing and interpreting the signal fluctuations observed during planetary occultations is presented and applied to process the dual-wavelength data from the Voyager radio occultations by Jupiter, Saturn, and Titan. Results concerning the plasma irregularities in the upper ionospheres of Jupiter and Saturn are reported. The measured orientation of the irregularities is used to infer the magnetic field direction at several locations in the ionospheres of these two planets; the occultation measurements conflict with the predictions of Jovian magnetic field models, but generally confirm current models of Saturn's field. Wave parameters, including the vertical fluxes of energy and momentum, are estimated, and the source of the internal gravity waves discovered in Titan's upper atmosphere is considered.

  18. Ertel Potential Vorticity versus Bernoulli Streamfunction in Earth's Southern Ocean: Comparison with the Atmospheres of Earth, Mars, Jupiter and Saturn

    Science.gov (United States)

    Dowling, Timothy E.; Stanley, Geoff; Bradley, Mary Elizabeth; Marshall, David P.

    2017-10-01

    We are working to expand the comparative planetology of vorticity-streamfunction correlations established for the atmospheres of Earth, Mars, Jupiter and Saturn to include Earth’s Antarctic Circumpolar Current (ACC), which is the only oceanic jet that encircles the planet. Interestingly, the ACC and its eddies scale like atmospheric jets and eddies on Jupiter and Saturn---the Southern Ocean is a “giant planet” with a zonal jet stream. Our input is the Southern Ocean State Estimate (SOSE; Mazloff et al 2010, J. Phys. Ocean. 40, 880-899), an optimal combination of observations and primitive-equation model that spans 2005-2010. Two hurdles not encountered in atmospheric work arise from the nonlinear equation of state of ocean water: non-zero helicity, which prevents the existence of truly neutral (analogous to adiabatic) surfaces, and the lack of a geostrophic streamfunction in general. We follow de Szoeke et al (2000, J. Phys. Ocean. 30, 2830-2852) to overcome these hurdles, regionally, by using orthobaric density as the vertical coordinate. In agreement with results for all atmospheres analyzed to date, scatter plots of Ertel potential vorticity, Q, versus Bernoulli streamfunction, B, on orthobaric density surfaces in the Southern Ocean are well correlated. The general shape of the correlation is like a hockey stick, with the “blade” corresponding to a broad horizontal region that spans the ACC, and the “handle” corresponding to shallow water. The same linear-regression Q versus B model employed for Mars is applied to the ACC (“blade”) signal. Results include that the deeper water on the equatorward side of the ACC is most prone to shear instability, and elsewhere the ACC is “supersonic” such that the net propagation of vorticity waves is eastward, not the usual westward. During the 6-year span of the SOSE data, there is a steady drift of the correlation to larger values at the top of the vertical profile, and to smaller values in the middle of

  19. Search for biochemical fossils on earth and non-biological organic molecules on Jupiter, Saturn and Titan

    Science.gov (United States)

    Nagy, Bartholomew

    1982-07-01

    Recognizable remnants of ancient biochemicals may survive under mild/moderate geological environments. Acyclic isoprenoid hydrocarbons, cyclic hydrocarbons with terpenoid carbon skeletons (e.g. hopanes) and vanadyl and nickel porphyrins have been isolated from organic matter, including petroleum, in Phanerozoic sedimentary rocks. Remnants of lignin have also been found. Usually, carbohydrates do not survive long; they degrade and/or react with other organic substances to form macromolecular matter. Proteins, e.g. apparently those in dinosaur bone collagen, break down relatively rapidly. Life arose during the Precambrian and potential biochemical fossils, e.g. n-alkanes, 2,5-dimethylfuran have been isolated from Precambrian kerogens. Traces of hydrocarbons, NH3, PH3 occur on Jupiter and Saturn. Hydrocarbons, N2 and HCN, the latter a key intermediary in the laboratory abiological syntheses of amino acids and nucleic acid bases, are present on Titan where life could not have evolved. Precursor abiological organic molecules of some complexity may have been synthesized on Titan and the Jovian planets.

  20. The rings of Saturn - New near-infrared reflectance measurements and a 0.326-4.08 micron summary

    International Nuclear Information System (INIS)

    Clark, R.N.; McCord, T.B.

    1980-01-01

    A new high-photometric-precision reflectance spectrum of Saturn's rings covering the spectral region 0.65 to 2.5 microns is presented and three previously unreported absorption features at 1.25, 0.85, and probably 1.04 microns are identified. The 1.25- and 1.04 micron absorptions are due to water ice. The 0.85 microns feature may be due to a combination of 0.81- and 0.90 micron ice absorptions but this feature appears too strong relative to the 1.04 micron band to be completely explained by water ice. Another possibility is that the 0.85 micron band is due to Fe(3+)-bearing minerals in an ice-mineral mixture. This explanation could also account for the drop in the visible and ultraviolet reflectance and the rise in reflectance around 3.6 microns. Finally, a composite spectrum from 0.325 to 4.08 is presented which will be useful for future analysis and laboratory studies

  1. Study of Oblique Propagating Whistler Mode Waves in Presence of Parallel DC Electric Field in Magnetosphere of Saturn

    Directory of Open Access Journals (Sweden)

    R. Kaur

    2017-03-01

    Full Text Available In this paper whistler mode waves have been investigated in magnetosphere of Saturn. The derivation for perturbed distribution function, dispersion relation and growth rate have been determined by using the method of characteristic and kinetic approach. Analytical expressions for growth rate and real frequency of whistlers propagating oblique to magnetic field direction are attained. Calculations have been performed at 6 radial distances in plasma sheet region of Saturn’s magnetosphere as per data provided by Cassini. Work has been extended for bi-Maxwellian as well as Loss-cone distribution function. Parametric analysis show that temperature anisotropy, increase in number density, energy density and angle of propagation increases the growth rate of whistler waves along with significant shift in wave number. In case of Loss-cone distribution, increase in growth rate of whistlers is significantly more than for bi-Maxwellian distribution function. Generation of second harmonics can also be seen in the graphs plotted. It is concluded that parallel DC field stabilizes the wave and temperature anisotropy, angle of propagation, number density and energy density of electrons enhances the growth rate. Thus the results are of importance in analyzing observed VLF emissions over wide spectrum of frequency range in Saturnian magnetosphere. The analytical model developed can also be used to study various types of instabilities in planetary magnetospheres.

  2. Solar Energetic Particles (SEP) and Galactic Cosmic Rays (GCR) as tracers of solar wind conditions near Saturn: Event lists and applications

    Science.gov (United States)

    Roussos, E.; Jackman, C. M.; Thomsen, M. F.; Kurth, W. S.; Badman, S. V.; Paranicas, C.; Kollmann, P.; Krupp, N.; Bučík, R.; Mitchell, D. G.; Krimigis, S. M.; Hamilton, D. C.; Radioti, A.

    2018-01-01

    The lack of an upstream solar wind monitor poses a major challenge to any study that investigates the influence of the solar wind on the configuration and the dynamics of Saturn's magnetosphere. Here we show how Cassini MIMI/LEMMS observations of Solar Energetic Particle (SEP) and Galactic Cosmic Ray (GCR) transients, that are both linked to energetic processes in the heliosphere such us Interplanetary Coronal Mass Ejections (ICMEs) and Corotating Interaction Regions (CIRs), can be used to trace enhanced solar wind conditions at Saturn's distance. SEP protons can be easily distinguished from magnetospheric ions, particularly at the MeV energy range. Many SEPs are also accompanied by strong GCR Forbush Decreases. GCRs are detectable as a low count-rate noise signal in a large number of LEMMS channels. As SEPs and GCRs can easily penetrate into the outer and middle magnetosphere, they can be monitored continuously, even when Cassini is not situated in the solar wind. A survey of the MIMI/LEMMS dataset between 2004 and 2016 resulted in the identification of 46 SEP events. Most events last more than two weeks and have their lowest occurrence rate around the extended solar minimum between 2008 and 2010, suggesting that they are associated to ICMEs rather than CIRs, which are the main source of activity during the declining phase and the minimum of the solar cycle. We also list of 17 time periods ( > 50 days each) where GCRs show a clear solar periodicity ( ∼ 13 or 26 days). The 13-day period that derives from two CIRs per solar rotation dominates over the 26-day period in only one of the 17 cases catalogued. This interval belongs to the second half of 2008 when expansions of Saturn's electron radiation belts were previously reported to show a similar periodicity. That observation not only links the variability of Saturn's electron belts to solar wind processes, but also indicates that the source of the observed periodicity in GCRs may be local. In this case GCR

  3. Outreach for Cassini Huyghens mission and future Saturn and Titan exploration: From the Antikythera Mechanism to the TSSM mission

    Science.gov (United States)

    Moussas, Xenophon; Bampasidis, Georgios; Coustenis, Athena; Solomonidou, Anezina

    2010-05-01

    These days Outreach is an activity tightly related to success in science. The public with its great interest to space and astronomy in general, the solar system exploration and Saturn and Titan in particular, loves the scientific outcome of Cassini and Huygens. This love of the public gives a lot, as its known interest to space, persuades politicians and policy makers to support space and future Saturn and Titan explorations. We use the scientific results from Cassini and Huyghens together with a mosaic from ancient science concerning the history of solar system exploration, such as the oldest known complex astronomical device, the Antikyhtera Mechanism, in outreach activities to ensure future missions and continuous support to present ones. A future mission to the Saturnian System focusing on exotic Titan will broaden people's interest not only to Physics and Astronomy, but to Mechanics, Technology and even Philosophy as well, since, obviously, the roots of the vast contribution of Space Science and Astronomy to the contemporary society can be traced back to the first astronomers of Antiquity. As an example we use the Antikythera Mechanism, a favourite astronomical device for the public, which is the first geared astronomical device ever, constructed that combines the spirit of the ancient Astronomy and scientific accuracy. It is common belief that Astronomy and Astrophysics is a perfect tool to easily involve people in Science, as the public is always interested in space subjects, captivated by the beauty and the mystery of the Universe. Years after the successful entry, descent and landing of the Huygens probe on Titan's surface, the outstanding achievements of the Cassini-Huygens mission enhance the outreach potential of Space Science. Titan is an earth-like world, embedded in a dense nitrogen atmospheric envelop and a surface carved by rivers, mountains, dunes and lakes, its exploration will certainly empower the perspective of the society for space activities

  4. Seasonal Variability of Saturn's Tropospheric Temperatures, Winds and Para-H2 from Cassini Far-IR Spectroscopy

    Science.gov (United States)

    Fletcher, Leigh N.; Irwin, P. G. J; Achterberg, R. K.; Orton, G. S.; Flasar, F. M.

    2015-01-01

    Far-IR 16-1000 micrometer spectra of Saturn's hydrogen-helium continuum measured by Cassini's Composite Infrared Spectrometer (CIRS) are inverted to construct a near-continuous record of upper tropospheric (70-700 mbar) temperatures and para-H2 fraction as a function of latitude, pressure and time for a third of a saturnian year (2004-2014, from northern winter to northern spring). The thermal field reveals evidence of reversing summertime asymmetries superimposed onto the belt/zone structure. The temperature structure is almost symmetric about the equator by 2014, with seasonal lag times that increase with depth and are qualitatively consistent with radiative climate models. Localised heating of the tropospheric hazes (100-250 mbar) create a distinct perturbation to the temperature profile that shifts in magnitude and location, declining in the autumn hemisphere and growing in the spring. Changes in the para-H2 (f(sub p)) distribution are subtle, with a 0.02-0.03 rise over the spring hemisphere (200-500 mbar) perturbed by (i) low-f(sub p) air advected by both the springtime storm of 2010 and equatorial upwelling; and (ii) subsidence of high-f(sub p) air at northern high latitudes, responsible for a developing north-south asymmetry in f(sub p). Conversely, the shifting asymmetry in the para-H2 disequilibrium primarily reflects the changing temperature structure (and hence the equilibrium distribution of f(sub p)), rather than actual changes in f(sub p) induced by chemical conversion or transport. CIRS results interpolated to the same point in the seasonal cycle as re-analysed Voyager-1 observations (early northern spring) show qualitative consistency from year to year (i.e., the same tropospheric asymmetries in temperature and f(sub p)), with the exception of the tropical tropopause near the equatorial zones and belts, where downward propagation of a cool temperature anomaly associated with Saturn's stratospheric oscillation could potentially perturb tropopause

  5. Simulations of the response function of a plasma ion beam spectrometer for the Cassini mission to Saturn

    International Nuclear Information System (INIS)

    Vilppola, J.H.; Tanskanen, P.J.; Huomo, H.; Barraclough, B.L.

    1996-01-01

    To obtain very high (∼1%) energy resolution with spherical-section electrostatic analyzers requires high precision in both fabrication and in the alignment process. In order to aid in the calibration of the instrument and to help minimize fabrication costs, we have applied simulation models to the ion beam spectrometer for the NASA/ESA Cassini mission to Saturn. Previously we studied the effects of misalignment and simple irregularities of the hemispherical surfaces on the performance of an electrostatic analyzer. We have considered a hemispherical electrostatic analyzer equipped with an aperture plate to collimate the stray electric field at the entrance apertures. The influence of a curved entrance aperture has also been added to the simulation model, and its effects have been studied in detail. A cylindrical three-dimensional simultaneous overrelaxation algorithm has been introduced to solve for the stray electric field. The maximum loss of transmitted particles with respect to the transmission of an ideal instrument has been set at 10%. We demonstrate that the deviation in the distributions of the energies is less than 0.2% and that the deviation in the distributions of entrance angles of transmitted particles is less than 0.1 degree. It has been found that the energy resolution of an electrostatic analyzer can be improved from ΔE/E=(1.6±0.2)% to ΔE/E=(1.3±0.2)% by the introduction of front aperture plates. Through the introduction of curved entrance slits, the azimuthal angle resolution has changed from β=(1.4±0.1)degree for the simplified geometry simulation results of our previous article to β=(2.3±0.1)degree. We have confirmed that an accuracy of 25 μm in the alignment of the two hemispherical surfaces is sufficient to give the instrument the desired resolutions. copyright 1996 American Institute of Physics

  6. A Nonequilibrium Figure of Saturn's Satellite Iapetus and the Origin of the Equatorial Ridge on Its Surface

    Science.gov (United States)

    Kondratyev, B. P.

    2018-03-01

    The structure, dynamical equilibrium, and evolution of Saturn's moon Iapetus are studied. It has been shown that, in the current epoch, the oblateness of the satellite ɛ2 ≈ 0.046 does not correspond to its angular velocity of rotation, which causes the secular spherization behavior of the ice shell of Iapetus. To study this evolution, we apply a spheroidal model, containing a rock core and an ice shell with an external surface ɛ2, to Iapetus. The model is based on the equilibrium finite-difference equation of the Clairaut theory, while the model parameters are taken from observations. The mean radius of the rock core and the oblateness of its level surface, ɛ1 ≈ 0.028, were determined. It was found that Iapetus is covered with a thick ice shell, which is 56.6% of the mean radius of the figure. We analyze a role of the core in the evolution of the shape of a gravitating figure. It was determined that the rock core plays a key part in the settling of the ice masses of the equatorial bulge, which finally results in the formation of a large circular equatorial ridge on the surface of the satellite. From the known mean altitude of this ice ridge, it was found that, in the epoch of its formation, the rotation period of Iapetus was 166 times shorter than that at present, as little as T ≈ 11h27m. This is consistent with the fact that a driving force of the evolution of the satellite in our model was its substantial despinning. The model also predicts that the ice ridge should be formed more intensively in the leading (dark and, consequently, warmer) hemisphere of the satellite, where the ice is softer. This inference agrees with the observations: in the leading hemisphere of Iapetus, the ridge is actually high and continuous everywhere, while it degenerates into individual ice peaks in the opposite colder hemisphere.

  7. Determination of the 20 MeV linear accelerator, new injector for the synchrotron Saturne. Choice of the electrical and dynamical particle parameters; Determination de l'accelerateur lineaire de 20 MeV, nouvel injecteur du synchrotron Saturne. Choix des parametres electriques, dynamique des particules

    Energy Technology Data Exchange (ETDEWEB)

    Prome, M [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1968-12-15

    This report takes place in the general determination of the 20 MeV linear accelerator which will be the new Saturne injector; it deals with particle dynamics. Starting from beam requirements at the output of the linac, cells lengths with variable synchronous phase angle, buncher and de-buncher parameters, beam emittances at the output in several phase spaces are successively determined. (author) [French] Dans le contexte general de la determination de l'accelerateur lineaire de 20 MeV, nouvel injecteur du synchrotron Saturne, ce rapport traite de la partie relative au mecanisme de l'acceleration des particules; a partir des caracteristiques souhaitees pour le faisceau a la sortie de cet accelerateur, on determine successivement les longueurs des cellules, compte tenu du choix d'un angle de phase synchrone variable, les caracteristiques du groupeur et du degroupeur et les emittances du faisceau en sortie dans les differents plans de phase. (auteur)

  8. Sobre el fragment dels Catasterismes d'Eratòstenes del manuscrit Parisinus Graecus 1310: el nom dels planetes Saturn i Júpiter

    OpenAIRE

    Pàmias i Massana, Jordi

    1998-01-01

    El ms. Parisinus Graecus 1310 inclou un breu fragment de l'Epítom dels Catasterismes, obra atribuïda a Eratòstenes. A banda d'alguna variant respecte del textus receptus, presenta un capítol (43) del tot reelaborat, en què l'excepcional irregularitat de l'Epítom dels Catasterismes, pel que fa a les correspondències divines dels dos primers planetes de la nòmina de cinc, ha estat corregida per tal d'adequar els noms dels planetes Faiuou i Faethou a Saturn i a Júpiter respectivament. The man...

  9. Study and development of a closed-loop automation system of a complex beam transport optics using beam transport optics using the CII 10020 computer of Saturne

    International Nuclear Information System (INIS)

    Haeffner, Catherine.

    1972-01-01

    The aim of this study was the focussing of a particle beam, the control and output parameters of such a system, the evaluation of a quality criterion and the physical constraints to take into account. The closed-loop automation system was entirely simulated; it was thus possible to test optimization methods in order to choose the best one for the experimental application envisaged, before optimizing the corresponding control. The experimental application on the beam of Saturne had to be modified but positive results were obtained [fr

  10. A change of seasons in Saturn's stratosphere from Cassini/CIRS: evolution of the equatorial oscillation and reversal of hemispheric transport.

    Science.gov (United States)

    Guerlet, Sandrine; Fouchet, Thierry; Hesman, Brigette; Bjoraker, Gordon; Spiga, Aymeric; Cassini/CIRS Team

    2016-10-01

    Due to its axial tilt of 26.7°, Saturn's atmosphere undergoes significant seasonal variations in insolation that impact its thermal structure, chemistry and dynamics. The exceptional longevity of the Cassini mission enables us to uniquely investigate these changes over almost half a Saturn year. In this study, thermal infrared spectra acquired in 2015 by CIRS in limb viewing geometry are analyzed to map the temperature and the meridional distribution of five hydrocarbons from the lower to the upper stratosphere (10 mbar - 10 microbar). These new maps represent a snapshot of Saturn's atmosphere at the end of the northern spring and are compared to previous results obtained during northern winter (2005/2006) and early spring (2010/2011) (Guerlet et al., Icarus, 2009; Sylvestre et al., Icarus, 2015). Spectacular seasonal changes in temperature are observed, not only at high latitudes where the most extreme insolation variations take place, but also at 20N-20S where the mechanical forcing of the equatorial oscillation induces temperature anomalies of up to +/-20K. These results are compared with predictions from a radiative climate model (Guerlet et al., Icarus, 2014). Apart from the equatorial region, the seasonal warming and cooling trends observed by CIRS are, to first order, consistent with the predictions. One notable exception is that the region under the ring's shadow is found warmer than expected from the radiative model, both in 2005 and 2015. The spatial distribution of hydrocarbons, by-products of the methane photochemistry, also undergoes significant seasonal change in the upper stratosphere. In 2005, a local maximum of hydrocarbons was observed at 20-30N, at odds with the low photochemical production in this region (under the ring's shadow at that time). Together with the high temperature anomaly, we had interpreted this result as the signature of a downwelling branch of the meridional circulation. In 2015, not only has this local maximum vanished, but a

  11. Problems of simulation of large, long-lived vortices in the atmospheres of the giant planets (jupiter, saturn, neptune)

    Science.gov (United States)

    Nezlin, Michael V.; Sutyrin, Georgi G.

    1994-01-01

    Large, long-lived vortices are abundant in the atmospheres of the giant planets. Some of them survive a few orders of magnitude longer than the dispersive linear Rossby wave packets, e.g. the Great Red Spot (GRS), Little Red Spot (LRS) and White Ovals (WO) of Jupiter, Big Bertha, Brown Spot and Anne's Spot of Saturn, the Great Dark Spot (GDS) of Neptune, etc. Nonlinear effects which prevent their dispersion spreading are the main subject of our consideration. Particular emphasis is placed on determining the dynamical processes which may explain the remarkable properties of observed vortices such as anticyclonic rotation in preference to cyclonic one and the uniqueness of the GRS, the largest coherent vortex, along the perimeter of Jupiter at corresponding latitude. We review recent experimental and theoretical studies of steadily translating solitary Rossby vortices (anticyclones) in a rotating shallow fluid. Two-dimensional monopolar solitary vortices trap fluid which is transported westward. These dualistic structures appear to be vortices, on the one hand, and solitary “waves”, on the other hand. Owing to the presence of the trapped fluid, such solitary structures collide inelastically and have a memory of the initial disturbance which is responsible for the formation of the structure. As a consequence, they have no definite relationship between the amplitude and characteristic size. Their vortical properties are connected with geostrophic advection of local vorticity. Their solitary properties (nonspreading and stationary translation) are due to a balance between Rossby wave dispersion and nonlinear effects which allow the anticyclones, with an elevation of a free surface, to propagate faster than the linear waves, without a resonance with linear waves, i.e. without wave radiation. On the other hand, cyclones, with a depression of a free surface, are dispersive and nonstationary features. This asymmetry in dispersion-nonlinear properties of cyclones and

  12. TWO PLANETARY COMPANIONS AROUND THE K7 DWARF GJ 221: A HOT SUPER-EARTH AND A CANDIDATE IN THE SUB-SATURN DESERT RANGE

    Energy Technology Data Exchange (ETDEWEB)

    Arriagada, Pamela; Minniti, Dante [Department of Astronomy, Pontificia Universidad Catolica de Chile, Casilla 306, Santiago 22 (Chile); Anglada-Escude, Guillem; Butler, R. Paul [Department of Terrestrial Magnetism, Carnegie Institution of Washington, 5241 Broad Branch Road NW, Washington, DC 20015-1305 (United States); Crane, Jeffrey D.; Shectman, Stephen A.; Thompson, Ian [The Observatories of the Carnegie Institution of Washington, 813 Santa Barbara Street, Pasadena, CA 91101 (United States); Wende, Sebastian, E-mail: parriaga@astro.puc.cl [Institut fuer Astrophysik, Universitaet Goettingen, Friedrich-Hund-Platz 1, D-37077 Goettingen (Germany)

    2013-07-01

    We report two low-mass companions orbiting the nearby K7 dwarf GJ 221 that have emerged from reanalyzing 4.4 yr of publicly available HARPS spectra complemented with 2 years of high-precision Doppler measurements with Magellan/PFS. The HARPS measurements alone contain the clear signal of a low-mass companion with a period of 125 days and a minimum mass of 53.2 M{sub Circled-Plus} (GJ 221b), falling in a mass range where very few planet candidates have been found (sub-Saturn desert). The addition of 17 PFS observations allows the confident detection of a second low-mass companion (6.5 M{sub Circled-Plus }) in a hot orbit (3.87 day period, GJ 221c). Spectroscopic and photometric calibrations suggest that GJ 221 is slightly depleted ([Fe/H] {approx} -0.1) compared to the Sun, so the presence of two low-mass companions in the system confirms the trend that slightly reduced stellar metallicity does not prevent the formation of planets in the super-Earth to sub-Saturn mass regime.

  13. Drift-resonant, relativistic electron acceleration at the outer planets: Insights from the response of Saturn's radiation belts to magnetospheric storms

    Science.gov (United States)

    Roussos, E.; Kollmann, P.; Krupp, N.; Paranicas, C.; Dialynas, K.; Sergis, N.; Mitchell, D. G.; Hamilton, D. C.; Krimigis, S. M.

    2018-05-01

    The short, 7.2-day orbital period of Cassini's Ring Grazing Orbits (RGO) provided an opportunity to monitor how fast the effects of an intense magnetospheric storm-time period (days 336-343/2016) propagated into Saturn's electron radiation belts. Following the storms, Cassini's MIMI/LEMMS instrument detected a transient extension of the electron radiation belts that in subsequent orbits moved towards the inner belts, intensifying them in the process. This intensification was followed by an equally fast decay, possibly due to the rapid absorption of MeV electrons by the planet's main rings. Surprisingly, all this cycle was completed within four RGOs, effectively in less than a month. That is considerably faster than the year-long time scales of Saturn's proton radiation belt evolution. In order to explain this difference, we propose that electron radial transport is partly controlled by the variability of global scale electric fields which have a fixed local time pointing. Such electric fields may distort significantly the orbits of a particular class of energetic electrons that cancel out magnetospheric corotation due to their westward gradient and curvature drifts (termed "corotation-resonant" or "local-time stationary" electrons) and transport them radially between the ring current and the radiation belts within several days and few weeks. The significance of the proposed process is highlighted by the fact that corotation resonance at Saturn occurs for electrons of few hundred keV to several MeV. These are the characteristic energies of seed electrons from the ring current that sustain the radiation belts of the planet. Our model's feasibility is demonstrated through the use of a simple test-particle simulation, where we estimate that uniform but variable electric fields with magnitudes lower that 1.0 mV/m can lead to a very efficient transport of corotation resonant electrons. Such electric fields have been consistently measured in the magnetosphere, and here we

  14. Study of atmospheric stratification influence on pollutants dispersion using a numerical fluid mechanics model. Code-Saturne validation with the Prairie Grass experiment/Study of atmospheric stratification influence on pollutants dispersion using a numerical fluid mechanics software

    International Nuclear Information System (INIS)

    Coulon, Fanny

    2010-09-01

    A validation of Code-Saturne, a computational fluids dynamics model developed by EDF, is proposed for stable conditions. The goal is to guarantee the performance of the model in order to use it for impacts study. A comparison with the Prairie Grass data field experiment and with two Gaussian plume models will be done [fr

  15. Image Gallery

    Science.gov (United States)

    ... R S T U V W X Y Z Image Gallery Share: The Image Gallery contains high-quality digital photographs available from ... Select a category below to view additional thumbnail images. Images are available for direct download in 2 ...

  16. Carbon dioxide on the satellites of Saturn: Results from the Cassini VIMS investigation and revisions to the VIMS wavelength scale

    Science.gov (United States)

    Cruikshank, D.P.; Meyer, A.W.; Brown, R.H.; Clark, R.N.; Jaumann, R.; Stephan, K.; Hibbitts, C.A.; Sandford, S.A.; Mastrapa, R.M.E.; Filacchione, G.; Ore, C.M.D.; Nicholson, P.D.; Buratti, B.J.; McCord, T.B.; Nelson, R.M.; Dalton, J.B.; Baines, K.H.; Matson, D.L.

    2010-01-01

    Several of the icy satellites of Saturn show the spectroscopic signature of the asymmetric stretching mode of C-O in carbon dioxide (CO2) at or near the nominal solid-phase laboratory wavelength of 4.2675 ??m (2343.3 cm-1), discovered with the Visible-Infrared Mapping Spectrometer (VIMS) on the Cassini spacecraft. We report here on an analysis of the variation in wavelength and width of the CO2 absorption band in the spectra of Phoebe, Iapetus, Hyperion, and Dione. Comparisons are made to laboratory spectra of pure CO2, CO2 clathrates, ternary mixtures of CO2 with other volatiles, implanted and adsorbed CO2 in non-volatile materials, and ab initio theoretical calculations of CO2 * nH2O. At the wavelength resolution of VIMS, the CO2 on Phoebe is indistinguishable from pure CO2 ice (each molecule's nearby neighbors are also CO2) or type II clathrate of CO2 in H2O. In contrast, the CO2 band on Iapetus, Hyperion, and Dione is shifted to shorter wavelengths (typically ???4.255 ??m (???2350.2 cm-1)) and broadened. These wavelengths are characteristic of complexes of CO2 with different near-neighbor molecules that are encountered in other volatile mixtures such as with H2O and CH3OH, and non-volatile host materials like silicates, some clays, and zeolites. We suggest that Phoebe's CO2 is native to the body as part of the initial inventory of condensates and now exposed on the surface, while CO2 on the other three satellites results at least in part from particle or UV irradiation of native H2O plus a source of C, implantation or accretion from external sources, or redistribution of native CO2 from the interior. The analysis presented here depends on an accurate VIMS wavelength scale. In preparation for this work, the baseline wavelength calibration for the Cassini VIMS was found to be distorted around 4.3 ??m, apparently as a consequence of telluric CO2 gas absorption in the pre-launch calibration. The effect can be reproduced by convolving a sequence of model detector

  17. The reaction of atomic hydrogen with germane - Temperature dependence of the rate constant and implications for germane photochemistry in the atmospheres of Jupiter and Saturn

    Science.gov (United States)

    Nava, David F.; Payne, Walter A.; Marston, George; Stief, Louis J.

    1993-01-01

    Studies of the formation and loss processes for GeH4 are required in order to provide data to help determine the major chemical form in which germanium exists in the atmospheres of Jupiter and Saturn. The reaction of hydrogen atoms with germane is one of the most important of these reactions. The absolute rate constant for this reaction as a function of temperature and pressure is studied. Flash photolysis of dilute mixtures of GeH4 in argon, combined with time-resolved detection of H atoms via Lyman alpha resonance fluorescence, is employed to measure the reaction rate. The reaction is shown to be moderately rapid, independent of total pressure, but possessing a positive temperature dependence.

  18. Oceanographic data collected from Saturn Estuary Station 03 by Center for Coastal Margin Observation and Prediction (CMOP) and assembled by Northwest Association of Networked Ocean Observation Systems (NANOOS) in the Columbia River Estuary and North East Pacific Ocean from 2008-04-19 to 2017-08-01 (NCEI Accession 0162617)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NCEI Accession 0162617 contains biological, chemical and physical data collected at Saturn Estuary Station 03, a fixed station in the Columbia River estuary -...

  19. Oceanographic data collected from SATURN-09 by Center for Coastal Margin Observation and Prediction (CMOP) and assembled by Northwest Association of Networked Ocean Observation Systems (NANOOS) in the Columbia River Estuary and North East Pacific Ocean from 2014-09-08 to 2016-06-10 (NCEI Accession 0162185)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NCEI Accession 0162185 contains biological, chemical and physical data collected at SATURN-09, a fixed station in the Columbia River estuary - Washington/Oregon....

  20. Oceanographic data collected from SATURN-10 by Center for Coastal Margin Observation and Prediction (CMOP) and assembled by Northwest Association of Networked Ocean Observation Systems (NANOOS) in the Columbia River Estuary and North East Pacific Ocean from 2015-09-01 to 2016-12-16 (NCEI Accession 0162186)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NCEI Accession 0162186 contains biological, chemical, meteorological and physical data collected at SATURN-10, a fixed station in the Columbia River estuary -...

  1. Oceanographic data collected from SATURN River Station 05 by Center for Coastal Margin Observation and Prediction (CMOP) and assembled by Northwest Association of Networked Ocean Observation Systems (NANOOS) in the Columbia River Estuary and North East Pacific Ocean from 2009-06-23 to 2016-12-06 (NCEI Accession 0162430)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NCEI Accession 0162430 contains biological, chemical, navigational and physical data collected at SATURN River Station 05, a fixed station in the Columbia River...

  2. Oceanographic data collected from SATURN-07 by Center for Coastal Margin Observation and Prediction (CMOP) and assembled by Northwest Association of Networked Ocean Observation Systems (NANOOS) in the Columbia River Estuary and North East Pacific Ocean from 2012-05-03 to 2017-01-24 (NCEI Accession 0162184)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NCEI Accession 0162184 contains biological, chemical and physical data collected at SATURN-07, a fixed station in the Columbia River estuary - Washington/Oregon....

  3. Oceanographic data collected from Saturn Estuary Station 01 by Center for Coastal Margin Observation and Prediction (CMOP) and assembled by Northwest Association of Networked Ocean Observation Systems (NANOOS) in the Columbia River Estuary and North East Pacific Ocean from 2008-04-13 to 2017-07-01 (NCEI Accession 0162182)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NCEI Accession 0162182 contains biological, chemical and physical data collected at Saturn Estuary Station 01, a fixed station in the Columbia River estuary -...

  4. Image Statistics

    Energy Technology Data Exchange (ETDEWEB)

    Wendelberger, Laura Jean [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-08-08

    In large datasets, it is time consuming or even impossible to pick out interesting images. Our proposed solution is to find statistics to quantify the information in each image and use those to identify and pick out images of interest.

  5. Image Guidance

    Science.gov (United States)

    Guidance that explains the process for getting images approved in One EPA Web microsites and resource directories. includes an appendix that shows examples of what makes some images better than others, how some images convey meaning more than others

  6. Data imaging

    International Nuclear Information System (INIS)

    Pepy, G.

    1999-01-01

    After an introduction about data imaging in general, the principles of imaging data collected via neutron scattering experiments are presented. Some computer programs designed for data imaging purposes are reviewed. (K.A.)

  7. Pancreatic imaging

    International Nuclear Information System (INIS)

    Potsaid, M.S.

    1978-01-01

    The clinical use of [ 75 Se] selenomethionine for visualising the pancreas is described. The physiological considerations, imaging procedure, image interpretations and reliability are considered. (C.F.)

  8. Rate Constant for the Reaction CH3 + CH3 Yields C2H6 at T = 155 K and Model Calculation of the CH3 Abundance in the Atmospheres of Saturn and Neptune

    Science.gov (United States)

    Cody, Regina J.; Romani, Paul N.; Nesbitt, Fred L.; Iannone, Mark A.; Tardy, Dwight C.; Stief, Louis J.

    2003-01-01

    The column abundances of CH3 observed by the Infrared Space Observatory (ISO) satellite on Saturn and Neptune were lower than predicted by atmospheric photochemical models, especially for Saturn. It has been suggested that the models underestimated the loss of CH3 due to poor knowledge of the rate constant k of the CH3 + CH3 self-reaction at the low temperatures and pressures of these atmospheres. Motivated by this suggestion, we undertook a combined experimental and photochemical modeling study of the CH3 + CH3 reaction and its role in determining planetary CH3 abundances. In a discharge flow-mass spectrometer system, k was measured at T = 155 K and three pressures of He. The results in units of cu cm/molecule/s are k(0.6 Torr) = 6.82 x 10(exp -11), k(1.0 Torr) = 6.98 x 10(exp -11), and k(1.5 Torr) = 6.91 x 10(exp -11). Analytical expressions for k were derived that (1) are consistent with the present laboratory data at T = 155 K, our previous data at T = 202 K and 298 K, and those of other studies in He at T = 296-298 K and (2) have some theoretical basis to provide justification for extrapolation. The derived analytical expressions were then used in atmospheric photochemical models for both Saturn and Neptune. These model results reduced the disparity with observations of Saturn, but not with observations of Neptune. However, the disparity for Neptune is much smaller. The solution to the remaining excess CH3 prediction in the models relative to the ISO observations lies, to a large extent, elsewhere in the CH3 photochemistry or transport, not in the CH3 + CH3 rate.

  9. Analysis of Hot Ions Detected during Equatorial Orbits of the Cassini Spacecraft at Saturn using the Convected Kappa Distribution Function and a Comparison to Voyager and Galileo Measurements at Jupiter

    Science.gov (United States)

    Kane, M.; Mitchell, D. G.; Carbary, J. F.; Hill, M. E.; Dialynas, K.; Mauk, B.; Krimigis, S. M.

    2017-12-01

    An extensive analysis of Cassini INCA and CHEMS measurements of 5-149 keV ions acquired during all equatorial orbits has been completed using a 3-D convected kappa distribution model. The computed plasma azimuthal speed, expressed as a fraction of the local corotation speed, decreases sharply with increasing distance from Saturn. The oxygen ion profile follows the hydrogen ion trend. For both species, the polar convection speed is the smallest of the 3 velocity components, and is centered about zero, but the radial speed has a significant radially outward component. Further, the radial component is enhanced in the pre-dawn sector. The hydrogen and oxygen temperatures increase with decreasing distance to Saturn. The calculated pattern of convection is consistent with an empirical model of plasma convection that includes outward radial transport and escape of plasma in a dawnside boundary layer of plasma entrained by the dawn magnetosheath flow. When the model convection pattern is scaled to the sub-solar magnetopause distance and to the sizes of Jupiter and Saturn, the pattern agrees with that derived from analysis of hot ions detected by the LECP detector on Voyager and the EPD instrument on Galileo. This and previous analysis of hot ion distributions has shown that the convected kappa distribution, with isotropy assumed in the plasma rest frame, has well described hot ion observed fluxes within a limited range of ion energies and has produced meaningful and ordered physical plasma parameters including plasma bulk velocity vectors, kappa distribution temperature profiles, and the general magnetospheric convection pattern at Jupiter and Saturn.

  10. Image city

    DEFF Research Database (Denmark)

    2003-01-01

    Image city exhibition explores a condition of mediation, through a focus on image and sound narratives with a point of departure on a number of Asian cities.......Image city exhibition explores a condition of mediation, through a focus on image and sound narratives with a point of departure on a number of Asian cities....

  11. Maxillofacial imaging

    Energy Technology Data Exchange (ETDEWEB)

    Larheim, T.A. [Oslo Univ. (Norway). Dept. of Maxillofacial Radiology; Westesson, P.L. [Univ. of Rochester School of Medicine and Dentistry, NY (United States). Div. of Diagnostic and Interventional Radiology

    2006-07-01

    Maxillofacial imaging has evolved dramatically over the past two decades with development of new cross-sectional imaging techniques. Traditional maxillofacial imaging was based on plain films and dental imaging. However, today's advanced imaging techniques with CT and MRI have only been partially implemented for maxillofacial questions. This book bridges the gap between traditional maxillofacial imaging and advanced medical imaging. We have applied CT and MRI to a variety of maxillofacial cases and these are illustrated with high-quality images and multiple planes. A comprehensive chapter on imaging anatomy is also included. This book is useful for oral and maxillofacial radiologists, oral and maxillofacial surgeons, dentists, radiologists, plastic surgeons, head and neck surgeons, and others that work with severe maxillofacial disorders. (orig.)

  12. IMPACT OF COHERENT BACKSCATTERING ON THE SPECTRA OF ICY SATELLITES OF SATURN AND THE IMPLICATIONS OF ITS EFFECTS FOR REMOTE SENSING

    International Nuclear Information System (INIS)

    Kolokolova, L.; Buratti, B.; Tishkovets, V.

    2010-01-01

    We have found systematic variations in the spectra of Saturn's icy satellites Rhea and Iapetus obtained by the Cassini Visual and Infrared Mapping Spectrometer (VIMS). The main attribute of these variations is a significantly different depth of the absorption bands at different phase angles. We show that these variations likely result from the coherent backscattering effect (CBE). This effect has been mainly known as the probable reason for a steep opposition spike in brightness observed for some asteroids, moons, and Kuiper Belt Objects at phase angles smaller than 3 deg. The opposition spike has different steepness at different albedos due to the strong dependence of the CBE on the absorption of the material. As a result of this dependence, the impact of the CBE should be different within and outside of the absorption spectral bands. This produces a systematic change in the depth of the absorption bands at different phase angles, as we see in the VIMS spectra of Rhea and Iapetus. Neglecting this effect may result in misinterpretation of the spectra and misleading conclusions about compositional and particle size differences of icy bodies studied at different phase angles. Our computer modeling of the CBE reproduces the observed spectral variations and also shows that they are strongly affected by the size and packing of particles. Thus, the variations in the absorption bands produced by the CBE not only allow us to improve interpretation of the spectra, but also provide a promising approach to study size and packing of the regolith and dust particles.

  13. The Mimas ghost revisited - An analysis of the electron flux and electron microsignatures observed in the vicinity of Mimas at Saturn

    Science.gov (United States)

    Chenette, D. L.; Stone, E. C.

    1983-01-01

    An analysis of the electron-absorption signature observed by the cosmic-ray system on Voyager 2 near the orbit of Mimas is presented. It is found that these observations cannot be explained as the absorption signature of Mimas. By combining Pioneer 11 and Voyager 2 measurements of the electron flux at Mimas's orbit (L = 3.1), an electron spectrum is found in which most of the flux above about 100 keV is concentrated near 1 to 3 MeV. This spectral form is qualitatively consistent with the bandpass filter model of Van Allen et al. (1980). The expected Mimas absorption signature is calculated from this spectrum neglecting radial diffusion. Since no Mimas absorption signature was observed in the inbound Voyager 2 data, a lower limit on the diffusion coefficient for MeV electrons at L = 3.1 of D greater than 10 to the -8th sq Saturn radii/sec is obtained. With a diffusion coefficient this large, both the Voyager 2 and the Pioneer 11 small-scale electron-absorption-signature observations in Mimas's orbit are enigmatic. Thus the mechanism for producing these signatures is referred to as the Mimas ghost. A cloud of material in orbit with Mimas may account for the observed electron signature if the cloud is at least 1-percent opaque to electrons across a region extending over a few hundred kilometers.

  14. THE LICK-CARNEGIE EXOPLANET SURVEY: A SATURN-MASS PLANET IN THE HABITABLE ZONE OF THE NEARBY M4V STAR HIP 57050

    International Nuclear Information System (INIS)

    Haghighipour, Nader; Vogt, Steven S.; Rivera, Eugenio J.; Laughlin, Greg; Meschiari, Stefano; Paul Butler, R.; Henry, Gregory W.

    2010-01-01

    Precision radial velocities (RV) from Keck/HIRES reveal a Saturn-mass planet orbiting the nearby M4V star HIP 57050. The planet has a minimum mass of Msin i ∼ 0.3 M J , an orbital period of 41.4 days, and an orbital eccentricity of 0.31. V-band photometry reveals a clear stellar rotation signature of the host star with a period of 98 days, well separated from the period of the RV variations and reinforcing a Keplerian origin for the observed velocity variations. The orbital period of this planet corresponds to an orbit in the habitable zone of HIP 57050, with an expected planetary temperature of ∼230 K. The star has a metallicity of [Fe/H] = 0.32 ± 0.06 dex, of order twice solar and among the highest metallicity stars in the immediate solar neighborhood. This newly discovered planet provides further support that the well-known planet-metallicity correlation for F, G, and K stars also extends down into the M-dwarf regime. The a priori geometric probability for transits of this planet is only about 1%. However, the expected eclipse depth is ∼7%, considerably larger than that yet observed for any transiting planet. Though long on the odds, such a transit is worth pursuing as it would allow for high quality studies of the atmosphere via transmission spectroscopy with Hubble Space Telescope. At the expected planetary effective temperature, the atmosphere may contain water clouds.

  15. The Lick-Carnegie Exoplanet Survey: A Saturn-Mass Planet in the Habitable Zone of the Nearby M4V Star HIP 57050

    Science.gov (United States)

    Haghighipour, Nader; Vogt, Steven S.; Butler, R. Paul; Rivera, Eugenio J.; Laughlin, Greg; Meschiari, Stefano; Henry, Gregory W.

    2010-05-01

    Precision radial velocities (RV) from Keck/HIRES reveal a Saturn-mass planet orbiting the nearby M4V star HIP 57050. The planet has a minimum mass of Msin i ~ 0.3 M J, an orbital period of 41.4 days, and an orbital eccentricity of 0.31. V-band photometry reveals a clear stellar rotation signature of the host star with a period of 98 days, well separated from the period of the RV variations and reinforcing a Keplerian origin for the observed velocity variations. The orbital period of this planet corresponds to an orbit in the habitable zone of HIP 57050, with an expected planetary temperature of ~230 K. The star has a metallicity of [Fe/H] = 0.32 ± 0.06 dex, of order twice solar and among the highest metallicity stars in the immediate solar neighborhood. This newly discovered planet provides further support that the well-known planet-metallicity correlation for F, G, and K stars also extends down into the M-dwarf regime. The a priori geometric probability for transits of this planet is only about 1%. However, the expected eclipse depth is ~7%, considerably larger than that yet observed for any transiting planet. Though long on the odds, such a transit is worth pursuing as it would allow for high quality studies of the atmosphere via transmission spectroscopy with Hubble Space Telescope. At the expected planetary effective temperature, the atmosphere may contain water clouds.

  16. Ground-based measurements of the 1.3 to 0.3 millimeter spectrum of Jupiter and Saturn, and their detailed calibration.

    Science.gov (United States)

    Pardo, Juan R; Serabyn, Eugene; Wiedner, Martina C; Moreno, Raphäel; Orton, Glenn

    2017-07-01

    One of the legacies of the now retired Caltech Submillimeter Observatory (CSO) is presented in this paper. We measured for the first time the emission of the giant planets Jupiter and Saturn across the 0.3 to 1.3 mm wavelength range using a Fourier Transform Spectrometer mounted on the 10.4-meter dish of the CSO at Mauna Kea, Hawaii, 4100 meters above sea level. A careful calibration, including the evaluation of the antenna performance over such a wide wavelength range and the removal of the Earth's atmosphere effects, has allowed the detection of broad absorption lines on those planets' atmospheres. The calibrated data allowed us to verify the predictions of standard models for both planets in this spectral region, and to confirm the absolute radiometry in the case of Jupiter. Besides their physical interest, the results are also important as both planets are calibration references in the current era of operating ground-based and space-borne submillimeter instruments.

  17. The Outer Planets and their Moons Comparative Studies of the Outer Planets prior to the Exploration of the Saturn System by Cassini-Huygens

    CERN Document Server

    Encrenaz, T; Owen, T. C; Sotin, C

    2005-01-01

    This volume gives an integrated summary of the science related to the four giant planets in our solar system. It is the result of an ISSI workshop on «A comparative study of the outer planets before the exploration of Saturn by Cassini-Huygens» which was held at ISSI in Bern on January 12-16, 2004. Representatives of several scientific communities, such as planetary scientists, astronomers, space physicists, chemists and astrobiologists have met with the aim to review the knowledge on four major themes: (1) the study of the formation and evolution processes of the outer planets and their satellites, beginning with the formation of compounds and planetesimals in the solar nebula, and the subsequent evolution of the interiors of the outer planets, (2) a comparative study of the atmospheres of the outer planets and Titan, (3) the study of the planetary magnetospheres and their interactions with the solar wind, and (4) the formation and properties of satellites and rings, including their interiors, surfaces, an...

  18. Optimisation and calibration of the polarimeter Polder at Saturne. Experiment t20 at the Jefferson Laboratory: Measurement of the deuteron form factors

    International Nuclear Information System (INIS)

    Eyraud, Laurent

    1998-01-01

    The topic of this thesis is the made for the upgrade of the deuteron tensor polarimeter Polder, and its use in the so-called t 20 experiment at the Jefferson Laboratory (USA). The Polder polarimeter is based on the analysing reaction H(d → ,2p)n which makes possible the measurement of the tensor polarization of deuterons in the kinetic energy range 160 MeV - 520 MeV. The first part of this thesis describes the polarimeter and its performances as obtained during the calibration experiment at Saturne (Saclay, France). Specific developments of this polarimeter for the t 20 experiment (Wire Chambers with 3 detections planes, target, hodoscopes) are described. An acquisition system based on Fastbus-VME standard was developed and used during the calibration runs. The second part of the thesis is devoted to the t 20 experiment. The experimental devices, the CEBAF accelerator and the data analysis are presented. Finally the preliminary results for the polarization t 20 and the extraction of the electromagnetic form factors of the deuteron (G c , G q and G m ) for six values of the transferred momentum Q in the range of 4.11 - 6.8 fm -1 are presented and discussed along various theoretical models predictions. (author) [fr

  19. Bruxas e índias filhas de Saturno: arte, bruxaria e canibalismo Witches and indian women, daughters of Saturn: arts, witchcraft and cannibalism

    Directory of Open Access Journals (Sweden)

    Yobenj Aucardo Chicangana-Bayona

    2009-08-01

    Full Text Available O artigo indaga pela representação da mulher nas pinturas e gravuras sobre a bruxaria dos séculos XVI e XVII, procurando estabelecer uma tipologia iconográfica e percorrendo a construção de estigmas negativos imputados no corpo feminino e na sua degradação natural. O texto, apoiado em fontes visuais como pinturas e gravuras, principalmente da Renascença alemã, demonstra como as índias do Novo Mundo foram associadas com as bruxas da Europa e com o deus clássico Saturno, através do mito do canibalismo.The article inquires into the representation of women in the paintings and engravings about witchcraft in the XVI-XVII centuries, trying to establish an iconographic typology and covering the construction of negative stigmas attributed to the feminine body and its natural degradation. Through the support of visual sources such as paintings and engravings, mainly from the German Renaissance, the text demonstrates how the Indian women of the New World were associated to the witches of Europe and with the classic god Saturn, through the myth of cannibalism.

  20. Ground-based measurements of the 1.3 to 0.3 mm spectrum of Jupiter and Saturn, and their detailed calibration

    Science.gov (United States)

    Pardo, Juan R.; Serabyn, Eugene; Wiedner, Martina C.; Moreno, Raphäel; Orton, Glenn

    2017-07-01

    One of the legacies of the now retired Caltech Submillimeter Observatory (CSO) is presented in this paper. We measured for the first time the emission of the giant planets Jupiter and Saturn across the 0.3 to 1.3 mm wavelength range using a Fourier Transform Spectrometer mounted on the 10.4 m dish of the CSO at Mauna Kea, Hawaii, 4100 m above sea level. A careful calibration, including the evaluation of the antenna performance over such a wide wavelength range and the removal of the Earth's atmosphere effects, has allowed the detection of broad absorption lines on those planets' atmospheres. The calibrated data allowed us to verify the predictions of standard models for both planets in this spectral region, and to confirm the absolute radiometry in the case of Jupiter. Besides their physical interest, the results are also important as both planets are calibration references in the current era of operating ground-based and space-borne submillimeter instruments.

  1. Organic environments on Saturn's moon, Titan: simulating chemical reactions and analyzing products by FT-ICR and ion-trap mass spectrometry.

    Science.gov (United States)

    Somogyi, Arpad; Oh, Chu-Ha; Smith, Mark A; Lunine, Jonathan I

    2005-06-01

    Laboratory simulations have been carried out to model chemical reactions that possibly take place in the stratosphere of Saturn's moon, Titan. The aerosol products of these reactions (tholin samples) have been systematically analyzed by mass spectrometry using electrospray ionization (ESI) and laser desorption (LD). A wide variety of ions with a general formula C(x)H(y)N(z) detected by ultrahigh resolution and accurate mass measurements in a Fourier transform/ion cyclotron resonance (FT-ICR) cell reflect the complexity of these polymeric products, both in chemical compositions and isomeric distributions. As a common feature, however, tandem mass spectral (MS/MS) data and H/D exchange products in the solution phase support the presence of amino and nitrile functionalities in these (highly unsaturated) "tholin" compounds. The present work demonstrates that ESI-MS coupled with FT-ICR is a suitable and "intact" method to analyze tholin components formed under anaerobic conditions; only species with C(x)H(y)N(z) are detected for freshly prepared and harvested samples. However, when intentionally exposed to water, oxygen-containing compounds are unambiguously detected.

  2. Imaging angiogenesis.

    Science.gov (United States)

    Charnley, Natalie; Donaldson, Stephanie; Price, Pat

    2009-01-01

    There is a need for direct imaging of effects on tumor vasculature in assessment of response to antiangiogenic drugs and vascular disrupting agents. Imaging tumor vasculature depends on differences in permeability of vasculature of tumor and normal tissue, which cause changes in penetration of contrast agents. Angiogenesis imaging may be defined in terms of measurement of tumor perfusion and direct imaging of the molecules involved in angiogenesis. In addition, assessment of tumor hypoxia will give an indication of tumor vasculature. The range of imaging techniques available for these processes includes positron emission tomography (PET), dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI), perfusion computed tomography (CT), and ultrasound (US).

  3. Spinal imaging and image analysis

    CERN Document Server

    Yao, Jianhua

    2015-01-01

    This book is instrumental to building a bridge between scientists and clinicians in the field of spine imaging by introducing state-of-the-art computational methods in the context of clinical applications.  Spine imaging via computed tomography, magnetic resonance imaging, and other radiologic imaging modalities, is essential for noninvasively visualizing and assessing spinal pathology. Computational methods support and enhance the physician’s ability to utilize these imaging techniques for diagnosis, non-invasive treatment, and intervention in clinical practice. Chapters cover a broad range of topics encompassing radiological imaging modalities, clinical imaging applications for common spine diseases, image processing, computer-aided diagnosis, quantitative analysis, data reconstruction and visualization, statistical modeling, image-guided spine intervention, and robotic surgery. This volume serves a broad audience as  contributions were written by both clinicians and researchers, which reflects the inte...

  4. Urogenital imaging

    International Nuclear Information System (INIS)

    Hamm, B.; Charite - Universitaetsmedizin Berlin; Asbach, P.; Beyersdorff, D.; Hein, P.; Lemke, U.

    2008-01-01

    The book in direct diagnosis in radiology, urogenital imaging, includes information concerning definition, imaging signs and clinical aspects on the following topics: kidneys and adrenals, the urinary tract, the male genitals and the female genitals

  5. Medical Imaging.

    Science.gov (United States)

    Barker, M. C. J.

    1996-01-01

    Discusses four main types of medical imaging (x-ray, radionuclide, ultrasound, and magnetic resonance) and considers their relative merits. Describes important recent and possible future developments in image processing. (Author/MKR)

  6. Microwave imaging

    CERN Document Server

    Pastorino, Matteo

    2010-01-01

    An introduction to the most relevant theoretical and algorithmic aspects of modern microwave imaging approaches Microwave imaging-a technique used in sensing a given scene by means of interrogating microwaves-has recently proven its usefulness in providing excellent diagnostic capabilities in several areas, including civil and industrial engineering, nondestructive testing and evaluation, geophysical prospecting, and biomedical engineering. Microwave Imaging offers comprehensive descriptions of the most important techniques so far proposed for short-range microwave imaging-in

  7. Tomographic imaging

    International Nuclear Information System (INIS)

    Das, B.K.; Noreen Norfaraheen Lee Abdullah

    2012-01-01

    Tomography is used to image anatomy of organs as in the case of CT and MRI or image body functions as in the case of SPECT and PET. The theory of reconstruction applies equally well to CT, SPECT and PET with a minor differences. The main difference between SPECT and PET is that SPECT images single photon emitters (radionuclides) which emit normal gamma rays (like Tc-99m), whereas PET images positron emitting radionuclides such as O 15 or F 18 . The word tomography means drawing of the body. Every tomography results in an image of the inside of the body and is represented as a slice. (author)

  8. In-situ Planetary Subsurface Imaging System

    Science.gov (United States)

    Song, W.; Weber, R. C.; Dimech, J. L.; Kedar, S.; Neal, C. R.; Siegler, M.

    2017-12-01

    Geophysical and seismic instruments are considered the most effective tools for studying the detailed global structures of planetary interiors. A planet's interior bears the geochemical markers of its evolutionary history, as well as its present state of activity, which has direct implications to habitability. On Earth, subsurface imaging often involves massive data collection from hundreds to thousands of geophysical sensors (seismic, acoustic, etc) followed by transfer by hard links or wirelessly to a central location for post processing and computing, which will not be possible in planetary environments due to imposed mission constraints on mass, power, and bandwidth. Emerging opportunities for geophysical exploration of the solar system from Venus to the icy Ocean Worlds of Jupiter and Saturn dictate that subsurface imaging of the deep interior will require substantial data reduction and processing in-situ. The Real-time In-situ Subsurface Imaging (RISI) technology is a mesh network that senses and processes geophysical signals. Instead of data collection then post processing, the mesh network performs the distributed data processing and computing in-situ, and generates an evolving 3D subsurface image in real-time that can be transmitted under bandwidth and resource constraints. Seismic imaging algorithms (including traveltime tomography, ambient noise imaging, and microseismic imaging) have been successfully developed and validated using both synthetic and real-world terrestrial seismic data sets. The prototype hardware system has been implemented and can be extended as a general field instrumentation platform tailored specifically for a wide variety of planetary uses, including crustal mapping, ice and ocean structure, and geothermal systems. The team is applying the RISI technology to real off-world seismic datasets. For example, the Lunar Seismic Profiling Experiment (LSPE) deployed during the Apollo 17 Moon mission consisted of four geophone instruments

  9. Models of bright storm clouds and related dark ovals in Saturn's Storm Alley as constrained by 2008 Cassini/VIMS spectra

    Science.gov (United States)

    Sromovsky, L. A.; Baines, K. H.; Fry, P. M.

    2018-03-01

    A 5° latitude band on Saturn centered near planetocentric latitude 36°S is known as "Storm Alley" because it has been for several extended periods a site of frequent lightning activity and associated thunderstorms, first identified by Porco et al. (2005). The thunderstorms appeared as bright clouds at short and long continuum wavelengths, and over a period of a week or so transformed into dark ovals (Dyudina et al., 2007). The ovals were found to be dark over a wide spectral range, which led Baines et al. (2009) to suggest the possibility that a broadband absorber such as soot produced by lightning could play a significant role in darkening the clouds relative to their surroundings. Here we show that an alternative explanation, which is that the clouds are less reflective because of reduced optical depth, provides an excellent fit to near infrared spectra of similar features obtained by the Cassini Visual and Infrared Mapping Spectrometer (VIMS) in 2008, and leads to a plausible scenario for cloud evolution. We find that the background clouds and the oval clouds are both dominated by the optical properties of a ubiquitous upper cloud layer, which has the same particle size in both regions, but about half the optical depth and physical thickness in the dark oval regions. The dark oval regions are also marked by enhanced emissions in the 5-μm window region, a result of lower optical depth of the deep cloud layer near 3.1-3.8 bar, presumably composed of ammonium hydrosulfide (NH4SH). The bright storm clouds completely block this deep thermal emission with a thick layer of ammonia (NH3) clouds extending from the middle of the main visible cloud layer probably as deep as the 1.7-bar NH3 condensation level. Other condensates might also be present at higher pressures, but are obscured by the NH3 cloud. The strong 3-μm spectral absorption that was displayed by Saturn's Great Storm of 2010-2011 (Sromovsky et al., 2013) is weaker in these storms because the contrast is

  10. 2D and 3D simulation of cavitating flows: development of an original algorithm in code Saturne and study of the influence of turbulence modeling

    International Nuclear Information System (INIS)

    Chebli, Rezki

    2014-01-01

    Cavitation is one of the most demanding physical phenomena influencing the performance of hydraulic machines. It is therefore important to predict correctly its inception and development, in order to quantify the performance drop it induces, and also to characterize the resulting flow instabilities. The aim of this work is to develop an unsteady 3D algorithm for the numerical simulation of cavitation in an industrial CFD solver 'Code Saturne'. It is based on a fractional step method and preserves the minimum/maximum principle of the void fraction. An implicit solver, based on a transport equation of the void fraction coupled with the Navier-Stokes equations is proposed. A specific numerical treatment of the cavitation source terms provides physical values of the void fraction (between 0 and 1) without including any artificial numerical limitation. The influence of RANS turbulence models on the simulation of cavitation on 2D geometries (Venturi and Hydrofoil) is then studied. It confirms the capability of the two-equation eddy viscosity models, k-epsilon and k-omega-SST, with the modification proposed by Reboud et al. (1998) to reproduce the main features of the unsteady sheet cavity behavior. The second order model RSM-SSG, based on the Reynolds stress transport, appears able to reproduce the highly unsteady flow behavior without including any arbitrary modification. The three-dimensional effects involved in the instability mechanisms are also analyzed. This work allows us to achieve a numerical tool, validated on complex configurations of cavitating flows, to improve the understanding of the physical mechanisms that control the three-dimensional unsteady effects involved in the mechanisms of instability. (author)

  11. HAT-P-12b: A LOW-DENSITY SUB-SATURN MASS PLANET TRANSITING A METAL-POOR K DWARF

    International Nuclear Information System (INIS)

    Hartman, J. D.; Bakos, G. A.; Torres, G.; Noyes, R. W.; Pal, A.; Latham, D. W.; Sipocz, B.; Esquerdo, G. A.; Sasselov, D. D.; Kovacs, Gabor; Stefanik, R. P.; Fernandez, J. M.; Kovacs, Geza; Fischer, D. A.; Johnson, J. A.; Marcy, G. W.; Howard, A. W.; Butler, R. P.; Lazar, J.; Papp, I.

    2009-01-01

    We report on the discovery of HAT-P-12b, a transiting extrasolar planet orbiting the moderately bright V ∼ 12.8 K4 dwarf GSC 03033 - 00706, with a period P = 3.2130598 ± 0.0000021 d, transit epoch T c = 2454419.19556 ± 0.00020 (BJD), and transit duration 0.0974 ± 0.0006 d. The host star has a mass of 0.73 ± 0.02 M sun , radius of 0.70 +0.02 -0.01 R sun , effective temperature 4650 ± 60 K, and metallicity [Fe/H] = -0.29 ± 0.05. We find a slight correlation between the observed spectral line bisector spans and the radial velocity, so we consider, and rule out, various blend configurations including a blend with a background eclipsing binary, and hierarchical triple systems where the eclipsing body is a star or a planet. We conclude that a model consisting of a single star with a transiting planet best fits the observations, and show that a likely explanation for the apparent correlation is contamination from scattered moonlight. Based on this model, the planetary companion has a mass of 0.211 ± 0.012 M J and radius of 0.959 +0.029 -0.021 R J yielding a mean density of 0.295 ± 0.025 g cm -3 . Comparing these observations with recent theoretical models, we find that HAT-P-12b is consistent with a ∼1-4.5 Gyr, mildly irradiated, H/He-dominated planet with a core mass M C ∼ + . HAT-P-12b is thus the least massive H/He-dominated gas giant planet found to date. This record was previously held by Saturn.

  12. Acoustical Imaging

    CERN Document Server

    Litniewski, Jerzy; Kujawska, Tamara; 31st International Symposium on Acoustical Imaging

    2012-01-01

    The International Symposium on Acoustical Imaging is a unique forum for advanced research, covering new technologies, developments, methods and theories in all areas of acoustics. This interdisciplinary Symposium has been taking place continuously since 1968. In the course of the years the proceedings volumes in the Acoustical Imaging Series have become a reference for cutting-edge research in the field. In 2011 the 31st International Symposium on Acoustical Imaging was held in Warsaw, Poland, April 10-13. Offering both a broad perspective on the state-of-the-art as well as  in-depth research contributions by the specialists in the field, this Volume 31 in the Series contains an excellent collection of papers in six major categories: Biological and Medical Imaging Physics and Mathematics of Acoustical Imaging Acoustic Microscopy Transducers and Arrays Nondestructive Evaluation and Industrial Applications Underwater Imaging

  13. Cerenkov Imaging

    OpenAIRE

    Das, Sudeep; Thorek, Daniel L.J.; Grimm, Jan

    2014-01-01

    Cerenkov luminescence (CL) has been used recently in a plethora of medical applications like imaging and therapy with clinically relevant medical isotopes. The range of medical isotopes used is fairly large and expanding. The generation of in vivo light is useful since it circumvents depth limitations for excitation light. Cerenkov luminescence imaging (CLI) is much cheaper in terms of infrastructure than positron emission tomography (PET) and is particularly useful for imaging of superficial...

  14. Image compression of bone images

    International Nuclear Information System (INIS)

    Hayrapetian, A.; Kangarloo, H.; Chan, K.K.; Ho, B.; Huang, H.K.

    1989-01-01

    This paper reports a receiver operating characteristic (ROC) experiment conducted to compare the diagnostic performance of a compressed bone image with the original. The compression was done on custom hardware that implements an algorithm based on full-frame cosine transform. The compression ratio in this study is approximately 10:1, which was decided after a pilot experiment. The image set consisted of 45 hand images, including normal images and images containing osteomalacia and osteitis fibrosa. Each image was digitized with a laser film scanner to 2,048 x 2,048 x 8 bits. Six observers, all board-certified radiologists, participated in the experiment. For each ROC session, an independent ROC curve was constructed and the area under that curve calculated. The image set was randomized for each session, as was the order for viewing the original and reconstructed images. Analysis of variance was used to analyze the data and derive statistically significant results. The preliminary results indicate that the diagnostic quality of the reconstructed image is comparable to that of the original image

  15. NMR imaging

    International Nuclear Information System (INIS)

    Andrew, E.R.

    1983-01-01

    Since hydrogen is the most abundant element in all living organisms, proton NMR lends itself well as a method of investigation in biology and medicine. NMR imaging has some special advantages as a diagnostic tool: no ionizing radiation is used, it is noninvasive; it provides a safer means of imaging than the use of x-rays, gamma rays, positrons, or heavy ions. In contrast with ultrasound, the radiation penetrates the bony structures without attenuation. In additional to morphological information, NMR imaging provides additional diagnostic insights through relaxation parameters, which are not available from other imaging methods. In the decade since the first primitive NMR images were obtained, the quality of images now obtained approaches those from CT x-ray scanners. Prototype instruments are being constructed for clinical evaluation and the first whole-body scanners are beginning to appear on the market at costs comparable to CT scanners. Primary differences in equipment for conventional NMR and NMR imaging are the much larger aperture magnets that are required for the examination of human subjects and the addition of coils to generate field gradients and facilities for manipulating the gradients. Early results from clinical trials in many parts of the world are encouraging, and in a few years, the usefuleness of this modality of medical imaging to the medical profession in diagnosis and treatment of disease will be defined. 10 figures

  16. Nuclear imaging

    International Nuclear Information System (INIS)

    Miller, J.H.; Reid, B.S.

    1985-01-01

    Nuclear imaging, utilizing relatively low photon energy emitting isotopes, allows an assessment of anatomic configuration and organ function. This method of imaging is predicted on the utilization of physiologically active radioisotope-labeled compounds or biologically active radioisotopes. Localization of such isotopes in normal or abnormal concentrations may be due to varying physiological or pathological mechanisms

  17. Cerenkov imaging.

    Science.gov (United States)

    Das, Sudeep; Thorek, Daniel L J; Grimm, Jan

    2014-01-01

    Cerenkov luminescence (CL) has been used recently in a plethora of medical applications like imaging and therapy with clinically relevant medical isotopes. The range of medical isotopes used is fairly large and expanding. The generation of in vivo light is useful since it circumvents depth limitations for excitation light. Cerenkov luminescence imaging (CLI) is much cheaper in terms of infrastructure than positron emission tomography (PET) and is particularly useful for imaging of superficial structures. Imaging can basically be done using a sensitive camera optimized for low-light conditions, and it has a better resolution than any other nuclear imaging modality. CLI has been shown to effectively diagnose disease with regularly used PET isotope ((18)F-FDG) in clinical setting. Cerenkov luminescence tomography, Cerenkov luminescence endoscopy, and intraoperative Cerenkov imaging have also been explored with positive conclusions expanding the current range of applications. Cerenkov has also been used to improve PET imaging resolution since the source of both is the radioisotope being used. Smart imaging agents have been designed based on modulation of the Cerenkov signal using small molecules and nanoparticles giving better insight of the tumor biology. © 2014 Elsevier Inc. All rights reserved.

  18. Brain imaging

    International Nuclear Information System (INIS)

    Mishkin, F.S.

    1978-01-01

    The techniques of brain imaging and results in perfusion studies and delayed images are outlined. An analysis of the advantages and disadvantages of the brain scan in a variety of common problems is discussed, especially as compared with other available procedures. Both nonneoplastic and neoplastic lesions are considered. (Auth/C.F.)

  19. Star Imager

    DEFF Research Database (Denmark)

    Madsen, Peter Buch; Jørgensen, John Leif; Thuesen, Gøsta

    1997-01-01

    The version of the star imager developed for Astrid II is described. All functions and features are described as well as the operations and the software protocol.......The version of the star imager developed for Astrid II is described. All functions and features are described as well as the operations and the software protocol....

  20. Retinal Imaging and Image Analysis

    Science.gov (United States)

    Abràmoff, Michael D.; Garvin, Mona K.; Sonka, Milan

    2011-01-01

    Many important eye diseases as well as systemic diseases manifest themselves in the retina. While a number of other anatomical structures contribute to the process of vision, this review focuses on retinal imaging and image analysis. Following a brief overview of the most prevalent causes of blindness in the industrialized world that includes age-related macular degeneration, diabetic retinopathy, and glaucoma, the review is devoted to retinal imaging and image analysis methods and their clinical implications. Methods for 2-D fundus imaging and techniques for 3-D optical coherence tomography (OCT) imaging are reviewed. Special attention is given to quantitative techniques for analysis of fundus photographs with a focus on clinically relevant assessment of retinal vasculature, identification of retinal lesions, assessment of optic nerve head (ONH) shape, building retinal atlases, and to automated methods for population screening for retinal diseases. A separate section is devoted to 3-D analysis of OCT images, describing methods for segmentation and analysis of retinal layers, retinal vasculature, and 2-D/3-D detection of symptomatic exudate-associated derangements, as well as to OCT-based analysis of ONH morphology and shape. Throughout the paper, aspects of image acquisition, image analysis, and clinical relevance are treated together considering their mutually interlinked relationships. PMID:22275207

  1. Medical imaging

    CERN Document Server

    Townsend, David W

    1996-01-01

    Since the introduction of the X-ray scanner into radiology almost 25 years ago, non-invasive imaging has become firmly established as an essential tool in the diagnosis of disease. Fully three-dimensional imaging of internal organs is now possible, b and for studies which explore the functional status of the body. Powerful techniques to correlate anatomy and function are available, and scanners which combine anatomical and functional imaging in a single device are under development. Such techniques have been made possible through r ecent technological and mathematical advances. This series of lectures will review both the physical basis of medical imaging techniques using X-rays, gamma and positron emitting radiosiotopes, and nuclear magnetic resonance, and the mathematical methods used to reconstruct three-dimentional distributions from projection data. The lectures will trace the development of medical imaging from simple radiographs to the present-day non-invasive measurement of in vivo biochemistry. They ...

  2. Acoustical Imaging

    CERN Document Server

    Akiyama, Iwaki

    2009-01-01

    The 29th International Symposium on Acoustical Imaging was held in Shonan Village, Kanagawa, Japan, April 15-18, 2007. This interdisciplinary Symposium has been taking place every two years since 1968 and forms a unique forum for advanced research, covering new technologies, developments, methods and theories in all areas of acoustics. In the course of the years the volumes in the Acoustical Imaging Series have developed and become well-known and appreciated reference works. Offering both a broad perspective on the state-of-the-art in the field as well as an in-depth look at its leading edge research, this Volume 29 in the Series contains again an excellent collection of seventy papers presented in nine major categories: Strain Imaging Biological and Medical Applications Acoustic Microscopy Non-Destructive Evaluation and Industrial Applications Components and Systems Geophysics and Underwater Imaging Physics and Mathematics Medical Image Analysis FDTD method and Other Numerical Simulations Audience Researcher...

  3. Image perception and image processing

    Energy Technology Data Exchange (ETDEWEB)

    Wackenheim, A.

    1987-01-01

    The author develops theoretical and practical models of image perception and image processing, based on phenomenology and structuralism and leading to original perception: fundamental for a positivistic approach of research work for the development of artificial intelligence that will be able in an automated system fo 'reading' X-ray pictures.

  4. Image perception and image processing

    International Nuclear Information System (INIS)

    Wackenheim, A.

    1987-01-01

    The author develops theoretical and practical models of image perception and image processing, based on phenomenology and structuralism and leading to original perception: fundamental for a positivistic approach of research work for the development of artificial intelligence that will be able in an automated system fo 'reading' X-ray pictures. (orig.) [de

  5. Retinal imaging and image analysis

    NARCIS (Netherlands)

    Abramoff, M.D.; Garvin, Mona K.; Sonka, Milan

    2010-01-01

    Many important eye diseases as well as systemic diseases manifest themselves in the retina. While a number of other anatomical structures contribute to the process of vision, this review focuses on retinal imaging and image analysis. Following a brief overview of the most prevalent causes of

  6. COLOR IMAGES

    Directory of Open Access Journals (Sweden)

    Dominique Lafon

    2011-05-01

    Full Text Available The goal of this article is to present specific capabilities and limitations of the use of color digital images in a characterization process. The whole process is investigated, from the acquisition of digital color images to the analysis of the information relevant to various applications in the field of material characterization. A digital color image can be considered as a matrix of pixels with values expressed in a vector-space (commonly 3 dimensional space whose specificity, compared to grey-scale images, is to ensure a coding and a representation of the output image (visualisation printing that fits the human visual reality. In a characterization process, it is interesting to regard color image attnbutes as a set of visual aspect measurements on a material surface. Color measurement systems (spectrocolorimeters, colorimeters and radiometers and cameras use the same type of light detectors: most of them use Charge Coupled Devices sensors. The difference between the two types of color data acquisition systems is that color measurement systems provide a global information of the observed surface (average aspect of the surface: the color texture is not taken into account. Thus, it seems interesting to use imaging systems as measuring instruments for the quantitative characterization of the color texture.

  7. Modeling low-temperature serpentinization reactions to estimate molecular hydrogen production with implications for potential microbial life on Saturn's moon Enceladus.

    Science.gov (United States)

    Zwicker, Jennifer; Smrzka, Daniel; Taubner, Ruth-Sophie; Bach, Wolfgang; Rittmann, Simon; Schleper, Christa; Peckmann, Jörn

    2017-04-01

    Serpentinization of ultramafic rocks attracts much interest in research on the origin of life on Earth and the search for life on extraterrestrial bodies including icy moons like Enceladus. Serpentinization on Earth occurs in peridotite-hosted systems at slow-spreading mid-ocean ridges, and produces large amounts of molecular hydrogen and methane. These reduced compounds can be utilized by diverse chemosynthetic microbial consortia as a metabolic energy source. Although many hydrothermal vents emit hot and acidic fluids today, it is more likely that life originated in the Archean at sites producing much cooler and more alkaline fluids that allowed for the synthesis and stability of essential organic molecules necessary for life. Therefore, a detailed understanding of water-rock interaction processes during low-temperature serpentinization is of crucial importance in assessing the life-sustaining potential of these environments. In the course of serpentinization, the metasomatic hydration of olivine and pyroxene produces various minerals including serpentine minerals, magnetite, brucite, and carbonates. Hydrogen production only occurs if ferrous iron within iron-bearing minerals is oxidized and incorporated as ferric iron into magnetite. The PHREEQC code was used to model the pH- and temperature-dependent dissolution of olivine and pyroxene to form serpentine, magnetite and hydrogen under pressure and temperature conditions that may exist on Saturn's icy moon Enceladus. Various model setups at 25 and 50°C were run to assess the influence of environmental parameters on hydrogen production. The results reveal that hydrogen production rates depend on the composition of the initial mineral assemblage and temperature. The current assumption is that there is a gaseous phase between Enceladus' ice sheet and subsurface ocean. To test various scenarios, model runs were conducted with and without the presence of a gas phase. The model results show that hydrogen production is

  8. CFD simulation with Code-Saturne of the light gas stratification erosion by a vertical air gas injection using a Low Mach number algorithm

    International Nuclear Information System (INIS)

    Hou Bingxu; Yu Jiyang; Senechal, Dorothee; Mechitoua, Namane; Min Jiesheng; Chen Guofei

    2015-01-01

    During CFD simulations of the flows at low Mach number regime, the classical assumption which neglects the dilatable effect of gas is no longer applicable when the temperature variation or the concentration variation of the mixture's components is too large in the fluid domain. To be able to correctly predict the flow at such a regime, some authors have recourse to a Low Mach number algorithm. This algorithm is based on the well-known pressure-based algorithm or elliptic solver for incompressible flows, SIMPLE, with a modification for the treatment of the pressure which is split into two parts (the hydrodynamic pressure and the thermodynamic pressure) and a dilatable term added in the mass equation. This algorithm has been implemented in the CFD code, Code_—Saturne, developed by EDF R and D, and applied for the CFD simulations of the erosion phenomena of light gas stratification by air injection. This paper is devoted to the analytical work with the Low Mach number algorithm based on the ST1 series of the SETH-2 campaign provided by the OECD project on the PANDA test facility of PSI. The first part is focused on a mesh sensitivity analysis, which is a common procedure for CFD codes validation. The second part of the paper presents a comparison between the CFD results obtained with the standard algorithms used for incompressible flows and the Low Mach number algorithm. The third part is an analysis of the CFD results obtained on the reference mesh with both different Froude numbers corresponding to the tests ST1_—7 (Fr=6.04) and ST1_—10 (Fr=7.95) from the ST1 series. In the last part the authors perform the knowledge of the initial light gas distribution effect on the stratification erosion and the capability of the CFD codes to predict this phenomenon with an area governed by diffusion regime (at the top of the vessel) and another one by forced convection near the injection. (author)

  9. Image retrieval

    DEFF Research Database (Denmark)

    Ørnager, Susanne

    1997-01-01

    The paper touches upon indexing and retrieval for effective searches of digitized images. Different conceptions of what subject indexing means are described as a basis for defining an operational subject indexing strategy for images. The methodology is based on the art historian Erwin Panofsky......), special knowledge about image codes, and special knowledge about history of ideas. The semiologist Roland Barthes has established a semiology for pictorial expressions based on advertising photos. Barthes uses the concepts denotation/connotation where denotations can be explained as the sober expression...

  10. Image analysis

    International Nuclear Information System (INIS)

    Berman, M.; Bischof, L.M.; Breen, E.J.; Peden, G.M.

    1994-01-01

    This paper provides an overview of modern image analysis techniques pertinent to materials science. The usual approach in image analysis contains two basic steps: first, the image is segmented into its constituent components (e.g. individual grains), and second, measurement and quantitative analysis are performed. Usually, the segmentation part of the process is the harder of the two. Consequently, much of the paper concentrates on this aspect, reviewing both fundamental segmentation tools (commonly found in commercial image analysis packages) and more advanced segmentation tools. There is also a review of the most widely used quantitative analysis methods for measuring the size, shape and spatial arrangements of objects. Many of the segmentation and analysis methods are demonstrated using complex real-world examples. Finally, there is a discussion of hardware and software issues. 42 refs., 17 figs

  11. Medical imaging

    International Nuclear Information System (INIS)

    Loshkajian, A.

    2000-01-01

    This didactical book presents the medical imaging techniques: radiography, scanner, nuclear magnetic resonance (NMR). Examples are given for the most common pathologies in all domains of medicine. (J.S.)

  12. Image Sensor

    OpenAIRE

    Jerram, Paul; Stefanov, Konstantin

    2017-01-01

    An image sensor of the type for providing charge multiplication by impact ionisation has plurality of multiplication elements. Each element is arranged to receive charge from photosensitive elements of an image area and each element comprises a sequence of electrodes to move charge along a transport path. Each of the electrodes has an edge defining a boundary with a first electrode, a maximum width across the charge transport path and a leading edge that defines a boundary with a second elect...

  13. Brain imaging

    International Nuclear Information System (INIS)

    Greenfield, L.D.; Bennett, L.R.

    1976-01-01

    Imaging with radionuclides should be used in a complementary fashion with other neuroradiologic techniques. It is useful in the early detection and evaluation of intracranial neoplasm, cerebrovascular accident and abscess, and in postsurgical follow-up. Cisternography yields useful information about the functional status of cerebrospinal fluid pathways. Computerized axial tomography is a new technique of great promise that produced a cross-sectional image of the brain

  14. Emerging images

    KAUST Repository

    Mitra, Niloy J.

    2009-01-01

    Emergence refers to the unique human ability to aggregate information from seemingly meaningless pieces, and to perceive a whole that is meaningful. This special skill of humans can constitute an effective scheme to tell humans and machines apart. This paper presents a synthesis technique to generate images of 3D objects that are detectable by humans, but difficult for an automatic algorithm to recognize. The technique allows generating an infinite number of images with emerging figures. Our algorithm is designed so that locally the synthesized images divulge little useful information or cues to assist any segmentation or recognition procedure. Therefore, as we demonstrate, computer vision algorithms are incapable of effectively processing such images. However, when a human observer is presented with an emergence image, synthesized using an object she is familiar with, the figure emerges when observed as a whole. We can control the difficulty level of perceiving the emergence effect through a limited set of parameters. A procedure that synthesizes emergence images can be an effective tool for exploring and understanding the factors affecting computer vision techniques. © 2009 ACM.

  15. PC image processing

    International Nuclear Information System (INIS)

    Hwa, Mok Jin Il; Am, Ha Jeng Ung

    1995-04-01

    This book starts summary of digital image processing and personal computer, and classification of personal computer image processing system, digital image processing, development of personal computer and image processing, image processing system, basic method of image processing such as color image processing and video processing, software and interface, computer graphics, video image and video processing application cases on image processing like satellite image processing, color transformation of image processing in high speed and portrait work system.

  16. Proton ejection project for Saturne

    International Nuclear Information System (INIS)

    Bronca, G.; Gendreau, G.

    1959-01-01

    The reasons for choosing the ejection system are given. The characteristics required for the ejected beam are followed by a description of the ejection process, in chronological order from the viewpoint of the protons: movement of the particles, taking into account the various elements which make up the system (internal magnet, external magnet, quadrupoles, ejection correction coils, thin and thick cables,...) and specification of these elements. Then follows an estimation of the delay in manufacture and the cost of the project. Finally, the characteristics of the magnets and quadrupoles are listed in an appendix. (author) [fr

  17. Medical imaging

    International Nuclear Information System (INIS)

    Elliott, Alex

    2005-01-01

    Diagnostic medical imaging is a fundamental part of the practice of modern medicine and is responsible for the expenditure of considerable amounts of capital and revenue monies in healthcare systems around the world. Much research and development work is carried out, both by commercial companies and the academic community. This paper reviews briefly each of the major diagnostic medical imaging techniques-X-ray (planar and CT), ultrasound, nuclear medicine (planar, SPECT and PET) and magnetic resonance. The technical challenges facing each are highlighted, with some of the most recent developments. In terms of the future, interventional/peri-operative imaging, the advancement of molecular medicine and gene therapy are identified as potential areas of expansion

  18. Ultrasound imaging

    International Nuclear Information System (INIS)

    Wells, P.N.T.

    1983-01-01

    Ultrasound is a form of energy which consists of mechanical vibrations the frequencies of which are so high that they are above the range of human hearing. The lower frequency limit of the ultrasonic spectrum may generally be taken to be about 20 kHz. Most biomedical applications of ultrasound employ frequencies in the range 1-15 MHz. At these frequencies, the wavelength is in the range 1.5 - 0.1 mm in soft tissues, and narrow beams of ultrasound can be generated which propagate through such tissues without excessive attenuation. This chapter begins with brief reviews of the physics of diagnostic ultrasound pulse-echo imaging methods and Doppler imaging methods. The remainder of the chapter is a resume of the applications of ultrasonic imaging to physiological measurement

  19. Fast imaging

    International Nuclear Information System (INIS)

    Wehrli, F.W.; Altas, S.W.

    1991-01-01

    This paper reports on MRI which has evolved rapidly and promises to continue to do so. The diagnostic armamentarium, as a result, has increased dramatically over recent years, which has necessitated constant interactions between clinicians, physicists, and biochemists. Pulse sequence design, coupled with advances in other software and hardware technology, offers practical improvements in scanning and image quality. Perhaps more importantly, these same advances hold promise for MRI to become, in addition to its traditional role as a morphological imaging technique, a functional imaging modality. The attractiveness of this prospect is that for the first time, a high-resolution technique has been shown to have the potential to provide both types of information from a single integrated examination, which promises to generate important insights into normal physiology as well as the natural history of pathophysiologic states

  20. Incompatible Images

    DEFF Research Database (Denmark)

    Sassene, Michel J.; Hertzum, Morten

    2008-01-01

    is, however, based on a taken-for-granted image of asthmatics as, per se, striving to be symptom-free. This image is incompatible with interviewed asthmatics' day-to-day performances of their asthma, and renders invisible (a) that their asthma performances emphasize an economy of good passages...... and of feeling capable, (b) that they achieve the objective of feeling capable in quite different ways, and (c) that feeling capable does not per se equal being symptom-free all the time. To attain long-term use of self-management systems and other patient-centred e-health systems, such systems must acknowledge...

  1. DBU's image

    OpenAIRE

    Nygaard, Katrin Hellesøe; Saugstrup, Annie; Yohannes, Adiam; Giesow, Katja Ludvigsen; Merved, Mikkel Dollerup

    2017-01-01

    The Danish Football Association (DBU) has a long history of crisis, which has led to a bad reputation for the organisation. The current crisis on the women’s national soccer team is in particular discussed in the media. Why are DBU often in crisis? How do they manage these crises and how does it affect their image? We are interested in identifying what they can do to change this pattern, which is why we conducted the following hypothesis: “DBU does still have an image problem“. We will examin...

  2. Kepler-77b: a very low albedo, Saturn-mass transiting planet around a metal-rich solar-like star

    Science.gov (United States)

    Gandolfi, D.; Parviainen, H.; Fridlund, M.; Hatzes, A. P.; Deeg, H. J.; Frasca, A.; Lanza, A. F.; Prada Moroni, P. G.; Tognelli, E.; McQuillan, A.; Aigrain, S.; Alonso, R.; Antoci, V.; Cabrera, J.; Carone, L.; Csizmadia, Sz.; Djupvik, A. A.; Guenther, E. W.; Jessen-Hansen, J.; Ofir, A.; Telting, J.

    2013-09-01

    We report the discovery of Kepler-77b (alias KOI-127.01), a Saturn-mass transiting planet in a 3.6-day orbit around a metal-rich solar-like star. We combined the publicly available Kepler photometry (quarters 1-13) with high-resolution spectroscopy from the Sandiford at McDonald and FIES at NOT spectrographs. We derived the system parameters via a simultaneous joint fit to the photometric and radial velocity measurements. Our analysis is based on the Bayesian approach and is carried out by sampling the parameter posterior distributions using a Markov chain Monte Carlo simulation. Kepler-77b is a moderately inflated planet with a mass of Mp = 0.430 ± 0.032 MJup, a radius of Rp = 0.960 ± 0.016 RJup, and a bulk density of ρp = 0.603 ± 0.055 g cm-3. It orbits a slowly rotating (Prot = 36 ± 6 days) G5 V star with M⋆ = 0.95 ± 0.04 M⊙, R⋆ = 0.99 ± 0.02 R⊙, Teff = 5520 ± 60 K, [M/H] = 0.20 ± 0.05 dex, that has an age of 7.5 ± 2.0 Gyr. The lack of detectable planetary occultation with a depth higher than ~10 ppm implies a planet geometric and Bond albedo of Ag ≤ 0.087 ± 0.008 and AB ≤ 0.058 ± 0.006, respectively, placing Kepler-77b among the gas-giant planets with the lowest albedo known so far. We found neither additional planetary transit signals nor transit-timing variations at a level of ~0.5 min, in accordance with the trend that close-in gas giant planets seem to belong to single-planet systems. The 106 transitsobserved in short-cadence mode by Kepler for nearly 1.2 years show no detectable signatures of the planet's passage in front of starspots. We explored the implications of the absence of detectable spot-crossing events for the inclination of the stellar spin-axis, the sky-projected spin-orbit obliquity, and the latitude of magnetically active regions. Based on observations obtained with the 2.1-m Otto Struve telescope at McDonald Observatory, Texas, USA.Based on observations obtained with the Nordic Optical Telescope, operated on the

  3. MRI (Magnetic Resonance Imaging)

    Science.gov (United States)

    ... Procedures Medical Imaging MRI (Magnetic Resonance Imaging) MRI (Magnetic Resonance Imaging) Share Tweet Linkedin Pin it More sharing options Linkedin Pin it Email Print Magnetic Resonance Imaging (MRI) is a medical imaging procedure for ...

  4. Imaging sciences workshop

    Energy Technology Data Exchange (ETDEWEB)

    Candy, J.V.

    1994-11-15

    This workshop on the Imaging Sciences sponsored by Lawrence Livermore National Laboratory contains short abstracts/articles submitted by speakers. The topic areas covered include the following: Astronomical Imaging; biomedical imaging; vision/image display; imaging hardware; imaging software; Acoustic/oceanic imaging; microwave/acoustic imaging; computed tomography; physical imaging; imaging algorithms. Selected papers are indexed separately for inclusion in the Energy Science and Technology Database.

  5. Forest Imaging

    Science.gov (United States)

    1992-01-01

    NASA's Technology Applications Center, with other government and academic agencies, provided technology for improved resources management to the Cibola National Forest. Landsat satellite images enabled vegetation over a large area to be classified for purposes of timber analysis, wildlife habitat, range measurement and development of general vegetation maps.

  6. Geriatric imaging

    Energy Technology Data Exchange (ETDEWEB)

    Guglielmi, Giuseppe [Scientific Institute Casa Sollievo della Sofferenza Hospital, San Giovanni Rotondo (Italy). Dept. of Radiology; Peh, Wilfred C.G. [Khoo Teck Puat Hospital, Singapore (Singapore). Dept. of Diagnostic Radiology; Guermazi, Ali (eds.) [Boston Univ. School of Medicine, Boston, MA (United States). Dept. of Radiology

    2013-08-01

    Considers all aspect of geriatric imaging. Explains clearly how to distinguish the healthy elderly from those in need of treatment. Superbly illustrated. Written by recognized experts in field. In the elderly, the coexistence of various diseases, the presence of involutional and degenerative changes, and the occurrence of both physical and cognitive problems represent ''the norm.'' It is therefore important to know how to distinguish the healthy elderly from those in need of treatment as a sound basis for avoiding overdiagnosis and overtreatment. This aspect is a central theme in Geriatric Imaging, which covers a wide range of applications of different imaging techniques and clearly explains both the potential and the limitations of diagnostic imaging in geriatric patients. Individual sections are devoted to each major region or system of the body, and a concluding section focuses specifically on interventional procedures. The book, written by recognized experts in the field, is superbly illustrated and will be an ideal resource for geriatricians, radiologists, and trainees.

  7. Image categorization

    NARCIS (Netherlands)

    Klein Teeselink, G.; Blommaert, F.J.J.; Ridder, de H.

    2000-01-01

    A study was conducted to investigate whether images of natural scenes can be categorized with respect to information content and whether a relation exists with perceived foreground-background separation. In an experiment, one group of subjects carried out a 'free categorization' task, (subjects were

  8. Featured Image | Galaxy of Images

    Science.gov (United States)

    2,600 images. more info The Book of the Fair The first Ferris Wheel, the creation of bridge builder George W. Ferris, was erected at the World’s Columbian Exposition in Chicago in 1893. To commemorate

  9. Medical Imaging 4: Image formation

    International Nuclear Information System (INIS)

    Schneider, R.H.

    1990-01-01

    This book contains papers relating to the 1990 meeting of The International Society for Optical Engineering. Included are the following papers: Effect of protective layer on Resolution Properties of Photostimulable Phosphor Detector for Digital Radiographic System, Neural Network Scatter Correction Technique for Digital Radiography, Use of Computer Radiography for Portal Imaging

  10. European Space Imaging & Skybox Imaging

    International Nuclear Information System (INIS)

    Clark, J.; Schichor, P.

    2015-01-01

    Skybox and European Space Imaging have partnered to bring timely, Very High-Resolution imagery to customers in Europe and North Africa. Leveraging Silicon Valley ingenuity and world-class aerospace expertise, Skybox designs, builds, and operates a fleet of imaging satellites. With two satellites currently on-orbit, Skybox is quickly advancing towards a planned constellation of 24+ satellites with the potential for daily or sub-daily imaging at 70-90 cm resolution. With consistent, high-resolution imagery and video, European customers can monitor the dynamic units of human activity - cars, trucks, shipping containers, ships, aircraft, etc. - and derive valuable insights about the global economy. With multiple imaging opportunities per day, the Skybox constellation provides unprecedented access to imagery and information about critical targets that require rapid analysis. Skybox's unique capability to deliver high-definition video from space enables European customers to monitor a network of globally distributed assets with full-motion snapshots, without the need to deploy an aircraft or field team. The movement captured in these 30-90 second video windows yield unique insights that improve operational decisions. Skybox and EUSI are excited to offer a unique data source that can drive a better understanding of our world through supply chain monitoring, natural resource management, infrastructure monitoring, and crisis response. (author)

  11. Imaging dementias

    Energy Technology Data Exchange (ETDEWEB)

    Savoiardo, M.; Grisoli, M. [Dept. of Neuroradiology, Istituto Nazionale Neurologico, Milan (Italy)

    2001-03-01

    Dementia is the progressive loss of intellectual functions due to involvement of cortical or subcortical areas. Specific involvement of certain brain areas in the different diseases leads to impairment of different functions, e. g., memory, language, visuospatial abilities, and behavior. Magnetic resonance imaging and other neuroradiological studies may indicate which structures are mainly or selectively involved in a demented patient, thus allowing clinical-radiological correlations. Clinical presentation and evolution of the disease, supported by imaging studies, may lead to a highly probable diagnosis. The most common disorders, or the most relevant from the neuroradiological point of view, such as Alzheimer's disease, frontotemporal dementia, vascular dementias, dementia associated with parkinsonism, Huntington's disease, Creutzfeldt-Jakob disease, and normal-pressure hydrocephalus, are briefly discussed. (orig.)

  12. Image Analysis

    DEFF Research Database (Denmark)

    The 19th Scandinavian Conference on Image Analysis was held at the IT University of Copenhagen in Denmark during June 15-17, 2015. The SCIA conference series has been an ongoing biannual event for more than 30 years and over the years it has nurtured a world-class regional research and development...... area within the four participating Nordic countries. It is a regional meeting of the International Association for Pattern Recognition (IAPR). We would like to thank all authors who submitted works to this year’s SCIA, the invited speakers, and our Program Committee. In total 67 papers were submitted....... The topics of the accepted papers range from novel applications of vision systems, pattern recognition, machine learning, feature extraction, segmentation, 3D vision, to medical and biomedical image analysis. The papers originate from all the Scandinavian countries and several other European countries...

  13. Imaging dementias

    International Nuclear Information System (INIS)

    Savoiardo, M.; Grisoli, M.

    2001-01-01

    Dementia is the progressive loss of intellectual functions due to involvement of cortical or subcortical areas. Specific involvement of certain brain areas in the different diseases leads to impairment of different functions, e. g., memory, language, visuospatial abilities, and behavior. Magnetic resonance imaging and other neuroradiological studies may indicate which structures are mainly or selectively involved in a demented patient, thus allowing clinical-radiological correlations. Clinical presentation and evolution of the disease, supported by imaging studies, may lead to a highly probable diagnosis. The most common disorders, or the most relevant from the neuroradiological point of view, such as Alzheimer's disease, frontotemporal dementia, vascular dementias, dementia associated with parkinsonism, Huntington's disease, Creutzfeldt-Jakob disease, and normal-pressure hydrocephalus, are briefly discussed. (orig.)

  14. MR imaging

    International Nuclear Information System (INIS)

    Barbaric, Z.L.; Sukov, R.M.; Boechat, I.M.

    1988-01-01

    MR images were obtained from six patients with surgically proved hemorrhagic renal cysts and three with adult polycystic renal disease that contained many hemorrhagic cysts. Their appearance was compared with that of 30 simple renal cysts. Simple cysts were hypointense on T1-weighted spin-echo sequences and hyperintense to the kidney on T2-weighted sequences. On the same sequences, hemorrhagic cysts showed three patterns: (1) hyperintense-hyperintense, (2) isointense-hyperintense, and (3) hypointense-hypointense. The fluid-fluid interphase was identified in a number of hemorrhagic cysts on T2-weighted images. Three hemorrhagic cysts contained renal carcinoma. Hemorrhagic cysts may be impossible to differentiate from solid renal tumors except for layering

  15. Image construction

    International Nuclear Information System (INIS)

    1976-01-01

    An image processing system fitting in an X-ray television circuit for tomography is described. The profiles registered by the X-ray television circuit are projected on the screen of an afterglow cathode ray tube which registration is convoluted in an analogue system with the help of either a one-dimensional or a two-dimensional convolution function after which it is stored or processed further such that a clear tomogram is obtained

  16. Intravital Imaging

    OpenAIRE

    Pittet, Mikael J.; Weissleder, Ralph

    2011-01-01

    Until recently, the idea of observing life deep within the tissues of a living mouse, at a resolution sufficient to pick out cellular behaviors and molecular signals underlying them, remained a much-coveted dream. Now, a new era of intravital fluorescence microscopy has dawned. In this Primer, we review the technologies that made this revolution possible, and demonstrate how intravital imaging is beginning to provide quantitative and dynamic insights into cell biology, immunology, tumor biolo...

  17. Brain imaging

    International Nuclear Information System (INIS)

    Bradshaw, J.R.

    1989-01-01

    This book presents a survey of the various imaging tools with examples of the different diseases shown best with each modality. It includes 100 case presentations covering the gamut of brain diseases. These examples are grouped according to the clinical presentation of the patient: headache, acute headache, sudden unilateral weakness, unilateral weakness of gradual onset, speech disorders, seizures, pituitary and parasellar lesions, sensory disorders, posterior fossa and cranial nerve disorders, dementia, and congenital lesions

  18. Cardiovascular imaging

    International Nuclear Information System (INIS)

    Anon.

    1987-01-01

    Nuclear cardiology has grown exponentially over the past decade. The introduction of the gamma camera, the development of new radionuclides, and the implementation of computers have transformed the field of nuclear cardiology from largely research in the 1970s to routine clinical applications in the 1980s. At first, noninvasive nuclear imaging techniques were used predominantly to aid disease detection. In the ensuing years, emphasis has shifted to the functional assessment of patients with known disease. Widely available noninvasive techniques now allow the quantitative assessment of left and right ventricular function, one of the most important predictors of survival in patients with cardiac disease. Exercise radionuclide ventriculography provides valuable information on the myocardial reserve in patients with normal resting function. The serial measurement of the ventricular ejection fraction assists in the timing of valvular replacement therapy. In patients receiving doxorubicin, serial ejection fraction follow-up helps prevent the development of irreversible, drug-induced cardiomyopathy. It is now generally acknowledged that the detection of latent coronary disease is improved by the addition of 201 T1 imaging to the standard exercise electrocardiogram. Thallium imaging and infarct avid imaging with /sup 99m/Tc-pyrophosphate have proven useful in quantifying myocardial infarction size, and in assessing the value of therapy aimed at limiting infarction extent. In the evaluation of coronary artery disease, scintigraphy provides physiologic data that complements angiography, which is more anatomic. An angiographic lesion, read as a 70 percent narrowing, may not necessarily be flow-limiting, whereas one read as 40 percent, may, in fact, have physiologic consequences, if it is of sufficient length or eccentricity, or is in series with another insignificant stenosis

  19. Fast forward modeling of Titan’s infrared spectra to invert VIMS/CASSINI hyperspectral images

    Science.gov (United States)

    Rodriguez, S.; Le Mouélic, S.; Rannou, P.; Combe, J.; Le Corre, L.; Griffith, C. A.; Tobie, G.; Barnes, J. W.; Sotin, C.; Brown, R. H.; Baines, K. H.; Buratti, B. J.; Clark, R. N.

    2009-12-01

    The surface of Titan, the largest icy moon of Saturn, is veiled by a very thick and hazy atmosphere. The Visual and Infrared Mapping Spectrometer onboard the Cassini spacecraft, in orbit around Saturn since July 2004, has been conducting an intensive survey of Titan with the objective of understanding the complex nature and interaction of the atmosphere and surface of this mysterious moon. Retrieving and separating contributions from the surface and the atmosphere in Titan’s infrared spectra requires accurate radiative transfer modeling, which is often very demanding of computer resources. As Cassini has gathered hitherto millions of spectra of Titan and will continue to observe it until at least 2010, we report here on the development of a new rapid, simple and versatile radiative transfer model specially designed to process VIMS datacubes. Currently, our model accounts for gas absorption, haze scattering and surface reflectance and can be implemented in an inversion scheme. First results of forward modeling provide spectral shapes that are consistent with VIMS measurements, as well as surface and aerosol properties in the range of validity for Titan. Further inversion tests will be carried on VIMS hyperspectral images for the estimate of spatial coherence of the results, accuracy of the surface reflectance within the atmospheric windows, and potential needs for improved input data and modeling. This work was partly performed at the Jet Propulsion Laboratory, California Institute of Technology, under contract to the National Aeronautics and Space Administration. Calibrated VIMS data appear courtesy of the VIMS team. We thank the CNES French agency for its financial support.

  20. Imaging system

    International Nuclear Information System (INIS)

    Rushbrooke, J.G.; Ansorge, R.E.

    1987-01-01

    A moving object such as a container on a conveyor belt is imaged by an optical system onto a charge coupled device array in which the lines of the array are arranged perpendicular to the direction of motion of the object. The speed of movement of the object is sensed to generate electrical signals which are processed to provide shift signals enabling the shifting of data row to row in the array in synchronism with the movement of the container. The electrical charge associated with a given point on the array is transferred from one line to the other until it appears at the last line of the array, from which it is read out in known manner in conjunction with all other electrical charges associated with the row of charge coupled devices in the last line of the array. Due to the integrating effect achieved, the aperture of the imaging system can be much smaller than otherwise would be required, and/or the level of light illumination can be reduced. The imaging system can be applied to X-ray inspection devices, aerial surveillance or scanning of moving documents in copying processes. (author)

  1. Genitourinary imaging

    International Nuclear Information System (INIS)

    Anon.

    1987-01-01

    The application of radionuclide studies in nephrology, urology, and gynecology has reached a measurable degree of maturity in recent years. However, the utilization of these techniques continues to be less frequent than the clinical advantages would seem to warrant, probably because of the complexities of renal physiology. This complexity has been resulted in the availability of large number of agents for renal studies. It is the functional nature of nuclear medicine studies that provides their tremendous potential for use in evaluation of the kidney, where the pathology of which is so often related to functional derangements rather than to anatomic problems. A familiarity with various measures of renal function and with the effects of these parameters on the handling of the commonly used radiopharmaceuticals is essential to the appropriate use of radionuclide studies. The types of studies commonly used include renal perfusion studies, renal imaging solely for anatomic information, and renal imaging combined with an estimate of renal function. Radionuclide techniques serve a complementary role to radiography, ultrasonography, and computed tomography in the morphologic diagnosis of renal diseases. Urethral abnormalities, bladder diverticula, and minimal distal urethral reflux are better demonstrated with radiographic than nuclear technique, but radionuclide cystography can be helpful for follow-up evaluations. Radionuclide testicular imaging is extremely useful in the differential diagnosis of testicular torsion

  2. Imaging AMS

    Energy Technology Data Exchange (ETDEWEB)

    Freeman, S.P.H.T. [Univ. of Oxford (United Kingdom)]|[Lawrence Livermore National Lab., CA (United States); Ramsey, C.B.; Hedges, R.E.M. [Univ. of Oxford (United Kingdom)

    1993-12-01

    The benefits of simultaneous high effective mass resolution and large spectrometer acceptance that accelerator mass spectrometry has afforded the bulk analysis of material samples by secondary ion mass spectrometry may also be applied to imaging SIMS. The authors are exploring imaging AMS with the addition to the Oxford {sup 14}C-AMS system of a scanning secondary ion source. It employs a sub micron probe and a separate Cs flood to further increase the useful ion yield. The source has been accommodated on the system by directly injecting sputtered ions into the accelerator without mass analysis. They are detected with a range of devices including new high-bandwidth detectors. Qualitative mass spectra may be easily generated by varying only the post-accelerator analysis magnet. Selected ion signals may be used for imaging. In developing the instrument for bioscience research the authors are establishing its capability for measuring the lighter elements prevalent in biological tissue. Importantly, the machine can map the distributions of radiocarbon labeled compounds with an efficiency of about 1{per_thousand}. A background due to misidentification of non-{sup 14}C ions as a result of the reduced ion mass filtering is too small to hinder high magnification microscopy.

  3. Electronic portal imaging devices

    International Nuclear Information System (INIS)

    Lief, Eugene

    2008-01-01

    The topics discussed include, among others, the following: Role of portal imaging; Port films vs. EPID; Image guidance: Elekta volume view; Delivery verification; Automation tasks of portal imaging; Types of portal imaging (Fluorescent screen, mirror, and CCD camera-based imaging; Liquid ion chamber imaging; Amorpho-silicon portal imagers; Fluoroscopic portal imaging; Kodak CR reader; and Other types of portal imaging devices); QA of EPID; and Portal dosimetry (P.A.)

  4. IMAGE DESCRIPTIONS FOR SKETCH BASED IMAGE RETRIEVAL

    OpenAIRE

    SAAVEDRA RONDO, JOSE MANUEL; SAAVEDRA RONDO, JOSE MANUEL

    2008-01-01

    Due to the massive use of Internet together with the proliferation of media devices, content based image retrieval has become an active discipline in computer science. A common content based image retrieval approach requires that the user gives a regular image (e.g, a photo) as a query. However, having a regular image as query may be a serious problem. Indeed, people commonly use an image retrieval system because they do not count on the desired image. An easy alternative way t...

  5. Intravital imaging.

    Science.gov (United States)

    Pittet, Mikael J; Weissleder, Ralph

    2011-11-23

    Until recently, the idea of observing life deep within the tissues of a living mouse, at a resolution sufficient to pick out cellular behaviors and molecular signals underlying them, remained a much-coveted dream. Now, a new era of intravital fluorescence microscopy has dawned. In this Primer, we review the technologies that made this revolution possible and demonstrate how intravital imaging is beginning to provide quantitative and dynamic insights into cell biology, immunology, tumor biology, and neurobiology. Copyright © 2011 Elsevier Inc. All rights reserved.

  6. Pituitary Imaging.

    Science.gov (United States)

    Pressman, Barry D

    2017-09-01

    Modern pituitary imaging is MRI. However, computed tomography (CT) still has limited usefulness. In addition, because CT offers much better bone detail and calcium detection, there are some cases in which such additional information is necessary. Before the advent of CT, plain radiography, pneumoencephalography, and angiography were used to diagnose pituitary masses. More recently, CT, and then especially MRI, made it possible to primarily delineate lesions within and around the pituitary gland rather than depend on secondary information that could only suggest their presence. Copyright © 2017 Elsevier Inc. All rights reserved.

  7. Imaging system

    International Nuclear Information System (INIS)

    Froggatt, R.J.

    1981-01-01

    The invention provides a two dimensional imaging system in which a pattern of radiation falling on the system is detected to give electrical signals for each of a plurality of strips across the pattern. The detection is repeated for different orientations of the strips and the whole processed by compensated back projection. For a shadow x-ray system a plurality of strip x-ray detectors are rotated on a turntable. For lower frequencies the pattern may be rotated with a Dove prism and the strips condensed to suit smaller detectors with a cylindrical lens. (author)

  8. Progress on molecular imaging

    International Nuclear Information System (INIS)

    Chen Quan; Zhang Yongxue

    2011-01-01

    Molecular imaging is a new era of medical imaging,which can non-invasively monitor biological processes at the cellular and molecular level in vivo, including molecular imaging of nuclear medicine, magnetic resonance molecular imaging, ultrasound molecular imaging,optical molecular imaging and molecular imaging with X-ray. Recently, with the development of multi-subjects amalgamation, multimodal molecular imaging technology has been applied in clinical imaging, such as PET-CT and PET-MRI. We believe that with development of molecular probe and multi-modal imaging, more and more molecular imaging techniques will be applied in clinical diagnosis and treatment. (authors)

  9. Imaging Case

    Directory of Open Access Journals (Sweden)

    Maria Adriana Rangel

    2018-04-01

    Full Text Available Introduction: Cephalohematoma is a collection of serosanguineous fluid below the periosteum and is the most frequent cranial injury in the newborn, occurring in 0.2-2.5% live births. The majority of cephalohematomas spontaneously resolve within three to four weeks, however, some persist beyond four weeks and begin to calcify. Case report: A seven-week-old boy, was referred to the emergency department because of a head lump on the right parietal region, with no other symptoms. He was born after a vacuum-assisted delivery, and presented a cephalohematoma in the first days of life, that progressively decreased and became more rigid. Physical examination, revealed a cranial asymmetry, and a head lump on the right parietal region, that was hard and fixed to the bone. Head X-ray revealed a radiopaque lump on the right parietal bone and a poorly defined arched line, as well as visible microcalcifications on the core of the cephalohematoma, typical findings of a calcified cephalohematoma. Discussion: Even though cephalohematoma is frequently encountered, calcified cephalohematoma is seen only sporadically, and is a rare clinical entity. History and clinical examination are important in the differential diagnosis and imaging strategy. Radiography and ultrasonography are often the initial screening diagnostic tests, followed by magnetic resonance imaging or computed tomography. Head x-ray features, in this case report, where particularly evocative of the diagnosis.

  10. Molecular MR Imaging Probes

    OpenAIRE

    MAHMOOD, UMAR; JOSEPHSON, LEE

    2005-01-01

    Magnetic resonance imaging (MRI) has been successfully applied to many of the applications of molecular imaging. This review discusses by example some of the advances in areas such as multimodality MR-optical agents, receptor imaging, apoptosis imaging, angiogenesis imaging, noninvasive cell tracking, and imaging of MR marker genes.

  11. Speckle imaging algorithms for planetary imaging

    Energy Technology Data Exchange (ETDEWEB)

    Johansson, E. [Lawrence Livermore National Lab., CA (United States)

    1994-11-15

    I will discuss the speckle imaging algorithms used to process images of the impact sites of the collision of comet Shoemaker-Levy 9 with Jupiter. The algorithms use a phase retrieval process based on the average bispectrum of the speckle image data. High resolution images are produced by estimating the Fourier magnitude and Fourier phase of the image separately, then combining them and inverse transforming to achieve the final result. I will show raw speckle image data and high-resolution image reconstructions from our recent experiment at Lick Observatory.

  12. NMR imaging

    International Nuclear Information System (INIS)

    Ouchi, Toshihiro; Steiner, R.E.

    1984-01-01

    Three epidermoid and two dermoid tumours, pathologically proven, were examined by NMR and CT scans. Although most brain tumours have a low signal with a long T 1 , a dermoid cyst and one of the two components of the other dermoid tumour had a high signal and therefore a short T 1 . All three epidermoid tumours had a low signal and a long T 1 . Because of the high level contrast between some of the tumours and cerebrospinal fluid, NMR is helpful to detect the lesion. Neither of the liquid fluid levels in the tumour cysts or floating fat in the subarachnoid space was recognized in one patients, but the fine leakage of the content from the epidermoid cyst into the lateral ventricle was detected on a saturation recovery 1000 image in one case. (author)

  13. Medical Imaging System

    Science.gov (United States)

    1991-01-01

    The MD Image System, a true-color image processing system that serves as a diagnostic aid and tool for storage and distribution of images, was developed by Medical Image Management Systems, Huntsville, AL, as a "spinoff from a spinoff." The original spinoff, Geostar 8800, developed by Crystal Image Technologies, Huntsville, incorporates advanced UNIX versions of ELAS (developed by NASA's Earth Resources Laboratory for analysis of Landsat images) for general purpose image processing. The MD Image System is an application of this technology to a medical system that aids in the diagnosis of cancer, and can accept, store and analyze images from other sources such as Magnetic Resonance Imaging.

  14. Medical imaging technology

    CERN Document Server

    Haidekker, Mark A

    2013-01-01

    Biomedical imaging is a relatively young discipline that started with Conrad Wilhelm Roentgen’s discovery of the x-ray in 1885. X-ray imaging was rapidly adopted in hospitals around the world. However, it was the advent of computerized data and image processing that made revolutionary new imaging modalities possible. Today, cross-sections and three-dimensional reconstructions of the organs inside the human body is possible with unprecedented speed, detail and quality. This book provides an introduction into the principles of image formation of key medical imaging modalities: X-ray projection imaging, x-ray computed tomography, magnetic resonance imaging, ultrasound imaging, and radionuclide imaging. Recent developments in optical imaging are also covered. For each imaging modality, the introduction into the physical principles and sources of contrast is provided, followed by the methods of image formation, engineering aspects of the imaging devices, and a discussion of strengths and limitations of the modal...

  15. Foundations of image science

    CERN Document Server

    Barrett, Harrison H

    2013-01-01

    Winner of the 2006 Joseph W. Goodman Book Writing Award! A comprehensive treatment of the principles, mathematics, and statistics of image science In today's visually oriented society, images play an important role in conveying messages. From seismic imaging to satellite images to medical images, our modern society would be lost without images to enhance our understanding of our health, our culture, and our world. Foundations of Image Science presents a comprehensive treatment of the principles, mathematics, and st

  16. High energy positron imaging

    International Nuclear Information System (INIS)

    Chen Shengzu

    2003-01-01

    The technique of High Energy Positron Imaging (HEPI) is the new development and extension of Positron Emission Tomography (PET). It consists of High Energy Collimation Imaging (HECI), Dual Head Coincidence Detection Imaging (DHCDI) and Positron Emission Tomography (PET). We describe the history of the development and the basic principle of the imaging methods of HEPI in details in this paper. Finally, the new technique of the imaging fusion, which combined the anatomical image and the functional image together are also introduced briefly

  17. scikit-image: image processing in Python.

    Science.gov (United States)

    van der Walt, Stéfan; Schönberger, Johannes L; Nunez-Iglesias, Juan; Boulogne, François; Warner, Joshua D; Yager, Neil; Gouillart, Emmanuelle; Yu, Tony

    2014-01-01

    scikit-image is an image processing library that implements algorithms and utilities for use in research, education and industry applications. It is released under the liberal Modified BSD open source license, provides a well-documented API in the Python programming language, and is developed by an active, international team of collaborators. In this paper we highlight the advantages of open source to achieve the goals of the scikit-image library, and we showcase several real-world image processing applications that use scikit-image. More information can be found on the project homepage, http://scikit-image.org.

  18. scikit-image: image processing in Python

    Directory of Open Access Journals (Sweden)

    Stéfan van der Walt

    2014-06-01

    Full Text Available scikit-image is an image processing library that implements algorithms and utilities for use in research, education and industry applications. It is released under the liberal Modified BSD open source license, provides a well-documented API in the Python programming language, and is developed by an active, international team of collaborators. In this paper we highlight the advantages of open source to achieve the goals of the scikit-image library, and we showcase several real-world image processing applications that use scikit-image. More information can be found on the project homepage, http://scikit-image.org.

  19. Nuclear medicine imaging instrumentations for molecular imaging

    International Nuclear Information System (INIS)

    Chung, Yong Hyun; Song, Tae Yong; Choi, Yong

    2004-01-01

    Small animal models are extensively utilized in the study of biomedical sciences. Current animal experiments and analysis are largely restricted to in vitro measurements and need to sacrifice animals to perform tissue or molecular analysis. This prevents researchers from observing in vivo the natural evolution of the process under study. Imaging techniques can provide repeatedly in vivo anatomic and molecular information noninvasively. Small animal imaging systems have been developed to assess biological process in experimental animals and increasingly employed in the field of molecular imaging studies. This review outlines the current developments in nuclear medicine imaging instrumentations including fused multi-modality imaging systems for small animal imaging

  20. Joint imaging

    International Nuclear Information System (INIS)

    Hengst, W.

    1984-01-01

    Joint imaging is a proven diagnostic procedure which has become indispensable to the detection and treatment of different joint diseases in almost all disciplines. The method is suited for early diagnosis of joint affections both in soft tissue and bone which cannot be detected by X-ray or other procedures. The local activity accumulation depends on the rate of metabolism and is visualized in the scan, which in turn enables the extension and floridity of focal lesions to be evaluated and followed-up. Although joint scans may often give hints to probabilities relevant to differential diagnosis, the method is non-specific and only useful if based on the underlying clinical picture and X-ray finding, if possible. The radiation exposure is very low and does not represent a hazard in cases of adequate assessment of indication. In pregnant women and children the assessment of indication has to be based on very strict principles. The method is suited for out-patient diagnosis and can be applied in all installations equipped with a gamma camera and a technetium generator. (orig.) [de

  1. Pediatric magnetic resonance imaging

    International Nuclear Information System (INIS)

    Cohen, M.D.

    1986-01-01

    This book defines the current clinical potential of magnetic resonance imaging and focuses on direct clinical work with pediatric patients. A section dealing with the physics of magnetic resonance imaging provides an introduction to enable clinicians to utilize the machine and interpret the images. Magnetic resonance imaging is presented as an appropriate imaging modality for pediatric patients utilizing no radiation

  2. Identifying Image Manipulation Software from Image Features

    Science.gov (United States)

    2015-03-26

    scales”. Educational and Psychological Measurement, 20(1):37, 1960. 7. Committee, Technical Standardization. Exchangeable image file format for digital...Digital Forensics. Springer, 2005. 23. Photography, Technical Committee. Photography and graphic technology - Ex- tended colour encodings for digital image

  3. Image processing with ImageJ

    CERN Document Server

    Pascau, Javier

    2013-01-01

    The book will help readers discover the various facilities of ImageJ through a tutorial-based approach.This book is targeted at scientists, engineers, technicians, and managers, and anyone who wishes to master ImageJ for image viewing, processing, and analysis. If you are a developer, you will be able to code your own routines after you have finished reading this book. No prior knowledge of ImageJ is expected.

  4. Medical imaging 4

    International Nuclear Information System (INIS)

    Loew, M.H.

    1990-01-01

    This book is covered under the following topics: human visual pattern recognition, fractals, rules, and segments, three-dimensional image processing, MRI, MRI and mammography, clinical applications 1, angiography, image processing systems, image processing poster session

  5. General Ultrasound Imaging

    Medline Plus

    Full Text Available ... News Physician Resources Professions Site Index A-Z General Ultrasound Ultrasound imaging uses sound waves to produce ... the limitations of General Ultrasound Imaging? What is General Ultrasound Imaging? Ultrasound is safe and painless, and ...

  6. General Ultrasound Imaging

    Medline Plus

    Full Text Available ... Imaging? Ultrasound waves are disrupted by air or gas; therefore ultrasound is not an ideal imaging technique ... with caption Pediatric Content Some imaging tests and treatments have special pediatric considerations. The teddy bear denotes ...

  7. Outpatient Imaging Efficiency - State

    Data.gov (United States)

    U.S. Department of Health & Human Services — Use of medical imaging - state data. These measures give you information about hospitals' use of medical imaging tests for outpatients. Examples of medical imaging...

  8. Viewing and imaging the solar system a guide for amateur astronomers

    CERN Document Server

    Clark, Jane

    2015-01-01

    Viewing and Imaging the Solar System: A Guide for Amateur Astronomers is for those who want to develop their ability to observe and image Solar System objects, including the planets and moons, the Sun, and comets and asteroids. They might be beginners, or they may have already owned and used an astronomical telescope for a year or more. Newcomers are almost always wowed by sights such as the rings of Saturn and the moons of Jupiter, but have little idea how to find these objects for themselves (with the obvious exceptions of the Sun and Moon). They also need guidance about what equipment to use, besides a telescope. This book is written by an expert on the Solar System, who has had a lot of experience with outreach programs, which teach others how to make the most of relatively simple and low-cost equipment. That does not mean that this book is not for serious amateurs. On the contrary, it is designed to show amateur astronomers, in a relatively light-hearted—and math-free way—how to become serious.

  9. Tomographic image reconstruction using training images

    DEFF Research Database (Denmark)

    Soltani, Sara; Andersen, Martin Skovgaard; Hansen, Per Christian

    2017-01-01

    We describe and examine an algorithm for tomographic image reconstruction where prior knowledge about the solution is available in the form of training images. We first construct a non-negative dictionary based on prototype elements from the training images; this problem is formulated within...

  10. To Image...or Not to Image?

    Science.gov (United States)

    Bruley, Karina

    1996-01-01

    Provides a checklist of considerations for installing document image processing with an electronic document management system. Other topics include scanning; indexing; the image file life cycle; benefits of imaging; document-driven workflow; and planning for workplace changes like postsorting, creating a scanning room, redeveloping job tasks and…

  11. Annotating images by mining image search results

    NARCIS (Netherlands)

    Wang, X.J.; Zhang, L.; Li, X.; Ma, W.Y.

    2008-01-01

    Although it has been studied for years by the computer vision and machine learning communities, image annotation is still far from practical. In this paper, we propose a novel attempt at model-free image annotation, which is a data-driven approach that annotates images by mining their search

  12. Image processing with ImageJ

    NARCIS (Netherlands)

    Abramoff, M.D.; Magalhães, Paulo J.; Ram, Sunanda J.

    2004-01-01

    Wayne Rasband of NIH has created ImageJ, an open source Java-written program that is now at version 1.31 and is used for many imaging applications, including those that that span the gamut from skin analysis to neuroscience. ImageJ is in the public domain and runs on any operating system (OS).

  13. Osteogenic sarcoma : imaging advances

    International Nuclear Information System (INIS)

    Gooding, C.A.

    1995-01-01

    The contents are classification of osteosarcoma, radiographic appearance, radionuclide imaging, PET - positron emission tomography scanning, arteriography, computed tomography, MRI imaging, response of chemotherapy (43 refs.)

  14. General Ultrasound Imaging

    Medline Plus

    Full Text Available ... through blood vessels. Ultrasound imaging is a noninvasive medical test that helps physicians diagnose and treat medical conditions. Conventional ultrasound displays the images in thin, ...

  15. Osteogenic sarcoma : imaging advances

    Energy Technology Data Exchange (ETDEWEB)

    Gooding, C A [California Univ., San Francisco, CA (United States)

    1996-12-31

    The contents are classification of osteosarcoma, radiographic appearance, radionuclide imaging, PET - positron emission tomography scanning, arteriography, computed tomography, MRI imaging, response of chemotherapy (43 refs.).

  16. Image processing and recognition for biological images.

    Science.gov (United States)

    Uchida, Seiichi

    2013-05-01

    This paper reviews image processing and pattern recognition techniques, which will be useful to analyze bioimages. Although this paper does not provide their technical details, it will be possible to grasp their main tasks and typical tools to handle the tasks. Image processing is a large research area to improve the visibility of an input image and acquire some valuable information from it. As the main tasks of image processing, this paper introduces gray-level transformation, binarization, image filtering, image segmentation, visual object tracking, optical flow and image registration. Image pattern recognition is the technique to classify an input image into one of the predefined classes and also has a large research area. This paper overviews its two main modules, that is, feature extraction module and classification module. Throughout the paper, it will be emphasized that bioimage is a very difficult target for even state-of-the-art image processing and pattern recognition techniques due to noises, deformations, etc. This paper is expected to be one tutorial guide to bridge biology and image processing researchers for their further collaboration to tackle such a difficult target. © 2013 The Author Development, Growth & Differentiation © 2013 Japanese Society of Developmental Biologists.

  17. Imaging Sciences Workshop Proceedings

    Energy Technology Data Exchange (ETDEWEB)

    Candy, J.V.

    1996-11-21

    This report contains the proceedings of the Imaging Sciences Workshop sponsored by C.A.S.LS., the Center for Advanced Signal & Image Sciences. The Center, established primarily to provide a forum where researchers can freely exchange ideas on the signal and image sciences in a comfortable intellectual environment, has grown over the last two years with the opening of a Reference Library (located in Building 272). The Technical Program for the 1996 Workshop include a variety of efforts in the Imaging Sciences including applications in the Microwave Imaging, highlighted by the Micro-Impulse Radar (MIR) system invented at LLNL, as well as other applications in this area. Special sessions organized by various individuals in Speech, Acoustic Ocean Imaging, Radar Ocean Imaging, Ultrasonic Imaging, and Optical Imaging discuss various applica- tions of real world problems. For the more theoretical, sessions on Imaging Algorithms and Computed Tomography were organized as well as for the more pragmatic featuring a session on Imaging Systems.

  18. Adolescence and Body Image.

    Science.gov (United States)

    Weinshenker, Naomi

    2002-01-01

    Discusses body image among adolescents, explaining that today's adolescents are more prone to body image distortions and dissatisfaction than ever and examining the historical context; how self-image develops; normative discontent; body image distortions; body dysmorphic disorder (BDD); vulnerability of boys (muscle dysmorphia); who is at risk;…

  19. Digital Imaging. Chapter 16

    Energy Technology Data Exchange (ETDEWEB)

    Clunie, D. [CoreLab Partners, Princeton (United States)

    2014-09-15

    The original means of recording X ray images was a photographic plate. Nowadays, all medical imaging modalities provide for digital acquisition, though globally, the use of radiographic film is still widespread. Many modalities are fundamentally digital in that they require image reconstruction from quantified digital signals, such as computed tomography (CT) and magnetic resonance imaging (MRI)

  20. Towards exaggerated image stereotypes

    DEFF Research Database (Denmark)

    Chen, Chen; Lauze, Francois Bernard; Igel, Christian

    2011-01-01

    Given a training set of images and a binary classifier,we introduce the notion of an exaggerated image stereotype forsome image class of interest, which emphasizes/exaggerates thecharacteristic patterns in an image and visualizes which visualinformation the classification relies on. This is useful...