WorldWideScience

Sample records for sun moon stars

  1. Many skies alternative histories of the Sun, Moon, planets, and stars

    CERN Document Server

    Upgren, Arthur

    2005-01-01

    Many Skies: Alternative Histories of the Sun, Moon, Planets, and Stars examines the changes in science that  alternative solar, stellar, and galactic arrangements would have brought, and explores the different theologies, astrologies, and methods of tracking time that would have developed to reflect them. Our perception of our surroundings, the number of gods we worship, the symbols we use in art and literature, even the way we form nations and empires are all closely tied to our particular (and accidental) placement in the universe.  Upgren also explores the actual ways tha

  2. Sun, Moon and Earthquakes

    Science.gov (United States)

    Kolvankar, V. G.

    2013-12-01

    During a study conducted to find the effect of Earth tides on the occurrence of earthquakes, for small areas [typically 1000km X1000km] of high-seismicity regions, it was noticed that the Sun's position in terms of universal time [GMT] shows links to the sum of EMD [longitude of earthquake location - longitude of Moon's foot print on earth] and SEM [Sun-Earth-Moon angle]. This paper provides the details of this relationship after studying earthquake data for over forty high-seismicity regions of the world. It was found that over 98% of the earthquakes for these different regions, examined for the period 1973-2008, show a direct relationship between the Sun's position [GMT] and [EMD+SEM]. As the time changes from 00-24 hours, the factor [EMD+SEM] changes through 360 degree, and plotting these two variables for earthquakes from different small regions reveals a simple 45 degree straight-line relationship between them. This relationship was tested for all earthquakes and earthquake sequences for magnitude 2.0 and above. This study conclusively proves how Sun and the Moon govern all earthquakes. Fig. 12 [A+B]. The left-hand figure provides a 24-hour plot for forty consecutive days including the main event (00:58:23 on 26.12.2004, Lat.+3.30, Long+95.980, Mb 9.0, EQ count 376). The right-hand figure provides an earthquake plot for (EMD+SEM) vs GMT timings for the same data. All the 376 events including the main event faithfully follow the straight-line curve.

  3. Hot moons and cool stars

    Directory of Open Access Journals (Sweden)

    Heller René

    2013-04-01

    Full Text Available The exquisite photometric precision of the Kepler space telescope now puts the detection of extrasolar moons at the horizon. Here, we firstly review observational and analytical techniques that have recently been proposed to find exomoons. Secondly, we discuss the prospects of characterizing potentially habitable extrasolar satellites. With moons being much more numerous than planets in the solar system and with most exoplanets found in the stellar habitable zone being gas giants, habitable moons could be as abundant as habitable planets. However, satellites orbiting planets in the habitable zones of cool stars will encounter strong tidal heating and likely appear as hot moons.

  4. The star ''Sun''

    International Nuclear Information System (INIS)

    Pecker, J.-C.

    1982-01-01

    The author gives a resume of our knowledge of the Sun. In particular, he discusses the mass, luminosity and chemical composition of the Sun, and then asks what an observer from Sirius would think about the Sun. (G.T.H.)

  5. Dynamics of the Sun-Earth-Moon System

    Indian Academy of Sciences (India)

    The dynamics of the Sun-Earth-Moon system is discussed with special attention to the effects of. Sun's perturbations on the Moon's orbit around the Earth. Important secular effects are the re- gression of the nodes, the advance of the perigee and the increase in the Moon's mean longitude. We discuss the relationship of the ...

  6. Moon and sun shadowing effect measurements

    International Nuclear Information System (INIS)

    Medeiros, Michelle Mesquita de; Gomes, Ricardo Avelino

    2011-01-01

    Full text: The deficit due to the absorption of cosmic rays by the Moon and the Sun can be observed detecting the muon flux generated in extensive air showers. This phenomenon, known as cosmic ray shadow, can be used to study the behaviour of the geomagnetic, solar and interplanetary magnetic fields, to measure the antiproton-proton ratio and to determine the angular resolution and alignment of the detectors to confirm its accuracy and precision. Many experiments using surface or underground detectors have measured the Moon and Sun shadow: MINOS, CYGNUS, CASA, Tibet, MACRO, Soudan2, L3+C, Milagro, BUST, GRAPE and HEGRA. The MINOS experiment (Main Injector Neutrino Oscillation Search) uses two layered steel and plastic scintillator detectors (Near Detector and Far Detector) along with a muon neutrino beam (NuMI - Neutrinos at the Main Injector) to search for ν μ disappearance, and thus neutrino oscillations. However the magnetic field and the fiducial volume of the underground Far Detector at Soudan Underground Mine State Park (Minnesota, USA) allow a great opportunity to investigate cosmic rays at TeV surface energy. The deficit caused by the Moon and the Sun was detected by the MINOS Far Detector and this could also be done using the Near Detector. In this report we describe the motivation of measuring this effect. We present the recent results from MINOS along with its experimental apparatus and, in addition, the main results from the various experiments. We also make considerations about the possibility of doing such a measurement with the MINOS Near Detector. (author)

  7. EARTH, MOON, SUN, AND CV ACCRETION DISKS

    International Nuclear Information System (INIS)

    Montgomery, M. M.

    2009-01-01

    Net tidal torque by the secondary on a misaligned accretion disk, like the net tidal torque by the Moon and the Sun on the equatorial bulge of the spinning and tilted Earth, is suggested by others to be a source to retrograde precession in non-magnetic, accreting cataclysmic variable (CV) dwarf novae (DN) systems that show negative superhumps in their light curves. We investigate this idea in this work. We generate a generic theoretical expression for retrograde precession in spinning disks that are misaligned with the orbital plane. Our generic theoretical expression matches that which describes the retrograde precession of Earths' equinoxes. By making appropriate assumptions, we reduce our generic theoretical expression to those generated by others, or to those used by others, to describe retrograde precession in protostellar, protoplanetary, X-ray binary, non-magnetic CV DN, quasar, and black hole systems. We find that spinning, tilted CV DN systems cannot be described by a precessing ring or by a precessing rigid disk. We find that differential rotation and effects on the disk by the accretion stream must be addressed. Our analysis indicates that the best description of a retrogradely precessing spinning, tilted, CV DN accretion disk is a differentially rotating, tilted disk with an attached rotating, tilted ring located near the innermost disk annuli. In agreement with the observations and numerical simulations by others, we find that our numerically simulated CV DN accretion disks retrogradely precess as a unit. Our final, reduced expression for retrograde precession agrees well with our numerical simulation results and with selective observational systems that seem to have main-sequence secondaries. Our results suggest that a major source to retrograde precession is tidal torques like that by the Moon and the Sun on the Earth. In addition, these tidal torques should be common to a variety of systems where one member is spinning and tilted, regardless if

  8. The Sun among the stars. Pt. 3

    International Nuclear Information System (INIS)

    Hardorp, J.

    1980-01-01

    Energy distributions from 3308 to 8390 Angstroem of two candidates for a solar spectral analog and of 14 other northern G-type dwarfs are compared to the solar energy distribution via stellar spectrophotometric standards. The reliability of the stellar and solar flux-calibrations is evaluated. While the stellar calibration seems to be in good shape, solar calibrations differ widely. Labs.and Neckel's calibration is the best match to the energy distributions from 4500 to 8390 Angstroem of those four stars that share the Sun's ultraviolet line spectrum (16 Cyg B, G5V, and the three Hyades stars VB 64, 106, and 142). Below 4500 Angstroem, discrepancies of up to 6% remain which do not seem to be genuine Sun-star differences. An error in the Labs and Neckel tables between 5700 and 6000 Angstroem is corrected. The NASA Standard Tables of Solar Spectral Irradiance cannot be trusted, since there seems to be no star in the sky that look like the NASA-sun. The four stars mentioned are taken to be perfect solar spectral analogs. An improved table of solar spectral irradiance is then given by the magnitudes of 16 Cyg B minus 32.945, based on Tueg's atellar and Labs and Neckel's solar calibrations. The Sun's place in the UBV system is V = -26.71 +- 0.03, B-V = 0.665 +- 0.005, and U-B = 0.20 +- 0.01. Most previous photometric investigations found a bluer Sun because they used the wrong solar calibration. For deriving accurate albedos of planets, any one of the calibrated G-type stars can be used as a standard star, when corrections are applied, although the solar analogs themselves are to be preferred. The MK system of spectral classification should be revised. (orig.)

  9. Cartography of the sun and the stars

    CERN Document Server

    Neiner, Coralie

    2016-01-01

    The mapping of the surface of stars requires diverse skills, analysis techniques and advanced modeling, i.e. the collaboration of scientists in various specialties. This volume gives insights into new techniques allowing for the first time to obtain resolved images of stars. It takes stock of what has been achieved so far in Chile, on the ESO VLTI instrument or, in the States, on the CHARA instrument. In recent times interferometry, combined with adaptive optics has allowed to reconstruct images of stars. Besides the Sun (of course) by now five stars have been resolved in detail. In addition to interferometry, this book highlights techniques used for mapping the surfaces of stars using photometry made by space observatories; Zeeman- and Doppler Imaging; mapping the surface element abundances via spectroscopy. This book will also take stock of the best images of the  solar surface, made by connecting the differential rotation to the underlying physical parameters derived from helioseismology. Recent measureme...

  10. Tidal effects on Earth, Planets, Sun by far visiting moons

    Science.gov (United States)

    Fargion, Daniele

    2016-07-01

    The Earth has been formed by a huge mini-planet collision forming our Earth surface and our Moon today. Such a central collision hit was statistically rare. A much probable skimming or nearby encounter by other moons or planets had to occur. Indeed Recent observations suggest that many planetary-mass objects may be present in the outer solar system between the Kuiper belt and the Oort cloud. Gravitational perturbations may occasionally bring them into the inner solar system. Their passage near Earth could have generated gigantic tidal waves, large volcanic eruptions, sea regressions, large meteoritic impacts and drastic changes in global climate. They could have caused the major biological mass extinctions in the past in the geological records. For instance a ten times a terrestrial radius nearby impact scattering by a peripherical encounter by a small moon-like object will force huge tidal waves (hundred meter height), able to lead to huge tsunami and Earth-quake. Moreover the historical cumulative planet hits in larger and wider planets as Juppiter, Saturn, Uranus will leave a trace, as observed, in their tilted spin axis. Finally a large fraction of counter rotating moons in our solar system probe and test such a visiting mini-planet captur origination. In addition the Earth day duration variability in the early past did show a rare discountinuity, very probably indebt to such a visiting planet crossing event. These far planets in rare trajectory to our Sun may, in thousands event capture, also explain sudden historical and recent temperature changes.

  11. Moon and Sun shadow observation with IceCube

    Energy Technology Data Exchange (ETDEWEB)

    Bos, Fabian; Tenholt, Frederik; Becker-Tjus, Julia [Theoretische Physik, Ruhr-Universitaet, Bochum (Germany); Westerhoff, Stefan [University of Wisconsin, Madison (United States); Collaboration: IceCube-Collaboration

    2015-07-01

    The analysis of the Moon shadow is a standard method in IceCube to determine the angular resolution and absolute pointing capabilities of the IceCube detector at the geographic South Pole. The Sun has not been used as a calibrator thus far, as its shadow is expected to be influenced by the solar magnetic field, which deflects the cosmic rays near the solar surface. This, on the other hand, provides indirect pieces of information on the magnetic field structure of the Sun. This talk shows a first analysis of the Sun shadow with IceCube data. The analysis is based on the data of the detector configurations with 79 (IC79) and 86 strings (IC86) from 2010 through 2012. To examine the shadows, a binned method is used to compare all events from one on-source with two off-source windows. For the IC40 and IC59 configuration a deficit with a statistical significance of more than 6σ was observed.

  12. Observing the Sun with NuSTAR

    Science.gov (United States)

    Kohler, Susanna

    2016-07-01

    The Nuclear Spectroscopic Telescope Array (NuSTAR) is a space telescope primarily designed to detect high-energy X-rays from faint, distant astrophysical sources. Recently, however, its occasionally been pointing much closer to home, with the goal of solving a few longstanding mysteries about the Sun.Intensity maps from an observation of a quiet-Sun region near the north solar pole and an active region just below the solar limb. The quiet-Sun data will be searched for small flares that could be heating the solar corona, and the high-altitude emission above the limb may provide clues about particle acceleration. [Adapted from Grefenstette et al. 2016]An Unexpected TargetThough we have a small fleet of space telescopes designed to observe the Sun, theres an important gap: until recently, there was no focusing telescope making solar observations in the hard X-ray band (above ~3 keV). Conveniently, there is a tool capable of doing this: NuSTAR.Though NuSTARs primary mission is to observe faint astrophysical X-ray sources, a team of scientists has recently conducted a series of observations in which NuSTAR was temporarily repurposed and turned to focus on the Sun instead.These observations pose an interesting challenge precisely because of NuSTARs extreme sensitivity: pointing at such a nearby, bright source can quickly swamp the detectors. But though the instrument cant be used to observe the bright flares and outbursts from the Sun, its the perfect tool for examining the parts of the Sun weve been unable to explore in hard X-rays before now such as faint flares, or the quiet, inactive solar surface.In a recently published study led by Brian Grefenstette (California Institute of Technology), the team describes the purpose and initial results of NuSTARs first observations of the Sun.Solar MysteriesWhat is NuSTAR hoping to accomplish with its solar observations? There are two main questions that hard X-ray observations may help to answer.How are particles accelerated in

  13. Tourism climate and thermal comfort in Sun Moon Lake, Taiwan

    Science.gov (United States)

    Lin, Tzu-Ping; Matzarakis, Andreas

    2008-03-01

    Bioclimate conditions at Sun Moon Lake, one of Taiwan’s most popular tourist destinations, are presented. Existing tourism-related climate is typically based on mean monthly conditions of air temperature and precipitation and excludes the thermal perception of tourists. This study presents a relatively more detailed analysis of tourism climate by using a modified thermal comfort range for both Taiwan and Western/Middle European conditions, presented by frequency analysis of 10-day intervals. Furthermore, an integrated approach (climate tourism information scheme) is applied to present the frequencies of each facet under particular criteria for each 10-day interval, generating a time-series of climate data with temporal resolution for tourists and tourism authorities.

  14. World cup soccer players tend to be born with sun and moon in adjacent zodiacal signs

    Science.gov (United States)

    Verhulst, J

    2000-01-01

    The ecliptic elongation of the moon with respect to the sun does not show uniform distribution on the birth dates of the 704 soccer players selected for the 1998 World Cup. However, a uniform distribution is expected on astronomical grounds. The World Cup players show a very pronounced tendency (p = 0.00001) to be born on days when the sun and moon are in adjacent zodiacal signs. Key Words: soccer; World Cup; astrology; moon PMID:11131239

  15. The finite - dimensional star and grade star irreducible representation of SU(n/1)

    International Nuclear Information System (INIS)

    Han Qi-zhi.

    1981-01-01

    We derive the conditions of star and grade star representations of SU(n/1) and give some examples of them. We also give a brief review of the finite - dimensional irreducible representations of SU(n/1). (author)

  16. The Moons of Jupiter / Journey to the Stars

    Science.gov (United States)

    Litwak, J.; Chatzichristou, E.

    2017-09-01

    The Moons of Jupiter/ Journey to the Stars uses the arts, most particularly theatre arts to inspire curiosity about science education. Using characters which include famous scientists as well as mythological figures, the project provokes thought and offers opportunity for discovery. The play and the subsequent creative teaching tools are accessible to scientists, artists and lay people in an out of the classroom.

  17. The Moon's Moment in the Sun - Extending Public Engagement after the Total Solar Eclipse with International Observe the Moon Night

    Science.gov (United States)

    Bleacher, L.; Jones, A. P.; Wasser, M. L.; Petro, N. E.; Wright, E. T.; Ladd, D.; Keller, J. W.

    2017-12-01

    2017 presented an amazing opportunity to engage the public in learning about lunar and space science, the motions of the Earth-Moon-Sun system, and NASA's fleet of space missions, beginning with the 2017 total solar eclipse on 21 August and continuing with International Observe the Moon Night (InOMN) on 28 October. On 21 August 2017, everyone in the continental United States had the opportunity to witness a solar eclipse, weather permitting, in total or partial form. The path of totality, in which the Sun was completely obscured from view by the Moon, stretched from Oregon to South Carolina. The Education and Communication Team of NASA's Lunar Reconnaissance Orbiter (LRO) worked to highlight the Moon, the "central player" in the total solar eclipse, in a variety of ways for the public. Efforts included collaborating with Minor League Baseball teams to host eclipse-viewing events along the path of totality, communicating the Moon's role in the eclipse through public engagement products, communicating about InOMN as an experiential opportunity beyond the eclipse, and more. InOMN is an annual event, during which everyone on Earth is invited to observe and learn about the Moon and its connection to planetary science, and to share personal and community connections we all have to the Moon [2, 3, 4 and references therein]. For viewers across the United States, the total solar eclipse of 21 August provided an exciting opportunity to watch a New Moon cross in front of the Sun, casting the viewer in shadow and providing amazing views of the solar corona. The public observed the Moon in a different part of its orbit, when reflected sunlight revealed a fascinating lunar landscape - and extended their excitement for space science - by participating in InOMN on 28 October. With InOMN taking place barely two months after the total solar eclipse, it offered an opportunity to sustain and grow public interest in lunar and space science generated by the eclipse. We will report on

  18. VUV Spectroscopy of the Sun as a Star

    Science.gov (United States)

    Kankelborg, Charles; Philip, Judge; Winebarger, Amy R.; Kobayashi, Ken; Smart, Roy

    2017-08-01

    We describe a new sounding rocket mission to obtain the first high resolution, high quality VUV (100-200 nm) spectrum of the Sun-as-a-star. Our immediate science goal is to understand better the processes of chromospheric and coronal heating. HST data exist for a dozen or so Sun-like stars of a quality already beyond our ability to construct a comparable sun-as-a-star UV spectrum. The solar spectrum we obtain will enable us to understand the nature of magnetic energy dissipation as a Sun-like star evolves, and the dependence of magnetic activity on stellar mass and metallicity. This poster presents the instrument design, scientific prospects, and broader impacts of the proposed mission.

  19. The sun as a star: Solar phenomena and stellar applications

    International Nuclear Information System (INIS)

    Noyes, R.W.

    1981-01-01

    Our Sun is a run-of-the-mill star, having no obvious extremes of stellar properties. For this reason it is perhaps more, rather than less, interesting as an astrophysical object, for its sameness to other stars suggests that in studying the Sun, we are studying at close hand common, rather than unusual stellar phenomena. Conversely, comparative study of the Sun and other solar-type stars is an invaluable tool for solar physics, for two reasons: First, it allows us to explore how solar properties and phenomena depend on parameters we cannot vary on the Sun - most fundamentally, rotation rate and mass. Second, study of solar-like stars of different ages allows us to see how stellar and solar phenomena depend on age; study of other stars may be one of the best ways to infer the earlier history of the Sun, as well as its future history. In this review we shall concentrate on phenomena common to the Sun and solar-type (main sequence) stars with different fundamental properties such as mass, age, and rotation. (orig.)

  20. A 3-D Virtual Reality Model of the Sun and the Moon for E-Learning at Elementary Schools

    Science.gov (United States)

    Sun, Koun-Tem; Lin, Ching-Ling; Wang, Sheng-Min

    2010-01-01

    The relative positions of the sun, moon, and earth, their movements, and their relationships are abstract and difficult to understand astronomical concepts in elementary school science. This study proposes a three-dimensional (3-D) virtual reality (VR) model named the "Sun and Moon System." This e-learning resource was designed by…

  1. Xbalanque's marriage : a commentary on the Q'eqchi' myth of sun and moon

    NARCIS (Netherlands)

    Braakhuis, Hyacinthus Edwinus Maria

    2010-01-01

    “Xbalanque’s Marriage” examines the Sun and Moon myth of the Q’eqchi’ Mayas from the perspective of marriage alliance and hunting ideology. On the negative side, the relationship between a tapir and the old adoptive mother of Xbalanque and his older brother can be read as the denial of alliance,

  2. Children's Concepts of the Shape and Size of the Earth, Sun and Moon

    Science.gov (United States)

    Bryce, T. G. K.; Blown, E. J.

    2013-01-01

    Children's understandings of the shape and relative sizes of the Earth, Sun and Moon have been extensively researched and in a variety of ways. Much is known about the confusions which arise as young people try to grasp ideas about the world and our neighbouring celestial bodies. Despite this, there remain uncertainties about the conceptual models…

  3. "Earth, Sun and Moon": Computer Assisted Instruction in Secondary School Science--Achievement and Attitudes

    Science.gov (United States)

    Ercan, Orhan; Bilen, Kadir; Ural, Evrim

    2016-01-01

    This study investigated the impact of a web-based teaching method on students' academic achievement and attitudes in the elementary education fifth grade Science and Technology unit, "System of Earth, Sun and Moon". The study was a quasi-experimental study with experimental and control groups comprising 54 fifth grade students attending…

  4. 7th Class Students' Opinions on Sun, Earth and Moon System

    Science.gov (United States)

    Aydin, Suleyman

    2017-01-01

    This study is conducted to detect the students' perceptions on Sun, Moon and Earth (SME) system and define the 7th grade students' attitudes on the subject. In the study, since it was aimed to detect and evaluate the students' perceptions on some basic astronomical concepts without changing the natural conditions, a descriptive approach was…

  5. Observed tidal braking in the earth/moon/sun system

    Science.gov (United States)

    Christodoulidis, D. C.; Smith, D. E.; Williamson, R. G.; Klosko, S. M.

    1987-01-01

    The low degree and order terms in the spherical harmonic model of the tidal potential were observed through the perturbations which are induced on near-earth satellite orbital motions. Evaluations of tracking observations from 17 satellites and a GEM-T1 geopotential model were used in the tidal recovery which was made in the presence of over 600 long-wavelength coefficients from 32 major and minor tides. Wahr's earth tidal model was used as a basis for the recovery of the ocean tidal terms. Using this tidal model, the secular change in the moon's mean motion due to tidal dissipation was found to be -25.27 + or - 0.61 arcsec/century squared. The estimation of lunar acceleration agreed with that observed from lunar laser ranging techniques (-24.9 + or - 1.0 arcsec/century squared), with the corresponding tidal braking of earth's rotation being -5.98 + or - 0.22 x 10 to the minus 22 rad/second squared. If the nontidal braking of the earth due to the observed secular change in the earth's second zonal harmonic is considered, satellite techniques yield a total value of the secular change of the earth's rotation rate of -4.69 + or - 0.36 x 10 to the minus 22 rad/second squared.

  6. Nearest star the surprising science of our sun

    CERN Document Server

    Golub, Leon

    2014-01-01

    How did the Sun evolve, and what will it become? What is the origin of its light and heat? How does solar activity affect the atmospheric conditions that make life on Earth possible? These are the questions at the heart of solar physics, and at the core of this book. The Sun is the only star near enough to study in sufficient detail to provide rigorous tests of our theories and help us understand the more distant and exotic objects throughout the cosmos. Having observed the Sun using both ground-based and spaceborne instruments, the authors bring their extensive personal experience to this sto

  7. A practical equation of state for the sun and sun-like stars

    International Nuclear Information System (INIS)

    Lin, H.H.; Daeppen, W.

    2012-01-01

    For models of the Sun and Sun-like stars, a high-quality equation of state is crucial. Conversely, helio- and asteroseismological observations put constraints on the physical formalisms. They effectively turn the Sun and stars into laboratories for dense plasmas. For models of the Sun and Sun-like stars, the most accurate equation of state so far has been the one developed as part of OPAL opacity project of Livermore. However, the OPAL equation of state is limited in two important respects. First, it is only available in the form of pre-computed tables that are provided from Lawrence Livermore National Laboratory. Applications to stellar modeling require therefore interpolation, with unavoidable loss of accuracy. Second, the OPAL equation of state is proprietary and not freely available. Varying its underlying physical parameters is therefore no option for the community. We report on the most recent progress with the development of a high-precision emulation of the OPAL equation of state that will lead to an in-line tool for modelers (copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  8. The Sun - From the star to domestic energy

    International Nuclear Information System (INIS)

    2009-06-01

    Considered as a star and a deity, for a long period of time the Sun was thought to be another planet, whereas the word 'star' was reserved for all the brilliant points of light in the night sky. The Sun's status as a star in the sense of 'an astral body producing and emitting energy' was firmly established only at the beginning of the 20. century. Today astrophysicists are revealing more and more secrets of the fusion burning region located in its core. It is thanks to the Sun that life has appeared and evolved on Earth; it controls the cycle of 'For the last 4.6 million years the Sun has being providing us with light and heat. Today it is man's ambition to control this energy source'. The seasons and provides us with heat and light. But what exactly is the nature and origin of this prodigious energy source, with which man attempts to provide warmth and produce electricity? What is happening in this gigantic ball of fire, impossible to observe without protective glasses? And finally, how long will it continue to shine? Questions such as these took many centuries to be solved and will continue to be the subject of research for a long time to come. (authors)

  9. OUTCOMES AND DURATION OF TIDAL EVOLUTION IN A STAR-PLANET-MOON SYSTEM

    International Nuclear Information System (INIS)

    Sasaki, Takashi; Barnes, Jason W.; O'Brien, David P.

    2012-01-01

    We formulated tidal decay lifetimes for hypothetical moons orbiting extrasolar planets with both lunar and stellar tides. Previous works neglected the effect of lunar tides on planet rotation, and are therefore applicable only to systems in which the moon's mass is much less than that of the planet. This work, in contrast, can be applied to the relatively large moons that might be detected around newly discovered Neptune-mass and super-Earth planets. We conclude that moons are more stable when the planet/moon systems are further from the parent star, the planets are heavier, or the parent stars are lighter. Inclusion of lunar tides allows for significantly longer lifetimes for a massive moon relative to prior formulations. We expect that the semimajor axis of the planet hosting the first detected exomoon around a G-type star is 0.4-0.6 AU and is 0.2-0.4 AU for an M-type star.

  10. PHOTOMETRIC VARIABILITY IN KEPLER TARGET STARS: THE SUN AMONG STARS-A FIRST LOOK

    International Nuclear Information System (INIS)

    Basri, Gibor; Walkowicz, Lucianne M.; Batalha, Natalie; Jenkins, Jon; Borucki, William J.; Koch, David; Caldwell, Doug; Gilliland, Ronald L.; Dupree, Andrea K.; Latham, David W.; Meibom, Soeren; Howell, Steve; Brown, Tim

    2010-01-01

    The Kepler mission provides an exciting opportunity to study the light curves of stars with unprecedented precision and continuity of coverage. This is the first look at a large sample of stars with photometric data of a quality that has heretofore been only available for our Sun. It provides the first opportunity to compare the irradiance variations of our Sun to a large cohort of stars ranging from very similar to rather different stellar properties, at a wide variety of ages. Although Kepler data are in an early phase of maturity, and we only analyze the first month of coverage, it is sufficient to garner the first meaningful measurements of our Sun's variability in the context of a large cohort of main-sequence stars in the solar neighborhood. We find that nearly half of the full sample is more active than the active Sun, although most of them are not more than twice as active. The active fraction is closer to a third for the stars most similar to the Sun, and rises to well more than half for stars cooler than mid-K spectral types.

  11. Is life most likely around Sun-like stars?

    Science.gov (United States)

    Lingam, Manasvi; Loeb, Abraham

    2018-05-01

    We consider the habitability of Earth-analogs around stars of different masses, which is regulated by the stellar lifetime, stellar wind-induced atmospheric erosion, and biologically active ultraviolet (UV) irradiance. By estimating the timescales associated with each of these processes, we show that they collectively impose limits on the habitability of Earth-analogs. We conclude that planets orbiting most M-dwarfs are not likely to host life, and that the highest probability of complex biospheres is for planets around K- and G-type stars. Our analysis suggests that the current existence of life near the Sun is slightly unusual, but not significantly anomalous.

  12. Dynamos of the Sun, Stars, and Planets - Preface

    Science.gov (United States)

    Stix, M.

    2005-04-01

    The conference ``Dynamos of the Sun, Stars, and Planets'' was organized by the Kiepenheuer-Institut für Sonnenphysik Freiburg, and was held at the University of Freiburg from 4th to 6th October 2004. About 50 participants attended the conference, with 8 review lectures, 20 contributed talks, and 6 posters. With only few exceptions, these contributions appear in the present issue of Astronomische Nachrichten. This preface summarizes the discussion of the closing session.

  13. Long-term radial-velocity variations of the Sun as a star: The HARPS view

    Science.gov (United States)

    Lanza, A. F.; Molaro, P.; Monaco, L.; Haywood, R. D.

    2016-03-01

    Context. Stellar radial velocities play a fundamental role in the discovery of extrasolar planets and the measurement of their physical parameters as well as in the study of stellar physical properties. Aims: We investigate the impact of the solar activity on the radial velocity of the Sun using the HARPS spectrograph to obtain measurements that can be directly compared with those acquired in the extrasolar planet search programmes. Methods: We used the Moon, the Galilean satellites, and several asteroids as reflectors to measure the radial velocity of the Sun as a star and correlated this velocity with disc-integrated chromospheric and magnetic indexes of solar activity that are similar to stellar activity indexes. We discuss in detail the systematic effects that affect our measurements and the methods to account for them. Results: We find that the radial velocity of the Sun as a star is positively correlated with the level of its chromospheric activity at ~95 percent significance level. The amplitude of the long-term variation measured in the 2006-2014 period is 4.98 ± 1.44 m/s, which is in good agreement with model predictions. The standard deviation of the residuals obtained by subtracting a linear best fit is 2.82 m/s and is due to the rotation of the reflecting bodies and the intrinsic variability of the Sun on timescales shorter than the activity cycle. A correlation with a lower significance is detected between the radial velocity and the mean absolute value of the line-of-sight photospheric magnetic field flux density. Conclusions: Our results confirm similar correlations found in other late-type main-sequence stars and provide support to the predictions of radial velocity variations induced by stellar activity based on current models.

  14. Observation in the MINOS far detector of the shadowing of cosmic rays by the sun and moon

    International Nuclear Information System (INIS)

    2010-01-01

    The shadowing of cosmic ray primaries by the the moon and sun was observed by the MINOS far detector at a depth of 2070 mwe using 83.54 million cosmic ray muons accumulated over 1857.91 live-days. The shadow of the moon was detected at the 5.6 σ level and the shadow of the sun at the 3.8 σ level using a log-likelihood search in celestial coordinates. The moon shadow was used to quantify the absolute astrophysical pointing of the detector to be 0.17 ± 0.12 o . Hints of Interplanetary Magnetic Field effects were observed in both the sun and moon shadow.

  15. Improved pointing information for SCIAMACHY from in-flight measurements of the viewing directions towards sun and moon

    Science.gov (United States)

    Bramstedt, Klaus; Stone, Thomas C.; Gottwald, Manfred; Noël, Stefan; Bovensmann, Heinrich; Burrows, John P.

    2017-07-01

    The SCanning Imaging Absorption spectroMeter for Atmospheric CHartographY (SCIAMACHY) on Envisat (2002-2012) performed nadir, limb, solar/lunar occultation and various monitoring measurements. The pointing information of the instrument is determined by the attitude information of the Envisat platform with its star trackers together with the encoder readouts of both the azimuth and the elevation scanner of SCIAMACHY. In this work, we present additional sources of attitude information from the SCIAMACHY measurements itself. The basic principle is the same as used by the star tracker: we measure the viewing direction towards celestial objects, i.e. sun and moon, to detect possible mispointings. In sun over limb port observations, we utilise the vertical scans over the solar disk. In horizontal direction, SCIAMACHY's sun follower device (SFD) is used to adjust the viewing direction. Moon over limb port measurements use for both the vertical and the horizontal direction the adjustment by the SFD. The viewing direction is steered towards the intensity centroid of the illuminated part of the lunar disk. We use reference images from the USGS Robotic Lunar Observatory (ROLO) to take into account the inhomogeneous surface and the variations by lunar libration and phase to parameterise the location of the intensity centroid from the observation geometry. Solar observations through SCIAMACHY's so-called sub-solar port (with a viewing direction closely to zenith) also use the SFD in the vertical direction. In the horizontal direction the geometry of the port defines the viewing direction. Using these three type of measurements, we fit improved mispointing parameters by minimising the pointing offsets in elevation and azimuth. The geolocation of all retrieved products will benefit from this; the tangent heights are especially improved. The altitudes assigned to SCIAMACHY's solar occultation measurements are changed in the range of -130 to -330 m, the lunar occultation

  16. Improved pointing information for SCIAMACHY from in-flight measurements of the viewing directions towards sun and moon

    Directory of Open Access Journals (Sweden)

    K. Bramstedt

    2017-07-01

    Full Text Available The SCanning Imaging Absorption spectroMeter for Atmospheric CHartographY (SCIAMACHY on Envisat (2002–2012 performed nadir, limb, solar/lunar occultation and various monitoring measurements. The pointing information of the instrument is determined by the attitude information of the Envisat platform with its star trackers together with the encoder readouts of both the azimuth and the elevation scanner of SCIAMACHY. In this work, we present additional sources of attitude information from the SCIAMACHY measurements itself. The basic principle is the same as used by the star tracker: we measure the viewing direction towards celestial objects, i.e. sun and moon, to detect possible mispointings. In sun over limb port observations, we utilise the vertical scans over the solar disk. In horizontal direction, SCIAMACHY's sun follower device (SFD is used to adjust the viewing direction. Moon over limb port measurements use for both the vertical and the horizontal direction the adjustment by the SFD. The viewing direction is steered towards the intensity centroid of the illuminated part of the lunar disk. We use reference images from the USGS Robotic Lunar Observatory (ROLO to take into account the inhomogeneous surface and the variations by lunar libration and phase to parameterise the location of the intensity centroid from the observation geometry. Solar observations through SCIAMACHY's so-called sub-solar port (with a viewing direction closely to zenith also use the SFD in the vertical direction. In the horizontal direction the geometry of the port defines the viewing direction. Using these three type of measurements, we fit improved mispointing parameters by minimising the pointing offsets in elevation and azimuth. The geolocation of all retrieved products will benefit from this; the tangent heights are especially improved. The altitudes assigned to SCIAMACHY's solar occultation measurements are changed in the range of −130 to −330 m, the lunar

  17. Children's Concepts of the Shape and Size of the Earth, Sun and Moon

    Science.gov (United States)

    Bryce, T. G. K.; Blown, E. J.

    2013-02-01

    Children's understandings of the shape and relative sizes of the Earth, Sun and Moon have been extensively researched and in a variety of ways. Much is known about the confusions which arise as young people try to grasp ideas about the world and our neighbouring celestial bodies. Despite this, there remain uncertainties about the conceptual models which young people use and how they theorise in the process of acquiring more scientific conceptions. In this article, the relevant published research is reviewed critically and in-depth in order to frame a series of investigations using semi-structured interviews carried out with 248 participants aged 3-18 years from China and New Zealand. Analysis of qualitative and quantitative data concerning the reasoning of these subjects (involving cognitive categorisations and their rank ordering) confirmed that (a) concepts of Earth shape and size are embedded in a 'super-concept' or 'Earth notion' embracing ideas of physical shape, 'ground' and 'sky', habitation of and identity with Earth; (b) conceptual development is similar in cultures where teachers hold a scientific world view and (c) children's concepts of shape and size of the Earth, Sun and Moon can be usefully explored within an ethnological approach using multi-media interviews combined with observational astronomy. For these young people, concepts of the shape and size of the Moon and Sun were closely correlated with their Earth notion concepts and there were few differences between the cultures despite their contrasts. Analysis of the statistical data used Kolmogorov-Smirnov Two-Sample Tests with hypotheses confirmed at K-S alpha level 0.05; rs : p < 0.01.

  18. HARPS-N OBSERVES THE SUN AS A STAR

    Energy Technology Data Exchange (ETDEWEB)

    Dumusque, Xavier; Glenday, Alex; Phillips, David F.; Charbonneau, David; Latham, David W.; Li, Chih-Hao; Sasselov, Dimitar; Szentgyorgyi, Andrew; Walsworth, Ronald [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Buchschacher, Nicolas; Lovis, Christophe; Pepe, Francesco; Udry, Stéphane [Observatoire Astronomique de l’Université de Genève, 51 Chemin des Maillettes, 1290 Sauverny (Switzerland); Cameron, Andrew Collier [SUPA, School of Physics and Astronomy, University of St. Andrews, North Haugh, St. Andrews, Fife, KY16 9SS (United Kingdom); Cecconi, Massimo; Cosentino, Rosario; Ghedina, Adriano; Lodi, Marcello; Molinari, Emilio, E-mail: xdumusque@cfa.harvard.edu [INAF—Fundación Galileo Galilei, Rambla José Ana Fernández Pérez 7, E-38712 Breña Baja (Spain)

    2015-12-01

    Radial velocity (RV) perturbations induced by stellar surface inhomogeneities including spots, plages and granules currently limit the detection of Earth-twins using Doppler spectroscopy. Such stellar noise is poorly understood for stars other than the Sun because their surface is unresolved. In particular, the effects of stellar surface inhomogeneities on observed stellar radial velocities are extremely difficult to characterize, and thus developing optimal correction techniques to extract true stellar radial velocities is extremely challenging. In this paper, we present preliminary results of a solar telescope built to feed full-disk sunlight into the HARPS-N spectrograph, which is in turn calibrated with an astro-comb. This setup enables long-term observation of the Sun as a star with state-of-the-art sensitivity to RV changes. Over seven days of observing in 2014, we show an average 50 cm s{sup −1} RV rms over a few hours of observation. After correcting observed radial velocities for spot and plage perturbations using full-disk photometry of the Sun, we lower by a factor of two the weekly RV rms to 60 cm s{sup −1}. The solar telescope is now entering routine operation, and will observe the Sun every clear day for several hours. We will use these radial velocities combined with data from solar satellites to improve our understanding of stellar noise and develop optimal correction methods. If successful, these new methods should enable the detection of Venus over the next two to three years, thus demonstrating the possibility of detecting Earth-twins around other solar-like stars using the RV technique.

  19. Analysis of the Herschel DEBRIS Sun-like star sample

    Science.gov (United States)

    Sibthorpe, B.; Kennedy, G. M.; Wyatt, M. C.; Lestrade, J.-F.; Greaves, J. S.; Matthews, B. C.; Duchêne, G.

    2018-04-01

    This paper presents a study of circumstellar debris around Sun-like stars using data from the Herschel DEBRIS Key Programme. DEBRIS is an unbiased survey comprising the nearest ˜90 stars of each spectral type A-M. Analysis of the 275 F-K stars shows that excess emission from a debris disc was detected around 47 stars, giving a detection rate of 17.1^{+2.6}_{-2.3} per cent, with lower rates for later spectral types. For each target a blackbody spectrum was fitted to the dust emission to determine its fractional luminosity and temperature. The derived underlying distribution of fractional luminosity versus blackbody radius in the population showed that most detected discs are concentrated at f ˜ 10-5 and at temperatures corresponding to blackbody radii 7-40 au, which scales to ˜40 au for realistic dust properties (similar to the current Kuiper belt). Two outlying populations are also evident; five stars have exceptionally bright emission ( f > 5 × 10-5), and one has unusually hot dust <4 au. The excess emission distributions at all wavelengths were fitted with a steady-state evolution model, showing that these are compatible with all stars being born with a narrow belt that then undergoes collisional grinding. However, the model cannot explain the hot dust systems - likely originating in transient events - and bright emission systems - arising potentially from atypically massive discs or recent stirring. The emission from the present-day Kuiper belt is predicted to be close to the median of the population, suggesting that half of stars have either depleted their Kuiper belts (similar to the Solar system) or had a lower planetesimal formation efficiency.

  20. The 3D Visualization of Slope Terrain in Sun Moon Lake.

    Science.gov (United States)

    Deng, F.; Gwo-shyn, S.; Pei-Kun, L.

    2015-12-01

    By doing topographical surveys in a reservoir, we can calculate siltation volume in the period of two measurements. It becomes basic requirement to provide more precise siltation value especially when the differential GPS positioning method and the multi-beams echo sounders have been prevailed; however, there are two problems making the result become challenging when doing the siltation-survey in reservoir. They are both relative with the difficulty in keeping survey accuracy to the area of side slope around the boundary of reservoir. Firstly, the efficiency or accuracy of horizontal positioning using the DGPS may decrease because of the satellite-blocking effect when the surveying ship nears the bank especially in the canyon type of reservoir. Secondly, measurement can only be acquired in the area covered by water using the echo sounder, such that the measuring data of side slope area above water surface are lack to decrease the accuracy or seriously affect the calculation of reservoir water volume. This research is to hold the terrain accuracy when measuring the reservoir side slope and the Sun Moon Lake Reservoir in central Taiwan is chosen as the experimental location. Sun Moon Lake is the most popular place for tourists in Taiwan and also the most important reservoir of the electricity facilities. Furthermore, it owns the biggest pumped-storage hydroelectricity in Asia. The water in the lake is self-contained, and its water supply has been input through two underground tunnels, such that a deposit fan is formed when the muds were settled down from the silty water of the Cho-Shui Shi. Three kinds of survey are conducted in this experiment. First, a close-range photogrammetry, around the border of the Sun Moon Lake is made, or it takes shoots along the bank using a camera linked with a computer running the software Pix4D. The result can provide the DTM data to the side slope above the water level. Second, the bathymetrical data can be obtained by sweeping the

  1. Long-Term Variability of the Sun in the Context of Solar-Analog Stars

    Science.gov (United States)

    Egeland, Ricky

    2018-06-01

    The Sun is the best observed object in astrophysics, but despite this distinction the nature of its well-ordered generation of magnetic field in 11-year activity cycles remains a mystery. In this work, we place the solar cycle in a broader context by examining the long-term variability of solar analog stars within 5% of the solar effective temperature, but varied in rotation rate and metallicity. Emission in the Fraunhofer H & K line cores from singly-ionized calcium in the lower chromosphere is due to magnetic heating, and is a proven proxy for magnetic flux on the Sun. We use Ca H & K observations from the Mount Wilson Observatory HK project, the Lowell Observatory Solar Stellar Spectrograph, and other sources to construct composite activity time series of over 100 years in length for the Sun and up to 50 years for 26 nearby solar analogs. Archival Ca H & K observations of reflected sunlight from the Moon using the Mount Wilson instrument allow us to properly calibrate the solar time series to the S-index scale used in stellar studies. We find the mean solar S-index to be 5–9% lower than previously estimated, and the amplitude of activity to be small compared to active stars in our sample. A detailed look at the young solar analog HD 30495, which rotates 2.3 times faster than the Sun, reveals a large amplitude ~12-year activity cycle and an intermittent short-period variation of 1.7 years, comparable to the solar variability time scales despite its faster rotation. Finally, time series analyses of the solar analog ensemble and a quantitative analysis of results from the literature indicate that truly Sun-like cyclic variability is rare, and that the amplitude of activity over both long and short timescales is linearly proportional to the mean activity. We conclude that the physical conditions conducive to a quasi-periodic magnetic activity cycle like the Sun’s are rare in stars of approximately the solar mass, and that the proper conditions may be restricted

  2. ASTROMETRIC JITTER OF THE SUN AS A STAR

    International Nuclear Information System (INIS)

    Makarov, V. V.; Parker, D.; Ulrich, R. K.

    2010-01-01

    The daily variation of the solar photocenter over some 11 yr is derived from the Mount Wilson data reprocessed by Ulrich et al. to closely match the surface distribution of solar irradiance. The standard deviations of astrometric jitter are 0.52 μAU and 0.39 μAU in the equatorial and the axial dimensions, respectively. The overall dispersion is strongly correlated with solar cycle, reaching 0.91 μAU at maximum activity in 2000. The largest short-term deviations from the running average (up to 2.6 μAU) occur when a group of large spots happen to lie on one side with respect to the center of the disk. The amplitude spectrum of the photocenter variations never exceeds 0.033 μAU for the range of periods 0.6-1.4 yr, corresponding to the orbital periods of planets in the habitable zone. Astrometric detection of Earth-like planets around stars as quiet as the Sun is not affected by star spot noise, but the prospects for more active stars may be limited to giant planets.

  3. ACTIVITY-BRIGHTNESS CORRELATIONS FOR THE SUN AND SUN-LIKE STARS

    International Nuclear Information System (INIS)

    Preminger, D. G.; Chapman, G. A.; Cookson, A. M.

    2011-01-01

    We analyze the effect of solar features on the variability of the solar irradiance in three different spectral ranges. Our study is based on two solar-cycles' worth of full-disk photometric images from the San Fernando Observatory, obtained with red, blue, and Ca II K-line filters. For each image we measure the photometric sum, Σ, which is the relative contribution of solar features to the disk-integrated intensity of the image. The photometric sums in the red and blue continuum, Σ r and Σ b , exhibit similar temporal patterns: they are negatively correlated with solar activity, with strong short-term variability, and weak solar-cycle variability. However, the Ca II K-line photometric sum, Σ K , is positively correlated with solar activity and has strong variations on solar-cycle timescales. We show that we can model the variability of the Sun's bolometric flux as a linear combination of Σ r and Σ K . We infer that, over solar-cycle timescales, the variability of the Sun's bolometric irradiance is directly correlated with spectral line variability, but inversely correlated with continuum variability. Our blue and red continuum filters are quite similar to the Stroemgren b and y filters used to measure stellar photometric variability. We conclude that active stars whose visible continuum brightness varies inversely with activity, as measured by the Ca HK index, are displaying a pattern that is similar to that of the Sun, i.e., radiative variability in the visible continuum that is spot-dominated.

  4. Detection to the DepositFan Occurring in the Sun Moon Lake Using Geophysical Sonar Data

    Science.gov (United States)

    Mimi, L.

    2014-12-01

    Located in central Taiwan, the Sun Moon Lake is an U-shaped basin with the waters capacity for 138.68 × 106m³. The water is input through two underground tunnels from the Wu-Jie dam in the upstream of the Zhuo-shui river. Although the Wu-Jie dam has been trying to keep the tunnels transporting clean water into the lake, the water is still mixed with muds. The silty water brings the deposits accumulating outwards from positions of the tunnel outlets resulting in a deposit fan formed in the lake. To monitor how the fan is accumulated is then very important in terms of environmental issue, tourism and electric power resources. Institute of Oceanography, National Taiwan University therefore conducted projects to use the multi-beam echo sounders to collect bathymetric data, and used the Chirp sub-bottom profiler to explore silted pattern inside the deposit fan. With these data, underwater topographic maps were plotted to observe the shape and internal structure of the fan. Moreover, two sets of data obtained in 2006 and 2012 were used to estimate the siltation magnitude and pattern in the six years period.The multi-beam sounder is Resons Seabat 9001s model; it collects 60 values in each of the swaths positioned by the DGPS method.The sub-bottom profiler is the EdgeTech 3100P Chirp Sonar, its acoustic wave frequency is in 2 ~ 16kHz. The data give the siltation amount in the Sun Moon Lake was around 3× 106 m³, which gives annual siltation rate at 5× 105 m³. The leading edge of the deposit fan has been expanded westwards 2 km from the water outlet since the tunnel was built 70 years ago; however, outside the deposit fan, the siltation shows insignificant amount on the water bottom.In the past few years the siltation mainly occurs outside in the east side of lake, more closer to the water outlets, the terrain had been increased from 744 m to 746 m (748.5 meters is stranded level of the lake).Observing sub-bottom profiler data, we can clearly see the location of the

  5. PEPSI deep spectra. I. The Sun-as-a-star

    Science.gov (United States)

    Strassmeier, K. G.; Ilyin, I.; Steffen, M.

    2018-04-01

    Context. Full-disk solar flux spectra can be directly compared to stellar spectra and thereby serve as our most important reference source for, for example stellar chemical abundances, magnetic activity phenomena, radial-velocity signatures or global pulsations. Aim. As part of the first Potsdam Echelle Polarimetric and Spectroscopic Instrument (PEPSI) key-science project, we aim to provide well-exposed and average-combined (viz. deep) high-resolution spectra of representative stellar targets. Such deep spectra contain an overwhelming amount of information, typically much more than what could be analyzed and discussed within a single publication. Therefore, these spectra will be made available in form of (electronic) atlases. The first star in this series of papers is our Sun. It also acts as a system-performance cornerstone. Methods: The Sun was monitored with PEPSI at the Large Binocular Telescope (LBT). Instead of the LBT we used a small robotic solar disk integration (SDI) telescope. The deep spectra in this paper are the results of combining up to ≈100 consecutive exposures per wavelength setting and are compared with other solar flux atlases. Results: Our software for the optimal data extraction and reduction of PEPSI spectra is described and verified with the solar data. Three deep solar flux spectra with a spectral resolution of up to 270 000, a continuous wavelength coverage from 383 nm to 914 nm, and a photon signal to noise ratio (S/N) of between 2000-8000:1 depending on wavelength are presented. Additionally, a time-series of 996 high-cadence spectra in one cross disperser is used to search for intrinsic solar modulations. The wavelength calibration based on Th-Ar exposures and simultaneous Fabry-Pérot combs enables an absolute wavelength solution within 10 m s-1 (rms) with respect to the HARPS laser-comb solar atlas and a relative rms of 1.2 m s-1 for one day. For science demonstration, we redetermined the disk-average solar Li abundance to 1.09

  6. Differential Rotation in Sun-like Stars from Surface Variability and Asteroseismology

    Science.gov (United States)

    Nielsen, Martin Bo

    2017-03-01

    The Sun and other stars are known to oscillate. Through the study of small perturbations to the frequencies of these oscillations the rotation of the deep interior can be inferred. However, thus far the internal rotation of other Sun-like stars is unknown. The NASA Kepler mission has observed a multitude of Sun-like stars over a period of four years. This has provided high-quality photometric data that can be used to study the rotation of stars with two different techniques: asteroseismology and surface activity. Asteroseismology provides a means of measuring rotation in the stellar interior, while photometric variability from magnetically active regions are sensitive to rotation at the stellar surface. The combination of these two methods can be used to constrain the radial differential rotation in Sun-like stars. First, we developed an automated method for measuring the rotation of stars using surface variability. This method was initially applied to the entire Kepler catalog, out of which we detected signatures of rotation in 12,000 stars across the main sequence, providing robust estimates of the surface rotation rates and the associated errors. Second, we performed an asteroseismic analysis of six Sun-like stars, where we were able to measure the rotational splitting as a function of frequency in the p-mode envelope. This was done by dividing the oscillation spectrum into individual segments, and fitting a model independently to each segment. We found that the measured splittings were all consistent with a constant value, indicating little differential rotation. Third, we compared the asteroseismic rotation rates of five Sun-like stars to their surface rotation rates. We found that the values were in good agreement, again indicating little differential rotation between the regions where the two methods are most sensitive. Finally, we discuss how the surface rotation rates may be used as a prior on the seismic envelope rotation rate in a double-zone model

  7. The First Focused Hard X-Ray Images of the Sun With NuSTAR

    DEFF Research Database (Denmark)

    Grefenstette, Brian W.; Glesener, Lindsay; Krucker, Sam

    2016-01-01

    We present results from the the first campaign of dedicated solar observations undertaken by the Nuclear Spectroscopic Telescope ARray (NuSTAR) hard X-ray (HXR) telescope. Designed as an astrophysics mission, NuSTAR nonetheless has the capability of directly imaging the Sun at HXR energies (>3 ke......V) with an increase in sensitivity of at least two magnitude compared to current non-focusing telescopes. In this paper we describe the scientific areas where NuSTAR will make major improvements on existing solar measurements. We report on the techniques used to observe the Sun with NuSTAR, their limitations......, and full-disk HXR images of the Sun....

  8. Students' annotated drawings of Sun, Moon and Earth mediating teachers' professional development

    DEFF Research Database (Denmark)

    Nielsen, Birgitte Lund

    A case study of a teacher examining her 4th graders’ conceptual understanding of factors causing day and night, seasons, and the phases of the Moon is presented. The teaching example and the data-collection are sourced from the Danish continuous professional development (CPD) project QUEST......-making model. The pre-teaching annotated drawings reveal several alternative conceptions, but based on the post-teaching drawings the teaching must be seen as rather efficient in most areas concerning challenging students’ alternative conceptions; however not in relation to the phases of the Moon. The teacher...

  9. Computer Programs for Sun and Moon Illuminance with Contingent Tables and Diagrams

    Science.gov (United States)

    1987-02-19

    data provided by the computer routines are also available from the tables and diagrams. Tables required for manual calculation of the Moon’s...8217 Winona MONTANA 104 45 Albion 110 45 Alpine 113 46 Anaconda 114 49 Apgar 104 46 Baker 110 48 Big Sandy 110 46 Big Timber 109 46 Billings 107

  10. Optimization method of star tracker orientation for sun-synchronous orbit based on space light distribution.

    Science.gov (United States)

    Wang, Geng; Xing, Fei; Wei, Minsong; Sun, Ting; You, Zheng

    2017-05-20

    Star trackers, optical attitude sensors with high precision, are susceptible to space light from the Sun and the Earth albedo. Until now, research in this field has lacked systematic analysis. In this paper, we propose an installation orientation method for a star tracker onboard sun-synchronous-orbit spacecraft and analyze the space light distribution by transforming the complicated relative motion among the Sun, Earth, and the satellite to the body coordinate system of the satellite. Meanwhile, the boundary-curve equations of the areas exposed to the stray light from the Sun and the Earth albedo were calculated by the coordinate-transformation matrix under different maneuver attitudes, and the installation orientation of the star tracker was optimized based on the boundary equations instead of the traditional iterative simulation method. The simulation and verification experiment indicate that this installation orientation method is effective and precise and can provide a reference for the installation of sun-synchronous orbit star trackers free from the stray light.

  11. Solar system a visual exploration of the planets, moons, and other heavenly bodies that orbit our sun

    CERN Document Server

    Chown, Marcus

    2011-01-01

    Based on the latest ebook sensation developed by Theodore Gray and his company Touch Press, this beautiful print book presents a new and fascinating way to experience the wonders of the solar system Following the stunning success of both the print edition and the app of The Elements, Black Dog & Leventhal and Touch Press have teamed up again. Solar System is something completely new under the sun. Never before have the wonders of our solar system—all its planets, dwarf planets, the sun, moons, rocky Asteroid Belt, and icy Kuiper Belt—been so immediately accessible to readers of all ages. Beginning with a fascinating overview and then organized by planet, in order of its distance from the sun, Solar System takes us on a trip across time and space that includes a front-row seat to the explosive birth of the solar system, a journey to (and then deep inside) each of its eight planets, and even an in-depth exploration of asteroids and comets. With hundreds of gorgeous images produced especially for this...

  12. Evolutionary status of stars with M> or approx. =50 M/sub sun/

    International Nuclear Information System (INIS)

    Tutukov, A.V.; Yungel'son, L.R.

    1980-01-01

    The observed masses and space velocities of main-sequence stars with M> or approx. =50 M/sub sun/ and of some of the brightest Wolf--Rayet stars (type WN 7/WN 8) are attributed to mass exchange and supernova explosions in close binary systems. Similar arguments suggest that blue supergiants intensively shedding mass may have an envelope in common with a compact, relativistic object

  13. Investigation of Preservice Science Teachers' Comprehension of the Star, Sun, Comet and Constellation Concepts

    Science.gov (United States)

    Cevik, Ebru Ezberci; Kurnaz, Mehmet Altan

    2017-01-01

    The purpose of this study is to reveal preservice science teachers' perceptions related to the sun, star, comet and constellation concepts. The research was carried out by 56 preservice science teachers (4th grade) at Kastamonu University taking astronomy course in 2014-2015 academic year. For data collection open-ended questions that required…

  14. "We Put on the Glasses and Moon Comes Closer!" Urban Second Graders Exploring the Earth, the Sun and Moon through 3D Technologies in a Science and Literacy Unit

    Science.gov (United States)

    Isik-Ercan, Zeynep; Zeynep Inan, Hatice; Nowak, Jeffrey A.; Kim, Beomjin

    2014-01-01

    This qualitative case study describes (a) the ways 3D visualization, coupled with other science and literacy experiences, supported young children's first exploration of the Earth-Sun-Moon system and (b) the perspectives of classroom teachers and children on using 3D visualization. We created three interactive 3D software modules that simulate day…

  15. Gravitational Waves from Stellar Black Hole Binaries and the Impact on Nearby Sun-like Stars

    Energy Technology Data Exchange (ETDEWEB)

    Lopes, Ilídio [Centro Multidisciplinar de Astrofísica, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais, 1049-001 Lisboa (Portugal); Silk, Joseph, E-mail: ilidio.lopes@tecnico.ulisboa.pt, E-mail: silk@astro.ox.ac.uk [Institut d’Astrophysique de Paris, UMR 7095 CNRS, Université Pierre et Marie Curie, 98 bis Boulevard Arago, Paris F-75014 (France)

    2017-07-20

    We investigate the impact of resonant gravitational waves on quadrupole acoustic modes of Sun-like stars located nearby stellar black hole binary systems (such as GW150914 and GW151226). We find that the stimulation of the low-overtone modes by gravitational radiation can lead to sizeable photometric amplitude variations, much larger than the predictions for amplitudes driven by turbulent convection, which in turn are consistent with the photometric amplitudes observed in most Sun-like stars. For accurate stellar evolution models, using up-to-date stellar physics, we predict photometric amplitude variations of 1–10{sup 3} ppm for a solar mass star located at a distance between 1 au and 10 au from the black hole binary and belonging to the same multi-star system. The observation of such a phenomenon will be within the reach of the Plato mission because the telescope will observe several portions of the Milky Way, many of which are regions of high stellar density with a substantial mixed population of Sun-like stars and black hole binaries.

  16. Global helioseismology (WP4.1): From the Sun to the stars & solar analogs

    Science.gov (United States)

    García, Rafael A.

    2017-10-01

    Sun-as-a star observations put our star as a reference for stellar observations. Here, I review the activities in which the SPACEINN global seismology team (Working Package WP4.1) has worked during the past 3 years. In particular, we will explain the new deliverables available on the SPACEINN seismic+ portal. Moreover, special attention will be given to surface dynamics (rotation and magnetic fields). After characterizing the rotation and the magnetic properties of around 300 solar-like stars and defining proper metrics for that, we use their seismic properties to characterize 18 solar analogues for which we study their surface magnetic and seismic properties. This allows us to put the Sun into context compared to its siblings.

  17. Global helioseismology (WP4.1: From the Sun to the stars & solar analogs

    Directory of Open Access Journals (Sweden)

    García Rafael A.

    2017-01-01

    Full Text Available Sun-as-a star observations put our star as a reference for stellar observations. Here, I review the activities in which the SPACEINN global seismology team (Working Package WP4.1 has worked during the past 3 years. In particular, we will explain the new deliverables available on the SPACEINN seismic+ portal. Moreover, special attention will be given to surface dynamics (rotation and magnetic fields. After characterizing the rotation and the magnetic properties of around 300 solar-like stars and defining proper metrics for that, we use their seismic properties to characterize 18 solar analogues for which we study their surface magnetic and seismic properties. This allows us to put the Sun into context compared to its siblings.

  18. First NuSTAR Limits on Quiet Sun Hard X-Ray Transient Events

    DEFF Research Database (Denmark)

    Marsh, Andrew J.; Smith, David M.; Glesener, Lindsay

    2017-01-01

    We present the first results of a search for transient hard X-ray (HXR) emission in the quiet solar corona with the Nuclear Spectroscopic Telescope Array (NuSTAR) satellite. While NuSTAR was designed as an astrophysics mission, it can observe the Sun above 2 keV with unprecedented sensitivity due...... to its pioneering use of focusing optics. NuSTAR first observed quiet-Sun regions on 2014 November 1, although out-of-view active regions contributed a notable amount of background in the form of single-bounce (unfocused) X-rays. We conducted a search for quiet-Sun transient brightenings on timescales...... as model-independent photon fluxes. The limits in both bands are well below previous HXR microflare detections, though not low enough to detect events of equivalent T and EM as quiet-Sun brightenings seen in soft X-ray observations. We expect future observations during solar minimum to increase the Nu...

  19. THE FIRST FOCUSED HARD X-RAY IMAGES OF THE SUN WITH NuSTAR

    Energy Technology Data Exchange (ETDEWEB)

    Grefenstette, Brian W.; Madsen, Kristin K.; Forster, Karl; Harrison, Fiona A. [Cahill Center for Astrophysics, 1216 E. California Blvd, California Institute of Technology, Pasadena, CA 91125 (United States); Glesener, Lindsay [School of Physics and Astronomy, University of Minnesota—Twin Cities, Minneapolis, MN 55455 (United States); Krucker, Säm; Hudson, Hugh; Boggs, Steven E.; Craig, William W. [Space Sciences Laboratory, University of California, Berkeley, CA 94720 (United States); Hannah, Iain G. [SUPA School of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ (United Kingdom); Smith, David M.; Marsh, Andrew J. [Physics Department and Santa Cruz Institute for Particle Physics, University of California, Santa Cruz, 1156 High Street, Santa Cruz, CA 95064 (United States); Vogel, Julia K. [Physics Division, Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, CA 94550 (United States); White, Stephen M. [Air Force Research Laboratory, Albuquerque, NM (United States); Caspi, Amir [Southwest Research Institute, Boulder, CO 80302 (United States); Chen, Bin [Harvard-Smithsonian Center for Astrophysics, Cambridge, MA 02138 (United States); Shih, Albert [Solar Physics Laboratory, NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Kuhar, Matej [University of Applied Sciences and Arts Northwestern Switzerland, CH-5210 Windisch (Switzerland); Christensen, Finn E. [DTU Space, National Space Institute, Technical University of Denmark, Elektrovej 327, DK-2800 Lyngby (Denmark); Hailey, Charles J., E-mail: bwgref@srl.caltech.edu [Columbia Astrophysics Laboratory, Columbia University, New York, NY 10027 (United States); and others

    2016-07-20

    We present results from the the first campaign of dedicated solar observations undertaken by the Nuclear Spectroscopic Telescope ARray ( NuSTAR ) hard X-ray (HXR) telescope. Designed as an astrophysics mission, NuSTAR nonetheless has the capability of directly imaging the Sun at HXR energies (>3 keV) with an increase in sensitivity of at least two magnitude compared to current non-focusing telescopes. In this paper we describe the scientific areas where NuSTAR will make major improvements on existing solar measurements. We report on the techniques used to observe the Sun with NuSTAR , their limitations and complications, and the procedures developed to optimize solar data quality derived from our experience with the initial solar observations. These first observations are briefly described, including the measurement of the Fe K-shell lines in a decaying X-class flare, HXR emission from high in the solar corona, and full-disk HXR images of the Sun.

  20. The First Focused Hard X-Ray Images of the Sun with NuSTAR

    Science.gov (United States)

    Grefenstette, Brian W.; Glesener, Lindsay; Kruckner, Sam; Hudson, Hugh; Hannah, Iain G.; Smith, David M.; Vogel, Julia K.; White, Stephen M.; Madsen, Kristin K.; Marsh, Andrew J.; hide

    2016-01-01

    We present results from the first campaign of dedicated solar observations undertaken by the Nuclear Spectroscopic Telescope ARray (NuSTAR) hard X-ray (HXR) telescope. Designed as an astrophysics mission, NuSTAR nonetheless has the capability of directly imaging the Sun at HXR energies (3 keV) with an increase in sensitivity of at least two magnitude compared to current non-focusing telescopes. In this paper we describe the scientific areas where NuSTAR will make major improvements on existing solar measurements. We report on the techniques used to observe the Sun with NuSTAR, their limitations and complications, and the procedures developed to optimize solar data quality derived from our experience with the initial solar observations. These first observations are briefly described, including the measurement of the Fe K-shell lines in a decaying X-class flare, HXR emission from high in the solar corona, and full-disk HXR images of the Sun.

  1. THE MASS-DEPENDENCE OF ANGULAR MOMENTUM EVOLUTION IN SUN-LIKE STARS

    International Nuclear Information System (INIS)

    Matt, Sean P.; Baraffe, Isabelle; Chabrier, Gilles; Brun, A. Sacha; Bouvier, Jérôme

    2015-01-01

    To better understand the observed distributions of the rotation rate and magnetic activity of Sun-like and low-mass stars, we derive a physically motivated scaling for the dependence of the stellar wind torque on the Rossby number. The torque also contains an empirically derived scaling with stellar mass (and radius), which provides new insight into the mass-dependence of stellar magnetic and wind properties. We demonstrate that this new formulation explains why the lowest mass stars are observed to maintain rapid rotation for much longer than solar-mass stars, and simultaneously why older populations exhibit a sequence of slowly rotating stars, in which the low-mass stars rotate more slowly than solar-mass stars. The model also reproduces some previously unexplained features in the period-mass diagram for the Kepler field, notably: the particular shape of the ''upper envelope'' of the distribution, suggesting that ∼95% of Kepler field stars with measured rotation periods are younger than ∼4 Gyr; and the shape of the ''lower envelope'', corresponding to the location where stars transition between magnetically saturated and unsaturated regimes

  2. THE OCCURRENCE RATE OF EARTH ANALOG PLANETS ORBITING SUN-LIKE STARS

    International Nuclear Information System (INIS)

    Catanzarite, Joseph; Shao, Michael

    2011-01-01

    Kepler is a space telescope that searches Sun-like stars for planets. Its major goal is to determine η Earth , the fraction of Sun-like stars that have planets like Earth. When a planet 'transits' or moves in front of a star, Kepler can measure the concomitant dimming of the starlight. From analysis of the first four months of those measurements for over 150,000 stars, Kepler's Science Team has determined sizes, surface temperatures, orbit sizes, and periods for over a thousand new planet candidates. In this paper, we characterize the period probability distribution function of the super-Earth and Neptune planet candidates with periods up to 132 days, and find three distinct period regimes. For candidates with periods below 3 days, the density increases sharply with increasing period; for periods between 3 and 30 days, the density rises more gradually with increasing period, and for periods longer than 30 days, the density drops gradually with increasing period. We estimate that 1%-3% of stars like the Sun are expected to have Earth analog planets, based on the Kepler data release of 2011 February. This estimate of η Earth is based on extrapolation from a fiducial subsample of the Kepler planet candidates that we chose to be nominally 'complete' (i.e., no missed detections) to the realm of the Earth-like planets, by means of simple power-law models. The accuracy of the extrapolation will improve as more data from the Kepler mission are folded in. Accurate knowledge of η Earth is essential for the planning of future missions that will image and take spectra of Earth-like planets. Our result that Earths are relatively scarce means that a substantial effort will be needed to identify suitable target stars prior to these future missions.

  3. Student Mastery of the Sun-Earth-Moon System in a Flipped Classroom of Pre-service Elementary Education Students

    Science.gov (United States)

    Larsen, Kristine

    2014-01-01

    One of the current trends in pedagogy at all levels(K-college) is the so-called ‘flipped classroom’, in which students prepare for a class meeting through self-study of the material. It is based on a rejection of the classic model of the faculty member as the ‘sage on the stage’ instead, responsibility for learning shifts to the individual student. The faculty member takes on the role of learning facilitator or mentor, and focuses the students’ learning by crafting and administering timely formative assessments (in multiple formats and applied multiple times) that aid both students and the faculty member in tracking the students’ mastery of the learning outcomes. In a flipped, freshman-only, section of SCI 111 Elementary Earth-Physical Sciences (a required introductory science course for pre-service elementary school teachers) the students learned through a combination of individual and group hands-on in-class activities, technology (including PowerPoint presentations and short videos viewed prior to attending class), in-class worksheets, and in-class discussions. Students self-differentiated in how they interacted with the available teaching materials, deciding which activities to spend the most time on based on their individual needs (based on an online quiz taken the night before the class period, and their personal self-confidence with the material). Available in-class activities and worksheets were developed by the faculty member based on student scores on the online quiz as well as personal messages submitted through the course management system the night before the class meeting. While this placed a significant burden on the faculty member in terms of course preparation, it allowed for just-in-time teaching to take place. This poster describes the results of student mastery of content centered on the sun-earth-moon system (specifically seasons, moon phases, and eclipses) as compared to traditional classroom sections.

  4. Gravitational Effects on Plasma Waves in Environment of Sun and Neutron Star

    International Nuclear Information System (INIS)

    Lu Quankang; Hsiao-Ling Zhou

    2014-01-01

    Local plasma phenomena in environment of Sun are observed closely by spacecrafts in recent years. We provide a new method to apply general relativity to astro-plasma physics in small local area. The relativistic dispersion relations of Langmuir, electromagnetic and cyclotron waves are obtained. The red shifts of Langmuir and cyclotron frequencies are given analytically. A new equilibrium velocity distribution of particles soaked in local gravitational field is suggested. The gravitational effect of a neutron star is also estimated

  5. From the sun to the Galactic Center: dust, stars and black hole(s)

    Science.gov (United States)

    Fritz, Tobias

    2013-07-01

    collision of stars in a dense young st! ar cluster. Such a cluster could sink to the GC by dynamical friction. There it would consist of few bright stars like IRS13E. Firstly, I analyze the SEDs of the objects in IRS13E. The SEDs of most objects can be explained by pure dust emission. Thus, most objects in IRS13E are pure dust clumps and only three young stars. This reduces the significance of the 'cluster' IRS13E compared to the stellar background. Secondly, I obtain acceleration limits for these three stars. The non-detection of accelerations makes an IMBH an unlikely scenario in IRS13E. However, since its three stars form a comoving association, which is unlikely to form by chance, the nature of IRS13E is not yet settled. In the third study (Chapter 4) I measure and analyze the extinction curve toward the GC. The extinction is a contaminant for GC observations and therefore it is necessary to know the extinction toward the GC to determine the luminosity properties of its stars. I obtain the extinction curve by measuring the flux of the HII region in the GC in several infrared HII lines and in the unextincted radio continuum. I compare these ratios with the ratios expected from recombination physics and obtain extinctions at 22 different lines between 1 and 19 micron. For the K-band I derive A_Ks=2.62+/-0.11. The extinction curve follows a power law with a steep slope of -2.11+/-0.06 shortward of 2.8 micron. At longer wavelengths the extinction is grayer and there are absorption features from ices. The extinction curve is a tool to constrain the properties of cosmic dust between the sun and the GC. The extinction curve cannot be explained by dust grains consisting of carbonaceous and silicate grains only. In addition composite particles, which also contain ices are necessary to fit the extinction curve. In the final part of this thesis (Chapter 5) I look at the properties of most of the stars in the GC. These are the old stars that form the nuclear cluster of the Milky

  6. Rotational studies of late-type stars. II. Ages of solar-type stars and the rotational history of the sun

    International Nuclear Information System (INIS)

    Soderblom, D.R.

    1983-01-01

    In the first part of this investigation, age indicators for solar-type stars are discussed. A Li abundance-age calibration is derived; it indicates that 1 M/sub sun/ stars have lost as much as 80% of their initial Li before reaching the main sequence. The e-folding time for Li depletion on the main sequence is 1 1/4 Gyr. The distribution of Li abundances for 1 M/sub sun/ stars is consistent with a uniform initial Li abundance for all stars

  7. ultra-Stable Spectrometer for Sky-Scanning, Sun-Tracking Atmospheric Research (5STAR)

    Science.gov (United States)

    Dunagan, S. E.; Johnson, R. R.; Redemann, J.; Holben, B. N.; Schmid, B.; Flynn, C. J.; Fahey, L.; LeBlanc, S. E.; Liss, J.; Kacenelenbogen, M. S.; Segal-Rosenhaimer, M.; Shinozuka, Y.; Dahlgren, R. P.; Pistone, K.; Karol, Y.

    2017-12-01

    The Spectrometer for Sky-Scanning, Sun-Tracking Atmospheric Research (4STAR) combines airborne sun tracking and sky scanning with diffraction spectroscopy to improve knowledge of atmospheric constituents and their links to air pollution and climate. Direct beam hyperspectral measurement of optical depth improves retrievals of gas constituents and determination of aerosol properties. Sky scanning enhances retrievals of aerosol type and size distribution. Hyperspectral cloud-transmitted radiance measurements enable the retrieval of cloud properties from below clouds. These measurements tighten the closure between satellite and ground-based measurements. 4STAR incorporates a modular sun-tracking/ sky-scanning optical head with optical fiber signal transmission to rack mounted spectrometers, permitting miniaturization of the external optical tracking head, and future detector evolution. 4STAR has supported a broad range of flight experiments since it was first flown in 2010. This experience provides the basis for a series of improvements directed toward reducing measurement uncertainty and calibration complexity, and expanding future measurement capabilities, to be incorporated into a new 5STAR instrument. A 9-channel photodiode radiometer with AERONET-matched bandpass filters will be incorporated to improve calibration stability. A wide dynamic range tracking camera will provide a high precision solar position tracking signal as well as an image of sky conditions around the solar axis. An ultrasonic window cleaning system design will be tested. A UV spectrometer tailored for formaldehyde and SO2 gas retrievals will be added to the spectrometer enclosure. Finally, expansion capability for a 4 channel polarized radiometer to measure the Stokes polarization vector of sky light will be incorporated. This paper presents initial progress on this next-generation 5STAR instrument. Keywords: atmosphere; climate; pollution; radiometry; technology; hyperspectral; fiber optic

  8. RETIRED A STARS AND THEIR COMPANIONS. III. COMPARING THE MASS-PERIOD DISTRIBUTIONS OF PLANETS AROUND A-TYPE STARS AND SUN-LIKE STARS

    International Nuclear Information System (INIS)

    Bowler, Brendan P.; Johnson, John Asher; Liu, Michael C.; Marcy, Geoffrey W.; Peek, Kathryn M. G.; Henry, Gregory W.; Fischer, Debra A.; Clubb, Kelsey I.; Reffert, Sabine; Schwab, Christian; Lowe, Thomas B.

    2010-01-01

    We present an analysis of ∼5 years of Lick Observatory radial velocity measurements targeting a uniform sample of 31 intermediate-mass (IM) subgiants (1.5 ∼ * /M sun ∼ +9 -8 %, which is significantly higher than the 5%-10% frequency observed around solar-mass stars. The median detection threshold for our sample includes minimum masses down to {0.2, 0.3, 0.5, 0.6, 1.3} M Jup within {0.1, 0.3, 0.6, 1.0, 3.0} AU. To compare the properties of planets around IM stars to those around solar-mass stars we synthesize a population of planets based on the parametric relationship dN ∝ M α P β dlnMdlnP, the observed planet frequency, and the detection limits we derived. We find that the values of α and β for planets around solar-type stars from Cumming et al. fail to reproduce the observed properties of planets in our sample at the 4σ level, even when accounting for the different planet occurrence rates. Thus, the properties of planets around A stars are markedly different than those around Sun-like stars, suggesting that only a small (∼50%) increase in stellar mass has a large influence on the formation and orbital evolution of planets.

  9. Retired A Stars and Their Companions. III. Comparing the Mass-Period Distributions of Planets Around A-Type Stars and Sun-Like Stars

    Science.gov (United States)

    Bowler, Brendan P.; Johnson, John Asher; Marcy, Geoffrey W.; Henry, Gregory W.; Peek, Kathryn M. G.; Fischer, Debra A.; Clubb, Kelsey I.; Liu, Michael C.; Reffert, Sabine; Schwab, Christian; Lowe, Thomas B.

    2010-01-01

    We present an analysis of ~5 years of Lick Observatory radial velocity measurements targeting a uniform sample of 31 intermediate-mass (IM) subgiants (1.5 lsim M */M sunlsim 2.0) with the goal of measuring the occurrence rate of Jovian planets around (evolved) A-type stars and comparing the distributions of their orbital and physical characteristics to those of planets around Sun-like stars. We provide updated orbital solutions incorporating new radial velocity measurements for five known planet-hosting stars in our sample; uncertainties in the fitted parameters are assessed using a Markov-Chain Monte Carlo method. The frequency of Jovian planets interior to 3 AU is 26+9 -8%, which is significantly higher than the 5%-10% frequency observed around solar-mass stars. The median detection threshold for our sample includes minimum masses down to {0.2, 0.3, 0.5, 0.6, 1.3} M Jup within {0.1, 0.3, 0.6, 1.0, 3.0} AU. To compare the properties of planets around IM stars to those around solar-mass stars we synthesize a population of planets based on the parametric relationship dN vprop M α P β dlnMdlnP, the observed planet frequency, and the detection limits we derived. We find that the values of α and β for planets around solar-type stars from Cumming et al. fail to reproduce the observed properties of planets in our sample at the 4σ level, even when accounting for the different planet occurrence rates. Thus, the properties of planets around A stars are markedly different than those around Sun-like stars, suggesting that only a small (~50%) increase in stellar mass has a large influence on the formation and orbital evolution of planets. Based on observations obtained at the Lick Observatory, which is operated by the University of California.

  10. OBSERVATIONS OF INTENSITY FLUCTUATIONS ATTRIBUTED TO GRANULATION AND FACULAE ON SUN-LIKE STARS FROM THE KEPLER MISSION

    Energy Technology Data Exchange (ETDEWEB)

    Karoff, C. [Stellar Astrophysics Centre, Department of Physics and Astronomy, Aarhus University, Ny Munkegade 120, DK-8000 Aarhus C (Denmark); Campante, T. L. [Centro de Astrofisica and Faculdade de Ciencias, Universidade do Porto, Rua das Estrelas, 4150-762 Porto (Portugal); Ballot, J. [CNRS, Institut de Recherche en Astrophysique et Planetologie, 14 avenue Edouard Belin, F-31400, Toulouse (France); Kallinger, T. [Instituut voor Sterrenkunde, K. U. Leuven, Celestijnenlaan 200D, B-3001 Leuven (Belgium); Gruberbauer, M. [Institute for Computational Astrophysics, Department of Astronomy and Physics, Saint Mary' s University, B3H 3C3 Halifax (Canada); Garcia, R. A. [Laboratoire AIM, CEA/DSM-CNRS-Universit Paris Diderot, IRFU/SAp, Centre de Saclay, F-91191 Gif-sur-Yvette Cedex (France); Caldwell, D. A.; Christiansen, J. L. [SETI Institute/NASA Ames Research Center, Moffett Field, CA 94035 (United States); Kinemuchi, K., E-mail: karoff@phys.au.dk [Bay Area Environmental Research Inst./NASA Ames Research Center, Moffett Field, CA 94035 (United States)

    2013-04-10

    Sun-like stars show intensity fluctuations on a number of timescales due to various physical phenomena on their surfaces. These phenomena can convincingly be studied in the frequency spectra of these stars-while the strongest signatures usually originate from spots, granulation, and p-mode oscillations, it has also been suggested that the frequency spectrum of the Sun contains a signature of faculae. We have analyzed three stars observed for 13 months in short cadence (58.84 s sampling) by the Kepler mission. The frequency spectra of all three stars, as for the Sun, contain signatures that we can attribute to granulation, faculae, and p-mode oscillations. The temporal variability of the signatures attributed to granulation, faculae, and p-mode oscillations was analyzed and the analysis indicates a periodic variability in the granulation and faculae signatures-comparable to what is seen in the Sun.

  11. Prevalence of Earth-size planets orbiting Sun-like stars.

    Science.gov (United States)

    Petigura, Erik A; Howard, Andrew W; Marcy, Geoffrey W

    2013-11-26

    Determining whether Earth-like planets are common or rare looms as a touchstone in the question of life in the universe. We searched for Earth-size planets that cross in front of their host stars by examining the brightness measurements of 42,000 stars from National Aeronautics and Space Administration's Kepler mission. We found 603 planets, including 10 that are Earth size ( ) and receive comparable levels of stellar energy to that of Earth (1 - 2 R[Symbol: see text] ). We account for Kepler's imperfect detectability of such planets by injecting synthetic planet-caused dimmings into the Kepler brightness measurements and recording the fraction detected. We find that 11 ± 4% of Sun-like stars harbor an Earth-size planet receiving between one and four times the stellar intensity as Earth. We also find that the occurrence of Earth-size planets is constant with increasing orbital period (P), within equal intervals of logP up to ~200 d. Extrapolating, one finds 5.7(-2.2)(+1.7)% of Sun-like stars harbor an Earth-size planet with orbital periods of 200-400 d.

  12. OBSERVATIONS OF INTENSITY FLUCTUATIONS ATTRIBUTED TO GRANULATION AND FACULAE ON SUN-LIKE STARS FROM THE KEPLER MISSION

    International Nuclear Information System (INIS)

    Karoff, C.; Campante, T. L.; Ballot, J.; Kallinger, T.; Gruberbauer, M.; García, R. A.; Caldwell, D. A.; Christiansen, J. L.; Kinemuchi, K.

    2013-01-01

    Sun-like stars show intensity fluctuations on a number of timescales due to various physical phenomena on their surfaces. These phenomena can convincingly be studied in the frequency spectra of these stars—while the strongest signatures usually originate from spots, granulation, and p-mode oscillations, it has also been suggested that the frequency spectrum of the Sun contains a signature of faculae. We have analyzed three stars observed for 13 months in short cadence (58.84 s sampling) by the Kepler mission. The frequency spectra of all three stars, as for the Sun, contain signatures that we can attribute to granulation, faculae, and p-mode oscillations. The temporal variability of the signatures attributed to granulation, faculae, and p-mode oscillations was analyzed and the analysis indicates a periodic variability in the granulation and faculae signatures—comparable to what is seen in the Sun.

  13. Optical Polarization of 1000 Stars Within 50-PARSECS from the Sun

    Science.gov (United States)

    Leroy, J. L.

    1993-11-01

    We have prepared a catalogue of optical polarization measurements for 1000 stars closer than 50 parsecs from the Sun. The distances, which are presently those given in the Sky Catalogue 2000.0, 2nd edition (Hirshfeld et al. 1991) are provisional: they will be replaced later by the much safer parallaxes which will result from the Hipparcos mission. The polarization data have been compiled, for 60% in various catalogues with due care to their accuracy for 40% they are new, unpublished, measurements obtained at Pic du Midi Observatory. We expect that this new data base will allow a better understanding of the interstellar medium around the Sun; the analysis, similar to the beautiful work by Tinbergen (1982), is to be found in a companion paper.

  14. THE DIFFERENT EVOLUTION OF GAS AND DUST IN DISKS AROUND SUN-LIKE AND COOL STARS

    International Nuclear Information System (INIS)

    Pascucci, I.; Apai, D.; Luhman, K.; Henning, Th.; Bouwman, J.; Meyer, M. R.; Lahuis, F.; Natta, A.

    2009-01-01

    Planet formation is profoundly impacted by the properties of protoplanetary disks and their central star. However, how disk properties vary with stellar parameters remains poorly known. Here, we present the first comprehensive, comparative Spitzer/IRS study of the dust and gas properties of disks around young Sun-like stars (K1-M5) and cool stars/brown dwarfs (M5-M9). The comparison of these two large samples of over 60 sources reveal major differences in the evolution of both the dust and gas components. We report the first detection of organic molecules in disks around brown dwarfs. The detection rate statistics and the line flux ratios of HCN and C 2 H 2 show a striking difference between the two samples, demonstrating a significant underabundance of HCN relative to C 2 H 2 in the disk surface of cool stars. We propose this to originate from the large difference in the UV irradiation around the two types of sources. The statistical comparison of the 10 μm silicate emission features also reveals a difference between the two samples. Cool stars and brown dwarfs show weaker features arising from more processed silicate grains in the disk atmosphere. These findings complement previous indications of flatter disk structures and longer disk lifetimes around cool stars. Our results highlight important differences in the chemical and physical evolution of protoplanetary disks as a function of stellar mass, temperature, and radiation field which should be taken into account in planet formation models. We note that the different chemistry of preplanetary materials in the disk may also influence the bulk composition and volatile content of the forming planets. In particular, if exogenous HCN has played a key role in the synthesis of prebiotic molecules on Earth as proposed, then prebiotic chemistry may unfold differently on planets around cool stars.

  15. News and Views: Kleopatra a pile of rubble, shedding moons; Did plasma flow falter to stretch solar minimum? Amateurs hit 20 million variable-star observations; Climate maths; Planetary priorities; New roles in BGA

    Science.gov (United States)

    2011-04-01

    Metallic asteroid 216 Kleopatra is shaped like a dog's bone and has two tiny moons - which came from the asteroid itself - according to a team of astronomers from France and the US, who also measured its surprisingly low density and concluded that it is a collection of rubble. The recent solar minimum was longer and lower than expected, with a low polar field and an unusually large number of days with no sunspots visible. Models of the magnetic field and plasma flow within the Sun suggest that fast, then slow meridional flow could account for this pattern. Variable stars are a significant scientific target for amateur astronomers. The American Association of Variable Star Observers runs the world's largest database of variable star observations, from volunteers, and reached 20 million observations in February.

  16. DISCOVERY OF THE COLDEST IMAGED COMPANION OF A SUN-LIKE STAR

    International Nuclear Information System (INIS)

    Thalmann, C.; Carson, J.; Goto, M.; Feldt, M.; Henning, T.; Klahr, H.; Mordasini, C.; Janson, M.; McElwain, M.; Egner, S.; Hayano, Y.; Suzuki, R.; Hashimoto, J.; Kandori, R.; Kudo, T.; Kusakabe, N.; Morino, J.-I.; Suto, H.; Tamura, M.; Hodapp, K. W.

    2009-01-01

    We present the discovery of a brown dwarf or possible planet at a projected separation of 1.''9 = 29 AU around the star GJ 758, placing it between the separations at which substellar companions are expected to form by core accretion (∼5 AU) or direct gravitational collapse (typically ∼>100 AU). The object was detected by direct imaging of its thermal glow with Subaru/HiCIAO. At 10-40 times the mass of Jupiter and a temperature of 550-640 K, GJ 758 B constitutes one of the few known T-type companions, and the coldest ever to be imaged in thermal light around a Sun-like star. Its orbit is likely eccentric and of a size comparable to Pluto's orbit, possibly as a result of gravitational scattering or outward migration. A candidate second companion is detected at 1.''2 at one epoch.

  17. Brightness Variations of Sun-like Stars: The Mystery Deepens - Astronomers facing Socratic "ignorance"

    Science.gov (United States)

    2009-12-01

    An extensive study made with ESO's Very Large Telescope deepens a long-standing mystery in the study of stars similar to the Sun. Unusual year-long variations in the brightness of about one third of all Sun-like stars during the latter stages of their lives still remain unexplained. Over the past few decades, astronomers have offered many possible explanations, but the new, painstaking observations contradict them all and only deepen the mystery. The search for a suitable interpretation is on. "Astronomers are left in the dark, and for once, we do not enjoy it," says Christine Nicholls from Mount Stromlo Observatory, Australia, lead author of a paper reporting the study. "We have obtained the most comprehensive set of observations to date for this class of Sun-like stars, and they clearly show that all the possible explanations for their unusual behaviour just fail." The mystery investigated by the team dates back to the 1930s and affects about a third of Sun-like stars in our Milky Way and other galaxies. All stars with masses similar to our Sun become, towards the end of their lives, red, cool and extremely large, just before retiring as white dwarfs. Also known as red giants, these elderly stars exhibit very strong periodic variations in their luminosity over timescales up to a couple of years. "Such variations are thought to be caused by what we call 'stellar pulsations'," says Nicholls. "Roughly speaking, the giant star swells and shrinks, becoming brighter and dimmer in a regular pattern. However, one third of these stars show an unexplained additional periodic variation, on even longer timescales - up to five years." In order to find out the origin of this secondary feature, the astronomers monitored 58 stars in our galactic neighbour, the Large Magellanic Cloud, over two and a half years. They acquired spectra using the high resolution FLAMES/GIRAFFE spectrograph on ESO's Very Large Telescope and combined them with images from other telescopes [1

  18. The Stability of Tidal Equilibrium for Hierarchical Star-Planet-Moon Systems

    Science.gov (United States)

    Adams, Fred C.

    2018-04-01

    Motivated by the current search for exomoons, this talk considers the stability of tidal equilibrium for hierarchical three-body systems containing a star, a planet, and a moon. In this treatment, the energy and angular momentum budgets include contributions from the planetary orbit, lunar orbit, stellar spin, planetary spin, and lunar spin. The goal is to determine the optimized energy state of the system subject to the constraint of constant angular momentum. Due to the lack of a closed form solution for the full three-body problem, however, we must use use an approximate description of the orbits. We first consider the Keplerian limit and find that the critical energy states are saddle points, rather than minima, so that these hierarchical systems have no stable tidal equilibrium states. We then generalize the calculation so that the lunar orbit is described by a time-averaged version of the circular restricted three-body problem. In this latter case, the critical energy state is a shallow minimum, so that a tidal equilibrium state exists. In both cases, however, the lunar orbit for the critical point lies outside the boundary (roughly half the Hill radius) where (previous) numerical simulations indicate dynamical instability.

  19. Family of the Sun-and-Stars Time-Determining Instruments (Ilseong-jeongsi-ui) Invented During the Joseon Dynasty

    OpenAIRE

    Yong Sam Lee; Sang Hyuk Kim; Byeong-Hee Mihn

    2016-01-01

    We analyze the design and specifications of the Sun-and-Stars Time-Determining group of instruments (Ilseong-jeongsi-ui, 日星定時儀) made during the Joseon dynasty. According to the records of the Sejong Sillok (Veritable Records of King Sejong), Sun-and-Stars Time-Determining Instruments measure the solar time of day and the sidereal time of night through three rings and an alidade. One such instrument, the Simplified Time-Determining Instrument (So-jeongsi-ui, 小定時儀), is made without ...

  20. Occurrence and core-envelope structure of 1-4x Earth-size planets around Sun-like stars

    OpenAIRE

    Marcy, Geoffrey W.; Weiss, Lauren M.; Petigura, Erik A.; Isaacson, Howard; Howard, Andrew W.; Buchhave, Lars A.

    2014-01-01

    Small planets, 1-4x the size of Earth, are extremely common around Sun-like stars, and surprisingly so, as they are missing in our solar system. Recent detections have yielded enough information about this class of exoplanets to begin characterizing their occurrence rates, orbits, masses, densities, and internal structures. The Kepler mission finds the smallest planets to be most common, as 26% of Sun-like stars have small, 1-2 R_e planets with orbital periods under 100 days, and 11% have 1-2...

  1. Richest Planetary System Discovered - Up to seven planets orbiting a Sun-like star

    Science.gov (United States)

    2010-08-01

    Astronomers using ESO's world-leading HARPS instrument have discovered a planetary system containing at least five planets, orbiting the Sun-like star HD 10180. The researchers also have tantalising evidence that two other planets may be present, one of which would have the lowest mass ever found. This would make the system similar to our Solar System in terms of the number of planets (seven as compared to the Solar System's eight planets). Furthermore, the team also found evidence that the distances of the planets from their star follow a regular pattern, as also seen in our Solar System. "We have found what is most likely the system with the most planets yet discovered," says Christophe Lovis, lead author of the paper reporting the result. "This remarkable discovery also highlights the fact that we are now entering a new era in exoplanet research: the study of complex planetary systems and not just of individual planets. Studies of planetary motions in the new system reveal complex gravitational interactions between the planets and give us insights into the long-term evolution of the system." The team of astronomers used the HARPS spectrograph, attached to ESO's 3.6-metre telescope at La Silla, Chile, for a six-year-long study of the Sun-like star HD 10180, located 127 light-years away in the southern constellation of Hydrus (the Male Water Snake). HARPS is an instrument with unrivalled measurement stability and great precision and is the world's most successful exoplanet hunter. Thanks to the 190 individual HARPS measurements, the astronomers detected the tiny back and forth motions of the star caused by the complex gravitational attractions from five or more planets. The five strongest signals correspond to planets with Neptune-like masses - between 13 and 25 Earth masses [1] - which orbit the star with periods ranging from about 6 to 600 days. These planets are located between 0.06 and 1.4 times the Earth-Sun distance from their central star. "We also have

  2. NuSTAR Detection of X-Ray Heating Events in the Quiet Sun

    Science.gov (United States)

    Kuhar, Matej; Krucker, Säm; Glesener, Lindsay; Hannah, Iain G.; Grefenstette, Brian W.; Smith, David M.; Hudson, Hugh S.; White, Stephen M.

    2018-04-01

    The explanation of the coronal heating problem potentially lies in the existence of nanoflares, numerous small-scale heating events occurring across the whole solar disk. In this Letter, we present the first imaging spectroscopy X-ray observations of three quiet Sun flares during the Nuclear Spectroscopic Telescope ARray (NuSTAR) solar campaigns on 2016 July 26 and 2017 March 21, concurrent with the Solar Dynamics Observatory/Atmospheric Imaging Assembly (SDO/AIA) observations. Two of the three events showed time lags of a few minutes between peak X-ray and extreme ultraviolet emissions. Isothermal fits with rather low temperatures in the range 3.2–4.1 MK and emission measures of (0.6–15) × 1044 cm‑3 describe their spectra well, resulting in thermal energies in the range (2–6) × 1026 erg. NuSTAR spectra did not show any signs of a nonthermal or higher temperature component. However, as the estimated upper limits of (hidden) nonthermal energy are comparable to the thermal energy estimates, the lack of a nonthermal component in the observed spectra is not a constraining result. The estimated Geostationary Operational Environmental Satellite (GOES) classes from the fitted values of temperature and emission measure fall between 1/1000 and 1/100 A class level, making them eight orders of magnitude fainter in soft X-ray flux than the largest solar flares.

  3. Massive stars evolution with mass-loss. 20-100 M(sun) models

    Energy Technology Data Exchange (ETDEWEB)

    Chiosi, C; Sreenivasan, S R [Calgary Univ., Alberta (Canada). Dept. of Physics; Nasi, E [Padua Univ. (Italy). Istituto di Astronomia

    1978-02-01

    The evolution of stars with initial masses 20, 30, 40, 60, 80, 100 M(sun) and Population I chemical composition (X = 0.700, Z = 0.02) is calculated, taking into account mass-loss due to stellar winds, from the main sequence up to the early stages of central He-burning. This study incorporates mass-loss rates predicted by the theory of Castor et al. (1975) for the early type phases and a novel way of treating mass-loss rates due to acoustic energy flux driven winds in the later stages analogous to the work of Fusi-Pecci and Renzini (1975a). The results are presented in terms of evolutionary tracks, isochrones, loci of constant mass-loss rates and loci of constant mass in the HR diagram. The effects of mass-loss on the internal structure of the models as well as on the occurrence of semiconvection are also investigated. A detailed comparison of the theoretical predictions and observational results is made and possible implications for O, Of, Wolf-Rayet stars and red supergiants are brought out.

  4. Configuration and Dynamics of the Earth-Sun-Moon System: An Investigation into Conceptions of Deaf and Hearing Pupils.

    Science.gov (United States)

    Roald, Ingvild; Mikalsen, Oyvind

    2001-01-01

    Reports and analyzes the day and night cycle, the seasons, and the phases of the moon as seen by Norwegian deaf pupils aged 7, 9, 11, and 17 years, and by hearing Norwegian pupils 9 years old. Among the 9-year-olds there was no difference in the inner coherence of the conceptions between deaf pupils. (Author/SAH)

  5. A Sun-Earth-Moon Activity to Develop Student Understanding of Lunar Phases and Frames of Reference

    Science.gov (United States)

    Ashmann, Scott

    2012-01-01

    The Moon is an ever-present subject of observation, and it is a recurring topic in the science curriculum from kindergarten's basic observations through graduate courses' mathematical analyses of its orbit. How do students come to comprehend Earth's nearest neighbor? What is needed for them to understand the lunar phases and other phenomena and…

  6. Influence of a stellar wind on the evolution of a star of 30 M/sub sun/

    International Nuclear Information System (INIS)

    Stothers, R.; Chin, C.

    1980-01-01

    A coarse grid of theoretical evolutionary tracks has been computed for a star of 30 M/sub sun/, in an attempt to delineate the role of mass loss in the star's evolution during core helium burning. For all of the tracks, Cox-Stewart opacities have been adopted, and the free parameters have included the rate of mass loss, criterion for convection, and initial chemical composition. With the use of the Schwarzschild criterion, the star suffers little mass loss during core helium burning and remains almost to the end, a blue supergiant, well separated from main-sequence stars on the H-R diagram. With the use of the Ledoux criterion, the same consequences are obtained only in the case of a relatively low initial hydrogen or initial metals abundance. Otherwise, the star evolves, first, into a red supergiant, whereupon rapid mass loss must be assumed to take place, if the observed paucity of very bright red supergiants is to be accounted for. The stellar remnant then consists of little more than the original helium core, and may appear, for a time, bluer than equally luminous main-sequence stars, provided that the the initial hydrogen and metals abundances are normal. Thus, a wide variety of possible evolutionary tracks can be obtained for an initial mass of 30 M/sub sun/ with reasonable choices of the free parameters

  7. WIDE COMPANIONS TO HIPPARCOS STARS WITHIN 67 pc OF THE SUN

    International Nuclear Information System (INIS)

    Tokovinin, Andrei; Lépine, Sébastien

    2012-01-01

    A catalog of common-proper-motion (CPM) companions to stars within 67 pc of the Sun is constructed based on the SUPERBLINK proper-motion survey. It contains 1392 CPM pairs with angular separations 30'' –1 , and magnitudes and colors of the secondaries consistent with those of dwarfs in the (M V , V – J) diagram. In addition, we list 21 candidate white dwarf CPM companions with separations under 300'', about half of which should be physical. We estimate a 0.31 fraction of pairs with red dwarf companions to be physical systems (about 425 objects), while the rest (mostly wide pairs) are chance alignments. For each candidate companion, the probability of a physical association is evaluated. The distribution of projected separations s of the physical pairs between 2 kAU and 64 kAU follows f(s)∝s –1.5 , which decreases faster than Öpik's law. We find that solar-mass dwarfs have no less than 4.4% ± 0.3% companions with separations larger than 2 kAU, or 3.8% ± 0.3% per decade of orbital separation in the 2-16 kAU range. The distribution of mass ratio of those wide companions is approximately uniform in the 0.1 < q < 1.0 range, although we observe a dip at q ≅ 0.5 which, if confirmed, could be evidence of bimodal distribution of companion masses. New physical CPM companions to two exoplanet host stars are discovered.

  8. WIDE COMPANIONS TO HIPPARCOS STARS WITHIN 67 pc OF THE SUN

    Energy Technology Data Exchange (ETDEWEB)

    Tokovinin, Andrei [Cerro Tololo Inter-American Observatory, Casilla 603, La Serena (Chile); Lepine, Sebastien, E-mail: atokovinin@ctio.noao.edu, E-mail: lepine@amnh.org [Department of Astrophysics, Division of Physical Sciences, American Museum of Natural History, Central Park West at 79th Street, New York, NY 10024 (United States)

    2012-10-01

    A catalog of common-proper-motion (CPM) companions to stars within 67 pc of the Sun is constructed based on the SUPERBLINK proper-motion survey. It contains 1392 CPM pairs with angular separations 30'' < {rho} < 1800'', relative proper motion between the two components less than 25 mas yr{sup -1}, and magnitudes and colors of the secondaries consistent with those of dwarfs in the (M{sub V} , V - J) diagram. In addition, we list 21 candidate white dwarf CPM companions with separations under 300'', about half of which should be physical. We estimate a 0.31 fraction of pairs with red dwarf companions to be physical systems (about 425 objects), while the rest (mostly wide pairs) are chance alignments. For each candidate companion, the probability of a physical association is evaluated. The distribution of projected separations s of the physical pairs between 2 kAU and 64 kAU follows f(s){proportional_to}s {sup -1.5}, which decreases faster than Oepik's law. We find that solar-mass dwarfs have no less than 4.4% {+-} 0.3% companions with separations larger than 2 kAU, or 3.8% {+-} 0.3% per decade of orbital separation in the 2-16 kAU range. The distribution of mass ratio of those wide companions is approximately uniform in the 0.1 < q < 1.0 range, although we observe a dip at q {approx_equal} 0.5 which, if confirmed, could be evidence of bimodal distribution of companion masses. New physical CPM companions to two exoplanet host stars are discovered.

  9. A SUPER-EARTH-SIZED PLANET ORBITING IN OR NEAR THE HABITABLE ZONE AROUND A SUN-LIKE STAR

    Energy Technology Data Exchange (ETDEWEB)

    Barclay, Thomas; Burke, Christopher J.; Howell, Steve B.; Rowe, Jason F.; Huber, Daniel; Jenkins, Jon M.; Quintana, Elisa V.; Still, Martin; Twicken, Joseph D.; Bryson, Stephen T.; Borucki, William J.; Caldwell, Douglas A.; Clarke, Bruce D.; Christiansen, Jessie L; Coughlin, Jeffrey L. [NASA Ames Research Center, M/S 244-30, Moffett Field, CA 94035 (United States); Isaacson, Howard; Kolbl, Rea; Marcy, Geoffrey W. [Department of Astronomy, University of California at Berkeley, Berkeley, CA 94720 (United States); Ciardi, David [NASA Exoplanet Science Institute, California Institute of Technology, 770 South Wilson Avenue, Pasadena, CA 91125 (United States); Fischer, Debra A. [Department of Astronomy, Yale University, New Haven, CT 06520 (United States); and others

    2013-05-10

    We present the discovery of a super-Earth-sized planet in or near the habitable zone of a Sun-like star. The host is Kepler-69, a 13.7 mag G4V-type star. We detect two periodic sets of transit signals in the 3-year flux time series of Kepler-69, obtained with the Kepler spacecraft. Using the very high precision Kepler photometry, and follow-up observations, our confidence that these signals represent planetary transits is >99.3%. The inner planet, Kepler-69b, has a radius of 2.24{sup +0.44}{sub -0.29} R{sub Circled-Plus} and orbits the host star every 13.7 days. The outer planet, Kepler-69c, is a super-Earth-sized object with a radius of 1.7{sup +0.34}{sub -0.23} R{sub Circled-Plus} and an orbital period of 242.5 days. Assuming an Earth-like Bond albedo, Kepler-69c has an equilibrium temperature of 299 {+-} 19 K, which places the planet close to the habitable zone around the host star. This is the smallest planet found by Kepler to be orbiting in or near the habitable zone of a Sun-like star and represents an important step on the path to finding the first true Earth analog.

  10. Origin of the Moon new concept geochemistry and dynamics

    CERN Document Server

    Galimov, Erik M

    2012-01-01

    The origin of the Moon remains an unsolved problem of the planetary science. Researchers engaged in celestial dynamics, geophysics, and geochemistry are still discussing various models of creation of our closest cosmic neighbour. The most popular scenario, the impact hypothesis involving a collision early in the Earth's history, has been substantially challenged by the new data. The birth and development of a planet-moon system always play a role in the formation of an entire planetary system around our Sun or around another star. This way, the story of our Moon acquires broader ramifications

  11. Ancient sun: fossil record in the earth, moon and meteorites. Proceedings of the Conference, Boulder, CO, October 16-19, 1979

    International Nuclear Information System (INIS)

    Pepin, R.O.; Eddy, J.A.; Merrill, R.B.

    1980-01-01

    Papers are presented concerning theories of solar variability and their consequences for luminosity, particle emission and magnetic field changes within the past 4.5 billion years, and on the records of such solar behavior in lunar, meteoritic and terrestrial materials. Specific topics include the neutrino luminosity of the sun, the relation of sunspots to the terrestrial climate of the past 100 years, solar modulation of galactic cosmic rays, the historical record of solar activity, C-14 variations in terrestrial and marine reservoirs, and solar particle fluxes as indicated by track, thermoluminescence and solar wind measurements in lunar rocks. Attention is also given to the spin-down of the solar interior through circulation currents and fluid instabilities, grain surface exposure models in planetary regoliths, rare gases in the solar wind, nitrogen isotopic variations in the lunar regolith, the influence of solar UV radiation on climate, and the pre-main sequence evolution of the sun and evidence of the primordial solar wind in the electromagnetic induction heating of the asteroids and moon

  12. Family of the Sun-and-Stars Time-Determining Instruments (Ilseong-jeongsi-ui Invented During the Joseon Dynasty

    Directory of Open Access Journals (Sweden)

    Yong Sam Lee

    2016-09-01

    Full Text Available We analyze the design and specifications of the Sun-and-Stars Time-Determining group of instruments (Ilseong-jeongsi-ui, 日星定時儀 made during the Joseon dynasty. According to the records of the Sejong Sillok (Veritable Records of King Sejong, Sun-and-Stars Time-Determining Instruments measure the solar time of day and the sidereal time of night through three rings and an alidade. One such instrument, the Simplified Time-Determining Instrument (So-jeongsi-ui, 小定時儀, is made without the essential component for alignment with the celestial north pole. Among this group of instruments, only two bronze Hundred-Interval-Ring Sundials (Baekgak-hwan-Ilgu, 百刻環日晷 currently exist. A comparison of the functions of these two relics with two Time-Determining Instruments suggests that the Hundred-Interval-Ring Sundial is a Simplified Sundial (So-ilyeong, 小日影, as recorded in the Sejong Sillok and the Seongjong Sillok (Veritable Records of King Seongjong. Furthermore, the Simplified Sundial is a model derived from the Simplified Time-Determining Instrument. During the King Sejong reign, the Sun-and-Stars Time-Determining Instruments were used in military camps of the kingdom’s frontiers, in royal ancestral rituals, and in royal astronomical observatories.

  13. Family of the Sun-and-Stars Time-Determining Instruments (Ilseong-jeongsi-ui) Invented During the Joseon Dynasty

    Science.gov (United States)

    Lee, Yong Sam; Kim, Sang Hyuk; Mihn, Byeong-Hee

    2016-09-01

    We analyze the design and specifications of the Sun-and-Stars Time-Determining group of instruments (Ilseong-jeongsi-ui, 日星定時儀) made during the Joseon dynasty. According to the records of the Sejong Sillok (Veritable Records of King Sejong), Sun-and-Stars Time-Determining Instruments measure the solar time of day and the sidereal time of night through three rings and an alidade. One such instrument, the Simplified Time-Determining Instrument (So-jeongsi-ui, 小定時儀), is made without the essential component for alignment with the celestial north pole. Among this group of instruments, only two bronze Hundred-Interval-Ring Sundials (Baekgak-hwan-Ilgu, 百刻環日晷) currently exist. A comparison of the functions of these two relics with two Time-Determining Instruments suggests that the Hundred-Interval-Ring Sundial is a Simplified Sundial (So-ilyeong, 小日影), as recorded in the Sejong Sillok and the Seongjong Sillok (Veritable Records of King Seongjong). Furthermore, the Simplified Sundial is a model derived from the Simplified Time-Determining Instrument. During the King Sejong reign, the Sun-and-Stars Time-Determining Instruments were used in military camps of the kingdom’s frontiers, in royal ancestral rituals, and in royal astronomical observatories.

  14. Detection of dark-matter-radiation of stars during visible sun eclipses

    International Nuclear Information System (INIS)

    Volkamer, Klaus

    2003-01-01

    Recently a so-far unknown form of quantized, cold dark matter was detected on a laboratory scale which shows a complementary structure as compared to known forms of matter. From the experiments results that the observed quanta of the new type of matter as integer multiples of the Planck mass (mp = n · √((h·c)/((2 · π · G))) = n 0 21.77 μg, with n = 1, 2, 3 etc.) exhibit a spatially extended 'field-like' structure ranging over distances of centimetres or more, opposite to the 'point-like' structure of the known elementary particles of the standard model. Association of quanta of the new form of 'soft' (or subtle) matter to clusters was observed, as well as re-clustering after absorption. Thus, between such quanta a physical interaction must exist. In addition, the new form of matter shows at least two interactions with normal matter, a gravitational one due to its real mass content and a so-far unknown 'topological', i.e. form-specific, interaction at phase borders. Additional indications for a weak electromagnetic interaction exist. Furthermore, the experimental results reveal that some types of quanta of the new form of 'field-like' matter exhibit positive mass, as normal matter, but others exhibit a negative mass content, both in the order of magnitude of the Planck mass. Memory effects in normal matter were detected after absorption of quanta of the new form of soft matter. In general, the findings characterize the quanta of 'fieldlike' matter as WIMP candidates of a cosmic background radiation of cold dark matter (quanta with positive mass) as well as of a cosmic background radiation of dark energy (quanta with negative mass). During visible sun eclipses in 1989, 1996 and. 1999, as well as during full moon of 6 January 2001, a so-far unknown form of dark-matter-radiation ('dark radiation') was detected. The quanta of this 'dark radiation' travel with the speed of light, but reveal macroscopic real mass, with positive and with negative mass content. The

  15. Radial-Velocity Signatures of Magnetic Features on the Sun Observed as a Star

    Science.gov (United States)

    Palumbo, M. L., III; Haywood, R. D.; Saar, S. H.; Dupree, A. K.; Milbourne, T. W.

    2017-12-01

    In recent years, the search for Earth-mass planets using radial-velocity measurements has become increasingly limited by signals arising from stellar activity. Individual magnetic features induce localized changes in intensity and velocity, which combine to change the apparent radial velocity of the star. Therefore it is critical to identify an indicator of activity-driven radial-velocity variations on the timescale of stellar rotation periods. We use 617.3 nm photospheric filtergrams, magnetograms, and dopplergrams from SDO/HMI and 170.0 nm chromospheric filtergrams from AIA to identify magnetically-driven solar features and reconstruct the integrated solar radial velocity with six samples per day over the course of 2014. Breaking the solar image up into regions of umbrae, penumbrae, quiet Sun, network, and plages, we find a distinct variation in the center-to-limb intensity-weighted velocity for each region. In agreement with past studies, we find that the suppression of convective blueshift is dominated by plages and network, rather than dark photospheric features. In the future, this work will be highly useful for identifying indicators which correlate with rotationally modulated radial-velocity variations. This will allow us to break the activity barrier that currently precludes the precise characterization of exoplanet properties at the lowest masses. This work was supported by the NSF-REU solar physics program at SAO, grant number AGS-1560313. This work was performed in part under contract with the California Institute of Technology (Caltech)/Jet Propulsion Laboratory (JPL) funded by NASA through the Sagan Fellowship Program executed by the NASA Exoplanet Science Institute.

  16. Local perturbations of the upper layers of a sun-like star: The impact on the acoustic oscillation spectrum

    Energy Technology Data Exchange (ETDEWEB)

    Brito, Ana; Lopes, Ilídio, E-mail: ana.brito@ist.utl.pt, E-mail: ilidio.lopes@ist.utl.pt [Centro Multidisciplinar de Astrofísica, Instituto Superior Técnico, Universidade Tecnica de Lisboa, Av. Rovisco Pais, 1049-001 Lisboa (Portugal)

    2014-02-10

    In the last decade, the quality and the amount of observational asteroseismic data that has been made available by space based missions had a tremendous upgrowth. The determination of asteroseismic parameters to estimate the fundamental physical processes occurring in stars' interiors can be done today in a way that has never been possible before. In this work, we propose to compute the seismic observable β, which is a proxy of the phase shift of the acoustic modes propagating in the envelope of the Sun-like stars. This seismic parameter β can be used to identify rapid variation regions usually known as glitches. We show that a small variation in the structure, smaller than 1% in the sound speed, produces a glitch in the acoustic potential that could explain the oscillatory character of β. This method allows us to determine the location and the thickness of the glitch with precision. We applied this idea to the Sun-like star α Centauri A and found a glitch located at approximately 0.94 R (1400 s) and with a thickness of 0.2% of the stars' radius. This is fully consistent with the data and also validates other seismic tests.

  17. KEPLER-63b: A GIANT PLANET IN A POLAR ORBIT AROUND A YOUNG SUN-LIKE STAR

    International Nuclear Information System (INIS)

    Sanchis-Ojeda, Roberto; Winn, Joshua N.; Albrecht, Simon; Marcy, Geoffrey W.; Isaacson, Howard; Howard, Andrew W.; Johnson, John Asher; Torres, Guillermo; Carter, Joshua A.; Dawson, Rebekah I.; Geary, John C.; Campante, Tiago L.; Chaplin, William J.; Davies, Guy R.; Lund, Mikkel N.; Buchhave, Lars A.; Everett, Mark E.; Fischer, Debra A.; Gilliland, Ronald L.; Horch, Elliott P.

    2013-01-01

    We present the discovery and characterization of a giant planet orbiting the young Sun-like star Kepler-63 (KOI-63, m Kp = 11.6, T eff = 5576 K, M * = 0.98 M ☉ ). The planet transits every 9.43 days, with apparent depth variations and brightening anomalies caused by large starspots. The planet's radius is 6.1 ± 0.2 R ⊕ , based on the transit light curve and the estimated stellar parameters. The planet's mass could not be measured with the existing radial-velocity data, due to the high level of stellar activity, but if we assume a circular orbit, then we can place a rough upper bound of 120 M ⊕ (3σ). The host star has a high obliquity (ψ = 104°), based on the Rossiter-McLaughlin effect and an analysis of starspot-crossing events. This result is valuable because almost all previous obliquity measurements are for stars with more massive planets and shorter-period orbits. In addition, the polar orbit of the planet combined with an analysis of spot-crossing events reveals a large and persistent polar starspot. Such spots have previously been inferred using Doppler tomography, and predicted in simulations of magnetic activity of young Sun-like stars

  18. KEPLER-63b: A GIANT PLANET IN A POLAR ORBIT AROUND A YOUNG SUN-LIKE STAR

    Energy Technology Data Exchange (ETDEWEB)

    Sanchis-Ojeda, Roberto; Winn, Joshua N.; Albrecht, Simon [Department of Physics, and Kavli Institute for Astrophysics and Space Research, Massachusetts Institute of Technology, Cambridge, MA 02139 (United States); Marcy, Geoffrey W.; Isaacson, Howard [Astronomy Department, University of California, Berkeley, CA 94720 (United States); Howard, Andrew W. [Institute for Astronomy, University of Hawaii, 2680 Woodlawn Drive, Honolulu, HI 96822 (United States); Johnson, John Asher [Department of Astronomy, California Institute of Technology, 1200 E. California Blvd., Pasadena, CA 91125 (United States); Torres, Guillermo; Carter, Joshua A.; Dawson, Rebekah I.; Geary, John C. [Harvard-Smithsonian Center for Astrophysics, Cambridge, MA 02138 (United States); Campante, Tiago L.; Chaplin, William J.; Davies, Guy R. [School of Physics and Astronomy, University of Birmingham, Edgbaston, Birmingham B15 2TT (United Kingdom); Lund, Mikkel N. [Stellar Astrophysics Centre (SAC), Department of Physics and Astronomy, Aarhus University, Ny Munkegade 120, DK-8000 Aarhus C (Denmark); Buchhave, Lars A. [Niels Bohr Institute, University of Copenhagen, Juliane Maries vej 30, DK-2100 Copenhagen (Denmark); Everett, Mark E. [National Optical Astronomy Observatory, 950 N. Cherry Ave, Tucson, AZ 85719 (United States); Fischer, Debra A. [Astronomy Department, Yale University, New Haven, CT (United States); Gilliland, Ronald L. [Center for Exoplanets and Habitable Worlds, The Pennsylvania State University, 525 Davey Lab, University Park, PA 16802 (United States); Horch, Elliott P. [Southern Connecticut State University, New Haven, CT 06515 (United States); and others

    2013-09-20

    We present the discovery and characterization of a giant planet orbiting the young Sun-like star Kepler-63 (KOI-63, m{sub Kp} = 11.6, T{sub eff} = 5576 K, M{sub *} = 0.98 M{sub ☉}). The planet transits every 9.43 days, with apparent depth variations and brightening anomalies caused by large starspots. The planet's radius is 6.1 ± 0.2 R{sub ⊕}, based on the transit light curve and the estimated stellar parameters. The planet's mass could not be measured with the existing radial-velocity data, due to the high level of stellar activity, but if we assume a circular orbit, then we can place a rough upper bound of 120 M{sub ⊕} (3σ). The host star has a high obliquity (ψ = 104°), based on the Rossiter-McLaughlin effect and an analysis of starspot-crossing events. This result is valuable because almost all previous obliquity measurements are for stars with more massive planets and shorter-period orbits. In addition, the polar orbit of the planet combined with an analysis of spot-crossing events reveals a large and persistent polar starspot. Such spots have previously been inferred using Doppler tomography, and predicted in simulations of magnetic activity of young Sun-like stars.

  19. Local perturbations of the upper layers of a sun-like star: The impact on the acoustic oscillation spectrum

    International Nuclear Information System (INIS)

    Brito, Ana; Lopes, Ilídio

    2014-01-01

    In the last decade, the quality and the amount of observational asteroseismic data that has been made available by space based missions had a tremendous upgrowth. The determination of asteroseismic parameters to estimate the fundamental physical processes occurring in stars' interiors can be done today in a way that has never been possible before. In this work, we propose to compute the seismic observable β, which is a proxy of the phase shift of the acoustic modes propagating in the envelope of the Sun-like stars. This seismic parameter β can be used to identify rapid variation regions usually known as glitches. We show that a small variation in the structure, smaller than 1% in the sound speed, produces a glitch in the acoustic potential that could explain the oscillatory character of β. This method allows us to determine the location and the thickness of the glitch with precision. We applied this idea to the Sun-like star α Centauri A and found a glitch located at approximately 0.94 R (1400 s) and with a thickness of 0.2% of the stars' radius. This is fully consistent with the data and also validates other seismic tests.

  20. Van Gogh's Starry Nights, Lincoln's Moon, Shakespeare's Stars, and More: Tales of Astronomy in Art, History, and Literature

    Science.gov (United States)

    Olson, Donald

    2009-10-01

    How do astronomical methods make it possible to calculate dates and times for Vincent van Gogh's night-sky paintings? Why is there a blood-red sky in Edvard Munch's The Scream? On what dates did Ansel Adams create his moonrise photographs in Yosemite? How can the 18.6-year cycle of the lunar nodes and the Moon's declination on the night of August 29-30, 1857, explain a long-standing mystery about Abraham Lincoln's honesty in the murder case known as the almanac trial? Why is a bright star described in Act 1, Scene 1, of Hamlet? To answer questions like these, our Texas State group has published a series of articles over the last two decades, applying astronomy to art, history, and literature.

  1. Occurrence and core-envelope structure of 1-4× Earth-size planets around Sun-like stars.

    Science.gov (United States)

    Marcy, Geoffrey W; Weiss, Lauren M; Petigura, Erik A; Isaacson, Howard; Howard, Andrew W; Buchhave, Lars A

    2014-09-02

    Small planets, 1-4× the size of Earth, are extremely common around Sun-like stars, and surprisingly so, as they are missing in our solar system. Recent detections have yielded enough information about this class of exoplanets to begin characterizing their occurrence rates, orbits, masses, densities, and internal structures. The Kepler mission finds the smallest planets to be most common, as 26% of Sun-like stars have small, 1-2 R⊕ planets with orbital periods under 100 d, and 11% have 1-2 R⊕ planets that receive 1-4× the incident stellar flux that warms our Earth. These Earth-size planets are sprinkled uniformly with orbital distance (logarithmically) out to 0.4 the Earth-Sun distance, and probably beyond. Mass measurements for 33 transiting planets of 1-4 R⊕ show that the smallest of them, R planets. Their densities increase with increasing radius, likely caused by gravitational compression. Including solar system planets yields a relation: ρ = 2:32 + 3:19 R=R ⊕ [g cm(-3)]. Larger planets, in the radius range 1.5-4.0 R⊕, have densities that decline with increasing radius, revealing increasing amounts of low-density material (H and He or ices) in an envelope surrounding a rocky core, befitting the appellation ''mini-Neptunes.'' The gas giant planets occur preferentially around stars that are rich in heavy elements, while rocky planets occur around stars having a range of heavy element abundances. Defining habitable zones remains difficult, without benefit of either detections of life elsewhere or an understanding of life's biochemical origins.

  2. Occurrence and core-envelope structure of 1–4× Earth-size planets around Sun-like stars

    Science.gov (United States)

    Marcy, Geoffrey W.; Weiss, Lauren M.; Petigura, Erik A.; Isaacson, Howard; Howard, Andrew W.; Buchhave, Lars A.

    2014-01-01

    Small planets, 1–4× the size of Earth, are extremely common around Sun-like stars, and surprisingly so, as they are missing in our solar system. Recent detections have yielded enough information about this class of exoplanets to begin characterizing their occurrence rates, orbits, masses, densities, and internal structures. The Kepler mission finds the smallest planets to be most common, as 26% of Sun-like stars have small, 1–2 R⊕ planets with orbital periods under 100 d, and 11% have 1–2 R⊕ planets that receive 1–4× the incident stellar flux that warms our Earth. These Earth-size planets are sprinkled uniformly with orbital distance (logarithmically) out to 0.4 the Earth–Sun distance, and probably beyond. Mass measurements for 33 transiting planets of 1–4 R⊕ show that the smallest of them, R planets. Their densities increase with increasing radius, likely caused by gravitational compression. Including solar system planets yields a relation: ρ=2.32+3.19R/R⊕ [g cm−3]. Larger planets, in the radius range 1.5–4.0 R⊕, have densities that decline with increasing radius, revealing increasing amounts of low-density material (H and He or ices) in an envelope surrounding a rocky core, befitting the appellation ‘‘mini-Neptunes.’’ The gas giant planets occur preferentially around stars that are rich in heavy elements, while rocky planets occur around stars having a range of heavy element abundances. Defining habitable zones remains difficult, without benefit of either detections of life elsewhere or an understanding of life’s biochemical origins. PMID:24912169

  3. Forward modeling of the corona of the sun and solarlike stars

    DEFF Research Database (Denmark)

    Hardi, Peter; Gudiksen, Boris V.; Nordlund, Å.

    2006-01-01

    Transition Region Lines, AB-Initio Approach; Nonequilibrium Inozation; Doppler Shifts; Emission-Lines; Quiet-Sun; Sumer Telescope; Atomic Database; Magnetic-Field; Thin Plasmas......Transition Region Lines, AB-Initio Approach; Nonequilibrium Inozation; Doppler Shifts; Emission-Lines; Quiet-Sun; Sumer Telescope; Atomic Database; Magnetic-Field; Thin Plasmas...

  4. Clementine Observes the Moon, Solar Corona, and Venus

    Science.gov (United States)

    1997-01-01

    In 1994, during its flight, the Clementine spacecraft returned images of the Moon. In addition to the geologic mapping cameras, the Clementine spacecraft also carried two Star Tracker cameras for navigation. These lightweight (0.3 kg) cameras kept the spacecraft on track by constantly observing the positions of stars, reminiscent of the age-old seafaring tradition of sextant/star navigation. These navigation cameras were also to take some spectacular wide angle images of the Moon.In this picture the Moon is seen illuminated solely by light reflected from the Earth--Earthshine! The bright glow on the lunar horizon is caused by light from the solar corona; the sun is just behind the lunar limb. Caught in this image is the planet Venus at the top of the frame.

  5. Effect of catalogues coordinate errors of a star onto determination of the physical libration of the Moon from the observations of stars

    Science.gov (United States)

    Petrova, Natalia; Kocoulin, Valerii; Nefediev, Yurii

    2016-07-01

    the time of observation), this error is reduced by an order, i.e. does not exceed the error of observation selenographic coordinates. 2. The worst thing - errors in coordinates of catalogue causes though a small but constant shift in the ρ and Iσ. So, when Δα, Δδ ˜0.01", then the shift reaches 0.0025". Moreover there is a trend, with a slight, but noticeable slope. 3. Effect of error in declination of a stars is substantially strong than the error in right ascension. Perhaps it is characteristic only for polar observations. For the required accuracy in determination of the physical libration these phenomena must be taken into account when processing the planned observations. Referencies. Nefediev et al., 2013. Uchenye zapiski Kazanskogo universiteta, v. 155, 1, p.188-194. Petrova, N., Abdulmyanov T., Hanada H. Some qualitative manifestations of the physical libration of the Moon by observing stars from the lunar surface. //J. Adv. Space Res., 2012a. V. 50, p. 1702-1711

  6. Deuterium and 15N fractionation in N2H+ during the formation of a Sun-like star

    Science.gov (United States)

    De Simone, M.; Fontani, F.; Codella, C.; Ceccarelli, C.; Lefloch, B.; Bachiller, R.; López-Sepulcre, A.; Caux, E.; Vastel, C.; Soldateschi, J.

    2018-05-01

    Although chemical models predict that the deuterium fractionation in N2H+ is a good evolutionary tracer in the star formation process, the fractionation of nitrogen is still a poorly understood process. Recent models have questioned the similar evolutionary trend expected for the two fractionation mechanisms in N2H+, based on a classical scenario in which ion-neutral reactions occurring in cold gas should have caused an enhancement of the abundance of N2D+, 15NNH+, and N15NH+. In the framework of the ASAI IRAM-30m large program, we have investigated the fractionation of deuterium and 15N in N2H+ in the best known representatives of the different evolutionary stages of the Sun-like star formation process. The goal is to ultimately confirm (or deny) the classical `ion-neutral reactions' scenario that predicts a similar trend for D and 15N fractionation. We do not find any evolutionary trend of the 14N/15N ratio from both the 15NNH+ and N15NH+ isotopologues. Therefore, our findings confirm that, during the formation of a Sun-like star, the core evolution is irrelevant in the fractionation of 15N. The independence of the 14N/15N ratio with time, found also in high-mass star-forming cores, indicates that the enrichment in 15N revealed in comets and protoplanetary discs is unlikely to happen at core scales. Nevertheless, we have firmly confirmed the evolutionary trend expected for the H/D ratio, with the N2H+/N2D+ ratio decreasing before the pre-stellar core phase, and increasing monotonically during the protostellar phase. We have also confirmed clearly that the two fractionation mechanisms are not related.

  7. Properties of an Earth-like planet orbiting a Sun-like star: Earth observed by the EPOXI mission.

    Science.gov (United States)

    Livengood, Timothy A; Deming, L Drake; A'hearn, Michael F; Charbonneau, David; Hewagama, Tilak; Lisse, Carey M; McFadden, Lucy A; Meadows, Victoria S; Robinson, Tyler D; Seager, Sara; Wellnitz, Dennis D

    2011-11-01

    NASA's EPOXI mission observed the disc-integrated Earth and Moon to test techniques for reconnoitering extrasolar terrestrial planets, using the Deep Impact flyby spacecraft to observe Earth at the beginning and end of Northern Hemisphere spring, 2008, from a range of ∼1/6 to 1/3 AU. These observations furnish high-precision and high-cadence empirical photometry and spectroscopy of Earth, suitable as "ground truth" for numerically simulating realistic observational scenarios for an Earth-like exoplanet with finite signal-to-noise ratio. Earth was observed at near-equatorial sub-spacecraft latitude on 18-19 March, 28-29 May, and 4-5 June (UT), in the range of 372-4540 nm wavelength with low visible resolving power (λ/Δλ=5-13) and moderate IR resolving power (λ/Δλ=215-730). Spectrophotometry in seven filters yields light curves at ∼372-948 nm filter-averaged wavelength, modulated by Earth's rotation with peak-to-peak amplitude of ≤20%. The spatially resolved Sun glint is a minor contributor to disc-integrated reflectance. Spectroscopy at 1100-4540 nm reveals gaseous water and carbon dioxide, with minor features of molecular oxygen, methane, and nitrous oxide. One-day changes in global cloud cover resulted in differences between the light curve beginning and end of ≤5%. The light curve of a lunar transit of Earth on 29 May is color-dependent due to the Moon's red spectrum partially occulting Earth's relatively blue spectrum. The "vegetation red edge" spectral contrast observed between two long-wavelength visible/near-IR bands is ambiguous, not clearly distinguishing between the verdant Earth diluted by cloud cover versus the desolate mineral regolith of the Moon. Spectrophotometry in at least one other comparison band at short wavelength is required to distinguish between Earth-like and Moon-like surfaces in reconnaissance observations. However, measurements at 850 nm alone, the high-reflectance side of the red edge, could be sufficient to

  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. Jupiter Analogs Orbit Stars with an Average Metallicity Close to That of the Sun

    DEFF Research Database (Denmark)

    Buchhave, Lars A.; Bitsch, Bertram; Johansen, Anders

    2018-01-01

    Jupiter played an important role in determining the structure and configuration of the Solar System. Whereas hot-Jupiter type exoplanets preferentially form around metal-rich stars, the conditions required for the formation of planets with masses, orbits, and eccentricities comparable to Jupiter...... (Jupiter analogs) are unknown. Using spectroscopic metallicities, we show that stars hosting Jupiter analogs have an average metallicity close to solar, in contrast to their hot-Jupiter and eccentric cool-Jupiter counterparts, which orbit stars with super-solar metallicities. Furthermore......, the eccentricities of Jupiter analogs increase with host-star metallicity, suggesting that planet-planet scatterings producing highly eccentric cool Jupiters could be more common in metal-rich environments. To investigate a possible explanation for these metallicity trends, we compare the observations to numerical...

  10. The sun, moon, wind, and biological imperative-shaping contrasting wintertime migration and foraging strategies of adult male and female northern fur seals (Callorhinus ursinus.

    Directory of Open Access Journals (Sweden)

    Jeremy T Sterling

    Full Text Available Adult male and female northern fur seals (Callorhinus ursinus are sexually segregated in different regions of the North Pacific Ocean and Bering Sea during their winter migration. Explanations for this involve interplay between physiology, predator-prey dynamics, and ecosystem characteristics, however possible mechanisms lack empirical support. To investigate factors influencing the winter ecology of both sexes, we deployed five satellite-linked conductivity, temperature, and depth data loggers on adult males, and six satellite-linked depth data loggers and four satellite transmitters on adult females from St. Paul Island (Bering Sea, Alaska, USA in October 2009. Males and females migrated to different regions of the North Pacific Ocean: males wintered in the Bering Sea and northern North Pacific Ocean, while females migrated to the Gulf of Alaska and California Current. Horizontal and vertical movement behaviors of both sexes were influenced by wind speed, season, light (sun and moon, and the ecosystem they occupied, although the expression of the behaviors differed between sexes. Male dive depths were aligned with the depth of the mixed layer during daylight periods and we suspect this was the case for females upon their arrival to the California Current. We suggest that females, because of their smaller size and physiological limitations, must avoid severe winters typical of the northern North Pacific Ocean and Bering Sea and migrate long distances to areas of more benign environmental conditions and where prey is shallower and more accessible. In contrast, males can better tolerate often extreme winter ocean conditions and exploit prey at depth because of their greater size and physiological capabilities. We believe these contrasting winter behaviors 1 are a consequence of evolutionary selection for large size in males, important to the acquisition and defense of territories against rivals during the breeding season, and 2 ease environmental

  11. The Sun, Moon, Wind, and Biological Imperative–Shaping Contrasting Wintertime Migration and Foraging Strategies of Adult Male and Female Northern Fur Seals (Callorhinus ursinus)

    Science.gov (United States)

    Sterling, Jeremy T; Springer, Alan M.; Iverson, Sara J.; Johnson, Shawn P.; Pelland, Noel A.; Johnson, Devin S.; Lea, Mary-Anne; Bond, Nicholas A.

    2014-01-01

    Adult male and female northern fur seals (Callorhinus ursinus) are sexually segregated in different regions of the North Pacific Ocean and Bering Sea during their winter migration. Explanations for this involve interplay between physiology, predator-prey dynamics, and ecosystem characteristics, however possible mechanisms lack empirical support. To investigate factors influencing the winter ecology of both sexes, we deployed five satellite-linked conductivity, temperature, and depth data loggers on adult males, and six satellite-linked depth data loggers and four satellite transmitters on adult females from St. Paul Island (Bering Sea, Alaska, USA) in October 2009. Males and females migrated to different regions of the North Pacific Ocean: males wintered in the Bering Sea and northern North Pacific Ocean, while females migrated to the Gulf of Alaska and California Current. Horizontal and vertical movement behaviors of both sexes were influenced by wind speed, season, light (sun and moon), and the ecosystem they occupied, although the expression of the behaviors differed between sexes. Male dive depths were aligned with the depth of the mixed layer during daylight periods and we suspect this was the case for females upon their arrival to the California Current. We suggest that females, because of their smaller size and physiological limitations, must avoid severe winters typical of the northern North Pacific Ocean and Bering Sea and migrate long distances to areas of more benign environmental conditions and where prey is shallower and more accessible. In contrast, males can better tolerate often extreme winter ocean conditions and exploit prey at depth because of their greater size and physiological capabilities. We believe these contrasting winter behaviors 1) are a consequence of evolutionary selection for large size in males, important to the acquisition and defense of territories against rivals during the breeding season, and 2) ease environmental

  12. Evolution of a 1 M(sun) star with a periodically mixed core

    Energy Technology Data Exchange (ETDEWEB)

    Gabriel, M; Noels, A; Scuflaire, R; Boury, A [Liege Univ. (Belgium). Inst. d' Astrophysique

    1976-02-01

    To solve the neutrino problem, Dilke and Gough have suggested that the vibrational instability of g/sup +/ modes of non radial oscillation may be the cause of recurrent mixing in the sun. Supposing this to be correct, the evolution of the sun is completely different from the standard one. Unmixed solar models are stable when older than 3 x 10/sup 9/ years. It is therefore necessary to check whether in the modified evolution, instabilities still exist at the solar age. They do, provided that the mass fraction of the mixed core is large enough. However, the neutrino flux at its minimum during a thermal pulse occurring at the solar age remains too high. Constraints imposed by ice age records are also discussed.

  13. Living with a Star: New Opportunities in Sun-Climate Research

    Science.gov (United States)

    Eddy, John Allen

    2003-01-01

    Enormous advances have been made in the last quarter century in all of these needed areas, covering the two essential halves of the Sun-Climate question: in what we know of solar variations and, equally important, in what we know of the climate system and of climatic changes. These research achievements allow us to examine all aspects of the question more directly and quantitatively than was ever possible before, and in the brighter light and more objective context of other known or suspected climate change mechanisms, including human-induced global greenhouse warming. Brief summaries of present status and current understanding are given below for nine facets of Sun-Climate science in which major progress has been made in recent years. At the same time it will be seen that in every instance, significant elements of uncertainty still remain, Some of the most important of these unanswered questions are considered later, in Section IV.

  14. Prevalence of Earth-size planets orbiting Sun-like stars

    OpenAIRE

    Petigura, Erik A.; Howard, Andrew W.; Marcy, Geoffrey W.

    2013-01-01

    Determining whether Earth-like planets are common or rare looms as a touchstone in the question of life in the universe. We searched for Earth-size planets that cross in front of their host stars by examining the brightness measurements of 42,000 stars from National Aeronautics and Space Administration's Kepler mission. We found 603 planets, including 10 that are Earth size (1-2 Earth-radii) and receive comparable levels of stellar energy to that of Earth (within a factor of four). We account...

  15. Upgrade of the NASA 4STAR (Spectrometer for Sky-Scanning, Sun-Tracking Atmospheric Research) to its Full Science Capability of Sun-Sky-Cloud-Trace Gas Spectrometry in Airborne Science Deployments

    Science.gov (United States)

    Johnson, Roy R.; Russell, P.; Dunagan, S.; Redemann, J.; Shinozuka, Y.; Segal-Rosenheimer, M.; LeBlanc, S.; Flynn, C.; Schmid, B.; Livingston, J.

    2014-01-01

    The objectives of this task in the AITT (Airborne Instrument Technology Transition) Program are to (1) upgrade the NASA 4STAR (Spectrometer for Sky-Scanning, Sun-Tracking Atmospheric Research) instrument to its full science capability of measuring (a) direct-beam sun transmission to derive aerosol optical depth spectra, (b) sky radiance vs scattering angle to retrieve aerosol absorption and type (via complex refractive index spectra, shape, and mode-resolved size distribution), (c) zenith radiance for cloud properties, and (d) hyperspectral signals for trace gas retrievals, and (2) demonstrate its suitability for deployment in challenging NASA airborne multiinstrument campaigns. 4STAR combines airborne sun tracking, sky scanning, and zenith pointing with diffraction spectroscopy to improve knowledge of atmospheric constituents and their links to air pollution, radiant energy budgets (hence climate), and remote measurements of Earth's surfaces. Direct beam hyperspectral measurement of optical depth improves retrievals of gas constituents and determination of aerosol properties. Sky scanning enhances retrievals of aerosol type and size distribution. 4STAR measurements are intended to tighten the closure between satellite and ground-based measurements. 4STAR incorporates a modular sun-tracking/sky-scanning optical head with fiber optic signal transmission to rack mounted spectrometers, permitting miniaturization of the external optical head, and future detector evolution. 4STAR test flights, as well as science flights in the 2012-13 TCAP (Two-Column Aerosol Project) and 2013 SEAC4RS (Studies of Emissions and Atmospheric Composition, Clouds and Climate Coupling by Regional Surveys) have demonstrated that the following are essential for 4STAR to achieve its full science potential: (1) Calibration stability for both direct-beam irradiance and sky radiance, (2) Improved light collection and usage, and (3) Improved flight operability and reliability. A particular challenge

  16. THE DIFFERENT EVOLUTION OF GAS AND DUST IN DISKS AROUND SUN-LIKE AND COOL STARS

    NARCIS (Netherlands)

    Pascucci, I.; Apai, D.; Luhman, K.; Henning, Th.; Bouwman, J.; Meyer, M. R.; Lahuis, F.; Natta, A.

    2009-01-01

    Planet formation is profoundly impacted by the properties of protoplanetary disks and their central star. However, how disk properties vary with stellar parameters remains poorly known. Here, we present the first comprehensive, comparative Spitzer/IRS study of the dust and gas properties of disks

  17. Differences in the Gas and Dust Distribution in the Transitional Disk of a Sun-like Young Star, PDS 70

    Science.gov (United States)

    Long, Zachary C.; Akiyama, Eiji; Sitko, Michael; Fernandes, Rachel B.; Assani, Korash; Grady, Carol A.; Cure, Michel; Danchi, William C.; Dong, Ruobing; Fukagawa, Misato; Hasegawa, Yasuhiro; Hashimoto, Jun; Henning, Thomas; Inutsuka, Shu-Ichiro; Kraus, Stefan; Kwon, Jungmi; Lisse, Carey M.; Baobabu Liu, Hauyu; Mayama, Satoshi; Muto, Takayuki; Nakagawa, Takao; Takami, Michihiro; Tamura, Motohide; Currie, Thayne; Wisniewski, John P.; Yang, Yi

    2018-05-01

    We present ALMA 0.87 mm continuum, HCO+ J = 4–3 emission line, and CO J = 3–2 emission line data of the disk of material around the young, Sun-like star PDS 70. These data reveal the existence of a possible two-component transitional disk system with a radial dust gap of 0.″42 ± 0.″05, an azimuthal gap in the HCO+ J = 4–3 moment zero map, as well as two bridge-like features in the gas data. Interestingly these features in the gas disk have no analog in the dust disk making them of particular interest. We modeled the dust disk using the Monte Carlo radiative transfer code HOCHUNK3D using a two-disk component. We find that there is a radial gap that extends from 15 to 60 au in all grain sizes, which differs from previous work.

  18. Connection between Herbig-Haro objects and flare stars in the neighborhood of the sun

    International Nuclear Information System (INIS)

    Giulbudagian, A.L.

    1984-01-01

    The origin of the K-M-dwarf flare stars observed with widely ranging spatial velocities in the solar neighborhood is investigated theoretically. It is proposed that these objects are Herbig-Haro objects (HHOs) which have lost their diffuse envelopes as they emerged from dark clouds. The number of HHOs in the Galaxy and their average lifetime are estimated as 150,000 and 3,000 yr, respectively, corresponding to a total of 5 x 10 to the 11th HHOs created in the Galaxy over 10 Gyr and in rough agreement with the number of low-mass flare stars (5 x 10 to the 10th) if some of them have ages of 1 Gyr or more

  19. Direct Imaging of a Cold Jovian Exoplanet in Orbit around the Sun-Like Star GJ 504

    Science.gov (United States)

    Kuzuhara, M.; Tamura, M.; Kudo, T.; Janson, M; Kandori, R.; Brandt, T. D.; Thalmann, C.; Spiegel, D.; Biller, B.; Carson, J.; hide

    2013-01-01

    Several exoplanets have recently been imaged at wide separations of >10 AU from their parent stars. These span a limited range of ages ( 0.5 mag), implying thick cloud covers. Furthermore, substantial model uncertainties exist at these young ages due to the unknown initial conditions at formation, which can lead to an order of magnitude of uncertainty in the modeled planet mass. Here, we report the direct imaging discovery of a Jovian exoplanet around the Sun-like star GJ 504, detected as part of the SEEDS survey. The system is older than all other known directly-imaged planets; as a result, its estimated mass remains in the planetary regime independent of uncertainties related to choices of initial conditions in the exoplanet modeling. Using the most common exoplanet cooling model, and given the system age of 160(+350/-60) Myr, GJ 504 b has an estimated mass of 4(+4.5/-1.0) Jupiter masses, among the lowest of directly imaged planets. Its projected separation of 43.5 AU exceeds the typical outer boundary of approx.. 30 AU predicted for the core accretion mechanism. GJ 504 b is also significantly cooler (510(+30/-20) K)) and has a bluer color (J - H = -0.23 mag) than previously imaged exoplanets, suggesting a largely cloud-free atmosphere accessible to spectroscopic characterization. Thus, it has the potential of providing novel insights into the origins of giant planets, as well as their atmospheric properties.

  20. MOON MOON DEVI

    Indian Academy of Sciences (India)

    Home; Journals; Pramana – Journal of Physics. MOON MOON DEVI. Articles written in Pramana – Journal of Physics. Volume 88 Issue 5 May 2017 pp 79 Research Article. Physics potential of the ICAL detector at the India-based Neutrino Observatory (INO) · A KUMAR A M VINOD KUMAR ABHIK JASH AJIT K MOHANTY ...

  1. DIRECT IMAGING OF A COLD JOVIAN EXOPLANET IN ORBIT AROUND THE SUN-LIKE STAR GJ 504

    Energy Technology Data Exchange (ETDEWEB)

    Kuzuhara, M. [Department of Earth and Planetary Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan); Tamura, M.; Kandori, R.; Hori, Y.; Suzuki, R.; Suenaga, T.; Takahashi, Y. H.; Kwon, J. [National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan); Kudo, T. [Subaru Telescope, National Astronomical Observatory of Japan, 650 North A' ohoku Place, Hilo, HI 96720 (United States); Janson, M.; Brandt, T. D.; Spiegel, D.; Burrows, A.; Turner, E. L.; Moro-Martin, A. [Department of Astrophysical Sciences, Princeton University, Peyton Hall, Ivy Lane, Princeton, NJ 08544 (United States); Thalmann, C. [Astronomical Institute ' ' Anton Pannekoek' ' , University of Amsterdam, Postbus 94249, 1090 GE, Amsterdam (Netherlands); Biller, B.; Henning, T. [Max Planck Institute for Astronomy, Koenigstuhl 17, D-69117 Heidelberg (Germany); Carson, J. [Department of Physics and Astronomy, College of Charleston, 58 Coming Street, Charleston, SC 29424 (United States); McElwain, M. W., E-mail: m.kuzuhara@nao.ac.jp [Exoplanets and Stellar Astrophysics Laboratory, Code 667, Goddard Space Flight Center, Greenbelt, MD 20771 (United States); and others

    2013-09-01

    Several exoplanets have recently been imaged at wide separations of >10 AU from their parent stars. These span a limited range of ages (<50 Myr) and atmospheric properties, with temperatures of 800-1800 K and very red colors (J - H > 0.5 mag), implying thick cloud covers. Furthermore, substantial model uncertainties exist at these young ages due to the unknown initial conditions at formation, which can lead to an order of magnitude of uncertainty in the modeled planet mass. Here, we report the direct-imaging discovery of a Jovian exoplanet around the Sun-like star GJ 504, detected as part of the SEEDS survey. The system is older than all other known directly imaged planets; as a result, its estimated mass remains in the planetary regime independent of uncertainties related to choices of initial conditions in the exoplanet modeling. Using the most common exoplanet cooling model, and given the system age of 160{sup +350}{sub -60} Myr, GJ 504b has an estimated mass of 4{sup +4.5}{sub -1.0} Jupiter masses, among the lowest of directly imaged planets. Its projected separation of 43.5 AU exceeds the typical outer boundary of {approx}30 AU predicted for the core accretion mechanism. GJ 504b is also significantly cooler (510{sup +30}{sub -20} K) and has a bluer color (J - H = -0.23 mag) than previously imaged exoplanets, suggesting a largely cloud-free atmosphere accessible to spectroscopic characterization. Thus, it has the potential of providing novel insights into the origins of giant planets as well as their atmospheric properties.

  2. Book Review: Stars (Copyright 1985, Golden Press; New York)

    Science.gov (United States)

    Marigza, R. N., Jr.

    2009-06-01

    Stars is a part of the Golden Guides collection produced by Golden Press. It is a small 160 page paperback guide to the constellations, the sun, the moon, planets, and other celestial bodies. The book is convenient to carry along wherever you go, making it an easy to access reference material.

  3. PLANETARY CONSTRUCTION ZONES IN OCCULTATION: DISCOVERY OF AN EXTRASOLAR RING SYSTEM TRANSITING A YOUNG SUN-LIKE STAR AND FUTURE PROSPECTS FOR DETECTING ECLIPSES BY CIRCUMSECONDARY AND CIRCUMPLANETARY DISKS

    Energy Technology Data Exchange (ETDEWEB)

    Mamajek, Eric E.; Quillen, Alice C.; Pecaut, Mark J.; Moolekamp, Fred; Scott, Erin L. [Department of Physics and Astronomy, University of Rochester, Rochester, NY 14627-0171 (United States); Kenworthy, Matthew A. [Leiden Observatory, Leiden University, P.O. Box 9513, 2300 RA Leiden (Netherlands); Cameron, Andrew Collier; Parley, Neil R. [School of Physics and Astronomy, University of St Andrews, North Haugh, St Andrews, Fife KY16 9SS (United Kingdom)

    2012-03-15

    The large relative sizes of circumstellar and circumplanetary disks imply that they might be seen in eclipse in stellar light curves. We estimate that a survey of {approx}10{sup 4} young ({approx}10 million year old) post-accretion pre-main-sequence stars monitored for {approx}10 years should yield at least a few deep eclipses from circumplanetary disks and disks surrounding low-mass companion stars. We present photometric and spectroscopic data for a pre-main-sequence K5 star (1SWASP J140747.93-394542.6 = ASAS J140748-3945.7), a newly discovered {approx}0.9 M{sub Sun} member of the {approx}16 Myr old Upper Centaurus-Lupus subgroup of Sco-Cen at a kinematic distance of 128 {+-} 13 pc. This star exhibited a remarkably long, deep, and complex eclipse event centered on 2007 April 29 (as discovered in Super Wide Angle Search for Planets (SuperWASP) photometry, and with portions of the dimming confirmed by All Sky Automated Survey (ASAS) data). At least five multi-day dimming events of >0.5 mag are identified, with a >3.3 mag deep eclipse bracketed by two pairs of {approx}1 mag eclipses symmetrically occurring {+-}12 days and {+-}26 days before and after. Hence, significant dimming of the star was taking place on and off over at least a {approx}54 day period in 2007, and a strong >1 mag dimming event occurring over a {approx}12 day span. We place a firm lower limit on the period of 850 days (i.e., the orbital radius of the eclipser must be >1.7 AU and orbital velocity must be <22 km s{sup -1}). The shape of the light curve is similar to the lopsided eclipses of the Be star EE Cep. We suspect that this new star is being eclipsed by a low-mass object orbited by a dense inner disk, further girded by at least three dusty rings of optical depths near unity. Between these rings are at least two annuli of near-zero optical depth (i.e., gaps), possibly cleared out by planets or moons, depending on the nature of the secondary. For possible periods in the range 2.33-200 yr, the

  4. The Sun

    CERN Document Server

    Golub, Leon

    2017-01-01

    Essential for life on earth and a major influence on our environment, the Sun is also the most fascinating object in the daytime sky. Every day we feel the effect of its coming and going – literally the difference between day and night. But figuring out what the Sun is, what it’s made of, why it glows so brightly, how old it is, how long it will last – all of these take thought and observation. Leon Golub and Jay M. Pasachoff offer an engaging and informative account of what scientists know about the Sun, and the history of these discoveries. Solar astronomers have studied the Sun over the centuries both for its intrinsic interest and in order to use it as a laboratory to reveal the secrets of other stars. The authors discuss the surface of the Sun, including sunspots and their eleven-year cycle, as well as the magnetism that causes them; the Sun’s insides, as studied mainly from seismic waves that astronomers record on its surface; the outer layers of the Sun that we see from Earth only at eclipses ...

  5. Miniaturized star tracker for micro spacecraft with high angular rate

    Science.gov (United States)

    Li, Jianhua; Li, Zhifeng; Niu, Zhenhong; Liu, Jiaqi

    2017-10-01

    There is a clear need for miniaturized, lightweight, accurate and inexpensive star tracker for spacecraft with large anglar rate. To face these new constraints, the Beijing Institute of Space Long March Vehicle has designed, built and flown a low cost miniaturized star tracker that provides autonomous ("Lost in Space") inertial attitude determination, 2 Hz 3-axis star tracking, and digital imaging with embedded compression. Detector with high sensitivity is adopted to meet the dynamic and miniature requirement. A Sun and Moon avoiding method based on the calculation of Sun and Moon's vector by astronomical theory is proposed. The produced prototype weight 0.84kg, and can be used for a spacecraft with 6°/s anglar rate. The average angle measure error is less than 43 arc second. The ground verification and application of the star tracker during the pick-up flight test showed that the capability of the product meet the requirement.

  6. Moon Phase as a Context for Teaching Scale Factor

    Science.gov (United States)

    Wallace, Ann; Dickerson, Daniel; Hopkins, Sara

    2007-01-01

    The Sun and the Moon are our most visible neighbors in space, yet their distance and size relative to the Earth are often misunderstood. Science textbooks fuel this misconception because they regularly depict linear images of Moon phases without respect to the actual sizes of the Sun, Earth, and Moon, nor their correlated distances from one…

  7. Columnar Aerosol Properties from Sun-and-star Photometry: Statistical Comparisons and Day-to-night Dynamic

    Science.gov (United States)

    Ramirez, Daniel Perez; Lyamani, H.; Olmo, F. J.; Whiteman, D. N.; Alados-Arboledas, L.

    2012-01-01

    This work presents the first analysis of longterm correlative day-to-night columnar aerosol optical properties. The aim is to better understand columnar aerosol dynamic from ground-based observations, which are poorly studied until now. To this end we have used a combination of sun-and-star photometry measurements acquired in the city of Granada (37.16 N, 3.60 W, 680 ma.s.l.; South-East of Spain) from 2007 to 2010. For the whole study period, mean aerosol optical depth (AOD) around 440 nm (+/-standard deviation) is 0.18 +/- 0.10 and 0.19 +/- 0.11 for daytime and nighttime, respectively, while the mean Angstr¨om exponent (alpha ) is 1.0 +/- 0.4 and 0.9 +/- 0.4 for daytime and nighttime. The ANOVA statistical tests reveal that there are no significant differences between AOD and obtained at daytime and those at nighttime. Additionally, the mean daytime values of AOD and obtained during this study period are coherent with the values obtained in the surrounding AERONET stations. On the other hand, AOD around 440 nm present evident seasonal patterns characterised by large values in summer (mean value of 0.20 +/- 0.10 both at daytime and nighttime) and low values in winter (mean value of 0.15 +/- 0.09 at daytime and 0.17 +/- 0.10 at nighttime). The Angstr¨om exponents also present seasonal patterns, but with low values in summer (mean values of 0.8 +/- 0.4 and 0.9 +/- 0.4 at dayand night-time) and relatively large values in winter (mean values of 1.2 +/- 0.4 and 1.0 +/- 0.3 at daytime and nighttime). These seasonal patterns are explained by the differences in the meteorological conditions and by the differences in the strength of the aerosol sources. To take more insight about the changes in aerosol particles between day and night, the spectral differences of the Angstrom exponent as function of the Angstr¨om exponent are also studied. These analyses reveal increases of the fine mode radius and of the fine mode contribution to AOD during nighttime, being more

  8. Design and Characterization of the 4STAR Sun-Sky Spectrometer with Results from 4- Way Intercomparison of 4STAR, AATS-14, Prede, and Cimel Photometers at Mauna Loa Observatory.

    Science.gov (United States)

    Flynn, C. J.; Dunagan, S. E.; Johnson, R. R.; Schmid, B.; Shinozuka, Y.; Ramachandran, S.; Livingston, J. M.; Russell, P. B.; Redemann, J.; Tran, A. K.; Holben, B. N.

    2008-12-01

    Uncertainties in radiative forcing of climate are still dominated by uncertainties in forcing by aerosols. Aerosols impact the radiation balance in three primary ways: the direct effect through scattering and absorption of radiation, the indirect effect by acting as cloud condensation nuclei affecting cloud optical depth and longevity, and the semi-direct effect affecting cloud formation and longevity through heating and thermodynamics. An active collaboration between the Pacific Northwest National Laboratory (PNNL), National Aeronautics and Space Administration (NASA) Ames Research Center (ARC), and NASA Goddard Space Flight Center (GSFC) is advancing new instrument concepts with application to reducing these aerosol uncertainties. The concept of 4STAR (Spectrometer for Sky-Scanning, Sun-Tracking Atmospheric Research) combines airborne sun tracking capabilities of the Ames Airborne Tracking Sun Photometer (AATS-14) and Aeronet-like sky scanning capability with state-of-the-art monolithic spectrometry. The overall science goal for the new instruments is to improve knowledge of atmospheric constituents and their links to climate. The high-resolution spectral capability will improve retrievals of gas constituents (e.g., H2O, O3, and NO2) and thereby improve determination of aerosol properties as residual components of the total optical depth. The sky scanning capability will enable retrievals of aerosol type (via complex refractive index and shape) and aerosol size distribution extending to larger sizes than attainable by direct-beam sun photometry alone. Additional technical goals are to reduce instrument size, weight, and power requirements while increasing autonomy and component modularity to permit operation on a wide range of aircraft including unmanned aerial vehicles (UAVs). To investigate techniques to accomplish these goals, we developed a ground-based prototype, 4STAR-Ground. The 4STAR-Ground operating performance has been characterized in many tests

  9. 100 billion suns

    International Nuclear Information System (INIS)

    Kippenhahn, R.

    1983-01-01

    A work on the world of astrophysics primarily for lay readers. The author writes only about the discoveries he ''experienced'' during the past 25 years (before 1979). Illustrated somewhat in color plus a set of superb colar plates. Contents, abridged: The long life of stars. The life story of the sun. The life story of massive stars. The end of stars. How stars are born. Planets and their inhabitants

  10. Automatic grid azimuth by hour angle of the sun, a star or a planet using an electronic theodolite Kern E2

    Science.gov (United States)

    Solaric, Nikola

    1991-03-01

    The paper describes a procedure for automatic determinations of the grid azimuth of an object on the earth surface by the hour angle of a celestial object (the sun, a star, or a planet), using the electronic theodolite Kern E2. The observation procedure is simple because the electronic calculator is directing the procedure, and the degree of accuracy is immediately determined. With this method, the external rms error of a single set is approximately two times smaller than in the case of the altitude method. The paper includes a flowchart of the program.

  11. The Sun

    International Nuclear Information System (INIS)

    Hejna, L.; Sobotka, M.

    1987-01-01

    The conference proceedings contain 50 papers classified in six parts. The introductory paper is devoted to magnetic fields of the Sun and of low-mass main-sequence stars. 7 papers discuss the morphology and fine structure of solar active regions, 9 papers deal with evolutionary aspects of the regions, 6 papers with observations and theories of the solar magnetic field, 9 deal with velocity fields, oscillations and waves in the active regions and 18 papers discuss the physical structure of active regions and its diagnostics. (M.D.). 218 figs., 19 tabs., 1,317 refs

  12. AXISYMMETRIC AB INITIO CORE-COLLAPSE SUPERNOVA SIMULATIONS OF 12-25 M{sub Sun} STARS

    Energy Technology Data Exchange (ETDEWEB)

    Bruenn, Stephen W.; Yakunin, Konstantin N. [Department of Physics, Florida Atlantic University, 777 Glades Road, Boca Raton, FL 33431-0991 (United States); Mezzacappa, Anthony; Hix, W. Raphael; Lingerfelt, Eric J. [Physics Division, Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, TN 37831-6354 (United States); Lentz, Eric J. [Department of Physics and Astronomy, University of Tennessee, Knoxville, TN 37996-1200 (United States); Messer, O. E. Bronson [National Center for Computational Sciences, Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, TN 37831-6164 (United States); Blondin, John M. [Department of Physics, North Carolina State University, Raleigh, NC 27695-8202 (United States); Endeve, Eirik [Computer Science and Mathematics Division, Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, TN 37831-6164 (United States); Marronetti, Pedro, E-mail: bruenn@fau.edu [Physics Division, National Science Foundation, Arlington, VA 22207 (United States)

    2013-04-10

    We present an overview of four ab initio axisymmetric core-collapse supernova simulations employing detailed spectral neutrino transport computed with our CHIMERA code and initiated from Woosley and Heger progenitors of mass 12, 15, 20, and 25 M{sub Sun }. All four models exhibit shock revival over {approx}200 ms (leading to the possibility of explosion), driven by neutrino energy deposition. Hydrodynamic instabilities that impart substantial asymmetries to the shock aid these revivals, with convection appearing first in the 12 M{sub Sun} model and the standing accretion shock instability appearing first in the 25 M{sub Sun} model. Three of the models have developed pronounced prolate morphologies (the 20 M{sub Sun} model has remained approximately spherical). By 500 ms after bounce the mean shock radii in all four models exceed 3000 km and the diagnostic explosion energies are 0.33, 0.66, 0.65, and 0.70 Bethe (B = 10{sup 51} erg) for the 12, 15, 20, and 25 M{sub Sun} models, respectively, and are increasing. The three least massive of our models are already sufficiently energetic to completely unbind the envelopes of their progenitors (i.e., to explode), as evidenced by our best estimate of their explosion energies, which first become positive at 320, 380, and 440 ms after bounce. By 850 ms the 12 M{sub Sun} diagnostic explosion energy has saturated at 0.38 B, and our estimate for the final kinetic energy of the ejecta is {approx}0.3 B, which is comparable to observations for lower mass progenitors.

  13. PRE-SUPERNOVA EVOLUTION OF ROTATING SOLAR METALLICITY STARS IN THE MASS RANGE 13-120 M {sub Sun} AND THEIR EXPLOSIVE YIELDS

    Energy Technology Data Exchange (ETDEWEB)

    Chieffi, Alessandro [Istituto Nazionale di Astrofisica-Istituto di Astrofisica e Planetologia Spaziali, Via Fosso del Cavaliere 100, I-00133 Roma (Italy); Limongi, Marco, E-mail: alessandro.chieffi@inaf.it, E-mail: marco.limongi@oa-roma.inaf.it [Centre for Stellar and Planetary Astrophysics, School of Mathematical Sciences, P.O. Box 28M, Monash University, Victoria 3800 (Australia)

    2013-02-10

    We present the first set of a new generation of models of massive stars with a solar composition extending between 13 and 120 M {sub Sun }, computed with and without the effects of rotation. We included two instabilities induced by rotation: the meridional circulation and the shear instability. We implemented two alternative schemes to treat the transport of the angular momentum: the advection-diffusion formalism and the simpler purely diffusive one. The full evolution from the pre-main sequence up to the pre-supernova stage is followed in detail with a very extended nuclear network. The explosive yields are provided for a variety of possible mass cuts and are available at the Web site http://www.iasf-roma.inaf.it/orfeo/public{sub h}tml. We find that both the He and the CO core masses are larger than those of their non-rotating counterparts. Also the C abundance left by the He burning is lower than in the non-rotating case, especially for stars with an initial mass of 13-25 M {sub Sun }, and this affects the final mass-radius relation, basically the final binding energy, at the pre-supernova stage. The elemental yields produced by a generation of stars rotating initially at 300 km s{sup -1} do not change substantially with respect to those produced by a generation of non-rotating massive stars, the main differences being a slight overproduction of the weak s-component and a larger production of F. Since rotation also affects the mass-loss rate, either directly or indirectly, we find substantial differences in the lifetimes as O-type and Wolf-Rayet subtypes between the rotating and non-rotating models. The maximum mass exploding as Type IIP supernova ranges between 15 and 20 M {sub Sun} in both sets of models (this value depends basically on the larger mass-loss rates in the red supergiant phase due to the inclusion of the dust-driven wind). This limiting value is in remarkably good agreement with current estimates.

  14. More Saturnian Moons

    Science.gov (United States)

    2000-10-01

    Saturn takes the lead Following the discovery of at least four additional moons of that planet, Saturn has again taken the lead as the planet with the greatest number of known natural satellites. A corresponding announcement was made today by an international team of astronomers [1] at a meeting of the Division for Planetary Sciences (DPS) of the American Astronomical Society (AAS) in Pasadena (California, USA). The four new faint bodies were spotted during observations in August-September 2000 at several astronomical telescopes around the world. Subsequent orbital calculations have indicated that these objects are almost certainly new satellites of the giant planet. Two Saturnian moons found at La Silla ESO PR Photo 29a/00 ESO PR Photo 29a/00 [Preview - JPEG: 263 x 400 pix - 26k] [Normal - JPEG: 525 x 800 pix - 93k] ESO PR Photo 29b/00 ESO PR Photo 29b/00 [Preview - JPG: 289 x 400 pix - 43k] [Normal - JPG: 578 x 800 pix - 432k] ESO PR Photo 29c/00 ESO PR Photo 29c/00 [Animated GIF: 330 x 400 pix - 208k] Captions : The photos show the discovery images of two new Saturnian moons, as registered on August 7, 2000, with the Wide-Field Imager (WFI) camera at the MPG/ESO 2.2-m telescope at the La Silla Observatory. Photo PR 29a/00 displays the faint image of the newly discovered moon S/2000 S 1 in the lower right corner of the field. A spiral galaxy is seen in the upper left corner of this photo. The other objects are (background) stars in the Milky Way. Photo PR 29b/00 is a combination of three successive WFI exposures of the second moon, S/2000 S 2 . Because of its motion, there are three images (to the left). Photo PR 29c/00 is an animated GIF image of the same three exposures that demonstrates this motion. Technical details are found below. The observations of the first two objects are described on a Circular of the International Astronomical Union (IAU) that was issued today [2]. The images of these new moons were first registered on exposures made on August 7, 2000

  15. DETECTABILITY OF EARTH-LIKE PLANETS IN CIRCUMSTELLAR HABITABLE ZONES OF BINARY STAR SYSTEMS WITH SUN-LIKE COMPONENTS

    International Nuclear Information System (INIS)

    Eggl, Siegfried; Pilat-Lohinger, Elke; Haghighipour, Nader

    2013-01-01

    Given the considerable percentage of stars that are members of binaries or stellar multiples in the solar neighborhood, it is expected that many of these binaries host planets, possibly even habitable ones. The discovery of a terrestrial planet in the α Centauri system supports this notion. Due to the potentially strong gravitational interaction that an Earth-like planet may experience in such systems, classical approaches to determining habitable zones (HZ), especially in close S-type binary systems, can be rather inaccurate. Recent progress in this field, however, allows us to identify regions around the star permitting permanent habitability. While the discovery of α Cen Bb has shown that terrestrial planets can be detected in solar-type binary stars using current observational facilities, it remains to be shown whether this is also the case for Earth analogs in HZs. We provide analytical expressions for the maximum and rms values of radial velocity and astrometric signals, as well as transit probabilities of terrestrial planets in such systems, showing that the dynamical interaction of the second star with the planet may indeed facilitate the planets' detection. As an example, we discuss the detectability of additional Earth-like planets in the averaged, extended, and permanent HZs around both stars of the α Centauri system.

  16. DETECTABILITY OF EARTH-LIKE PLANETS IN CIRCUMSTELLAR HABITABLE ZONES OF BINARY STAR SYSTEMS WITH SUN-LIKE COMPONENTS

    Energy Technology Data Exchange (ETDEWEB)

    Eggl, Siegfried; Pilat-Lohinger, Elke [University of Vienna, Institute for Astrophysics, Tuerkenschanzstr. 17, A-1180 Vienna (Austria); Haghighipour, Nader, E-mail: siegfried.eggl@univie.ac.at [Institute for Astronomy and NASA Astrobiology Institute, 2680 Woodlawn Drive, Honolulu, HI 96822 (United States)

    2013-02-20

    Given the considerable percentage of stars that are members of binaries or stellar multiples in the solar neighborhood, it is expected that many of these binaries host planets, possibly even habitable ones. The discovery of a terrestrial planet in the {alpha} Centauri system supports this notion. Due to the potentially strong gravitational interaction that an Earth-like planet may experience in such systems, classical approaches to determining habitable zones (HZ), especially in close S-type binary systems, can be rather inaccurate. Recent progress in this field, however, allows us to identify regions around the star permitting permanent habitability. While the discovery of {alpha} Cen Bb has shown that terrestrial planets can be detected in solar-type binary stars using current observational facilities, it remains to be shown whether this is also the case for Earth analogs in HZs. We provide analytical expressions for the maximum and rms values of radial velocity and astrometric signals, as well as transit probabilities of terrestrial planets in such systems, showing that the dynamical interaction of the second star with the planet may indeed facilitate the planets' detection. As an example, we discuss the detectability of additional Earth-like planets in the averaged, extended, and permanent HZs around both stars of the {alpha} Centauri system.

  17. NEW RARE EARTH ELEMENT ABUNDANCE DISTRIBUTIONS FOR THE SUN AND FIVE r-PROCESS-RICH VERY METAL-POOR STARS

    International Nuclear Information System (INIS)

    Sneden, Christopher; Lawler, James E.; Den Hartog, Elizabeth A.; Cowan, John J.; Ivans, Inese I.

    2009-01-01

    We have derived new abundances of the rare earth elements Pr, Dy, Tm, Yb, and Lu for the solar photosphere and for five very metal-poor, neutron-capture r-process-rich giant stars. The photospheric values for all five elements are in good agreement with meteoritic abundances. For the low-metallicity sample, these abundances have been combined with new Ce abundances from a companion paper, and reconsideration of a few other elements in individual stars, to produce internally consistent Ba, rare earth, and Hf (56 ≤ Z ≤ 72) element distributions. These have been used in a critical comparison between stellar and solar r-process abundance mixes.

  18. Solar neutrinos, rendezvous with the moon. An eclipse provides an indication for the huge neutrinos inquiry

    International Nuclear Information System (INIS)

    Vannucci, F.

    1996-01-01

    Solar neutrinos have raised for twenty years a puzzling problem: the neutrinos flux received on the Earth is greatly lower than the flux predicted by the prevailing model of star functioning. The neutrino oscillation hypothesis has been put forward to explain this problem. This paper describes a simple experiment carried out in Viet Nam using a telescope during a sun eclipse to measure the photon emission due to the neutrinos decay between the moon and the Earth. In this experiment, the moon plays the role of a filter which eliminates the sun photons. No significant excess of photons has been detected. This result gives some additional constraints to the existing models. (J.S.). 3 refs., 1 photo

  19. K- and M-type dwarf stars within 25 parsecs of the sun. I. The age-chromospheric activity relations from H-alpha equivalent widths

    Energy Technology Data Exchange (ETDEWEB)

    Eggen, O.J. (Observatorio Interamericano de Cerro Totolo, La Serena (Chile))

    1990-02-01

    The available equivalent-width measurements of H-alpha in dwarf K and M stars within 25 pc of the sun indicate that, as a chromospheric diagnostic, the H-alpha decay rate is about t exp 0.5. The decay rate of line emission in Mg II h and k (Ca II H and K) is about t exp 0.3. The decay rates are derived from observations of members of a few stellar superclusters and groups, for which the consistency of results argues strongly for the importance of more data. The only major inconsistency encountered is for the unique HR 1614 group which, in the age/chromospheric-activity progression, gives different results from Mg II h and k and from WH-alpha. 63 refs.

  20. Habitability in the Solar System and on Extrasolar Planets and Moons

    Science.gov (United States)

    McKay, Christopher P.

    2015-01-01

    The criteria for a habitable world initially was based on Earth and centered around liquid water on the surface, warmed by a Sun-like star. The moons of the outer Solar System, principally Europa and Enceladus, have demonstrated that liquid water can exist below the surface warmed by tidal forces from a giant planet. Titan demonstrates that surface liquids other than water - liquid methane/ethane - may be common on other worlds. Considering the numerous extrasolar planets so far discovered and the prospect of discovering extrasolar moons it is timely to reconsider the possibilities for habitability in the Solar System and on extrasolar planets and moons and enumerate the attributes and search methods for detecting habitable worlds and evidence of life.

  1. The star book an introduction to stargazing and the solar system

    CERN Document Server

    Grego, Peter

    2012-01-01

    An Introduction to Stargazing and the Solar System is an introductory section taken from The Star Book that guides you through the night skies, from the history and lives of the stars, to deep-sky objects beyond the Milky Way, and the Celestial Sphere. Followed by an introductory guide to the solar system with high quality images and observational drawings of the planets, covering the Sun, Moon, Inferior and Superior planets. Everyone is interested in the stars and on a clear night astonished by them. The Star Book will answer any questions you may have whe

  2. A SPITZER MIPS STUDY OF 2.5-2.0 M{sub Sun} STARS IN SCORPIUS-CENTAURUS

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Christine H.; Bitner, Martin [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Pecaut, Mark; Mamajek, Eric E. [Department of Physics and Astronomy, University of Rochester, Rochester, NY 14627 (United States); Su, Kate Y. L., E-mail: cchen@stsci.edu [Steward Observatory, University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721 (United States)

    2012-09-10

    We have obtained Spitzer Space Telescope Multiband Imaging Photometer for Spitzer (MIPS) 24 {mu}m and 70 {mu}m observations of 215 nearby, Hipparcos B- and A-type common proper-motion single and binary systems in the nearest OB association, Scorpius-Centaurus. Combining our MIPS observations with those of other ScoCen stars in the literature, we estimate 24 {mu}m B+A-type disk fractions of 17/67 (25{sup +6}{sub -5}%), 36/131 (27{sup +4}{sub -4}%), and 23/95 (24{sup +5}{sub -4}%) for Upper Scorpius ({approx}11 Myr), Upper Centaurus Lupus ({approx}15 Myr), and Lower Centaurus Crux ({approx}17 Myr), respectively, somewhat smaller disk fractions than previously obtained for F- and G-type members. We confirm previous IRAS excess detections and present new discoveries of 51 protoplanetary and debris disk systems, with fractional infrared luminosities ranging from L{sub IR}/L{sub *} = 10{sup -6} to 10{sup -2} and grain temperatures ranging from T{sub gr} = 40 to 300 K. In addition, we confirm that the 24 {mu}m and 70 {mu}m excesses (or fractional infrared luminosities) around B+A-type stars are smaller than those measured toward F+G-type stars and hypothesize that the observed disk property dependence on stellar mass may be the result of a higher stellar companion fraction around B- and A-type stars at 10-200 AU. Finally, we note that the majority of the ScoCen 24 {mu}m excess sources also possess 12 {mu}m excess, indicating that Earth-like planets may be forming via collisions in the terrestrial planet zone at {approx}10-100 Myr.

  3. Sun, the Earth, and Near-Earth Space: A Guide to the Sun-Earth System

    Science.gov (United States)

    Eddy, John A.

    2010-01-01

    In a world of warmth and light and living things we soon forget that we are surrounded by a vast universe that is cold and dark and deadly dangerous, just beyond our door. On a starry night, when we look out into the darkness that lies around us, the view can be misleading in yet another way: for the brightness and sheer number of stars, and their chance groupings into familiar constellations, make them seem much nearer to each other, and to us, that in truth they are. And every one of them--each twinkling, like a diamond in the sky--is a white-hot sun, much like our own. The nearest stars in our own galaxy--the Milky Way-- are more than a million times further away from us than our star, the Sun. We could make a telephone call to the Moon and expect to wait but a few seconds between pieces of a conversation, or but a few hours in calling any planet in our solar system.

  4. MagAO IMAGING OF LONG-PERIOD OBJECTS (MILO). II. A PUZZLING WHITE DWARF AROUND THE SUN-LIKE STAR HD 11112

    International Nuclear Information System (INIS)

    Rodigas, Timothy J.; Arriagada, Pamela; Faherty, Jacqueline K.; Weinberger, Alycia; Butler, R. Paul; Bergeron, P.; Simon, Amélie; Anglada-Escudé, Guillem; Mamajek, Eric E.; Males, Jared R.; Morzinski, Katie; Close, Laird M.; Hinz, Philip M.; Bailey, Jeremy; Tinney, C. G.; Wittenmyer, Rob; Carter, Brad; Jenkins, James S.; Jones, Hugh; O’Toole, Simon

    2016-01-01

    HD 11112 is an old, Sun-like star that has a long-term radial velocity (RV) trend indicative of a massive companion on a wide orbit. Here we present direct images of the source responsible for the trend using the Magellan Adaptive Optics system. We detect the object (HD 11112B) at a separation of 2.″2 (100 au) at multiple wavelengths spanning 0.6–4 μ m and show that it is most likely a gravitationally bound cool white dwarf. Modeling its spectral energy distribution suggests that its mass is 0.9–1.1 M ⊙ , which corresponds to very high eccentricity, near edge-on orbits from a Markov chain Monte Carlo analysis of the RV and imaging data together. The total age of the white dwarf is >2 σ , which is discrepant with that of the primary star under most assumptions. The problem can be resolved if the white dwarf progenitor was initially a double white dwarf binary that then merged into the observed high-mass white dwarf. HD 11112B is a unique and intriguing benchmark object that can be used to calibrate atmospheric and evolutionary models of cool white dwarfs and should thus continue to be monitored by RV and direct imaging over the coming years.

  5. MagAO IMAGING OF LONG-PERIOD OBJECTS (MILO). II. A PUZZLING WHITE DWARF AROUND THE SUN-LIKE STAR HD 11112

    Energy Technology Data Exchange (ETDEWEB)

    Rodigas, Timothy J.; Arriagada, Pamela; Faherty, Jacqueline K.; Weinberger, Alycia; Butler, R. Paul [Department of Terrestrial Magnetism, Carnegie Institution of Washington, 5241 Broad Branch Road, NW, Washington, DC 20015 (United States); Bergeron, P.; Simon, Amélie [Département de Physique, Université de Montréal, C.P. 6128, Succ. Centre-Ville, Montréal, Québec H3C 3J7 (Canada); Anglada-Escudé, Guillem [School of Physics and Astronomy, Queen Mary, University of London, 327 Mile End Road, London (United Kingdom); Mamajek, Eric E. [Department of Physics and Astronomy, University of Rochester, Rochester, NY 14627-0171 (United States); Males, Jared R.; Morzinski, Katie; Close, Laird M.; Hinz, Philip M. [Steward Observatory, The University of Arizona, 933 N. Cherry Avenue, Tucson, AZ 85721 (United States); Bailey, Jeremy; Tinney, C. G.; Wittenmyer, Rob [Exoplanetary Science at UNSW, School of Physics, UNSW Australia, Sydney, NSW 2052 (Australia); Carter, Brad [Computational Engineering and Science Research Centre, University of Southern Queensland, Springfield, QLD 4300 (Australia); Jenkins, James S. [Departamento de Astronomia, Universidad de Chile, Casilla 36-D, Las Condes, Santiago (Chile); Jones, Hugh [Centre for Astrophysics Research, University of Hertfordshire, College Lane, Hatfield, Herts AL10 9AB (United Kingdom); O’Toole, Simon, E-mail: trodigas@carnegiescience.edu [Australian Astronomical Observatory, P.O. Box 915, North Ryde, NSW 1670 (Australia); and others

    2016-11-10

    HD 11112 is an old, Sun-like star that has a long-term radial velocity (RV) trend indicative of a massive companion on a wide orbit. Here we present direct images of the source responsible for the trend using the Magellan Adaptive Optics system. We detect the object (HD 11112B) at a separation of 2.″2 (100 au) at multiple wavelengths spanning 0.6–4 μ m and show that it is most likely a gravitationally bound cool white dwarf. Modeling its spectral energy distribution suggests that its mass is 0.9–1.1 M {sub ⊙}, which corresponds to very high eccentricity, near edge-on orbits from a Markov chain Monte Carlo analysis of the RV and imaging data together. The total age of the white dwarf is >2 σ , which is discrepant with that of the primary star under most assumptions. The problem can be resolved if the white dwarf progenitor was initially a double white dwarf binary that then merged into the observed high-mass white dwarf. HD 11112B is a unique and intriguing benchmark object that can be used to calibrate atmospheric and evolutionary models of cool white dwarfs and should thus continue to be monitored by RV and direct imaging over the coming years.

  6. Is the Dark Side of the Moon Ever Illuminated by the Sun? (Breton Title: O Lado Escuro da Lua Nunca Apanha Sol?) El Lado Oscuro de la Luna Nunca Toma Sol?

    Science.gov (United States)

    Giovannini, Odilon; Pellenz, Daiana; Catelli, Francisco

    2014-07-01

    This work presents the elaboration of an answer to the question "Is the dark side of the moon ever illuminated by the sun?", in which issues related to the students' conceptions, how they arise, and the core elements that constitute a "good answer" are considered. These issues are initially elaborated from a literature review of the research in the field; then, and also based on this review, a didactic model that involves the relative motions of the Earth - Moon - Sun system is proposed. A description of the application of this model in a learning environment within middle school students is described. This work confirms the students' initial concepts described in the literature; on the other hand, the questions asked by students during the activity provide evidence that meaningful learning, at least to some degree, has occurred. Este trabalho apresenta a elaboração de uma resposta à pergunta "O lado escuro da Lua nunca apanha sol?" na qual são consideradas questões relacionadas às concepções iniciais dos alunos, de onde elas surgem e os elementos centrais que constituem uma "boa resposta". Essas questões são tratadas, inicialmente, a partir de uma revisão da literatura sobre pesquisas na área e, em seguida, também com base nessa revisão, um objeto modelo didático que envolve os movimentos relativos do sistema Terra - Lua - Sol é proposto. Uma descrição detalhada da aplicação deste modelo em um ambiente de aprendizagem com alunos do ensino fundamental é relatada. As concepções iniciais apresentadas na literatura se confirmam e os questionamentos feitos pelos estudantes por ocasião da aplicação do modelo fornecem indícios de que uma aprendizagem significativa, pelo menos em algum grau, ocorreu. El artículo se presenta el desarrollo de una respuesta a la pregunta "¿El lado oscuro de la luna nunca toma sol?", en la que se consideran algunas cuestiones vinculadas que se refieren a las concepciones iniciales de los estudiantes, dónde surgen

  7. Histograms Constructed from the Data of 239-Pu Alpha-Activity Manifest a Tendency for Change in the Similar Way as at the Moments when the Sun, the Moon, Venus, Mars and Mercury Intersect the Celestial Equator

    Directory of Open Access Journals (Sweden)

    Kharakoz D. P.

    2011-04-01

    Full Text Available Earlier, the shape of histograms of the results of measurements obtained in processes of different physical nature had been shown to be determined by cosmophysical factors. Appearance of histograms of a similar shape is repeated periodically: these are the near-a-day, near-27-days and annual periods of increased probability of the similar shapes. There are two distinctly distinguished near-a-day periods: the sidereal-day (1,436 minutes and solar-day (1,440 minutes ones. The annual periods are represented by three sub-periods: the "calendar" (365 average solar days, "tropical" (365 days 5 hours and 48 minutes and "sidereal" (365 days 6 hours and 9 minutes ones. The tropical year period indicates that fact that histogram shape depends on the time elapsed since the spring equinox.The latter dependence is studied in more details in this work. We demonstrate that the appearance of similar histograms is highly probable at the same time count off from the moments of equinoxes, independent from the geographic location where the measurements had been performed: in Pushchino, Moscow Region (54 deg NL, 37 deg EL, and in Novolazarevskaya, Antarctic (70 deg SL, 11 deg EL. The sequence of the changed histogram shapes observed at the spring equinoxes was found to be opposite to that observed at the autumnal equinoxes. As the moments of equinoxes are defined by the cross of the celestial equator by Sun, we also studied that weather is not the same as observed at the moments when the celestial equator was crossed by other celestial bodies - the Moon, Venus, Mars and Mercury. Let us, for simplicity, refer to these moments as a similar term "planetary equinoxes". The regularities observed at these "planetary equinoxes" had been found to be the same as in the case of true solar equinoxes. In this article, we confine ourselves to considering the phenomenological observations only; their theoretical interpretation is supposed to be subject of further studies.

  8. Sun Allergy

    Science.gov (United States)

    Sun allergy Overview Sun allergy is a term often used to describe a number of conditions in which an itchy red rash occurs on skin that has been exposed to sunlight. The most common form of sun allergy is ...

  9. Experience the Moon

    Science.gov (United States)

    Ortiz-Gil, A.; Benacchio, L.; Boccato, C.

    2011-10-01

    The Moon is, together with the Sun, the very first astronomical object that we experience in our life. As this is an exclusively visual experience, people with visual impairments need a different mode to experience it too. This statement is especially true when events, such as more and more frequent public observations of sky, take place. This is the reason why we are preparing a special package for visual impaired people containing three brand new items: 1. a tactile 3D Moon sphere in Braille with its paper key in Braille. To produce it we used imaging data obtained by NASA's mission Clementine, along with free image processing and 3D rendering software. In order to build the 3D small scale model funding by Europlanet and the Italian Ministry for Research have been used. 2. a multilingual web site for visually impaired users of all ages, on basic astronomy together with an indepth box about the Moon; 3. a book in Braille with the same content of the Web site mentioned above. All the items will be developed with the collaboration of visually impaired people that will check each step of the project and support their comments and criticism to improve it. We are going to test this package during the next International Observe the Moon Night event. After a first testing phase we'll collect all the feedback data in order to give an effective form to the package. Finally the Moon package could be delivered to all those who will demand it for outreach or educational goals.

  10. The Sun in Time: Activity and Environment

    Directory of Open Access Journals (Sweden)

    Güdel Manuel

    2007-12-01

    Full Text Available The Sun's magnetic activity has steadily declined during its main-sequence life. While the solar photospheric luminosity was about 30% lower 4.6 Gyr ago when the Sun arrived on the main sequence compared to present-day levels, its faster rotation generated enhanced magnetic activity; magnetic heating processes in the chromosphere, the transition region, and the corona induced ultraviolet, extreme-ultraviolet, and X-ray emission about 10, 100, and 1000 times, respectively, the present-day levels, as inferred from young solar-analog stars. Also, the production rate of accelerated, high-energy particles was orders of magnitude higher than in present-day solar flares, and a much stronger wind escaped from the Sun, permeating the entire solar system. The consequences of the enhanced radiation and particle fluxes from the young Sun were potentially severe for the evolution of solar-system planets and moons. Interactions of high-energy radiation and the solar wind with upper planetary atmospheres may have led to the escape of important amounts of atmospheric constituents. The present dry atmosphere of Venus and the thin atmosphere of Mars may be a product of early irradiation and heating by solar high-energy radiation. High levels of magnetic activity are also inferred for the pre-main sequence Sun. At those stages, interactions of high-energy radiation and particles with the circumsolar disk in which planets eventually formed were important. Traces left in meteorites by energetic particles and anomalous isotopic abundance ratios in meteoritic inclusions may provide evidence for a highly active pre-main sequence Sun. The present article reviews these various issues related to the magnetic activity of the young Sun and the consequent interactions with its environment. The emphasis is on the phenomenology related to the production of high-energy photons and particles. Apart from the activity on the young Sun, systematic trends applicable to the entire

  11. The Sun and Earth

    Science.gov (United States)

    Gopalswamy, Natchimuthuk

    2012-01-01

    Thus the Sun forms the basis for life on Earth via the black body radiation it emits. The Sun also emits mass in the form of the solar wind and the coronal mass ejections (CMEs). Mass emission also occurs in the form of solar energetic particles (SEPs), which happens during CMEs and solar flares. Both the mass and electromagnetic energy output of the Sun vary over a wide range of time scales, thus introducing disturbances on the space environment that extends from the Sun through the entire heliosphere including the magnetospheres and ionospheres of planets and moons of the solar system. Although our habitat is located in the neutral atmosphere of Earth, we are intimately connected to the non-neutral space environment starting from the ionosphere to the magnetosphere and to the vast interplanetary space. The variability of the solar mass emissions results in the interaction between the solar wind plasma and the magnetospheric plasma leading to huge disturbances in the geospace. The Sun ionizes our atmosphere and creates the ionosphere. The ionosphere can be severely disturbed by the transient energy input from solar flares and the solar wind during geomagnetic storms. The complex interplay between Earth's magnetic field and the solar magnetic field carried by the solar wind presents varying conditions that are both beneficial and hazardous to life on earth. This seminar presents some of the key aspects of this Sun-Earth connection that we have learned since the birth of space science as a scientific discipline some half a century ago.

  12. FOOLISH MOON

    OpenAIRE

    Wang, Jingjing

    2017-01-01

    Foolish Moon is a product design for Chinese young adults who come to big Chinese cities to fight for their dreams to help them to slow down, to think more, to be practical and patient under the influence of fast culture which makes people eager to quick success. It has two physical parts, a moon phase clock anda work journal book, and three functions: 1) a new time experience of slow, stable and circular; 2) to encourage people to write down their goals and plans; 3) to make time capsules to...

  13. Stars Just Got Bigger - A 300 Solar Mass Star Uncovered

    Science.gov (United States)

    2010-07-01

    they age," says Paul Crowther. "Being a little over a million years old, the most extreme star R136a1 is already 'middle-aged' and has undergone an intense weight loss programme, shedding a fifth of its initial mass over that time, or more than fifty solar masses." If R136a1 replaced the Sun in our Solar System, it would outshine the Sun by as much as the Sun currently outshines the full Moon. "Its high mass would reduce the length of the Earth's year to three weeks, and it would bathe the Earth in incredibly intense ultraviolet radiation, rendering life on our planet impossible," says Raphael Hirschi from Keele University, who belongs to the team. These super heavyweight stars are extremely rare, forming solely within the densest star clusters. Distinguishing the individual stars - which has now been achieved for the first time - requires the exquisite resolving power of the VLT's infrared instruments [2]. The team also estimated the maximum possible mass for the stars within these clusters and the relative number of the most massive ones. "The smallest stars are limited to more than about eighty times more than Jupiter, below which they are 'failed stars' or brown dwarfs," says team member Olivier Schnurr from the Astrophysikalisches Institut Potsdam. "Our new finding supports the previous view that there is also an upper limit to how big stars can get, although it raises the limit by a factor of two, to about 300 solar masses." Within R136, only four stars weighed more than 150 solar masses at birth, yet they account for nearly half of the wind and radiation power of the entire cluster, comprising approximately 100 000 stars in total. R136a1 alone energises its surroundings by more than a factor of fifty compared to the Orion Nebula cluster, the closest region of massive star formation to Earth. Understanding how high mass stars form is puzzling enough, due to their very short lives and powerful winds, so that the identification of such extreme cases as R136a1

  14. sanghoon moon

    Indian Academy of Sciences (India)

    Home; Journals; Journal of Genetics. SANGHOON MOON. Articles written in Journal of Genetics. Volume 96 Issue 6 December 2017 pp 1041-1046 Research article. Genome-based exome sequencing analysis identifies GYG1, DIS3L and DDRGK1 are associated with myocardial infarction in Koreans · JI-YOUNG LEE ...

  15. The sun in time

    International Nuclear Information System (INIS)

    Sonett, C.P.; Giampapa, M.S.; Matthews, M.S.

    1991-01-01

    Various papers on solar science are presented. The topics considered include: variability of solar irradiance, sunspot number, solar diameter, and solar wind properties; theory of luminosity and radius variations; standard solar models; the sun and the IMF; variations of cosmic-ray flux with time; accelerated particles in solar flares; solar cosmic ray fluxes during the last 10 million yrs; solar neutrinos and solar history; time variations of Be-10 and solar activity; solar and terrestrial components of the atmospheric C-14 variation spectrum; solar flare heavy-ion tracks in extraterrestrial objects. Also addressed are: the faint young sun problem; atmospheric responses to solar irradiation; quaternary glaciations; solar-terrestrial relationships in recent sea sediments; magnetic history of the sun; pre- and main-sequence evolution of solar activity; magnetic activity in pre-main-sequence stars; classical T Tauri stars; relict magnetism of meteorites; luminosity variability of solar-type stars; evolution of angular momentum in solar-mass stars; time evolution of magnetic fields on solarlike stars

  16. Sun protection

    Science.gov (United States)

    ... sun exposure. The start of summer is when UV rays can cause the most skin damage. Use sun protection, even on cloudy days. Clouds and haze don't protect you from the sun. Avoid surfaces that reflect light, such as water, sand, concrete, snow, and areas ...

  17. Tracking Planets around the Sun

    Science.gov (United States)

    Riddle, Bob

    2008-01-01

    In earlier columns, the celestial coordinate system of hour circles of right ascension and degrees of declination was introduced along with the use of an equatorial star chart (see SFA Star Charts in Resources). This system shows the planets' motion relative to the ecliptic, the apparent path the Sun follows during the year. An alternate system,…

  18. NEW SUNS IN THE COSMOS?

    Energy Technology Data Exchange (ETDEWEB)

    De Freitas, D. B.; Leao, I. C.; Lopes, C. E. Ferreira; Paz-Chinchon, F.; Canto Martins, B. L.; Alves, S.; De Medeiros, J. R. [Departamento de Fisica, Universidade Federal do Rio Grande do Norte, 59072-970 Natal, RN (Brazil); Catelan, M. [Departamento de Astronomia y Astrofisica, Pontificia Universidad Catolica de Chile, Av. Vicuna Mackenna 4860, 782-0436 Macul, Santiago (Chile)

    2013-08-20

    The present work reports on the discovery of three stars that we have identified to be rotating Sun-like stars, based on rotational modulation signatures inferred from light curves from the CoRoT mission's Public Archives. In our analysis, we performed an initial selection based on the rotation period and position in the period-T{sub eff} diagram. This revealed that the stars CoRoT IDs 100746852, 102709980, and 105693572 provide potentially good matches to the Sun with a similar rotation period. To refine our analysis, we applied a novel procedure, taking into account the fluctuations of the features associated with photometric modulation at different time intervals and the fractality traces that are present in the light curves of the Sun and of these ''New Sun'' candidates alike. In this sense, we computed the so-called Hurst exponent for the referred stars, for a sample of 14 CoRoT stars with sub- and super-solar rotational periods, and for the Sun itself in its active and quiet phases. We found that the Hurst exponent can provide a strong discriminant of Sun-like behavior, going beyond what can be achieved with solely the rotation period itself. In particular, we find that CoRoT ID 105693572 is the star that most closely matches the solar rotation properties as far as the latter's imprints on light curve behavior are concerned. The stars CoRoT IDs 100746852 and 102709980 have significant smaller Hurst exponents than the Sun, notwithstanding their similarity in rotation periods.

  19. The Moon

    Science.gov (United States)

    Warren, P. H.

    2003-12-01

    Oxygen isotopic data suggest that there is a genetic relationship between the constituent matter of the Moon and Earth (Wiechert et al., 2001). Yet lunar materials are obviously different from those of the Earth. The Moon has no hydrosphere, virtually no atmosphere, and compared to the Earth, lunar materials uniformly show strong depletions of even mildly volatile constituents such as potassium, in addition to N2, O2, and H2O (e.g., Wolf and Anders, 1980). Oxygen fugacity is uniformly very low ( BVSP, 1981) and even the earliest lunar magmas seem to have been virtually anhydrous. These features have direct and far-reaching implications for mineralogical and geochemical processes. Basically, they imply that mineralogical diversity and thus variety of geochemical processes are subdued; a factor that to some extent offsets the comparative dearth of available data for lunar geochemistry.The Moon's gross physical characteristics play an important role in the more limited range of selenochemical compared to terrestrial geochemical processes. Although exceptionally large (radius=1,738 km) in relation to its parent planet, the Moon is only 0.012 times as massive as Earth. By terrestrial standards, pressures inside the Moon are feeble: the upper mantle gradient is 0.005 GPa km -1 (versus 0.033 GPa km -1 in Earth) and the central pressure is slightly less than 5 GPa. However, lunar interior pressures are sufficient to profoundly influence igneous processes (e.g., Warren and Wasson, 1979b; Longhi, 1992, 2002), and in this sense the Moon more resembles a planet than an asteroid.Another direct consequence of the Moon's comparatively small size was early, rapid decay of its internal heat engine. But the Moon's thermal disadvantage has resulted in one great advantage for planetology. Lunar surface terrains, and many of the rock samples acquired from them, retain for the most part characteristics acquired during the first few hundred million years of solar system existence. The

  20. The Solar system.Stars and constellations

    Science.gov (United States)

    Horia Minda, Octavian

    2017-04-01

    It is important for students to understand what is in our Solar System. The Students need to know that there are other things besides the Earth, Sun and Moon in the solar sky. The students will learn about the other eight planets and a few other celestial objects like stars and constellations. Constellations are useful because they can help people to recognize stars in the sky. By looking for patterns, the stars and locations can be much easier to spot. The constellations had uses in ancient times. They were used to help keep track of the calendar. This was very important so that people knew when to plant and harvest crops. Another important use for constellations was navigation. By finding Ursa Minor it is fairly easy to spot the North Star (Polaris). Using the height of the North Star in the sky, navigators could figure out their latitude helping ships to travel across the oceans. Objective: 1. The students will be introduced to the origin of the stars they see at night. 2. They will learn that there are groups of stars called constellations. The students will individually create their own constellations. They will be given the chance to tell the class a small story explaining their constellation. Evaluation of Children: The children will be evaluated through the creation of their constellations and ability to work in groups on the computers.

  1. Sun Safety

    Science.gov (United States)

    ... Children from the Sun? Are There Benefits to Spending Time Outdoors? The Surgeon General’s Call to Action to Prevent Skin Cancer Related Resources Sun Safety Tips for Men Tips for Families Tips for Schools Tips for Employers Tips for ...

  2. baonan sun

    Indian Academy of Sciences (India)

    Home; Journals; Pramana – Journal of Physics. BAONAN SUN. Articles written in Pramana – Journal of Physics. Volume 90 Issue 2 February 2018 pp 23 Research Article. Rogue waves in the multicomponent Mel'nikov system and multicomponent Schrödinger–Boussinesq system · BAONAN SUN ZHAN LIAN.

  3. Fengrui Sun

    Indian Academy of Sciences (India)

    Home; Journals; Sadhana. Fengrui Sun. Articles written in Sadhana. Volume 34 Issue 5 October 2009 pp 851-864. Profit rate performance optimization for a generalized irreversible combined refrigeration cycle · Kang Ma Lingen Chen Fengrui Sun · More Details Abstract Fulltext PDF. Finite-time exergoeconomic ...

  4. Life of a star

    International Nuclear Information System (INIS)

    Henbest, Nigel.

    1988-01-01

    The paper concerns the theory of stellar evolution. A description is given of:- how a star is born, main sequence stars, red giants, white dwarfs, supernovae, neutron stars and black holes. A brief explanation is given of how the death of a star as a supernova can trigger off the birth of a new generation of stars. Classification of stars and the fate of our sun, are also described. (U.K.)

  5. Solar sketching a comprehensive guide to drawing the sun

    CERN Document Server

    Rix, Erika; Russell, Sally; Handy, Richard

    2015-01-01

    From the authors of Sketching the Moon comes a comprehensive guide filled with richly illustrated, detailed drawing tutorials that cover a variety of solar phenomena. Time-honored, traditional methods and media are described in tandem with innovative techniques developed and shared by contemporary astronomical sketchers. Explanations of what to expect visually from white light, Hydrogen-alpha and Calcium K filters are provided for those new to solar observing, along with essential tips on equipment, observing techniques and the practicalities of drawing at the eyepiece. For the technically minded, detailed descriptions are given on how to use image manipulation software to bring your sketches to life through animation.   The Sun is the most visually dynamic object in our solar system and offers compelling, spectacular views. Knotted magnetic field lines give rise to powerful eruptions and form the intricate sunspots and arching prominences that make our nearest star one of the most exciting, yet challenging,...

  6. Precession of the Earth-Moon System

    Science.gov (United States)

    Urbassek, Herbert M.

    2009-01-01

    The precession rate of the Earth-Moon system by the gravitational influence of the Sun is derived. Attention is focussed on a physically transparent but complete presentation accessible to first- or second-year physics students. Both a shortcut and a full analysis are given, which allows the inclusion of this material as an example of the physics…

  7. Sun meter

    Science.gov (United States)

    Younskevicius, Robert E.

    1978-01-01

    A simple, inexpensive device for measuring the radiation energy of the sun impinging on the device. The measurement of the energy over an extended period of time is accomplished without moving parts or tracking mechanisms.

  8. Tribute to Sun Kwok

    International Nuclear Information System (INIS)

    Leung, Kam Ching

    2016-01-01

    Sun Kwok was bom in Hong Kong in 1949. He did all his early schooling in Hong Kong and went to the same high school, Pui Ching Middle School, as I did but he was more than a decade later. There are two Education Systems in Hong Kong; the Chinese Language Schools and English Language School. Pui Ching was started by Christian missionaries in China and has a long history of providing quality education. Pui Ching is a Chinese Language School, and during colonial times, school entrance was difficult for students as we were not eligible to apply for admission to the University of Hong Kong, nor were we able to join the civil service. In spite of these handicaps, the school still managed to produce many excellent academics, including one Nobel Prize winner in physics and one Field's medalist in mathematics. Most of its graduates who sought further education went to the U.S. Or Canada as Sun Kwok did. Sun graduated from McMaster University and then went to the University of Minnesota for graduate studies. In the early 1970s, the University of Minnesota had just built one of the world's first infrared bolometers and the astronomers there (Nick Woolf and Ed Ney) were able to make some of the first infrared observations in the mid-infrared region. Through these observations, circumstellar dust was discovered, leading to the realization the evolved stars are losing mass. Sun wrote his PhD thesis on the mass loss mechanism of red giant stars, proposing that the stellar winds are driven by the mechanism of radiation pressure on grains. His 1975 paper is still widely cited to this date. In the same thesis, he showed that OH maser emission is a manifestation of the mass loss process and OH/IR stars are the most heavily mass-losing stars known. He went back to Canada for postdoctoral studies, first at UBC and then at York University. While at York, he applied his knowledge of mass loss to the problem of formation of planetary nebulae, leading to now well-established interacting

  9. The Early Years: The Earth-Sun System

    Science.gov (United States)

    Ashbrook, Peggy

    2015-01-01

    We all experience firsthand many of the phenomena caused by Earth's Place in the Universe (Next Generation Science Standard 5-ESS1; NGSS Lead States 2013) and the relative motion of the Earth, Sun, and Moon. Young children can investigate phenomena such as changes in times of sunrise and sunset (number of daylight hours), Moon phases, seasonal…

  10. Little sun

    DEFF Research Database (Denmark)

    Ebbesen, Toke Riis

    2017-01-01

    the ideas of Alfred Gell’s anthropology of art and the indicative framework derived from Argentinian semiotician Juan Pablo Bonta and Jørn Guldberg. The toy-like solar lamp Little Sun by Olafur Eliasson and Frederik Ottesen is used as case that blends the registers of social design and art......, and as an example of how designers attempt to determine meaning potentials through design in a complex interplay of different strategies. In the final analysis, what characterise objects like Little Sun is seldom that they communicate their meanings in themselves, but instead rely on forceful mediations to gain...

  11. The moon as a high temperature condensate.

    Science.gov (United States)

    Anderson, D. L.

    1973-01-01

    The accretion during condensation mechanism, if it occurs during the early over-luminous stage of the sun, can explain the differences in composition of the terrestrial planets and the moon. An important factor is the variation of pressure and temperature with distance from the sun, and in the case of the moon and captured satellites of other planets, with distance from the median plane. Current estimates of the temperature and pressure in the solar nebula suggest that condensation will not be complete in the vicinity of the terrestrial planets, and that depending on location, iron, magnesium silicates and the volatiles will be at least partially held in the gaseous phase and subject to separation from the dust by solar wind and magnetic effects associated with the transfer of angular momentum just before the sun joins the Main Sequence. Many of the properties of the moon, including the 'enrichment' in Ca, Al, Ti, U, Th, Ba, Sr and the REE and the 'depletion' in Fe, Rb, K, Na and other volatiles can be understood if the moon represents a high temperature condensate from the solar nebula.

  12. Sun Proof

    Centers for Disease Control (CDC) Podcasts

    2012-10-23

    In this podcast for kids, the Kidtastics talk about the harmful effects of the sun and how to protect yourself from it.  Created: 10/23/2012 by Centers for Disease Control and Prevention (CDC).   Date Released: 10/23/2012.

  13. yimin sun

    Indian Academy of Sciences (India)

    Home; Journals; Journal of Genetics. YIMIN SUN. Articles written in Journal of Genetics. Volume 96 Issue 4 September 2017 pp 687-693 RESEARCH NOTE. The association study of nonsyndromic cleft lip with or without cleft palate identified risk variants of the GLI3 gene in a Chinese population · YIRUI WANG YIMIN SUN ...

  14. jianhua sun

    Indian Academy of Sciences (India)

    Home; Journals; Journal of Biosciences. JIANHUA SUN. Articles written in Journal of Biosciences. Volume 42 Issue 4 December 2017 pp 575-584 Article. MicroRNA-486-5p suppresses TGF-b2-induced proliferation, invasion and epithelial–mesenchymal transition of lens epithelial cells by targeting Smad2.

  15. Origin of the earth and moon

    International Nuclear Information System (INIS)

    Ringwood, A.E.

    1981-01-01

    The composition of the Earth's interior and its bearing on the Earth's origin are discussed. It seems likely that the terrestrial planets formed by the accretion of solid planetisimals from the nebula of dust and gas left behind during the formation of the Sun. The scenario proposed is simpler than others. New evidence based upon a comparison of siderophile element abundances in the Earth's mantle and in the Moon imply that the Moon was derived from the Earth's mantle after the Earth's core had segregated

  16. Kepler-22b: a 2.4 Earth-radius Planet in the Habitable Zone of a Sun-like Star

    NARCIS (Netherlands)

    Borucki, W.J.; Koch, D.G.; Batalha, N.; Bryson, S.T.; Rowe, J.; Fressin, F.; Torres, G.; Caldwell, D.A.; Christensen-Dalsgaard, J.; Cochran, W.D.; DeVore, E.; Gautier, T.N.; Geary, J.C.; Gilliland, R.; Gould, A.; Howell, S.B.; Jenkins, J.M.; Latham, D.W.; Lissauer, J.J.; Marcy, G.W.; Sasselov, D.; Boss, A.; Charbonneau, D.; Ciardi, D.; Kaltenegger, L.; Doyle, L.; Dupree, A.K.; Ford, E.B.; Fortney, J.; Holman, M.J.; Steffen, J.H.; Mullally, F.; Still, M.; Tarter, J.; Ballard, S.; Buchhave, L.A.; Carter, J.; Christiansen, J.L.; Demory, B.O.; Désert, J.M.; Dressing, C.; Endl, M.; Fabrycky, D.; Fischer, D.; Haas, M.R.; Henze, C.; Horch, E.; Howard, A.W.; Isaacson, H.; Kjeldsen, H.; Johnson, J.A.; Klaus, T.; Kolodziejczak, J.; Barclay, T.; Li, J.; Meibom, S.; Prsa, A.; Quinn, S.N.; Quintana, E.V.; Robertson, P.; Sherry, W.; Shporer, A.; Tenenbaum, P.; Thompson, S.E.; Twicken, J.D.; Van Cleve, J.; Welsh, W.F.; Basu, S.; Chaplin, W.; Miglio, A.; Kawaler, S.D.; Arentoft, T.; Stello, D.; Metcalfe, T.S.; Verner, G.A.; Karoff, C.; Lundkvist, M.; Lund, M.N.; Handberg, R.; Elsworth, Y.; Hekker, S.; Huber, D.; Bedding, T.R.; Rapin, W.

    2012-01-01

    A search of the time-series photometry from NASA's Kepler spacecraft reveals a transiting planet candidate orbiting the 11th magnitude G5 dwarf KIC 10593626 with a period of 290 days. The characteristics of the host star are well constrained by high-resolution spectroscopy combined with an

  17. Art on the Moon?

    DEFF Research Database (Denmark)

    Lee, Rosemary; Minch, Manuel

    2018-01-01

    Manuel Minch launched Internet Moon Gallery in 2016 with the intention of exploring new modes of creating and engaging with digital art. This article is the result of a collaborative conversation between Manuel Minch and Rosemary Lee, which has evolved from their work together on the exhibition...... “Memory Palace”, launched on Internet Moon Gallery on the full moon, May 2017....

  18. ON THE CARBON-TO-OXYGEN RATIO MEASUREMENT IN NEARBY SUN-LIKE STARS: IMPLICATIONS FOR PLANET FORMATION AND THE DETERMINATION OF STELLAR ABUNDANCES

    International Nuclear Information System (INIS)

    Fortney, Jonathan J.

    2012-01-01

    Recent high-resolution spectroscopic analysis of nearby FGK stars suggests that a high C/O ratio of greater than 0.8, or even 1.0, is relatively common. Two published catalogs find C/O > 0.8 in 25%-30% of systems, and C/O > 1.0 in ∼6%-10%. It has been suggested that in protoplanetary disks with C/O > 0.8 that the condensation pathways to refractory solids will differ from what occurred in our solar system, where C/O = 0.55. The carbon-rich disks are calculated to make carbon-dominated rocky planets, rather than oxygen-dominated ones. Here we suggest that the derived stellar C/O ratios are overestimated. One constraint on the frequency of high C/O is the relative paucity of carbon dwarf stars (10 –3 -10 –5 ) found in large samples of low-mass stars. We suggest reasons for this overestimation, including a high C/O ratio for the solar atmosphere model used for differential abundance analysis, the treatment of a Ni blend that affects the O abundance, and limitations of one-dimensional LTE stellar atmosphere models. Furthermore, from the estimated errors on the measured stellar C/O ratios, we find that the significance of the high C/O tail is weakened, with a true measured fraction of C/O > 0.8 in 10%-15% of stars, and C/O > 1.0 in 1%-5%, although these are still likely overestimates. We suggest that infrared T-dwarf spectra could show how common high C/O is in the stellar neighborhood, as the chemistry and spectra of such objects would differ compared to those with solar-like abundances. While possible at C/O > 0.8, we expect that carbon-dominated rocky planets are rarer than others have suggested.

  19. Weighing the Smallest Stars

    Science.gov (United States)

    2005-01-01

    VLT Finds Young, Very Low Mass Objects Are Twice As Heavy As Predicted Summary Thanks to the powerful new high-contrast camera installed at the Very Large Telescope, photos have been obtained of a low-mass companion very close to a star. This has allowed astronomers to measure directly the mass of a young, very low mass object for the first time. The object, more than 100 times fainter than its host star, is still 93 times as massive as Jupiter. And it appears to be almost twice as heavy as theory predicts it to be. This discovery therefore suggests that, due to errors in the models, astronomers may have overestimated the number of young "brown dwarfs" and "free floating" extrasolar planets. PR Photo 03/05: Near-infrared image of AB Doradus A and its companion (NACO SDI/VLT) A winning combination A star can be characterised by many parameters. But one is of uttermost importance: its mass. It is the mass of a star that will decide its fate. It is thus no surprise that astronomers are keen to obtain a precise measure of this parameter. This is however not an easy task, especially for the least massive ones, those at the border between stars and brown dwarf objects. Brown dwarfs, or "failed stars", are objects which are up to 75 times more massive than Jupiter, too small for major nuclear fusion processes to have ignited in its interior. To determine the mass of a star, astronomers generally look at the motion of stars in a binary system. And then apply the same method that allows determining the mass of the Earth, knowing the distance of the Moon and the time it takes for its satellite to complete one full orbit (the so-called "Kepler's Third Law"). In the same way, they have also measured the mass of the Sun by knowing the Earth-Sun distance and the time - one year - it takes our planet to make a tour around the Sun. The problem with low-mass objects is that they are very faint and will often be hidden in the glare of the brighter star they orbit, also when viewed

  20. TRANSIT MODEL OF PLANETS WITH MOON AND RING SYSTEMS

    International Nuclear Information System (INIS)

    Tusnski, Luis Ricardo M.; Valio, Adriana

    2011-01-01

    Since the discovery of the first exoplanets, those most adequate for life to begin and evolve have been sought. Due to observational bias, however, most of the discovered planets so far are gas giants, precluding their habitability. However, if these hot Jupiters are located in the habitable zones of their host stars, and if rocky moons orbit them, then these moons may be habitable. In this work, we present a model for planetary transit simulation considering the presence of moons and planetary rings around a planet. The moon's orbit is considered to be circular and coplanar with the planetary orbit. The other physical and orbital parameters of the star, planet, moon, and rings can be adjusted in each simulation. It is possible to simulate as many successive transits as desired. Since the presence of spots on the surface of the star may produce a signal similar to that of the presence of a moon, our model also allows for the inclusion of starspots. The result of the simulation is a light curve with a planetary transit. White noise may also be added to the light curves to produce curves similar to those obtained by the CoRoT and Kepler space telescopes. The goal is to determine the criteria for detectability of moons and/or ring systems using photometry. The results show that it is possible to detect moons with radii as little as 1.3 R ⊕ with CoRoT and 0.3 R ⊕ with Kepler.

  1. The Solar Dynamics Observatory, Studying the Sun and Its Influence on Other Bodies in the Solar System

    Science.gov (United States)

    Chamberlin, P. C.

    2011-01-01

    The solar photon output, which was once thought to be constant, varies over all time scales from seconds during solar flares to years due to the solar cycle. These solar variations cause significant deviations in the Earth and space environments on similar time scales, such as affecting the atmospheric densities and composition of particular atoms, molecules, and ions in the atmospheres of the Earth and other planets. Presented and discussed will be examples of unprecedented observations from NASA's new solar observatory, the Solar Dynamics Observatory (SDO). Using three specialized instruments, SDO measures the origins of solar activity from inside the Sun, though its atmosphere, then accurately measuring the Sun's radiative output in X-ray and EUV wavelengths (0.1-121 nm). Along with the visually appealing observations will be discussions of what these measurements can tell us about how the plasma motions in all layers of the Sun modifies and strengthens the weak solar dipole magnetic field to drive large energy releases in solar eruptions. Also presented will be examples of how the release of the Sun's energy, in the form of photons and high energy particles, physically influence other bodies in the solar system such as Earth, Mars, and the Moon, and how these changes drive changes in the technology that we are becoming dependent upon. The presentation will continuously emphasize how SDO, the first satellite in NASA's Living with a Star program, improving our understanding of the variable Sun and its Heliospheric influence.

  2. The New Sun-Sky-Lunar Cimel CE318-T Multiband Photometer - A Comprehensive Performance Evaluation

    Science.gov (United States)

    Barreto, Africa; Cuevas, Emilio; Granados-Munoz, Maria-Jose; Alados-Arboledas, Lucas; Romero, Pedro M.; Grobner, Julian; Kouremeti, Natalia; Almansa, Antonio F.; Stone, Tom; Toledano, Carlos; hide

    2016-01-01

    measurements from independent reference instruments has served to assess the CE318-T performance as well as to confirm its estimated uncertainty. Daytime AOD evaluation, performed at Izana station from March to June 2014, encompassed measurements from a reference CE318-T, a CE318-AERONET master instrument, a Precision Filter Radiometer (PFR) and a Precision Spectroradiometer (PSR) prototype, reporting low AOD discrepancies between the four instruments (up to 0.006). The nocturnal AOD evaluation was performed using CE318-T- and starphotometer-collocated measurements and also by means of a day/night coherence transition test using the CE318-T master instrument and the CE318 daytime data from the CE318-AERONET master instrument. Results showed low discrepancies with the star photometer at 870 and 500 nm channels(less tna or equal to 0.013) and differences with AERONET daytime data (1 h after and before sunset and sunrise) in agreement with the estimated u(sup N)(sub AOD) values at all illumination conditions in the case of channels within the visible spectral range, and only for high moon's illumination conditions in the case of near infrared channels. Perceptible water vapour (PWV) validation showed a good agreement between CE318-T and Global Navigation Satellite System (GNSS) PWV values for all illumination conditions, within the expected precision for sun photometry. Finally, two case studies have been included to highlight the ability of the new CE318-T to capture the diurnal cycle of aerosols and water vapour as well as short-term atmospheric variations, critical for climate studies.

  3. Evolution of 0.7--3.0 M/sub sun/ stars having -1.0< or =[Fe/H]< or =0.0

    International Nuclear Information System (INIS)

    VandenBerg, D.A.

    1985-01-01

    Five grids of stellar models have been calculated for masses ranging from 0.7 to 3.0 M/sub sun/ assuming, in turn, a metal abundance [Fe/H] = -1.0, -0.76, -0.46, -0.23, and 0.0. All of the calculations are based on a value of Y = 0.25 for the helium content and α = 1.6 for the ratio of the mixing length to the pressure scale height. The latest improvements in opacity data and nuclear reaction rates have been incorporated into the computations. Moreover, model atmospheres have been used to provide the boundary conditions for the stellar interior calculations as well as to transpose the isochrones, computed for ages from 0.3 x 10 9 to 15 x 10 9 yr, from the theoretical to the (M/sub v/, B-V)-plane. Cousins V-I and V-R colors are also predicted for each of the model sequences, which are extensively tabulated

  4. 78 FR 58378 - Culturally Significant Objects Imported for Exhibition Determinations: “Peru: Kingdoms of the Sun...

    Science.gov (United States)

    2013-09-23

    ... DEPARTMENT OF STATE [Public Notice 8478] Culturally Significant Objects Imported for Exhibition Determinations: ``Peru: Kingdoms of the Sun and the Moon'' SUMMARY: Notice is hereby given of the following... ``Peru: Kingdoms of the Sun and the Moon,'' imported from abroad for temporary exhibition within the...

  5. Energy production in stars

    International Nuclear Information System (INIS)

    Bethe, Hans.

    1977-01-01

    Energy in stars is released partly by gravitation, partly by nuclear reactions. For ordinary stars like our sun, nuclear reactions predominate. However, at the end of the life of a star very large amounts of energy are released by gravitational collapse; this can amount to as much as 10 times the total energy released nuclear reactions. The rotational energy of pulsars is a small remnant of the energy of gravitation. The end stage of small stars is generally a white dwarf, of heavy stars a neutron star of possibly a black hole

  6. GO JUP POS MOONS TRAJ JUPITER CENTERED COORDINATES V1.0

    Data.gov (United States)

    National Aeronautics and Space Administration — This data set contains the System III (1965.0) trajectory and Sun and Earth phase angles of Galileo and selected Jovian moons when Galileo was inside 30 Jupiter...

  7. Two Moons and the Pleiades from Mars

    Science.gov (United States)

    2005-01-01

    [figure removed for brevity, see original site] Inverted image of two moons and the Pleiades from Mars Taking advantage of extra solar energy collected during the day, NASA's Mars Exploration Rover Spirit recently settled in for an evening of stargazing, photographing the two moons of Mars as they crossed the night sky. In this view, the Pleiades, a star cluster also known as the 'Seven Sisters,' is visible in the lower left corner. The bright star Aldebaran and some of the stars in the constellation Taurus are visible on the right. Spirit acquired this image the evening of martian day, or sol, 590 (Aug. 30, 2005). The image on the right provides an enhanced-contrast view with annotation. Within the enhanced halo of light is an insert of an unsaturated view of Phobos taken a few images later in the same sequence. On Mars, Phobos would be easily visible to the naked eye at night, but would be only about one-third as large as the full Moon appears from Earth. Astronauts staring at Phobos from the surface of Mars would notice its oblong, potato-like shape and that it moves quickly against the background stars. Phobos takes only 7 hours, 39 minutes to complete one orbit of Mars. That is so fast, relative to the 24-hour-and-39-minute sol on Mars (the length of time it takes for Mars to complete one rotation), that Phobos rises in the west and sets in the east. Earth's moon, by comparison, rises in the east and sets in the west. The smaller martian moon, Deimos, takes 30 hours, 12 minutes to complete one orbit of Mars. That orbital period is longer than a martian sol, and so Deimos rises, like most solar system moons, in the east and sets in the west. Scientists will use images of the two moons to better map their orbital positions, learn more about their composition, and monitor the presence of nighttime clouds or haze. Spirit took the five images that make up this composite with the panoramic camera, using the camera's broadband filter, which was designed specifically

  8. Low energy trajectories for the Moon-to-Earth space flight

    Indian Academy of Sciences (India)

    The Moon-to-Earth low energy trajectories of `detour'type are found and studied within the frame of the Moon –Earth –Sun-particle system. ... This results in the particle flight to a distance of about 1.5 million km from the Earth where the Sun gravitation decreases the particle orbit perigee distance to a small value that leads to ...

  9. Apollo 11 Moon Landing

    Science.gov (United States)

    1969-01-01

    The crowning achievement for the Saturn V rocket came when it launched Apollo 11 astronauts, Neil Armstrong, Edwin (Buzz) Aldrin, and Michael Collins, to the Moon in July 1969. In this photograph, astronaut Aldrin takes his first step onto the surface of the Moon.

  10. Radio emission of the sun and planets

    CERN Document Server

    Zheleznyakov, V V

    1970-01-01

    International Series of Monographs in Natural Philosophy, Volume 25: Radio Emission of the Sun and Planets presents the origin of the radio emission of the planets. This book examines the outstanding triumphs achieved by radio astronomy of the solar system. Comprised of 10 chapters, this volume begins with an overview of the physical conditions in the upper layers of the Sun, the Moon, and the planets. This text then examines the three characteristics of radio emission, namely, the frequency spectrum, the polarization, and the angular spectrum. Other chapters consider the measurements of the i

  11. Low energy trajectories for the Moon-to-Earth space flight

    Indian Academy of Sciences (India)

    The Moon-to-Earth low energy trajectories of 'detour' type are found and studied within the frame ... km from the Earth where the Sun gravitation decreases the particle orbit perigee distance to a small value .... The solid curve in fig- ... the Moon, respectively, as is the semimajor axis .... inclination i0 = 90 .... Then, according to.

  12. Transits of extrasolar moons around luminous giant planets

    Science.gov (United States)

    Heller, R.

    2016-04-01

    Beyond Earth-like planets, moons can be habitable, too. No exomoons have been securely detected, but they could be extremely abundant. Young Jovian planets can be as hot as late M stars, with effective temperatures of up to 2000 K. Transits of their moons might be detectable in their infrared photometric light curves if the planets are sufficiently separated (≳10 AU) from the stars to be directly imaged. The moons will be heated by radiation from their young planets and potentially by tidal friction. Although stellar illumination will be weak beyond 5 AU, these alternative energy sources could liquify surface water on exomoons for hundreds of Myr. A Mars-mass H2O-rich moon around β Pic b would have a transit depth of 1.5 × 10-3, in reach of near-future technology.

  13. Nuclear physics of stars

    CERN Document Server

    Iliadis, Christian

    2015-01-01

    Most elements are synthesized, or ""cooked"", by thermonuclear reactions in stars. The newly formed elements are released into the interstellar medium during a star's lifetime, and are subsequently incorporated into a new generation of stars, into the planets that form around the stars, and into the life forms that originate on the planets. Moreover, the energy we depend on for life originates from nuclear reactions that occur at the center of the Sun. Synthesis of the elements and nuclear energy production in stars are the topics of nuclear astrophysics, which is the subject of this book

  14. The Sodium Tail of the Moon

    Science.gov (United States)

    Matta, M.; Smith, S.; Baumgardner, J.; Wilson, J.; Martinis, C.; Mendillo, M.

    2009-01-01

    During the few days centered about new Moon, the lunar surface is optically hidden from Earth-based observers. However, the Moon still offers an observable: an extended sodium tail. The lunar sodium tail is the escaping "hot" component of a coma-like exosphere of sodium generated by photon-stimulated desorption, solar wind sputtering and meteoroid impact. Neutral sodium atoms escaping lunar gravity experience solar radiation pressure that drives them into the anti-solar direction forming a comet-like tail. During new Moon time, the geometry of the Sun, Moon and Earth is such that the anti-sunward sodium flux is perturbed by the terrestrial gravitational field resulting in its focusing into a dense core that extends beyond the Earth. An all-sky camera situated at the El Leoncito Observatory (CASLEO) in Argentina has been successfully imaging this tail through a sodium filter at each lunation since April 2006. This paper reports on the results of the brightness of the lunar sodium tail spanning 31 lunations between April 2006 and September 2008. Brightness variability trends are compared with both sporadic and shower meteor activity, solar wind proton energy flux and solar near ultra violet (NUV) patterns for possible correlations. Results suggest minimal variability in the brightness of the observed lunar sodium tail, generally uncorrelated with any single source, yet consistent with a multi-year period of minimal solar activity and non-intense meteoric fluxes.

  15. Evolution of massive stars

    International Nuclear Information System (INIS)

    Loore, C. de

    1984-01-01

    The evolution of stars with masses larger than 15 sun masses is reviewed. These stars have large convective cores and lose a substantial fraction of their matter by stellar wind. The treatment of convection and the parameterisation of the stellar wind mass loss are analysed within the context of existing disagreements between theory and observation. The evolution of massive close binaries and the origin of Wolf-Rayet Stars and X-ray binaries is also sketched. (author)

  16. Dynamics of the Sun-Earth-Moon System

    Indian Academy of Sciences (India)

    GENERAL I ARTICLE the repetition is close but not exact over the time scale of 112 synodic months. From the data studied, b:.P / P over a period of 112 luna- tion is 0.3/27.3 = 0.011. Therefore b:.a/a = 2/3{tl.P/ P). = 0.007. Thus on the larger time scale of about 9 years tl.E / E varies by about 0.7 percent. This may be com-.

  17. Heavy Metal Stars

    Science.gov (United States)

    2001-08-01

    La Silla Telescope Detects Lots of Lead in Three Distant Binaries Summary Very high abundances of the heavy element Lead have been discovered in three distant stars in the Milky Way Galaxy . This finding strongly supports the long-held view that roughly half of the stable elements heavier than Iron are produced in common stars during a phase towards the end of their life when they burn their Helium - the other half results from supernova explosions. All the Lead contained in each of the three stars weighs about as much as our Moon. The observations show that these "Lead stars" - all members of binary stellar systems - have been more enriched with Lead than with any other chemical element heavier than Iron. This new result is in excellent agreement with predictions by current stellar models about the build-up of heavy elements in stellar interiors. The new observations are reported by a team of Belgian and French astronomers [1] who used the Coude Echelle Spectrometer on the ESO 3.6-m telescope at the La Silla Observatory (Chile). PR Photo 26a/01 : A photo of HD 196944 , one of the "Lead stars". PR Photo 26b/01 : A CES spectrum of HD 196944 . The build-up of heavy elements Astronomers and physicists denote the build-up of heavier elements from lighter ones as " nucleosynthesis ". Only the very lightest elements (Hydrogen, Helium and Lithium [2]) were created at the time of the Big Bang and therefore present in the early universe. All the other heavier elements we now see around us were produced at a later time by nucleosynthesis inside stars. In those "element factories", nuclei of the lighter elements are smashed together whereby they become the nuclei of heavier ones - this process is known as nuclear fusion . In our Sun and similar stars, Hydrogen is being fused into Helium. At some stage, Helium is fused into Carbon, then Oxygen, etc. The fusion process requires positively charged nuclei to move very close to each other before they can unite. But with increasing

  18. The Sun A User's Manual

    CERN Document Server

    Vita-Finzi, Claudio

    2008-01-01

    The Sun is an account of the many ways in which our nearest star affects our planet, how its influence has changed over the last few centuries and millennia, and the extent to which we can predict its future impact. The Sun's rays foster the formation of Vitamin D by our bodies, but it can also promote skin cancer, cataracts, and mutations in our DNA. Besides providing the warmth and light essential to most animal and plant life, solar energy contributes substantially to global warming. Although the charged particles of the solar wind shield us from harmful cosmic rays, solar storms may damage artificial satellites and cripple communication systems and computer networks. The Sun is the ideal renewable energy source, but its exploitation is still bedevilled by the problems of storage and distribution. Our nearest star, in short, is a complex machine which needs to be treated with caution, and this book will equip every reader with the knowledge that is required to understand the benefits and dangers it can bri...

  19. Plutonian Moon confirmed

    Science.gov (United States)

    In late February, two separate observations confirmed the 1978 discovery by U.S. Naval Observatory scientist James W. Christy of a moon orbiting the planet Pluto. According to the U.S. Naval Observatory, these two observations were needed before the International Astronomical Society (IAS) would officially recognize the discovery.Two types of observations of the moon, which was named Charon after the ferryman in Greek mythology who carried the dead to Pluto's realm, were needed for confirmation: a transit, in which the moon passes in front of Pluto, and an occultation, in which the moon passes behind the planet. These two phenomena occur only during an 8-year period every 124 years that had been calculated to take place during 1984-1985. Both events were observed in late February.

  20. Moon nature and culture

    CERN Document Server

    Williams, Edgar

    2014-01-01

    Long before a rocket hit the Man in the Moon in the eye in Georges Méliès's early film Le Voyage dans la Lune, the earth's lone satellite had entranced humans. We have worshipped it as a deity, believed it to cause madness, used it as a means of organizing time, and we now know that it manipulates the tides-our understanding of the moon continues to evolve. Following the moon from its origins to its rich cultural resonance in literature, art, religion, and politics, Moon provides a comprehensive account of the significance of our lunar companion. Edgar Williams explores the interdependence of

  1. Observations spotted solar type stars in Pleiades

    International Nuclear Information System (INIS)

    Magnitskij, A.K.

    1987-01-01

    The september - october 1986 observations discovered periodic light variations in three solar type stars in the Pleiades cluster: Hz 296 (0.8 M Sun ), Hz152(0.91 M Sun ) and Hz739(1.15 M Sun ). Periods and amplitudes are accordingly 2 d and 0 m .11, 4 d .12 and 0 m .07, 2 d .70 and 0 m .05. Considerable light variations of these stars in Pleiades are due to the rotation of spotted stars. Contrast spots of solar type stars likely exist when stars are young and rapidly rotate

  2. Halo star streams in the solar neighborhood

    NARCIS (Netherlands)

    Kepley, Amanda A.; Morrison, Heather L.; Helmi, Amina; Kinman, T. D.; Van Duyne, Jeffrey; Martin, John C.; Harding, Paul; Norris, John E.; Freeman, Kenneth C.

    2007-01-01

    We have assembled a sample of halo stars in the solar neighborhood to look for halo substructure in velocity and angular momentum space. Our sample ( 231 stars) includes red giants, RR Lyrae variable stars, and red horizontal branch stars within 2.5 kpc of the Sun with [Fe/H] less than -1.0. It was

  3. Neutrinos and our Sun - Part 2

    Indian Academy of Sciences (India)

    the sun during its lifetime of four and a half billion years is given by ... The balance between ... per unit time (the luminosity): ... are operative in all stars during the bulk of their life: (a) ..... Thus the data collected over several years of hard work.

  4. Young and Waltzing Binary Stars

    Science.gov (United States)

    2001-10-01

    star determines its fate . Massive stars (with masses more than 50 times that of the Sun) lead a glorious, but short life. They are hot and very luminous and exhaust their energy supply in just a few million years. At the other end of the scale, low-mass stars like the Sun are more economical with their resources. Being cooler and dimmer, they are able to shine for billions of years [2]. But although the mass determines the fate of a star, it is not a trivial matter to measure this crucial parameter. In fact, it can only be determined directly if the star happens to be gravitationally bound to another star in a binary stellar system. Observations of the orbital motions of the two stars as they circle each other allows to "weigh" them, and also provide other important information, e.g. about their sizes and temperatures. Orbital motions The understanding of orbital motions has a long history in astronomy. The basic laws of Johannes Kepler (1571-1630) are still used to calculate the masses of orbiting objects, in the solar system as well as in binary stellar systems. However, while the observations of the motion of the nine planets and moons have allowed us to measure quite accurately the masses of objects in our vicinity, the information needed to "weigh" the binary stellar systems is not that easy to obtain. As a result, the mass estimates of the stars in binary systems are often rather uncertain. A main problem is that the individual stars in many binary systems can not be visually separated, even in the best telescopes. The information about the orbit may then come from the motions of the stars, if these are revealed by spectroscopic observations of the combined light (such systems are referred to as "spectroscopic binaries"). If absorption lines from both components are present in the spectrum, the measured wavelength of these double lines will shift periodically back and forth. This is the well-known Doppler effect and it directly reflects the changing velocities

  5. Galileo's Medicean Moons (IAU S269)

    Science.gov (United States)

    Barbieri, Cesare; Chakrabarti, Supriya; Coradini, Marcello; Lazzarin, Monica

    2010-11-01

    Preface; 1. Galileo's telescopic observations: the marvel and meaning of discovery George V. Coyne, S. J.; 2. Popular perceptions of Galileo Dava Sobel; 3. The slow growth of humility Tobias Owen and Scott Bolton; 4. A new physics to support the Copernican system. Gleanings from Galileo's works Giulio Peruzzi; 5. The telescope in the making, the Galileo first telescopic observations Alberto Righini; 6. The appearance of the Medicean Moons in 17th century charts and books. How long did it take? Michael Mendillo; 7. Navigation, world mapping and astrometry with Galileo's moons Kaare Aksnes; 8. Modern exploration of Galileo's new worlds Torrence V. Johnson; 9. Medicean Moons sailing through plasma seas: challenges in establishing magnetic properties Margaret G. Kivelson, Xianzhe Jia and Krishan K. Khurana; 10. Aurora on Jupiter: a magnetic connection with the Sun and the Medicean Moons Supriya Chakrabarti and Marina Galand; 11. Io's escaping atmosphere: continuing the legacy of surprise Nicholas M. Schneider; 12. The Jovian Rings Wing-Huen Ip; 13. The Juno mission Scott J. Bolton and the Juno Science Team; 14. Seeking Europa's ocean Robert T. Pappalardo; 15. Europa lander mission: a challenge to find traces of alien life Lev Zelenyi, Oleg Korablev, Elena Vorobyova, Maxim Martynov, Efraim L. Akim and Alexander Zakahrov; 16. Atmospheric moons Galileo would have loved Sushil K. Atreya; 17. The study of Mercury Louise M. Prockter and Peter D. Bedini; 18. Jupiter and the other giants: a comparative study Thérèse Encrenaz; 19. Spectroscopic and spectrometric differentiation between abiotic and biogenic material on icy worlds Kevin P. Hand, Chris McKay and Carl Pilcher; 20. Other worlds, other civilizations? Guy Consolmagno, S. J.; 21. Concluding remarks Roger M. Bonnet; Posters; Author index; Object index.

  6. A Look into the Hellish Cradles of Suns and Solar Systems

    Science.gov (United States)

    2009-09-01

    found a handful of protostars - the faintly luminous precursors to fully realised stars - and dozens of other candidate stars that have eked out an existence here despite the powerful ultraviolet light radiated by IRS2. Some of these gestating stars may, however, not get past the protostar stage. IRS2's strong radiation energises and disperses the material that might otherwise collapse into new stars, or that has settled into so-called protoplanetary discs around developing stars. In the course of several million years, the surviving discs may give rise to the planets, moons and comets that make up planetary systems like our own. As if intense ultraviolet rays were not enough, crowded stellar nurseries like RCW 38 also subject their brood to frequent supernovae when giant stars explode at the ends of their lives. These explosions scatter material throughout nearby space, including rare isotopes - exotic forms of chemical elements that are created in these dying stars. This ejected material ends up in the next generation of stars that form nearby. Because these isotopes have been detected in our Sun, scientists have concluded that the Sun formed in a cluster like RCW 38, rather than in a more rural portion of the Milky Way. "Overall, the details of astronomical objects that adaptive optics reveals are critical in understanding how new stars and planets form in complex, chaotic regions like RCW 38", says co-author Dieter Nürnberger. Notes [1] The name "NACO" is a combination of the Nasmyth Adaptive Optics System (NAOS) and the Near-Infrared Imager and Spectrograph (CONICA). Adaptive optics cancels out most of the image-distorting turbulence in Earth's atmosphere caused by temperature variations and wind. More information This research was presented in a paper that appeared in the Astronomical Journal: A Very Large Telescope / NACO study of star formation in the massive embedded cluster RCW 38, by DeRose et al. (2009, AJ, 138, 33-45). The team is composed of K.L. De

  7. Moon (Form-Origin)

    Science.gov (United States)

    Tsiapas, Elias; Soumelidou, Despina; Tsiapas, Christos

    2017-04-01

    When the Earth was formed, it was in a state of burning heat. As time went by, temperature on the planet's surface was falling due to radiation and heat transfer, and various components (crusts) began taking solid form at the Earth's poles. The formation of crusts took place at the Earth's poles, because the stirring of burning and fluid masses on the surface of the Earth was significantly slighter there than it was on the equator. Due to centrifugal force and Coriolis Effect, these solid masses headed towards the equator; those originating from the North Pole followed a south-western course, while those originating from the South Pole followed a north-western course and there they rotated from west to east at a lower speed than the underlying burning and liquid earth, because of their lower initial linear velocity, their solid state and inertia. Because inertia is proportional to mass, the initially larger solid body swept all new solid ones, incorporating them to its western side. The density of the new solid masses was higher, because the components on the surface would freeze and solidify first, before the underlying thicker components. As a result, the western side of the initial islet of solid rocks submerged, while the east side elevated. . As a result of the above, this initial islet began to spin in reverse, and after taking on the shape of a sphere, it formed the "heart" of the Moon. The Moon-sphere, rolling on the equator, would sink the solid rocks that continued to descend from the Earth's poles. The sinking rocks partially melted because of higher temperatures in the greater depths that the Moon descended to, while part of the rocks' mass bonded with the Moon and also served as a heat-insulating material, preventing the descended side of the sphere from melting. Combined with the Earth's liquid mass that covered its emerging eastern surface, new sphere-shaped shells were created, with increased density and very powerful structural cohesion. During the

  8. An International Parallax Campaign to Measure Distance to the Moon and Mars

    Science.gov (United States)

    Cenadelli, D.; Zeni, M.; Bernagozzi, A.; Calcidese, P.; Ferreira, L.; Hoang, C.; Rijsdijk, C.

    2009-01-01

    Trigonometric parallax is a powerful method to work out the distance of celestial bodies, and it was used in the past to measure the distance of the Moon, Venus, Mars and nearby stars. We set up an observation campaign for high school and undergraduate students with the purpose to measure both the Moon's and Mars' parallax. To have a large enough…

  9. Sun and Sun Worship in Different Cultures

    Science.gov (United States)

    Farmanyan, S. V.; Mickaelian, A. M.

    2014-10-01

    The Sun symbol is found in many cultures throughout history, it has played an important role in shaping our life on Earth since the dawn of time. Since the beginning of human existence, civilisations have established religious beliefs that involved the Sun's significance to some extent. As new civilisations and religions developed, many spiritual beliefs were based on those from the past so that there has been an evolution of the Sun's significance throughout cultural development. For comparing and finding the origin of the Sun we made a table of 66 languages and compared the roots of the words. For finding out from where these roots came from, we also made a table of 21 Sun Gods and Goddesses and proved the direct crossing of language and mythology.

  10. Structure of the moon's surface

    CERN Document Server

    Fielder, Gilbert

    1961-01-01

    Structure of the Moon's Surface aims to assemble and marshal relevant matter, and to produce a largely unprejudiced text which brings lunar studies up to date and stresses the importance of certain features of the Moon which have frequently been disregarded in the past, largely because of lack of knowledge about them. The book contains 14 chapters organized into two parts. Part I reviews and summarizes important physical problems. These include the liberations of the moon; height determinations of points of the moon's surface; the figure of the moon; and the moon's temperature and atmosphere.

  11. Moons a very short introduction

    CERN Document Server

    Rothery, David A

    2015-01-01

    Moons: A Very Short Introduction introduces the reader to the varied and fascinating moons of our Solar System. Beginning with the early discoveries of Galileo and others, it describes their variety of mostly mythological names, and the early use of Jupiter’s moons to establish position at sea and to estimate the speed of light. It discusses the structure, formation, and profound influence of our Moon, those of the other planets, and ends with the recent discovery of moons orbiting asteroids, whilst looking forward to the possibility of discovering microbial life beyond Earth and of finding moons of exoplanets in planetary systems far beyond our own.

  12. The Tethered Moon

    Science.gov (United States)

    Zahnle, Kevin; Lupu, Roxana Elena; Dubrovolskis, A. R.

    2014-01-01

    A reasonable initial condition on Earth after the Moonforming impact is that it begins as a hot global magma ocean1,2. We therefore begin our study with the mantle as a liquid ocean with a surface temperature on the order of 3000- 4000 K at a time some 100-1000 years after the impact, by which point we can hope that early transients have settled down. A 2nd initial condition is a substantial atmosphere, 100-1000 bars of H2O and CO2, supplemented by smaller amounts of CO, H2, N2, various sulfur-containing gases, and a suite of geochemical volatiles evaporated from the magma. Third, we start the Moon with its current mass at the relevant Roche limit. The 4th initial condition is the angular momentum of the Earth-Moon system. Canonical models hold this constant, whilst some recent models begin with considerably more angular momentum than is present today. Here we present a ruthlessly simplified model of Earth's cooling magmasphere based on a full-featured atmosphere and including tidal heating by the newborn Moon. Thermal blanketing by H2O-CO2 atmospheres slows cooling of a magma ocean. Geochemical volatiles - chiefly S, Na, and Cl - raise the opacity of the magma ocean's atmosphere and slow cooling still more. We assume a uniform mantle with a single internal (potential) temperature and a global viscosity. The important "freezing point" is the sharp rheological transition between a fluid carrying suspended crystals and a solid matrix through which fluids percolate. Most tidal heating takes place at this "freezing point" in a gel that is both pliable and viscous. Parameterized convection links the cooling rate to the temperature and heat generation inside the Earth. Tidal heating is a major effect. Tidal dissipation in the magma ocean is described by viscosity. The Moon is entwined with Earth by the negative feedback between thermal blanketing and tidal heating that comes from the temperature-dependent viscosity of the magma ocean. Because of this feedback, the rate

  13. MedSun Reports

    Data.gov (United States)

    U.S. Department of Health & Human Services — The Medical Product Safety Network (MedSun) is an adverse event reporting program launched in 2002. The primary goal for MedSun is to work collaboratively with the...

  14. Seasons by the Sun

    Science.gov (United States)

    Stark, Meri-Lyn

    2005-01-01

    Understanding the Sun has challenged people since ancient times. Mythology from the Greek, Inuit, and Inca cultures attempted to explain the daily appearance and nightly disappearance of the Sun by relating it to a chariot being chased across the sky. While people no longer believe the Sun is a chariot racing across the sky, teachers are still…

  15. The Sun and How to Observe It

    CERN Document Server

    Jenkins, Jamey L

    2009-01-01

    Without the Sun, all life on Earth would perish. But what exactly do we know about this star that lights, heats, and powers Earth? Actually, we know quite a lot, thanks mainly to a host of eager solar observers. Looking directly at the Sun is EXTREMELY hazardous. But many astronomers, both professional and amateur, have found ways to view the Sun safely to learn about it. You, too, can view the Sun in all of its glorious detail. Some of the newest, most exciting telescopes on the market are affordable to amateur astronomers or even just curious sky watchers, and with this guide to what the Sun has to offer, including sunspots, prominences, and flares, plus reviews of the latest instruments for seeing and capturing images of the Sun, you can contribute to humankind’s knowledge of this immense ball of glowing gases that gives us all life. For a complete guide to Sun viewing, see also Total Solar Eclipses and How to Observe Them (2007) by Martin Mobberley in this same series.

  16. Archaeoastronomy introduction to the science of stars and stones

    CERN Document Server

    Magli, Giulio

    2016-01-01

    This book provides the first complete, easy to read, up-to-date account of the fascinating discipline of archaeoastronomy, in which the relationship between ancient constructions and the sky is studied in order to gain a better understanding of the ideas of the architects of the past and of their religious and symbolic worlds. The book is divided into three sections, the first of which explores the past relations between astronomy and people, power, the afterworld, architecture, and landscape. The fundamentals of archaeoastronomy are then addressed in detail, with coverage of the celestial coordinates; the apparent motion of the Sun, Moon, stars, and planets; observation of celestial bodies at the horizon; the use of astronomical software in archaeoastronomy; and current methods for making and analyzing measurements. The final section reviews what archaeoastronomy can now tell us about the nature and purpose of such sites and structures as Stonehenge, the Pyramids of Giza, Chichen Itza, the Campus Martius, an...

  17. The Moon Challenge

    Science.gov (United States)

    Fitzsimmons, Pat; Leddy, Diana; Johnson, Lindy; Biggam, Sue; Locke, Suzan

    2013-01-01

    This article describes a first-grade research project that incorporates trade books and challenges misconceptions. Educators see the power of their students' wonder at work in their classrooms on a daily basis. This wonder must be nourished by students' own experiences--observing the moon on a crystal clear night--as well as by having…

  18. Santa and the Moon

    NARCIS (Netherlands)

    Barthel, P.

    This article reflects on the use of illustrations of the Moon in images of Santa Claus, on Christmas gift-wrapping paper and in children's books, in two countries which have been important in shaping the image of Santa Claus and his predecessor Sinterklaas: the USA and the Netherlands. The

  19. The moon's origins

    International Nuclear Information System (INIS)

    Boss, P.; Benz, W.

    1987-01-01

    Planet formation theory is recalled. The different existing hypothesis on the moon's origins are reviewed also to see how much they are compatible with the planet formation theory. Up to now, the giant impact model seems to be the only model to satisfy all the constraints. Computerized simulation results have been presented in colloquiums and their scenarios are recalled [fr

  20. Island of the Sun: Elite and Non-Elite Observations of the June Solstice

    Science.gov (United States)

    Dearborn, David S. P.; Bauer, Brian S.

    In Inca times (AD 1400-1532), two small islands in Lake Titicaca had temples dedicated to the sun and the moon. Colonial documents indicate that the islands were the focus of large-scale pilgrimages. Recent archaeoastronomical work suggests that rituals, attended by both elites and commoners, were held on the Island of the Sun to observe the setting sun on the June solstice.

  1. Moon-bevægelsen

    DEFF Research Database (Denmark)

    Pedersen, René Dybdal

    2014-01-01

    Moon-bevægelsen er det populære navn for religionen "Family Federation for World peace and Unification", som også tidligere kaldte sig "Unification Church". Moon-bevægelsen ser sig selv som den sande kristne kirke. Til forskel fra mange andre kristne kirker mener Moon-bevægelsen, at Gud ønskede...

  2. Long-term coherent periodicities in the mean magnetic field of the Sun

    International Nuclear Information System (INIS)

    Kotov, V.A.; Levitsky, L.S.

    1983-01-01

    To investigate periodic variations of the magnetic field of the Sun as a star, the authors have used the mean field measurements made in Crimea, Mt. Wilson, and Stanford observatories; in total N = 5783 daily values were available for the time interval 1968 - 1981. In essence, these data offer a unique possibility to study the Sun as a variable magnetic star. (Auth.)

  3. GLOBAL INSTABILITY OF THE EXO-MOON SYSTEM TRIGGERED BY PHOTO-EVAPORATION

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Ming; Xie, Ji-Wei; Zhou, Ji-Lin; Liu, Hui-Gen; Zhang, Hui, E-mail: jwxie@nju.edu.cn, E-mail: zhoujl@nju.edu.cn [School of Astronomy and Space Science and Key Laboratory of Modern Astronomy and Astrophysics in Ministry of Education, Nanjing University, 210093 (China)

    2016-12-10

    Many exoplanets have been found in orbits close to their host stars and thus they are subject to the effects of photo-evaporation. Previous studies have shown that a large portion of exoplanets detected by the Kepler mission have been significantly eroded by photo-evaporation. In this paper, we numerically study the effects of photo-evaporation on the orbital evolution of a hypothesized moon system around a planet. We find that photo-evaporation is crucial to the stability of the moon system. Photo-evaporation can erode the atmosphere of the planet thus leading to significant mass loss. As the planet loses mass, its Hill radius shrinks and its moons increase their orbital semimajor axes and eccentricities. When some moons approach their critical semimajor axes, global instability of the moon system would be triggered, which usually ends up with two, one or even zero surviving moons. Some lost moons could escape from the moon system to become a new planet orbiting the star or run away further to become a free-floating object in the Galaxy. Given the destructive role of photo-evaporation, we speculate that exomoons are less common for close-in planets (<0.1 au), especially those around M-type stars, because they are more X-ray luminous and thus enhancing photo-evaporation. The lessons we learn in this study may be helpful for the target selection of on-going/future exomoon searching programs.

  4. Survival of extrasolar giant planet moons in planet-planet scattering

    Science.gov (United States)

    CIAN HONG, YU; Lunine, Jonathan; Nicholson, Phillip; Raymond, Sean

    2015-12-01

    Planet-planet scattering is the best candidate mechanism for explaining the eccentricity distribution of exoplanets. Here we study the survival and dynamics of exomoons under strong perturbations during giant planet scattering. During close encounters, planets and moons exchange orbital angular momentum and energy. The most common outcomes are the destruction of moons by ejection from the system, collision with the planets and the star, and scattering of moons onto perturbed but still planet-bound orbits. A small percentage of interesting moons can remain bound to ejected (free-floating) planets or be captured by a different planet. Moons' survival rate is correlated with planet observables such as mass, semi-major axis, eccentricity and inclination, as well as the close encounter distance and the number of close encounters. In addition, moons' survival rate and dynamical outcomes are predetermined by the moons' initial semi-major axes. The survival rate drops quickly as moons' distances increase, but simulations predict a good chance of survival for the Galilean moons. Moons with different dynamical outcomes occupy different regions of orbital parameter space, which may enable the study of moons' past evolution. Potential effects of planet obliquity evolution caused by close encounters on the satellites’ stability and dynamics will be reported, as well as detailed and systematic studies of individual close encounter events.

  5. Evolution of helium rich stars with hydrogen burning

    International Nuclear Information System (INIS)

    Roeser, M.

    1975-08-01

    Evolutionary tracks of stars with an initial chemical composition X = 0.100, Y = 0.8790, Z = 0.021 are calculated for masses of 0.35 M(sun), 0.66 M(sun), 1.00 M(sun), 2.00 M(sun), and 5.00 M(sun) and with X = 0.302, Y = 0.677, Z = 0.021 for masses of 1.00 M(sun), 3.00 M(sun), and 5.00 M(sun). The evolution is followed from hydrogen burning to helium burning and to carbon burning when the occasion arises. The data of evolution are presented and compared with normal Population I-stars. The helium rich stars show higher effective temperatures, much higher luminosities and therefore shorter time scales. They are situated in regions of the HR-diagram where observed helium stars are found. (orig.) [de

  6. Exploring the Moon

    CERN Document Server

    Harland, David M

    2008-01-01

    David Harland opens with a review of the robotic probes, namely the Rangers which returned television before crashing into the Moon, the Surveyors which ''soft landed'' in order to investigate the nature of the surface, and the Lunar Orbiters which mapped prospective Apollo landing sites. He then outlines the historic landing by Apollo 11 in terms of what was discovered, and how over the next several missions the program was progressively geared up to enable the final three missions each to spend three days on comprehensive geological investigations. He concludes with a review of the robotic spacecraft that made remote-sensing observations of the Moon. Although aimed at the enthusiast, and can be read as an adventure in exploration, the book develops the scientific theme of lunar geology, and therefore will be of use as background reading for undergraduate students of planetary sciences. In addition, with the prospect of a resumption of human missions, it will help journalists understand what Apollo achieved ...

  7. Stars the size of planets

    International Nuclear Information System (INIS)

    Whitehouse, D.

    1984-01-01

    Red dwarf stars, the faintest and smallest stars that can be seen, sometimes host flares of immense violence. The article discusses the energy of these flares in terms of mass, x-rays, brightness, variation in light output, the sun and magnetic phenomena. (U.K.)

  8. Our turbulent sun

    International Nuclear Information System (INIS)

    Frazier, K.

    1982-01-01

    The quest for a new understanding of the sun and its surprising irregularities, variations, and effects is described. Attention is given to the sun's impact on life on earth, the weather and geomagnetic storms, sunspots, solar oscillations, the missing neutrinos in the sun, the 'shrinking sun', the 'dance' of the orbits, and the search for the 'climate connection'. It is noted that the 1980s promise to be the decade of the sun: not only because solar power may be a crucial ingredient in efforts to solve the energy crisis, but also because there will be brilliant auroras over North America, because sunspot activity will be the second highest since the 17th century, and because an unmanned spacecraft (i.e., the solar polar mission) will leave the plane of the solar system and observe the sun from above and below

  9. How to Observe the Sun Safely

    CERN Document Server

    Macdonald, Lee

    2012-01-01

    How to Observe the Sun Safely, Second Edition gives all the basic information and advice the amateur astronomer needs to get started in observing our own ever-fascinating star. Unlike many other astronomical objects, you do not need a large telescope or expensive equipment to observe the Sun. And it is possible to take excellent pictures of the Sun with today's low-cost digital cameras! This book surveys what is visible on the Sun and then describes how to record solar features and measure solar activity levels. There is also an account of how to use H-alpha and Calcium-K filters to observe and record prominences and other features of the solar chromosphere, the Sun's inner atmosphere. Because we are just entering a period of high activity on the Sun, following a long, quiet period, this is a great time to get involved with solar observing. Still emphasizing safety first, this Second Edition reflects recent and exciting advances in solar observing equipment. Chapters 6 through 8 have been completely revised ...

  10. Sun's dynamics and nucleosynthesis

    International Nuclear Information System (INIS)

    Gavanescu, Adela; Rusu, Mircea V.

    2005-01-01

    Nucleosynthesis processes in the sun are one of the main results related to the evolution of the Sun. Dynamics and energetics of the Sun could be studied indirectly by their elements products in produced by nucleosynthesis. Also solar atmosphere and its characteristics reveled in its full development is observed during the solar eclipses. We try to correlate these facts in order to obtained data to be used in solar models. (authors)

  11. Sounds of a Star

    Science.gov (United States)

    2001-06-01

    Acoustic Oscillations in Solar-Twin "Alpha Cen A" Observed from La Silla by Swiss Team Summary Sound waves running through a star can help astronomers reveal its inner properties. This particular branch of modern astrophysics is known as "asteroseismology" . In the case of our Sun, the brightest star in the sky, such waves have been observed since some time, and have greatly improved our knowledge about what is going on inside. However, because they are much fainter, it has turned out to be very difficult to detect similar waves in other stars. Nevertheless, tiny oscillations in a solar-twin star have now been unambiguously detected by Swiss astronomers François Bouchy and Fabien Carrier from the Geneva Observatory, using the CORALIE spectrometer on the Swiss 1.2-m Leonard Euler telescope at the ESO La Silla Observatory. This telescope is mostly used for discovering exoplanets (see ESO PR 07/01 ). The star Alpha Centauri A is the nearest star visible to the naked eye, at a distance of a little more than 4 light-years. The new measurements show that it pulsates with a 7-minute cycle, very similar to what is observed in the Sun . Asteroseismology for Sun-like stars is likely to become an important probe of stellar theory in the near future. The state-of-the-art HARPS spectrograph , to be mounted on the ESO 3.6-m telescope at La Silla, will be able to search for oscillations in stars that are 100 times fainter than those for which such demanding observations are possible with CORALIE. PR Photo 23a/01 : Oscillations in a solar-like star (schematic picture). PR Photo 23b/01 : Acoustic spectrum of Alpha Centauri A , as observed with CORALIE. Asteroseismology: listening to the stars ESO PR Photo 23a/01 ESO PR Photo 23a/01 [Preview - JPEG: 357 x 400 pix - 96k] [Normal - JPEG: 713 x 800 pix - 256k] [HiRes - JPEG: 2673 x 3000 pix - 2.1Mb Caption : PR Photo 23a/01 is a graphical representation of resonating acoustic waves in the interior of a solar-like star. Red and blue

  12. Neutron stars

    International Nuclear Information System (INIS)

    Irvine, J.M.

    1978-01-01

    The subject is covered in chapters entitled: introduction (resume of stellar evolution, gross characteristics of neutron stars); pulsars (pulsar characteristics, pulsars as neutron stars); neutron star temperatures (neutron star cooling, superfluidity and superconductivity in neutron stars); the exterior of neutron stars (the magnetosphere, the neutron star 'atmosphere', pulses); neutron star structure; neutron star equations of state. (U.K.)

  13. The Power of Stars How Celestial Observations Have Shaped Civilization

    CERN Document Server

    Penprase, Bryan E

    2011-01-01

    What are some of the connections that bind us to the stars? How have these connections been established? And how have people all around the world and throughout time reacted to the night sky, the sun and moon, in their poetry, mythology, rituals, and temples? This book explores the influence of the sky on both ancient and modern civilization, by providing a clear overview of the many ways in which humans have used the stars as an ordering principle in their cultures, and which today still inspire us intellectually, emotionally, and spiritually. The book explores constellation lore from around the world, celestial alignments of monuments and temples, both from ancient and modern civilizations, and the role the sky has played in the cultures of the Greek, Egyptian, Babylonian, Native American, Chinese, Mayan, Aztec, and Inca. Models of the universe from each of these cultures are described clearly, and each culture’s explanation of the stars, planets, and other celestial objects are described. The roots of as...

  14. Pre-main-sequence evolution of the sun

    International Nuclear Information System (INIS)

    Gough, D.

    1980-01-01

    The phase of solar evolution after the dynamical collapse is considered. The physics of the Kelvin-Helmholtz phase of gravitational collapse is described, attention being given to the early stages of the star when it was completely convective. It is noted that subsequently, a radiative core developed and evolution was controlled by the rate at which heat can diffuse through it by radiative transfer. Since the study of the Kelvin-Helmholtz contraction alone does not give enough information regarding the state of the sun when it first settled down to approximate hydrostatic equilibrium, other stars are studied, and information on the sun is obtained by analogy. Many young solar-type stars, such as the T Tauri stars, are not in the completely convective Hayashi (1961) phase hence it is proposed that the sun was completely mixed soon after its formation, which has some bearing on the sun's chemical structure. It is suggested that the surface of the sun was very nonuniform compared with the photosphere of today. The simple solar evolution model presented gives a good guide to the general way in which the sun contracted to the main sequence

  15. Convective penetration in a young sun

    Science.gov (United States)

    Pratt, Jane; Baraffe, Isabelle; Goffrey, Tom; MUSIC developers group

    2018-01-01

    To interpret the high-quality data produced from recent space-missions it is necessary to study convection under realistic stellar conditions. We describe the multi-dimensional, time implicit, fully compressible, hydrodynamic, implicit large eddy simulation code MUSIC. We use MUSIC to study convection during an early stage in the evolution of our sun where the convection zone covers approximately half of the solar radius. This model of the young sun possesses a realistic stratification in density, temperature, and luminosity. We approach convection in a stellar context using extreme value theory and derive a new model for convective penetration, targeted for one-dimensional stellar evolution calculations. This model provides a scenario that can explain the observed lithium abundance in the sun and in solar-like stars at a range of ages.

  16. Giant Black Hole Rips Apart Star

    Science.gov (United States)

    2004-02-01

    was equivalent to a supernova. "Now, with all the data in hand, we have the smoking gun proof that this spectacular event has occurred," said coauthor Günther Hasinger, also of MPE. The black hole in the center of RX J1242-11 is estimated to have a mass of about 100 million times Earth's Sun. By contrast, the destroyed star probably had a mass about equal to the Sun, making it a lopsided battle of gravity. "This is the ultimate David versus Goliath battle, but here David loses," said Hasinger. The astronomers estimated about one percent of the star's mass was ultimately consumed, or accreted, by the black hole. This small amount is consistent with predictions that the momentum and energy of the accretion process will cause most of the destroyed star's gas to be flung away from the black hole. XMM-Newton Spectrum &Illustration of RX J1242-11 XMM-Newton Spectrum & Illustration of RX J1242-11 The force that disrupted the star in RX J1242-11 is an extreme example of the tidal force caused by differences in gravity acting on the front and back of an object. The tidal force from the Moon causes tides in Earth's oceans. A tidal force from Jupiter pulled Comet Shoemaker-Levy apart, before it plunged into the giant planet. The odds stellar tidal disruption will happen in a typical galaxy are low, about one in 10,000 annually. If it happened at the center of the Milky Way Galaxy, 26,000 light-years from Earth, the resulting X-ray outburst would be about 50,000 times brighter than the brightest X-ray source in our galaxy, beside the Sun, but it would not pose a threat to Earth. Other dramatic flares have been seen from galaxies, but this is the first studied with the high-spatial resolution of Chandra and the high-spectral resolution of XMM-Newton. Both instruments made a critical advance. Chandra showed the RX J1242-11 event occurred in the center of a galaxy, where the black hole lurks. The XMM-Newton spectrum revealed the fingerprints expected for the surroundings of a black

  17. Stars rich in heavy metals tend to harbor planets

    CERN Multimedia

    2003-01-01

    "A comparison of 754 nearby stars like our Sun - some with planets and some without - shows definitively that the more iron and other metals there are in a star, the greater the chance it has a companion planet" (1 page).

  18. Examples of the nonlinear dynamics of ballistic capture and escape in the earth-moon system

    Science.gov (United States)

    Belbruno, Edward A.

    1990-01-01

    An example of a trajectory is given which is initially captured in an elliptic resonant orbit about the earth and then ballistically escapes the earth-moon system. This is demonstrated by a numerical example in three-dimensions using a planetary ephemeris. Another example shows a mechanism of how an elliptic orbit about the earth can increase its energy by performing a complex nonlinear transition to an elliptic orbit of a larger semi-major axis. Capture is also considered. An application of ballistic capture at the moon via an unstable periodic orbit using the four-body sun-earth-moon-S/C interaction is described.

  19. Kug Sun Hong

    Indian Academy of Sciences (India)

    Home; Journals; Bulletin of Materials Science. Kug Sun Hong. Articles written in Bulletin of Materials Science. Volume 33 Issue 1 February 2010 pp 43-47 Composites. Microstructure and mechanical properties of Mg–HAP composites · Asit Kumar Khanra Hwa Chul Jung Seung Hoon Yu Kug Sun Hong Kwang Seon Shin.

  20. F F Sun

    Indian Academy of Sciences (India)

    Home; Journals; Bulletin of Materials Science. F F Sun. Articles written in Bulletin of Materials Science. Volume 37 Issue 1 February 2014 pp 71-76. Study of electroless copper plating on ABS resin surface modified by heterocyclic organosilane self-assembled film · H N Zhang J Wang F F Sun D Liu H Y Wang F Wang.

  1. When Moons Collide

    Science.gov (United States)

    Rufu, Raluca; Aharonson, Oded

    2017-10-01

    Impacts between two orbiting satellites is a natural consequence of Moon formation. Mergers between moonlets are especially important for the newly proposed multiple-impact hypothesis as these moonlets formed from different debris disks merge together to form the final Moon. However, this process is relevant also for the canonical giant impact, as previous work shows that multiple moonlets are formed from the same debris disk.The dynamics of impacts between two orbiting bodies is substantially different from previously heavily studied planetary-sized impacts. Firstly, the impact velocities are smaller and limited to, thus heating is limited. Secondly, both fragments have similar mass therefore, they would contribute similarly and substantially to the final satellite. Thirdly, this process can be more erosive than planetary impacts as the velocity of ejected material required to reach the mutual Hill sphere is smaller than the escape velocity, altering the merger efficiency. Previous simulations show that moonlets inherit different isotopic signatures from their primordial debris disk, depending on the parameters of the collision with the planet. We therefore, evaluate the degree of mixing in moonlet-moonlet collisions in the presence of a planetary gravitational field, using Smooth Particle Hydrodynamics (SPH). Preliminary results show that the initial thermal state of the colliding moonlets has only a minor influence on the amount of mixing, compared to the effects of velocity and impact angle over their likely ranges. For equal mass bodies in accretionary collisions, impact angular momentum enhances mixing. In the hit-and-run regime, only small amounts of material are transferred between the bodies therefore mixing is limited. Overall, these impacts can impart enough energy to melt ~15-30% of the mantle extending the magma ocean phase of the final Moon.

  2. Reconnection on the Sun

    Science.gov (United States)

    Kohler, Susanna

    2016-05-01

    Because the Sun is so close, it makes an excellent laboratory to study processes we cant examinein distant stars. One openquestion is that of how solar magnetic fields rearrange themselves, producing the tremendous releases of energy we observe as solar flares and coronal mass ejections (CMEs).What is Magnetic Reconnection?Magnetic reconnection occurs when a magnetic field rearranges itself to move to a lower-energy state. As field lines of opposite polarity reconnect, magnetic energy is suddenly converted into thermal and kinetic energy.This processis believed to be behind the sudden releases of energy from the solar surface in the form of solar flares and CMEs. But there are many different models for how magnetic reconnection could occur in the magnetic field at the Suns surface, and we arent sure which one of these reconnection types is responsible for the events we see.Recently, however, several studies have been published presenting some of the first observational support of specific reconnection models. Taken together, these observations suggest that there are likely several different types of reconnection happening on the solar surface. Heres a closer look at two of these recent publications:A pre-eruption SDO image of a flaring region (b) looks remarkably similar to a 3D cartoon for typical breakout configuration (a). Click for a closer look! [Adapted from Chen et al. 2016]Study 1:Magnetic BreakoutLed by Yao Chen (Shandong University in China), a team of scientists has presented observations made by the Solar Dynamics Observatory (SDO) of a flare and CME event that appears to have been caused by magnetic breakout.In the magnetic breakout model, a series of loops in the Suns lower corona are confined by a surrounding larger loop structure called an arcade higher in the corona. As the lower loops push upward, reconnection occurs in the upper corona, removing the overlying, confining arcade. Without that extra confinement, the lower coronal loops expand upward

  3. Magmatism on the Moon

    Science.gov (United States)

    Michaut, Chloé; Thorey, Clément; Pinel, Virginie

    2016-04-01

    Volcanism on the Moon is dominated by large fissure eruptions of mare basalt and seems to lack large, central vent, shield volcanoes as observed on all the other terrestrial planets. Large shield volcanoes are constructed over millions to several hundreds of millions of years. On the Moon, magmas might not have been buoyant enough to allow for a prolonged activity at the same place over such lengths of time. The lunar crust was indeed formed by flotation of light plagioclase minerals on top of the lunar magma ocean, resulting in a particularly light and relatively thick crust. This low-density crust acted as a barrier for the denser primary mantle melts. This is particularly evident in the fact that subsequent mare basalts erupted primarily within large impact basins where at least part of the crust was removed by the impact process. Thus, the ascent of lunar magmas might have been limited by their reduced buoyancy, leading to storage zone formation deep in the lunar crust. Further magma ascent to shallower depths might have required local or regional tensional stresses. Here, we first review evidences of shallow magmatic intrusions within the lunar crust of the Moon that consist in surface deformations presenting morphologies consistent with models of magma spreading at depth and deforming an overlying elastic layer. We then study the preferential zones of magma storage in the lunar crust as a function of the local and regional state of stress. Evidences of shallow intrusions are often contained within complex impact craters suggesting that the local depression caused by the impact exerted a strong control on magma ascent. The depression is felt over a depth equivalent to the crater radius. Because many of these craters have a radius less than 30km, the minimum crust thickness, this suggests that the magma was already stored in deeper intrusions before ascending at shallower depth. All the evidences for intrusions are also preferentially located in the internal

  4. Sun-Earth Day Connects History, Culture and Science

    Science.gov (United States)

    Cline, T.; Thieman, J.

    2003-12-01

    The NASA Sun-Earth Connection Education forum annually promotes and event called Sun-Earth Day: a national celebration of the Sun, the space around the Earth (geospace), and how all of it affects life on our planet. For the past 3 years this event has provided a venue by which classrooms, museums, planetaria, and at NASA centers have had a sensational time sharing stories, images, and activities related to the Sun-Earth connections and the views o fthe Sun from Earth. Each year we select a different theme by which NASA Space Science can be further related to cross-curricular activities. Sun-Earth Day 2002, "Celebrate the Equinox", drew parallels between Native American Cultures and NASA's Sun-Earth Connection research via cultural stories, interviews, web links, activities and Native American participation. Sun-Earth Day 2003, "Live From the Aurora", shared the beauty of the Aurora through a variety of activities and stories related to perspectives of Northern Peoples. Sun-Earth Day 2004 will share the excitement of the transit of Venus through comparisons of Venus with Earth and Mars, calculations of the distances to nearby stars, and the use of transits to identify extra-solar planets. Finally, Sun-Earth Day 2005 will bring several of these themes together by turning our focus to the history and culture surrounding ancient observatories such as Chaco Canyon, Machu Picchu, and Chichen Itza.

  5. Giant black hole rips star apart

    Science.gov (United States)

    2004-02-01

    Astronomers believe that a doomed star came too close to a giant black hole after a close encounter with another star threw it off course. As it neared the enormous gravity of the black hole, the star was stretched by tidal forces until it was torn apart. This discovery provides crucial information on how these black holes grow and affect the surrounding stars and gas. "Stars can survive being stretched a small amount, as they are in binary star systems, but this star was stretched beyond its breaking point," said Dr Stefanie Komossa of the Max Planck Institute for Extraterrestrial Physics (MPE) in Germany, who led the international team of researchers. "This unlucky star just wandered into the wrong neighbourhood." While other observations have hinted that stars are destroyed by black holes (events known as ‘stellar tidal disruptions’), these new results are the first strong evidence. Observations with XMM-Newton and Chandra, combined with earlier images from the German Roentgensatellite (ROSAT), detected a powerful X-ray outburst from the centre of the galaxy RXJ1242-11. This outburst, one of the most extreme ever detected in a galaxy, was caused by gas from the destroyed star that was heated to millions of degrees before being swallowed by the black hole. The energy liberated in this process is equivalent to that of a supernova. "Now, with all of the data in hand, we have the smoking gun proof that this spectacular event has occurred," said co-author Prof. Guenther Hasinger, also of MPE. The black hole in the centre of RX J1242-11 is estimated to have a mass about 100 million times that of the Sun. By contrast, the destroyed star probably had a mass about equal to that of the Sun, making it a lopsided battle of gravity. "This is the ultimate ‘David versus Goliath’ battle, but here David loses," said Hasinger. The astronomers estimated that about one hundredth of the mass of the star was ultimately consumed, or accreted, by the black hole. This small

  6. Capture of terrestrial-sized moons by gas giant planets.

    Science.gov (United States)

    Williams, Darren M

    2013-04-01

    Terrestrial moons with masses >0.1 M (symbol in text) possibly exist around extrasolar giant planets, and here we consider the energetics of how they might form. Binary-exchange capture can occur if a binary-terrestrial object (BTO) is tidally disrupted during a close encounter with a giant planet and one of the binary members is ejected while the other remains as a moon. Tidal disruption occurs readily in the deep gravity wells of giant planets; however, the large encounter velocities in the wells make binary exchange more difficult than for planets of lesser mass. In addition, successful capture favors massive binaries with large rotational velocities and small component mass ratios. Also, since the interaction tends to leave the captured moons on highly elliptical orbits, permanent capture is only possible around planets with sizable Hill spheres that are well separated from their host stars.

  7. The sun and space weather Second Edition

    CERN Document Server

    Hanslmeier, Arnold

    2007-01-01

    This second edition is a great enhancement of literature which will help the reader get deeper into the specific topics. There are new sections included such as space weather data sources and examples, new satellite missions, and the latest results. At the end a comprehensive index is given which will allow the reader to quickly find his topics of interest. The Sun and Space weather are two rapidly evolving topics. The importance of the Sun for the Earth, life on Earth, climate and weather processes was recognized long ago by the ancients. Now, for the first time there is a continuous surveillance of solar activity at nearly all wavelengths. These data can be used to improve our understanding of the complex Sun-Earth interaction. The first chapters of the book deal with the Sun as a star and its activity phenomena as well as its activity cycle in order to understand the complex physics of the Sun-Earth system. The reader will see that there are many phenomena but still no definite explanations and models exis...

  8. Tidal Friction in the Earth-Moon System and Laplace Planes: Darwin Redux

    Science.gov (United States)

    Rubincam, David P.

    2015-01-01

    The dynamical evolution of the Earth-Moon system due to tidal friction is treated here. George H. Darwin used Laplace planes (also called proper planes) in his study of tidal evolution. The Laplace plane approach is adapted here to the formalisms of W.M. Kaula and P. Goldreich. Like Darwin, the approach assumes a three-body problem: Earth, Moon, and Sun, where the Moon and Sun are point-masses. The tidal potential is written in terms of the Laplace plane angles. The resulting secular equations of motion can be easily integrated numerically assuming the Moon is in a circular orbit about the Earth and the Earth is in a circular orbit about the Sun. For Earth-Moon distances greater than 10 Earth radii, the Earth's approximate tidal response can be characterized with a single parameter, which is a ratio: a Love number times the sine of a lag angle divided by another such product. For low parameter values it can be shown that Darwin's low-viscosity molten Earth, M. Ross's and G. Schubert's model of an Earth near melting, and Goldreich's equal tidal lag angles must all give similar histories. For higher parameter values, as perhaps has been the case at times with the ocean tides, the Earth's obliquity may have decreased slightly instead of increased once the Moon's orbit evolved further than 50 Earth radii from the Earth, with possible implications for climate. This is contrast to the other tidal friction models mentioned, which have the obliquity always increasing with time. As for the Moon, its orbit is presently tilted to its Laplace plane by 5.2deg. The equations do not allow the Moon to evolve out of its Laplace plane by tidal friction alone, so that if it was originally in its Laplace plane, the tilt arose with the addition of other mechanisms, such as resonance passages.

  9. Comparative Magnetic Minima: Characterizing Quiet Times in the Sun and Stars. Symposium of the International Astronomical Union (286th) Held in Mendoza, Argentina on October 3-7, 2011

    Science.gov (United States)

    2011-10-01

    11:15 – 11:45 Invited Talk – Stars in Magnetic Grand Minima: Where Are They and What Are They Like? Steven Saar (Presentation file) 11:45 – 12:00...of Archaeology and Ancient History, University Rd, Leicester LE1 7RH, United Kingdom IAUS 279 Death of Massive Stars: Supernovae and Gamma-Ray Bursts...of Astronomy & Astrophysics, 525 Davey Lab, University Park, PA 16802, USA IAUS 283 Planetary Nebulae: an Eye to the Future A. MANCHADO, Instituto de

  10. Sun and Sjogren's Syndrome

    Science.gov (United States)

    Patient Education Sheet The Sun and Sjögren’s Syndrome The SSF thanks Mona Z. Mofid, MD, FAAD, Diplomate, American Board of Dermatology, and Medical Director, American Melanoma Foundation, San Diego, California, ...

  11. Mercury is Moon's brother

    International Nuclear Information System (INIS)

    Ksanfomalifi, L.V.

    1976-01-01

    The latest information on Mercury planet is presented obtained by studying the planet with the aid of radar and space vehicles. Rotation of Mercury about its axis has been discovered; within 2/3 of its year it executes a complete revolution about its axis. In images obtained by the ''Mariner-10'' Mercurys surface differs little from that of the Moon. The ''Mariner-10'' has also discovered the Mercurys atmosphere, which consists of extremely rarefied helium. The helium is continuously supplied to the planet by the solar wind. The Mercury's magnetic field has been discovered, whose strength is 35 x 10 -4 at the Equator and 70 x 10 -4 E at the poles. The inclination of the dipole axis to the Mercury's rotation axis is 7 deg

  12. Shooting the Moon

    Science.gov (United States)

    Andrews, Daniel R.

    2011-01-01

    This story is about an unlikely NASA mission to the Moon. It was unlikely because it was started with far too little time and too-little money to complete. It was unlikely because it was able to take chances to accept risk of failure. It was unlikely because it was searching for the unthinkable: water-ice on the moon... Figure 1-1: LCROSS Mission. The mission of the Lunar CRater Observation and Sensing Satellite (LCROSS) was to investigate the possibility of water ice in craters on the Moon s poles. This is certainly an interesting scientific topic in itself, but I intend to focus on the compelling experience of managing the LCROSS Project in the context of this storied Agency. Perhaps most interesting are the implications this story has for managing any development effort, lunar or not, and working a balance to achieve success. NASA is by design a risk-taking agency within the US Government. It could be argued that NASA s purpose in the aerospace community is to take on the really big challenges that either the corporate world can t afford, are not yet profitable endeavors, or are just too risky for private corporations to entertain. However, expectations of the Agency have evolved. A combination of grim human tragedies and some very public cost and schedule overruns have challenged the public s and Congress s tolerance for risk-taking within the Agency. NASA, which is supposed to be in the business of taking risks to do bold, difficult things, has become less and less able to do so within its cost framework. Yet effectively replacing prudent risk management with attempts to "risk-eliminate" is completely unaffordable. So where does risk-taking fit within the Agency, or within private/corporate organizations for that matter? Where astronauts play there is clearly concern about risk. When an organization puts humans in harm s way, it is understandably going to take extra effort to assure nobody gets hurt. Doing so, of course, costs money - a lot of money to pay for

  13. The Brick Moon

    Science.gov (United States)

    2004-01-01

    Science fiction writers, like Jules Verne in France and Edward Everett Hale in America, had discovered one of the most vital elements in the formula for space travel-a fertile imagination. The first known proposal for a marned-satellite appears in a story by Hale entitled 'The Brick Moon' published in 1899. The story involved a group of young Bostonians who planned to put an artificial satellite into polar orbit for sailors to use to determine longitude accurately and easily. They planned to send a brick satellite into orbit because the satellite would have to withstand fire very well. The Satellite's 37 inhabitants signaled the Earth in morse code by jumping up and down on the outside of the satellite.

  14. 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.

  15. XMM-Newton detects X-ray 'solar cycle' in distant star

    Science.gov (United States)

    2004-05-01

    whether the Sun's X-ray cycle is common among other solar-type stars, and in particular among those hosting potential rocky planets, can give scientists much needed clues on whether and where other forms of life might exist outside the Solar System. At the same time, understanding how typical and long-lasting is the solar behaviour will tell us more about the evolution of the climate on Earth. Further observations of HD 81809 and other similar stars are already planned with XMM-Newton. They will allow astronomers to study whether the large modulations in X-ray brightness observed in the Sun are indeed the norm for stars of its type. Understanding how other solar-like stars behave in general will give scientists better insight into the past and future of our own Sun. Note to editors The results described here were published in the April issue of the scientific journal Astronomy and Astrophysics (Vol. 418, p. L13). The authors of the paper are F. Favata, G. Micela, S. Baliunas, J. Schmitt, M. Guedel, F. Harnden Jr., S. Sciortino and R. Stern. A reprint of the paper can be found at: http://arxiv.org/abs/astro-ph/0403142 More about XMM-Newton XMM-Newton can detect more X-ray sources than any previous satellite and is helping to solve many cosmic mysteries of the violent Universe, from black holes to the formation of galaxies. It was launched on 10 December 1999, using an Ariane-5 rocket from French Guiana. It is expected to return data for a decade. XMM-Newton's high-tech design uses over 170 wafer-thin cylindrical mirrors spread over three telescopes. Its orbit takes it almost a third of the way to the Moon, so that astronomers can enjoy long, uninterrupted views of celestial objects. More information on XMM-Newton can be found at: http://www.esa.int/esaSC/SEMM8IGHZTD_1_spk.html More about SOHO SOHO is a project of international cooperation between ESA and NASA to study the Sun, from its deep core to the outer corona, and the solar wind. Fourteen European countries, led by

  16. Symbiotic star AG Dra

    International Nuclear Information System (INIS)

    Ipatov, A.P.; Yudin, B.F.; Moskovskij Gosudarstvennyj Univ.

    1986-01-01

    The results obtained from photometric (in the UBVRJHKLM system) and spectrophotometric (in the range 0.33-0.75 μm) observations of symbiotic star AG Dra are presented. The cool component of this star is a red giant with approximately constant brightness (ΔJ ≤ 0 m .3) classified as K4-K5. This red giant fills it's Roche loble and probably is on the assymptotic giant branch of the HR diagramm. The presence of IR excess in 5 μm associated with radiation of the gaseous envelope with the mass of M≅ 10 -6 M sun have been detected. Observations of AG Dra indicate that growing of the bolometric flux of a hot component is accompanied with decreasing effective temperature. The hot component of the system is probably an accerting red dwarf with the mass M≅ 0.4 M sun and disk accretion of matter of cool star with the rate M >or ∼ 10 -4 M sun year in equatorial region. Increase of accretion rate during the outburst of AG Dra leads to the increase of stellar wind from the red dwarf surface and the decrease of it's effective temperature. The hot component of AG Dra may also be considered as a white Dwarf with luminosity L 3 L sun and R eff >or approx. 0.2 R sun . In this case gravitational energy of accreting matter M > or ∼ 10 -6 M sun / year would be the source of the hot component outbursts. The luminosity between outbursts is determined by energy generation from the burning hydrogen layer source

  17. Physics and astronomy of the Moon

    CERN Document Server

    Kopal, Zdenek

    2013-01-01

    Physics and Astronomy of the Moon focuses on the application of principles of physics in the study of the moon, including perturbations, equations, light scattering, and photometry. The selection first offers information on the motion of the moon in space and libration of the moon. Topics include Hill's equations of motion, non-solar perturbations, improved lunar ephemeris, optical and physical libration of the moon, and adjustment of heliometric observations of the moon's libration. The text then elaborates on the dynamics of the earth-moon system, photometry of the moon, and polarization of

  18. Thai student existing understanding about the solar system model and the motion of the stars

    Science.gov (United States)

    Anantasook, Sakanan; Yuenyong, Chokchai

    2018-01-01

    The paper examined Thai student existing understanding about the solar system model and the motion of the stars. The participants included 141 Grade 9 students in four different schools of the Surin province, Thailand. Methodology regarded interpretive paradigm. The tool of interpretation included the Student Celestial Motion Conception Questionnaire (SCMCQ) and informal interview. Given understandings in the SCMCQ were read through and categorized according to students' understandings. Then, students were further probed as informal interview. Students' understandings in each category were counted and percentages computed. Finally, students' understandings across four different schools were compared and contrasted using the percentage of student responses in each category. The findings revealed that most students understand about Sun-Moon-Earth (SME) system and solar system model as well, they can use scientific explanations to explain the celestial objects in solar system and how they orbiting. Unfortunately, most of students (more than 70%) never know about the Polaris, the North Star, and 90.1% of them never know about the ecliptic, and probably also the 12 zodiac constellations. These existing understanding suggested some ideas of teaching and learning about solar system model and the motion of the stars. The paper, then, discussed some learning activities to enhance students to further construct meaning about solar system model and the motion of the stars.

  19. Which of Kepler's Stars Flare?

    Science.gov (United States)

    Kohler, Susanna

    2017-12-01

    The habitability of distant exoplanets is dependent upon many factors one of which is the activity of their host stars. To learn about which stars are most likely to flare, a recent study examines tens of thousands of stellar flares observed by Kepler.Need for a Broader SampleArtists rendering of a flaring dwarf star. [NASAs Goddard Space Flight Center/S. Wiessinger]Most of our understanding of what causes a star to flare is based on observations of the only star near enough to examine in detail the Sun. But in learning from a sample size of one, a challenge arises: we must determine which conclusions are unique to the Sun (or Sun-like stars), and which apply to other stellar types as well.Based on observations and modeling, astronomers think that stellar flares result from the reconnection of magnetic field lines in a stars outer atmosphere, the corona. The magnetic activity is thought to be driven by a dynamo caused by motions in the stars convective zone.HR diagram of the Kepler stars, with flaring main-sequence (yellow), giant (red) and A-star (green) stars in the authors sample indicated. [Van Doorsselaere et al. 2017]To test whether these ideas are true generally, we need to understand what types of stars exhibit flares, and what stellar properties correlate with flaring activity. A team of scientists led by Tom Van Doorsselaere (KU Leuven, Belgium) has now used an enormous sample of flares observed by Kepler to explore these statistics.Intriguing TrendsVan Doorsselaere and collaborators used a new automated flare detection and characterization algorithm to search through the raw light curves from Quarter 15 of the Kepler mission, building a sample of 16,850 flares on 6,662 stars. They then used these to study the dependence of the flare occurrence rate, duration, energy, and amplitude on the stellar spectral type and rotation period.This large statistical study led the authors to several interesting conclusions, including:Flare star incidence rate as a a

  20. MoonNEXT: A European Mission to the Moon

    Science.gov (United States)

    Carpenter, J. D.; Koschny, D.; Crawford, I.; Falcke, H.; Kempf, S.; Lognonne, P.; Ricci, C.; Houdou, B.; Pradier, A.

    2008-09-01

    MoonNEXT is a mission currently being studied, under the direction of the European Space Agency, whose launch is foreseen between 2015 and 2018. MoonNEXT is intended to prepare the way for future exploration activities on the Moon, while addressing key science questions. Exploration Objectives The primary goal for the MoonNEXT mission is to demonstrate autonomous soft precision landing with hazard avoidance; a key capability for future exploration missions. The nominal landing site is at the South Pole of the Moon, at the edge of the Aitken basin and in the region of Shackleton crater, which has been identified as an optimal location for a future human outpost by the NASA lunar architecture team [1]. This landing site selection ensures a valuable contribution by MoonNEXT to the Global Exploration Strategy [2]. MoonNEXT will also prepare for future lunar exploration activities by characterising the environment at the lunar surface. The potentially hazardous radiation environment will me monitored while a dedicated instrument package will investigate the levitation and mobility of lunar dust. Experience on Apollo demonstrated the potentially hazardous effects of dust for surface operations and human activities and so an understanding of these processes is important for the future. Life sciences investigations will be carried out into the effects of the lunar environment (including radiation, gravity and illumination conditions) on a man made ecosystem analogous to future life support systems. In doing so MoonNEXT will demonstrate the first extraterrestrial man made ecosystem and develop valuable expertise for future missions. Geological and geochemical investigations will explore the possibilities for In Situ Resource Utilisation (ISRU), which will be essential for long term human habitation on the Moon and is of particular importance at the proposed landing site, given its potential as a future habitat location. Science Objectives In addition to providing extensive

  1. Precise nuclear physics for the sun

    International Nuclear Information System (INIS)

    Bemmerer, Daniel

    2012-01-01

    For many centuries, the study of the Sun has been an important testbed for understanding stars that are further away. One of the first astronomical observations Galileo Galilei made in 1612 with the newly invented telescope concerned the sunspots, and in 1814, Joseph von Fraunhofer employed his new spectroscope to discover the absorption lines in the solar spectrum that are now named after him. Even though more refined and new modes of observation are now available than in the days of Galileo and Fraunhofer, the study of the Sun is still high on the agenda of contemporary science, due to three guiding interests. The first is connected to the ages-old human striving to understand the structure of the larger world surrounding us. Modern telescopes, some of them even based outside the Earth's atmosphere in space, have succeeded in observing astronomical objects that are billions of light-years away. However, for practical reasons precision data that are important for understanding stars can still only be gained from the Sun. In a sense, the observations of far-away astronomical objects thus call for a more precise study of the closeby, of the Sun, for their interpretation. The second interest stems from the human desire to understand the essence of the world, in particular the elementary particles of which it consists. Large accelerators have been constructed to produce and collide these particles. However, man-made machines can never be as luminous as the Sun when it comes to producing particles. Solar neutrinos have thus served not only as an astronomical tool to understand the Sun's inner workings, but their behavior on the way from the Sun to the Earth is also being studied with the aim to understand their nature and interactions. The third interest is strictly connected to life on Earth. A multitude of research has shown that even relatively slight changes in the Earth's climate may strongly affect the living conditions in a number of densely populated areas

  2. Precise nuclear physics for the sun

    Energy Technology Data Exchange (ETDEWEB)

    Bemmerer, Daniel

    2012-07-01

    For many centuries, the study of the Sun has been an important testbed for understanding stars that are further away. One of the first astronomical observations Galileo Galilei made in 1612 with the newly invented telescope concerned the sunspots, and in 1814, Joseph von Fraunhofer employed his new spectroscope to discover the absorption lines in the solar spectrum that are now named after him. Even though more refined and new modes of observation are now available than in the days of Galileo and Fraunhofer, the study of the Sun is still high on the agenda of contemporary science, due to three guiding interests. The first is connected to the ages-old human striving to understand the structure of the larger world surrounding us. Modern telescopes, some of them even based outside the Earth's atmosphere in space, have succeeded in observing astronomical objects that are billions of light-years away. However, for practical reasons precision data that are important for understanding stars can still only be gained from the Sun. In a sense, the observations of far-away astronomical objects thus call for a more precise study of the closeby, of the Sun, for their interpretation. The second interest stems from the human desire to understand the essence of the world, in particular the elementary particles of which it consists. Large accelerators have been constructed to produce and collide these particles. However, man-made machines can never be as luminous as the Sun when it comes to producing particles. Solar neutrinos have thus served not only as an astronomical tool to understand the Sun's inner workings, but their behavior on the way from the Sun to the Earth is also being studied with the aim to understand their nature and interactions. The third interest is strictly connected to life on Earth. A multitude of research has shown that even relatively slight changes in the Earth's climate may strongly affect the living conditions in a number of densely

  3. The earth and the moon

    CERN Document Server

    Elkins-Tanton, Linda T

    2010-01-01

    The moon is the only body in the solar system outside of the Earth that has been visited by humans. More than 440 pounds of lunar material are brought by NASA and Soviet space missions to Earth for study. The information gleaned about the moon from this relatively small pile of rocks is mind-boggling and stands as the greatest proof that Martian planetary science would be greatly enhanced by returning samples to Earth. Compositional studies of lunar rocks show that the moon and the Earth are made of similar material, and because lunar material has not been reworked through erosion and plate te

  4. Cosmic acceleration of Earth and the Moon by dark matter

    Science.gov (United States)

    Nordtvedt, Kenneth L.

    1994-01-01

    In order to test the hypothesis that the gravitational interaction between our Galaxy's dark matter and the ordinary matter in Earth and the Moon might not fulfill the equivalence principle (universality of free fall), we consider the pertinent perturbation of the lunar orbit -- a sidereal month period range oscillation resulting from a spatially fixed polarization of the orbit. Lunar laser ranging (LLR) data can measure this sidereal perturbation to an accuracy equal to or better than its existing measurement of the synodic month period range oscillation amplitude (+/- 3 cm) which has been used for testing whether Earth and the Moon accelerate at equal rates toward the Sun. Because of the slow precession rate of the Moon's perigree (8.9 yr period), the lunar orbit is particularly sensitive to a cosmic acceleration; the LLR fit of the orbit places an upper limit of 10(exp -13) cm/sq. s for any cosmic differential acceleration between Earth (Fe) and the Moon (silicates). This is 10(exp -5) of the total galactic acceleration of the solar system, of which, it has been suggested, a large portion is produced by dark matter.

  5. Short-term capture of the Earth-Moon system

    Science.gov (United States)

    Qi, Yi; de Ruiter, Anton

    2018-06-01

    In this paper, the short-term capture (STC) of an asteroid in the Earth-Moon system is proposed and investigated. First, the space condition of STC is analysed and five subsets of the feasible region are defined and discussed. Then, the time condition of STC is studied by parameter scanning in the Sun-Earth-Moon-asteroid restricted four-body problem. Numerical results indicate that there is a clear association between the distributions of the time probability of STC and the five subsets. Next, the influence of the Jacobi constant on STC is examined using the space and time probabilities of STC. Combining the space and time probabilities of STC, we propose a STC index to evaluate the probability of STC comprehensively. Finally, three potential STC asteroids are found and analysed.

  6. On Choosing a Rational Flight Trajectory to the Moon

    Science.gov (United States)

    Gordienko, E. S.; Khudorozhkov, P. A.

    2017-12-01

    The algorithm for choosing a trajectory of spacecraft flight to the Moon is discussed. The characteristic velocity values needed for correcting the flight trajectory and a braking maneuver are estimated using the Monte Carlo method. The profile of insertion and flight to a near-circular polar orbit with an altitude of 100 km of an artificial lunar satellite (ALS) is given. The case of two corrections applied during the flight and braking phases is considered. The flight to an ALS orbit is modeled in the geocentric geoequatorial nonrotating coordinate system with the influence of perturbations from the Earth, the Sun, and the Moon factored in. The characteristic correction costs corresponding to corrections performed at different time points are examined. Insertion phase errors, the errors of performing the needed corrections, and the errors of determining the flight trajectory parameters are taken into account.

  7. Stars, Galaxies, and the Origin of Chemical Elements

    Science.gov (United States)

    Peter, Ulmschneider

    "That I am mortal I know, and that my days are numbered, but when in my mind I follow the multiply entwined orbits of the stars, then my feet do no longer touch the Earth. At the table of Zeus himself do I eat Ambrosia, the food of the Gods". These words by Ptolemy from around 125 A.D. are handed down together with his famous book The Almagest, the bible of astronomy for some 1500 years. They capture mankind's deep fascination with the movements of the heavens, and the miracles of the biological world. After the Babylonians observed the motions of the Sun, Moon, and planets for millennia, the ancient Greeks were the first to speculate about the nature of these celestial bodies. Yet it is only as a consequence of developments in the last 150 years that a much clearer picture of the physical universe has begun to emerge. Among the most important discoveries have been the stellar parallax, confirming Copernicus's heliocentric system, the realization that galaxies are comprised of billions of stars, the awareness of the size of the universe, and the evolutionary nature of living organisms.

  8. Does the sun ring

    International Nuclear Information System (INIS)

    Isaak, G.R.

    1978-01-01

    The work of various groups, which have been investigating the possibility of measuring the periodicities of solar oscillations in an attempt to test theoretical models of the sun, is reported. In particular the observation of small velocity oscillations of the surface layers of the sun that permits the measurement of the sound waves (or phonons) in the solar atmosphere, is discussed. Oscillations with periods of 2.65 h, 58 and 40 min and amplitudes of 2.7, 0.8 and 0.7 ms -1 respectively are reported. Support for a periodicity at about 2.65 h from a number of other groups using other measuring techniques are considered. It is felt that the most probable interpretation of the observed solar oscillations is that the sun is a resonator which is ringing. (UK)

  9. The formation of the moon

    Science.gov (United States)

    O'Keefe, J. A., III

    1974-01-01

    Supporting evidence for the fission hypothesis for the origin of the moon is offered. The maximum allowable amount of free iron now present in the moon would not suffice to extract the siderophiles from the lunar silicates with the observed efficiency. Hence extraction must have been done with a larger amount of iron, as in the mantle of the earth, of which the moon was once a part, according to the fission hypothesis. The fission hypothesis gives a good resolution of the tektite paradox. Tektites are chemically much like products of the mantle of the earth; but no physically possible way has been found to explain their production from the earth itself. Perhaps they are a product of late, deep-seated lunar volcanism. If so, the moon must have inside it some material with a strong resemblance to the earth's mantle.

  10. Impact History of the Moon

    Science.gov (United States)

    Cohen, B. A.; Bottke, W. F.; Norman, M. V.; van der Bogert, C. H.; Fassett, C. I.; Hiesinger, H.; Joy, K. H.; Mazrouei, S. A.; Nemchin, A.; Neumann, G. A.; Zellner, N. E. B.

    2018-04-01

    Establishing an absolute planetary chronology has important ramifications for understanding the early structure of the solar system and the geologic history of the planets. The Moon is the cornerstone for understanding this impact history.

  11. No smoking guns under the Sun

    CERN Document Server

    CERN. Geneva

    2000-01-01

    The Sun is a typical main sequence star that generates its energy via the fusion of hydrogen into helium in two chains of nuclear reactions: the so-called pp chain and the CNO chain. If the nucleon number, electric charge, lepton flavour and energy are conserved and the Sun is in a steady state, then the total solar neutrino flux is fixed, to a good approximation, by the solar luminosity (approximately 65 billion neutrinos/cm2/s at Earth), independent of the specific nuclear reactions that power the Sun and produce neutrinos by beta decay or the electron capture of reaction products. The neutrinos from the dominant pp chain are produced by the beta decay of proton pairs (pp), boron-8 and lithium-4, and by electron capture by pp pairs and beryllium-7. Their spectra can be measured directly in the laboratory or calculated from the standard theory of electroweak interactions. To a very good approximation, they are independent of the conditions in the Sun. Only their relative contributions depend on the detailed ...

  12. Radio astronomy on the moon

    International Nuclear Information System (INIS)

    Burns, J.O.; Asbell, J.

    1987-01-01

    The advantages and opportunities for radio astronomy on the moon during the early to mid 21st century are reviewed. In particular, it is argued that the lack of atmosphere, the extremely low seismic activity, the low RF background, and the natural cryogenic environment make the moon (particularly the far side and the poles) a nearly ideal locale for submillimeter/FIR to VLF (below 10 MHz) radio astronomy. 22 references

  13. Sun, weather, and climate

    International Nuclear Information System (INIS)

    Herman, J.R.; Goldberg, R.A.

    1985-01-01

    The general field of sun-weather/climate relationships that is, apparent weather and climate responses to solar activity is introduced and theoretical and experimental suggestions for further research to identify and investigate the unknown casual mechanisms are provided. Topics of discussion include: (1) solar-related correlation factors and energy sources; (2) long-term climate trends; (3) short-term meteorological correlations; (4) miscellaneous obscuring influences; (5) physical processes and mechanisms; (6) recapitulation of sun-weather relationships; and (7) guidelines for experiments. 300 references

  14. Sun and solar flares

    Energy Technology Data Exchange (ETDEWEB)

    McKenna-Lawlor, S. (Saint Patrick' s Coll., Maynooth (Ireland))

    1982-07-01

    The subject is discussed under the headings: the sun's core (thermonuclear reactions, energy transfer from core through radiation zone, convection zone, photosphere, chromosphere and corona); the photosphere (convection, granulation, sunspots, magnetic fields, solar cycle, rotation of the sun); solar variability and paleoclimatic records (correlation of low solar activity with increased /sup 14/C production in atmosphere); the chromosphere and corona (turbulence, temperature, coronal streamers, energy transfer); solar flares (cosmic rays, aurorae, spectra, velocity of flares, prominences, mechanisms of flares); the solar wind.

  15. Piece of the sun

    CERN Document Server

    Wayne, Teddy

    2015-01-01

    Our rapidly industrialising world has an insatiable hunger for energy, and conventional sources are struggling to meet demand. Oil is running out, coal is damaging our climate, many nations are abandoning nuclear, yet solar, wind and water will never be a complete replacement. The solution, says Daniel Clery in this deeply researched and revelatory book, is to be found in the original energy source: the Sun itself. There, at its centre, the fusion of 630 million tonnes of hydrogen every second generates an unfathomable amount of energy. By replicating even a tiny piece of the Sun's power

  16. General Relativity and Compact Stars

    International Nuclear Information System (INIS)

    Glendenning, Norman K.

    2005-01-01

    Compact stars--broadly grouped as neutron stars and white dwarfs--are the ashes of luminous stars. One or the other is the fate that awaits the cores of most stars after a lifetime of tens to thousands of millions of years. Whichever of these objects is formed at the end of the life of a particular luminous star, the compact object will live in many respects unchanged from the state in which it was formed. Neutron stars themselves can take several forms--hyperon, hybrid, or strange quark star. Likewise white dwarfs take different forms though only in the dominant nuclear species. A black hole is probably the fate of the most massive stars, an inaccessible region of spacetime into which the entire star, ashes and all, falls at the end of the luminous phase. Neutron stars are the smallest, densest stars known. Like all stars, neutron stars rotate--some as many as a few hundred times a second. A star rotating at such a rate will experience an enormous centrifugal force that must be balanced by gravity or else it will be ripped apart. The balance of the two forces informs us of the lower limit on the stellar density. Neutron stars are 10 14 times denser than Earth. Some neutron stars are in binary orbit with a companion. Application of orbital mechanics allows an assessment of masses in some cases. The mass of a neutron star is typically 1.5 solar masses. They can therefore infer their radii: about ten kilometers. Into such a small object, the entire mass of our sun and more, is compressed

  17. Isotopic evolution of the protoplanetary disk and the building blocks of Earth and the Moon

    DEFF Research Database (Denmark)

    Schiller, Martin; Bizzarro, Martin; Fernandes, Vera Assis

    2018-01-01

    Nucleosynthetic isotope variability among Solar System objects is often used to probe the genetic relationship between meteorite groups and the rocky planets (Mercury, Venus, Earth and Mars), which, in turn, may provide insights into the building blocks of the Earth-Moon system. Using this approach......, it has been inferred that no primitive meteorite matches the terrestrial composition and the protoplanetary disk material from which Earth and the Moon accreted is therefore largely unconstrained. This conclusion, however, is based on the assumption that the observed nucleosynthetic variability of inner...... into the thermally processed inner protoplanetary disk associated with the accretion of mass to the proto-Sun. The identical calcium isotope composition of Earth and the Moon reported here is a prediction of our model if the Moon-forming impact involved protoplanets or precursors that completed their accretion near...

  18. The Electrostatic Environments of the Moon and Mars: Implications for Human Missions

    Science.gov (United States)

    Calle, Carlos I.; Mackey, Paul J.; Johansen, Michael R.; Hogue, Michael D.; Phillips, James; Cox, Rachel E.

    2016-01-01

    Lacking a substantial atmosphere, the moon is exposed to the full spectrum of solar radiation as well as to cosmic rays. Electrostatically, the moon is a charged body in a plasma. A Debye sheet meters high on the dayside of the moon and kilometers high on the night side envelops the moon. This sheet isolates the lunar surface from high energy particles coming from the sun. The electrostatic environment on Mars is controlled by its ever present atmospheric dust. Dust devils and dust storms tribocharge this dust. Theoretical studies predict that lightning and/or glow discharges should be present on Mars, but none have been directly observed. Experiments are planned to shed light on this issue.

  19. Symbiotic stars

    International Nuclear Information System (INIS)

    Boyarchuk, A.A.

    1975-01-01

    There are some arguments that the symbiotic stars are binary, where one component is a red giant and the other component is a small hot star which is exciting a nebula. The symbiotic stars belong to the old disc population. Probably, symbiotic stars are just such an evolutionary stage for double stars as planetary nebulae for single stars. (Auth.)

  20. Triana Safehold: A New Gyroless, Sun-Pointing Attitude Controller

    Science.gov (United States)

    Chen, J.; Morgenstern, Wendy; Garrick, Joseph

    2001-01-01

    Triana is a single-string spacecraft to be placed in a halo orbit about the sun-earth Ll Lagrangian point. The Attitude Control Subsystem (ACS) hardware includes four reaction wheels, ten thrusters, six coarse sun sensors, a star tracker, and a three-axis Inertial Measuring Unit (IMU). The ACS Safehold design features a gyroless sun-pointing control scheme using only sun sensors and wheels. With this minimum hardware approach, Safehold increases mission reliability in the event of a gyroscope anomaly. In place of the gyroscope rate measurements, Triana Safehold uses wheel tachometers to help provide a scaled estimation of the spacecraft body rate about the sun vector. Since Triana nominally performs momentum management every three months, its accumulated system momentum can reach a significant fraction of the wheel capacity. It is therefore a requirement for Safehold to maintain a sun-pointing attitude even when the spacecraft system momentum is reasonably large. The tachometer sun-line rate estimation enables the controller to bring the spacecraft close to its desired sun-pointing attitude even with reasonably high system momentum and wheel drags. This paper presents the design rationale behind this gyroless controller, stability analysis, and some time-domain simulation results showing performances with various initial conditions. Finally, suggestions for future improvements are briefly discussed.

  1. Strings in the Sun?

    International Nuclear Information System (INIS)

    Chudnovsky, E.; Vilenkin, A.

    1988-01-01

    If light superconducting strings were formed in the early Universe, then it is very likely that now they exist in abundance in the interstellar plasma and in stars. The dynamics of such strings can be dominated by friction, so that they are ''frozen'' into the plasma. Turbulence of the plasma twists and stretches the strings, forming a stochastic string network. Such networks must generate particles and magnetic fields, and may play an important role in the physics of stars and of the Galaxy

  2. Inca Moon: Some Evidence of Lunar Observations in Tahuantinsuyu

    Science.gov (United States)

    Ziółkowski, Mariusz; Kościuk, Jacek; Astete, Fernando

    So far, scientists have not investigated thoroughly if and for what purpose the Incas observed the Moon. As far as the orientation of architectural structures is concerned, the researchers focus their attention almost entirely on the position of the Sun. However, a more accurate analysis of two well-known sites - the caves of Intimachay and Cusilluchayoc - may provide evidence of their function as observatories of the lunar 18.6-year cycle. Those results may confirm the hypothesis, presented some years ago, that the Incas had elaborated a rudimentary method of predicting lunar eclipses.

  3. Moon Teachings for the Masses at the U.Mass. Sunwheel and around the World

    Science.gov (United States)

    Young, J. S.

    2004-12-01

    With the culmination of the 18.6 year cycle of the Moon in 2006, the major lunar standstill, we are afforded the unique opportunity to teach the public about the monthly, annual, and 18.6-year wanderings of the Moon. The 18.6 year cycle is caused by the precession of the plane of the lunar orbit, while this orbit maintains a 5 degree tilt relative to the ecliptic. At the peak of this cycle, the Moon's declination swings from -28.8 to +28.8 degrees each month. And even though we are more than 1 year away from the peak of the 18.6-year cycle, already the Moon's declination ranges each month between -28 and +28 degrees. What this means is that each month for the years 2005-2007, the Moon can be seen to rise and set more northerly and also more southerly than the solar extremes, and will transit monthly with altitudes which are higher in the sky than the summer Sun and lower in the sky than the winter Sun. The U.Mass. Sunwheel is a stone circle calendar constructed in 1997 on the campus of U.Mass. Amherst, with 8'-10' tall stones marking the cardinal directions, the solstice sunrise and sunset directions, and the northernmost and southernmost moonrise and moonset directions. Over 13,000 people have visited the Sunwheel since its construction, and over 5,000 have attended the seasonal sunrise and sunset gatherings which I host. Already, late in 2004, I have begun showning the public the Moon at it's extremes, and there will be monthly opportunities over the next several years for all of us to notice the very high or very low transiting Moon. Finally, Moon teachings from calendar sites at Callanish, Chaco Canyon, and Stonehenge will be presented.

  4. Sun, Earth and Sky

    CERN Document Server

    Lang, Kenneth R

    2006-01-01

    This Second Edition of Sun, Earth and Sky updates the popular text by providing comprehensive accounts of the most recent discoveries made by five modern solar spacecraft during the past decade. Their instruments have used sound waves to peer deep into the Sun’s inner regions and measure the temperature of its central nuclear reactor, and extended our gaze far from the visible Sun to record energetic outbursts that threaten Earth. Breakthrough observations with the underground Sudbury Neutrino Observatory are also included, which explain the new physics of ghostly neutrinos and solve the problematic mismatch between the predicted and observed amounts of solar neutrinos. This new edition of Sun, Earth and Sky also describes our recent understanding of how the Sun’s outer atmosphere is heated to a million degrees, and just where the Sun’s continuous winds come from. As humans we are more intimately linked with our life-sustaining Sun than with any other astronomical object, and the new edition therefore p...

  5. Licensing the Sun

    Science.gov (United States)

    Demski, Jennifer

    2013-01-01

    The University of San Diego (USD) and Point Loma Nazarene University (PLNU) are licensing the sun. Both California schools are generating solar power on campus without having to sink large amounts of capital into equipment and installation. By negotiating power purchasing agreements (PPAs) with Amsolar and Perpetual Energy Systems, respectively,…

  6. The Sun in Time

    Science.gov (United States)

    Adams, Mitzi L.; Bero, Elizabeth; Sever, Thomas L.

    1999-01-01

    Leveraging funds from NASA's Initiative to Develop Education through Astronomy and Space Science (IDEAS) program, we combined the expertise of an archaeoastronomer, a solar scientist, and a teacher to trace humankind's view of the Sun and how that has changed, from the time of Stonehenge in about 1800 B.C.E., to the time of the Maya in 700 C.E., up to the modem era. Our program was aimed at middle-school students in an attempt to explain not only how science is done today, but how science has evolved from the observations of ancient societies. From these varied cultures, we touched on methods of observing the Sun, ideas of the composition of the Sun, and the relationship of the Sun to everyday life. Further, using the von Braun Astronomical Society's Planetarium in Huntsville, Alabama as a test-bed for the program, we illustrated concepts such as solstices, equinoxes, and local noon with approximately 800 eighth grade students from the local area. Our presentation to SEPA will include a description of NASA's IDEAS program and how to go about partnering with a NASA astronomer, some slides from our planetarium program and web-site, and some hands-on activities.

  7. The Toboggan Sun

    NARCIS (Netherlands)

    Davidson, WPS; van der Werf, SY

    2005-01-01

    Special variants of the Novaya Zemlya effect may arise from localized temperature inversions that follow the height profile of hills or mountains. Rather than following its natural path, the rising or setting Sun may, under such circumstances, appear to slide along a distant mountain slope. We found

  8. Our Explosive Sun

    Science.gov (United States)

    Brown, D. S.

    2009-01-01

    The Sun's atmosphere is a highly structured but dynamic place, dominated by the solar magnetic field. Hot charged gas (plasma) is trapped on lines of magnetic force that can snap like an elastic band, propelling giant clouds of material out into space. A range of ground-based and space-based solar telescopes observe these eruptions, particularly…

  9. Sun Ultra 5

    CERN Multimedia

    1998-01-01

    The Sun Ultra 5 is a 64-bit personal computer based on the UltraSPARC microprocessor line at a low price. The Ultra 5 has been declined in several variants: thus, some models have a processor with less cache memory to further decrease the price of the computer.

  10. YUAN-BO SUN

    Indian Academy of Sciences (India)

    Home; Journals; Journal of Genetics. YUAN-BO SUN. Articles written in Journal of Genetics. Volume 97 Issue 1 March 2018 pp 173-178 RESEARCH ARTICLE. Investigating multiple dysregulated pathways in rheumatoid arthritis based on pathway interaction network · XIAN-DONG SONG XIAN-XU SONG GUI-BO LIU ...

  11. The moon as a symbol of death in "The Romance of the Moon, Moon"

    Directory of Open Access Journals (Sweden)

    William Leonardo Perdomo Vanegas

    2008-02-01

    Full Text Available The following article is an approach to semiotic analysis of the artistic text, specifically the poem. It takes up the thesis that consider poetic language as an integral element of semiotics, not linguistics. From a semiotic perspective, the text discusses the symbol of death in the Ballad of the Moon, Moon by Federico García Lorca, the analysis establishes a relationship between natural language and poetic language, reflecting part of Gypsy culture.

  12. The Sun on Trial

    Science.gov (United States)

    Robitaille, Pierre-Marie

    2014-03-01

    For 150 years, the Sun has been seen as a gaseous object devoid of a surface, as required by the Standard Solar Model (SSM). Yet, not one line of observational evidence supports a gaseous Sun. In contrast, overwhelming evidence exists that the Sun is comprised of condensed matter. Recently, 40 proofs have been compiled in conjunction with the Liquid Metallic Hydrogen Solar Model (LMHSM). This model advances that the Sun has a true surface. Photospheric structures, such as sunspots, granules, and faculae, are not optical illusions, as in the SSM, but real objects with a condensed nature. The LMHSM accounts for the thermal spectrum by invoking true inter-atomic structure on the photosphere in the form of the graphite-like layered hexagonal metallic hydrogen lattice first proposed by Wigner and Huntington. Within the convection zone, layered metallic hydrogen, insulated by intercalate atoms, enables the generation of the solar dynamo. Electrons located in conduction bands provide a proper means of generating magnetic fields. Metallic hydrogen ejected from the photosphere also thinly populates the corona, as reflected by the continuous K-coronal spectrum. This coronal matter harvests electrons, resulting in the production of highly ionized atoms. Electron affinity, not temperature, governs the ion profile. The chromosphere is a site of hydrogen and proton capture. Line emission in this region, strongly supports the idea that exothermic condensation reactions are occurring in the chromosphere. In the LMHSM, solar activity and solar winds are regulated by exfoliation reactions occurring in the Sun itself, as the metallic hydrogen lattice excludes non-hydrogen elements from the solar body.

  13. COMPARISON OF KEPLER PHOTOMETRIC VARIABILITY WITH THE SUN ON DIFFERENT TIMESCALES

    International Nuclear Information System (INIS)

    Basri, Gibor; Walkowicz, Lucianne M.; Reiners, Ansgar

    2013-01-01

    We utilize Kepler data to study the precision differential photometric variability of solar-type and cooler stars at different timescales, ranging from half an hour to three months. We define a diagnostic that characterizes the median differential intensity change between data bins of a given timescale. We apply the same diagnostics to Solar and Heliospheric Observatory data that has been rendered comparable to Kepler. The Sun exhibits similar photometric variability on all timescales as comparable solar-type stars in the Kepler field. The previously defined photometric ''range'' serves as our activity proxy (driven by starspot coverage). We revisit the fraction of comparable stars in the Kepler field that are more active than the Sun. The exact active fraction depends on what is meant by ''more active than the Sun'' and on the magnitude limit of the sample of stars considered. This active fraction is between a quarter and a third (depending on the timescale). We argue that a reliable result requires timescales of half a day or longer and stars brighter than M Kep of 14, otherwise non-stellar noise distorts it. We also analyze main sequence stars grouped by temperature from 6500 to 3500 K. As one moves to cooler stars, the active fraction of stars becomes steadily larger (greater than 90% for early M dwarfs). The Sun is a good photometric model at all timescales for those cooler stars that have long-term variability within the span of solar variability.

  14. Solar flare leaves sun quaking

    Science.gov (United States)

    1998-05-01

    energy, and produce X-rays, microwaves and a shock wave that heats the solar surface. Kosovichev and Zharkova developed a theory that predicts the nature and magnitude of the shock waves that this beam of energetic electrons should create when they slam down into the solar atmosphere. Although their theory directed them to the right area to search for the seismic waves, the waves that they found were 10 times stronger than they had predicted. "They were so strong that you can see them in the raw data," Kosovichev says. The solar seismic waves appear to be compression waves like the "P" waves generated by an earthquake. They travel throughout the Sun's interior. In fact, the waves should recombine on the opposite side of the Sun from the location of the flare to create a faint duplicate of the original ripple pattern, Kosovichev predicts. Now that they know how to find them, the SOHO scientists say that the seismic waves generated by solar flares should allow them to verify independently some of the conditions in the solar interior that they have inferred from studying the pattern of waves that are continually ruffling the Sun's surface. SOHO is part of the International Solar-Terrestrial Physics (ISTP) program, a global effort to observe and understand our star and its effects on our environment. The ISTP mission includes more than 20 satellites, coupled with with ground-based observatories and modeling centers, that allow scientists to study the Sun, the Earth, and the space between them in unprecedented detail. ISTP is a joint program of NASA, ESA, Japan's Institute for Astronautical Science, and Russia's Space Research Institute. Still images of the solar quake can be found at the following internet address: FTP://PAO.GSFC.NASA.GOV/newsmedia/QUAKE/ For further information, please contact : ESA Public Relations Division Tel:+33(0)1.53.69.71.55 Fax: +33(0)1.53.69.76.90 3

  15. ESO Observations of New Moon of Jupiter

    Science.gov (United States)

    2000-08-01

    Two astronomers, both specialists in minor bodies in the solar system, have performed observations with ESO telescopes that provide important information about a small moon, recently discovered in orbit around the solar system's largest planet, Jupiter. Brett Gladman (of the Centre National de la Recherche Scientifique (CNRS) and working at Observatoire de la Cote d'Azur, France) and Hermann Boehnhardt ( ESO-Paranal) obtained detailed data on the object S/1999 J 1 , definitively confirming it as a natural satellite of Jupiter. Seventeen Jovian moons are now known. The S/1999 J 1 object On July 20, 2000, the Minor Planet Center (MPC) of the International Astronomical Union (IAU) announced on IAU Circular 7460 that orbital computations had shown a small moving object, first seen in the sky in 1999, to be a new candidate satellite of Jupiter. The conclusion was based on several positional observations of that object made in October and November 1999 with the Spacewatch Telescope of the University of Arizona (USA). In particular, the object's motion in the sky was compatible with that of an object in orbit around Jupiter. Following the official IAU procedure, the IAU Central Bureau for Astronomical Telegrams designated the new object as S/1999 J 1 (the 1st candidate Satellite of Jupiter to be discovered in 1999). Details about the exciting detective story of this object's discovery can be found in an MPC press release and the corresponding Spacewatch News Note. Unfortunately, Jupiter and S/1999 J 1 were on the opposite side of the Sun as seen from the Earth during the spring of 2000. The faint object remained lost in the glare of the Sun in this period and, as expected, a search in July 2000 through all available astronomical data archives confirmed that it had not been seen since November 1999, nor before that time. With time, the extrapolated sky position of S/1999 J 1 was getting progressively less accurate. New observations were thus urgently needed to "recover

  16. Stars, their evolution and their stability

    International Nuclear Information System (INIS)

    Chandrasekhar, S.

    1984-01-01

    The most important fact concerning a star is its mass. It is measured in units of the mass of the sun, which is 2 x 10 33 g: stars with masses very much less than, or very much more than the mass of the sun are relatively infrequent. The current theories of stellar structure and evolution derive their successes largely from the fact that the following combination of the dimensions of a mass provides a correct measure of stellar masses: natural constant = (hc/G) 3 2 1/H 2 approx. = 29.2 times the mass of sun where G is the constant of gravitation and H is the mass of hydrogen atom. There is an upper limit, M sub limit, to the mass of stars which can become degenerate configurations, as the last stage in their evolution; and stars with M > M sub limit must have end states which cannot be predicted from the considerations presented in this paper. For stars with mass less than 0.43 x the mass of the sun, the end stage of evolution can only be that of the white dwarfs. The inability of massive stars to become white dwarfs must result in the development of much more extreme conditions in their interiors and eventually in the onset of gravitational collapse attended by the supernova phenomena. Neutron stars or black holes form as the natural end products of stellar evolution of massive stars. 24 references, 7 figures, 2 tables

  17. Star formations rates in the Galaxy

    International Nuclear Information System (INIS)

    Smith, L.F.; Mezger, P.G.; Biermann, P.

    1978-01-01

    Data relevant to giant HII regions in the Galaxy are collected. The production rate for Lyman continuum photons by O stars in giant HII regions is 4.7 10 52 s -1 in the whole Galaxy. The corresponding present rate of star formation is M (sun)/yr, of which 74% occurs in main spiral arms, 13% in the interarm region and 13% in the galactic center. The star formation rates, the observed heavy element and deuterium abundances in the solar neighbourhood are compared to model predictions based on star formation proportional to a power (k) of the gas surface density. The mass function is terminated at Msub(u)=100 M (sun) above and M 1 below. Msub(u)=50 M (sun) is also considered. Comparing with data derived from observations a) the star formation rate, b) metal abundances, c) deuterium abundances, and d) colors of the stellar population, we find that models of k=1/2 to 1, and M 1 1 M (sun) are formed together with O and B stars, but under rather special conditions of the interstellar gas, while lower mass stars form wherever dense molecular clouds exist. The high rate of star formation in the galactic center may represent a burst. (orig.) [de

  18. International lunar observatory / power station: from Hawaii to the Moon

    Science.gov (United States)

    Durst, S.

    becoming the place to go to honeymoon, and to go to the Moon. A world apart, Hawaii, with its microgravity environment, is part way in space already, a stepping stone to the Moon, stars, and beyond. References 1. NASA Technical Memorandum 4757; Paul D. Lowman Jr, "Lunar Limb Observatory", An Incremental Plan for the Utilization, Exploration and Settlement of the Moon; Goddard Space Flight Center, October 1996. 2. Japan NASDA Report 61; "An Infinity of Twinkling Stars Visible from the Moon", The Day the Moon Becomes the Heartland of Humankind - Series 4; July 1997. 3. China Space Flight High Tech Program 863; "Research on the Necessity and Feasibility of Lunar Exploration in our Country"; May 1995. 4. European Space Agency SP-1150; "Mission to the Moon", Europe's Priorities for the Scientific Exploration and Utilization of the Moon; 1992. 5. Lavochkin Association; Company Prospectus; Moscow, Russia; August 1995. 6. India Space Research Organization; Lunar Spacecraft 2005 Feasibility Study; Bangalore; due late 2000. 7. "International Lunar Observatory", Steve Durst; 3rd International Conference on Exploration and Utilization of the Moon; Russian Academy of Sciences, Moscow; October 1998. 8. "Lunar Observatories: Why, Where, and When?"; Paul D. Lowman Jr, Peter C. Chen, Steve Durst; 8th International Space Conference of Pacific -basin Societies; Xian, China; June 1999. 9. "International Lunar Observatory: From Hawaii to the Moon", Steve Durst; 4th International Conference on Exploration and Utilization of the Moon; ESA / ESTEC, Noordwijk, The Netherlands, July 2000. (Paper Revised; Prepared for but not Presented to the 2nd Annual Lunar Development Conference: `Return to the Moon II' 20-21 July 2000, Caesars Palace, Las Vegas, Nevada)

  19. SCIENCE OF SUN PHOTOMETRY

    Directory of Open Access Journals (Sweden)

    Alexandru Dan Toma

    2013-07-01

    Full Text Available Typically, the total amount of gases and particles in a column of atmosphere cannot be determined from measurements just at Earth's surface, by a single measurement essentially at the bottom of the atmosphere column. Balloons, airplanes, and rockets are all used to perform direct measurements in the atmosphere at altitudes up to and beyond the stratosphere. Satellite-based instruments provide global views, but it is difficult to infer surface and column distributions from space-based measurements, so such measurements must still be supplemented by ground-based measurements. Sun photometry is an important way of probing the atmosphere from the ground to measure the effects of the atmosphere on Sun radiation crossing through the atmosphere to Earth's surface. These indirect technique provide information about the entire atmosphere above the observer, not just the atmosphere that can be sampled directly close to Earth's surface.

  20. GRAVITY ANOMALIES OF THE MOON

    Directory of Open Access Journals (Sweden)

    S. G. Pugacheva

    2015-01-01

    Full Text Available The source of gravity anomalies of the Moon are large mascons with a high mass concentration at a depth of volcanic plains and lunar Maria. New data on the gravitational field of the Moon were obtained from two Grail spacecrafts. The article presents the data of physical and mechanical properties of the surface soil layer of the lunar Maria and gives an assessment of the chemical composition of the soil. There have been calculated heterogeneity parameters of the surface macro-relief of the lunar Maria: albedo, soil density, average grain diameter of the particles forming the surface layer and the volume fraction occupied by particles. It can be assumed that mascons include rich KREEP rocks with a high content of thorium and iron oxide. Formation of mascons is connected with intensive development of basaltic volcanism on the Moon in the early periods of its existence.

  1. Tracking Apollo to the Moon

    CERN Document Server

    Lindsay, Hamish

    2001-01-01

    This is perhaps the most complete, detailed and readable story of manned space-flight ever published Beginning with the historical origins of the dream of walking on the Moon, Tracking Apollo to the Moon is the complete story of manned spaceflight, from the earliest Mercury and Gemini flights through to the end of the Apollo era In readable, fascinating detail, Hamish Lindsay - who was directly involved in all three programs - chronicles mankind's greatest adventure with a great narrative, interviews, quotes and masses of photographs, including some previously unpublished As well as bringing the history of these missions to life Tracking Apollo to the Moon serves as a detailed reference for space enthusiasts and students Having seen the manuscript, the Smithsonian requested two copies of the finished book, and Buzz Aldrin asked for five!

  2. The flight over the sun

    International Nuclear Information System (INIS)

    Ducrocq, A.

    1985-01-01

    With the ''Ulysse'' mission, a satellite is going for the first time to leave the ecliptic plane to observe the sun poles. The ISPM (International Solar Polar Mission) probe will go and visit the sun in passing Jupiter way. Sun pole regions are surmised to play a major role in solar wind production [fr

  3. Optical region elemental abundance analyses of B and A stars

    International Nuclear Information System (INIS)

    Adelman, S.J.; Young, J.M.; Baldwin, H.E.

    1984-01-01

    Abundance analyses using optical region data and fully line blanketed model atmospheres have been performed for two sharp-lined hot Am stars o Pegasi and σ Aquarii and for the sharp-lined marginally peculiar A star v Cancri. The derived abundances exhibit definite anomalies compared with those of normal B-type stars and the Sun. (author)

  4. Sun Radio Interferometer Space Experiment (SunRISE)

    Science.gov (United States)

    Kasper, Justin C.; SunRISE Team

    2018-06-01

    The Sun Radio Interferometer Space Experiment (SunRISE) is a NASA Heliophysics Explorer Mission of Opportunity currently in Phase A. SunRISE is a constellation of spacecraft flying in a 10-km diameter formation and operating as the first imaging radio interferometer in space. The purpose of SunRISE is to reveal critical aspects of solar energetic particle (SEP) acceleration at coronal mass ejections (CMEs) and transport into space by making the first spatially resolved observations of coherent Type II and III radio bursts produced by electrons accelerated at CMEs or released from flares. SunRISE will focus on solar Decametric-Hectometric (DH, 0.1 space before major SEP events, but cannot be seen on Earth due to ionospheric absorption. This talk will describe SunRISE objectives and implementation. Presented on behalf of the entire SunRISE team.

  5. Evolution of massive close binaries and formation of neutron stars and black holes

    International Nuclear Information System (INIS)

    Massevitch, A.G.; Tutukov, A.V.; Yungelson, L.R.

    1976-01-01

    Main results of computations of evolution for massive close binaries (10 M(Sun)+9.4 M(Sun), 16 M(Sun)+15 M(Sun), 32 M(Sun)+30 M(Sun), 64 M(Sun)+60 M(Sun)) up to oxygen exhaustion in the core are described. Mass exchange starting in core hydrogen, shell hydrogen and core helium burning stages was studied. Computations were performed assuming both the Ledoux and Schwarzschild stability criteria for semiconvection. The influence of UFI-neutrino emission on evolution of close binaries was investigated. The results obtained allow to outline the following evolutionary chain: two detached Main-Sequence stars - mass exchange - Wolf-Rayet star or blue supergiant plus main sequence star - explosion of the initially more massive star appearing as a supernova event - collapsed or neutron star plus Main-Sequence star, that may be observed as a 'runaway star' - mass exchange leading to X-rays emission - collapsed or neutron star plus WR-star or blue supergiant - second explosion of supernova that preferentially disrupts the system and gives birth to two single high spatial velocity pulsars. Numerical estimates concerning the number and properties of WR-stars, pulsars and X-ray sources are presented. The results are in favour of the existence of UFI-neutrino and of the Ledoux criterion for describing semiconvection. Properties of several well-known X-ray sources and the binary pulsar are discussed on base of evolutionary chain of close binaries. (Auth.)

  6. Young Stars with SALT

    Energy Technology Data Exchange (ETDEWEB)

    Riedel, Adric R. [Department of Astronomy, California Institute of Technology, Pasadena, CA 91125 (United States); Alam, Munazza K.; Rice, Emily L.; Cruz, Kelle L. [Department of Astrophysics, The American Museum of Natural History, New York, NY 10024 (United States); Henry, Todd J., E-mail: arr@caltech.edu [RECONS Institute, Chambersburg, PA (United States)

    2017-05-10

    We present a spectroscopic and kinematic analysis of 79 nearby M dwarfs in 77 systems. All of these dwarfs are low-proper-motion southern hemisphere objects and were identified in a nearby star survey with a demonstrated sensitivity to young stars. Using low-resolution optical spectroscopy from the Red Side Spectrograph on the South African Large Telescope, we have determined radial velocities, H-alpha, lithium 6708 Å, and potassium 7699 Å equivalent widths linked to age and activity, and spectral types for all of our targets. Combined with astrometric information from literature sources, we identify 44 young stars. Eighteen are previously known members of moving groups within 100 pc of the Sun. Twelve are new members, including one member of the TW Hydra moving group, one member of the 32 Orionis moving group, 9 members of Tucana-Horologium, one member of Argus, and two new members of AB Doradus. We also find 14 young star systems that are not members of any known groups. The remaining 33 star systems do not appear to be young. This appears to be evidence of a new population of nearby young stars not related to the known nearby young moving groups.

  7. Heating the Chromosphere in the Quiet Sun

    Science.gov (United States)

    Kohler, Susanna

    2018-04-01

    The best-studied star the Sun still harbors mysteries for scientists to puzzle over. A new study has now explored the role of tiny magnetic-field hiccups in an effort to explain the strangely high temperatures of the Suns upper atmosphere.Schematic illustrating the temperatures in different layers of the Sun. [ESA]Strange Temperature RiseSince the Suns energy is produced in its core, the temperature is hottest here. As expected, the temperature decreases further from the Suns core up until just above its surface, where it oddly begins to rise again. While the Suns surface is 6,000 K, the temperature is higher above this: 10,000 K in the outer chromosphere.So how is the chromosphere of the Sun heated? Its possible that the explanation can be found not amid high solar activity, but in quiet-Sun regions.In a new study led by Milan Goi (Lockheed Martin Solar and Astrophysics Laboratory, Bay Area Environmental Research Institute), a team of scientists has examined a process that quietly happens in the background: the cancellation of magnetic field lines in the quiet Sun.Activity in a SupergranuleTop left: SDO AIA image of part of the solar disk. The next three panels are a zoom of the particular quiet-Sun region that the authors studied, all taken with IRIS at varying wavelengths: 1400 (top right), 2796 (bottom left), and 2832 (bottom right). [Goi et al. 2018]The Sun is threaded by strong magnetic field lines that divide it into supergranules measuring 30 million meters across (more than double the diameter of Earth!). Supergranules may seem quiet inside, but looks can be deceiving: the interiors of supergranules contain smaller, transient internetwork fields that move about, often resulting in magnetic elements of opposite polarity encountering and canceling each other.For those internetwork flux cancellations that occur above the Suns surface, a small amount of energy could be released that locally heats the chromosphere. But though each individual event has a small

  8. Chemical Soups Around Cool Stars

    Science.gov (United States)

    2009-01-01

    This artist's conception shows a young, hypothetical planet around a cool star. A soupy mix of potentially life-forming chemicals can be seen pooling around the base of the jagged rocks. Observations from NASA's Spitzer Space Telescope hint that planets around cool stars the so-called M-dwarfs and brown dwarfs that are widespread throughout our galaxy might possess a different mix of life-forming, or prebiotic, chemicals than our young Earth. Life on our planet is thought to have arisen out of a pond-scum-like mix of chemicals. Some of these chemicals are thought to have come from a planet-forming disk of gas and dust that swirled around our young sun. Meteorites carrying the chemicals might have crash-landed on Earth. Astronomers don't know if these same life-generating processes are taking place around stars that are cooler than our sun, but the Spitzer observations show their disk chemistry is different. Spitzer detected a prebiotic molecule, called hydrogen cyanide, in the disks around yellow stars like our sun, but found none around cooler, less massive, reddish stars. Hydrogen cyanide is a carbon-containing, or organic compound. Five hydrogen cyanide molecules can join up to make adenine a chemical element of the DNA molecule found in all living organisms on Earth.

  9. The Sun/Earth System and Space Weather

    Science.gov (United States)

    Poland, Arthur I.; Fox, Nicola; Lucid, Shannon

    2003-01-01

    Solar variability and solar activity are now seen as significant drivers with respect to the Earth and human technology systems. Observations over the last 10 years have significantly advanced our understanding of causes and effects in the Sun/Earth system. On a practical level the interactions between the Sun and Earth dictate how we build our systems in space (communications satellites, GPS, etc), and some of our ground systems (power grids). This talk will be about the Sun/Earth system: how it changes with time, its magnetic interactions, flares, the solar wind, and how the Sun effects human systems. Data will be presented from some current spacecraft which show, for example, how we are able to currently give warnings to the scientific community, the Government and industry about space storms and how this data has improved our physical understanding of processes on the Sun and in the magnetosphere. The scientific advances provided by our current spacecraft has led to a new program in NASA to develop a 'Space Weather' system called 'Living With a Star'. The current plan for the 'Living With a Star' program will also be presented.

  10. Lunar Plants Prototype for Moon Express

    Data.gov (United States)

    National Aeronautics and Space Administration — The goal of our project is to bring the first full life cycle to the moon: to demonstrate germination of plants in lunar gravity and radiation.The Moon Express...

  11. NIMPH - Nano Icy Moons Propellant Harvester

    Data.gov (United States)

    National Aeronautics and Space Administration — The latest Decadal Survey lists multiple sample return missions to the Moon, Mars and Jovian moons as high priority goals. In particular, a mission to Jupiter's...

  12. Surface material of the moon

    Science.gov (United States)

    Warren, C.R.

    1963-01-01

    A skeletal fuzz that consists mostly of open space probably covers the moon to a depth of several millimeters or centimeters. The solid part of the fuzz probably consists of randomly oriented linear units, with or without enlarged nodes, which either anastomose in a mesh or are branching.

  13. Europe rediscovers the Moon with SMART-1

    Science.gov (United States)

    2006-08-01

    spiralling journey accounted for more than 100 million kilometres, while the Moon - if you wanted to go there in a straight line - is only between 350,000 and 400,000 kilometres away from the Earth. As SMART-1 neared its destination, it began using the gravity of the Moon to bring it into a position where it was captured by the Moon’s gravitational field. This occurred in November 2004. After being captured by the Moon, in January 2005, SMART-1 started to spiral down to its final operational polar elliptical orbit with a perilune (closest point to the lunar surface) altitude of 300 km and apolune (farthest point) altitude of 3000 km. to conduct its scientific exploration mission. What was there to know that we didn’t know already? Despite the number of spacecraft that have visited the Moon, many scientific questions concerning our natural satellite remained unanswered, notably to do with the origin and evolution of the Moon, and the processes that shape rocky planetary bodies (such as tectonics, volcanism, impacts and erosion). Thanks to SMART-1, scientists all over Europe and around the world now have the best resolution surface images ever from lunar orbit, as well as a better knowledge of the Moon’s minerals. For the first time from orbit, they have detected calcium and magnesium using an X-ray instrument. They have measured compositional changes from the central peaks of craters, volcanic plains and giant impact basins. SMART-1 has also studied impact craters, volcanic features and lava tubes, and monitored the polar regions. In addition, it found an area near the north pole where the Sun always shines, even in winter. SMART-1 has roamed over the lunar poles, enabling it to map the whole Moon, including its lesser known far side. The poles are particularly interesting to scientists because they are relatively unexplored. Moreover, some features in the polar regions have a geological history which is distinct from the more closely studied equatorial regions where

  14. A child's view of the moon

    OpenAIRE

    Grilc, Tina

    2014-01-01

    This diploma paper is divided into two parts, the theoretical and the practical one. The first part describes the history of travelling and landing on the Moon, general information on the Moon (its evolution, composition, surface, visibility, and moon phases), and the astronomical instruments. The development of a child's way of thinking is also briefly presented. The second, more practical part, is introduced by a questionnaire consisting of 10 general questions about the Moon. The aim ...

  15. Dream recall and the full moon.

    Science.gov (United States)

    Schredl, Michael; Fulda, Stephany; Reinhard, Iris

    2006-02-01

    There is ongoing debate on whether the full moon is associated with sleep and dreaming. The analysis of diaries kept by the participants (N = 196) over 28 to 111 nights showed no association of a full moon and dream recall. Psychological factors might explain why some persons associate a full moon with increased dream recall.

  16. The Sun in Time

    Science.gov (United States)

    Adams, Mitzi L.; Sever, Thomas L.; Bero, Elizabeth

    1998-01-01

    Using a grant from NASA's Initiative to Develop Education through Astronomy and Space Science (IDEAS) program, we have developed an inter-disciplinary curriculum for middle-school students which targets both history and astronomy. Our curriculum explores the attitudes and techniques of ancient spiritual leaders, specifically those of the Maya and Inca cultures, who observed and tried to control the Sun. We wish students to understand the probable importance of astronomical observations to these ancient peoples. In addition, using the experience of an archaeologist, we show how modern techniques of viewing the Earth through satellite imagery, has allowed the re-discovery of ancient sites where solar observations and attempted manipulation of the universe took place. To contrast ancient observations of the Sun with modern ones, we use the experience of a solar astronomer and bring to the classroom up-to-date information about solar astronomy and the impact of solar activity on the Earth's environment. In this presentation, we will present fragments of our curriculum as well as results from pre- and post-tests given to participating groups of students. Finally, we will discuss comments from local middle-school teachers who were asked to evaluate our curriculum.

  17. Eruptions from the Sun

    Science.gov (United States)

    Kohler, Susanna

    2015-11-01

    The Sun often exhibits outbursts, launching material from its surface in powerful releases of energy. Recent analysis of such an outburst captured on video by several Sun-monitoring spacecraft may help us understand the mechanisms that launch these eruptions.Many OutburstsSolar jets are elongated, transient structures that are thought to regularly release magnetic energy from the Sun, contributing to coronal heating and solar wind acceleration. Coronal mass ejections (CMEs), on the other hand, are enormous blob-like explosions, violently ejecting energy and mass from the Sun at incredible speeds.But could these two types of events actually be related? According to a team of scientists at the University of Science and Technology of China, they may well be. The team, led by Jiajia Liu, has analyzed observations of a coronal jet that they believe prompted the launch of a powerful CME.Observing an ExplosionGif of a movie of the CME, taken by the Solar Dynamics Observatorys Atmospheric Imaging Assembly at a wavelength of 304. The original movie can be found in the article. [Liu et al.]An army of spacecraft was on hand to witness the event on 15 Jan 2013 including the Solar Dynamics Observatory (SDO), the Solar and Heliospheric Observatory (SOHO), and the Solar Terrestrial Relations Observatory (STEREO). The instruments on board these observatories captured the drama on the northern limb of the Sun as, at 19:32 UT, a coronal jet formed. Just eight minutes later, a powerful CME was released from the same active region.The fact that the jet and CME occurred in the same place at roughly the same time suggests theyre related. But did the initial motions of the CME blob trigger the jet? Or did the jet trigger the CME?Tying It All TogetherIn a recently published study, Liu and collaborators analyzed the multi-wavelength observations of this event to find the heights and positions of the jet and CME. From this analysis, they determined that the coronal jet triggered the release

  18. More Sophisticated Fits of the Oribts of Haumea's Interacting Moons

    Science.gov (United States)

    Oldroyd, William Jared; Ragozzine, Darin; Porter, Simon

    2018-04-01

    Since the discovery of Haumea's moons, it has been a challenge to model the orbits of its moons, Hi’iaka and Namaka. With many precision HST observations, Ragozzine & Brown 2009 succeeded in calculating a three-point mass model which was essential because Keplerian orbits were not a statistically acceptable fit. New data obtained in 2010 could be fit by adding a J2 and spin pole to Haumea, but new data from 2015 was far from the predicted locations, even after an extensive exploration using Bayesian Markov Chain Monte Carlo methods (using emcee). Here we report on continued investigations as to why our model cannot fit the full 10-year baseline of data. We note that by ignoring Haumea and instead examining the relative motion of the two moons in the Hi’iaka centered frame leads to adequate fits for the data. This suggests there are additional parameters connected to Haumea that will be required in a full model. These parameters are potentially related to photocenter-barycenter shifts which could be significant enough to affect the fitting process; these are unlikely to be caused by the newly discovered ring (Ortiz et al. 2017) or by unknown satellites (Burkhart et al. 2016). Additionally, we have developed a new SPIN+N-bodY integrator called SPINNY that self-consistently calculates the interactions between n-quadrupoles and is designed to test the importance of other possible effects (Haumea C22, satellite torques on the spin-pole, Sun, etc.) on our astrometric fits. By correctly determining the orbit of Haumea’s satellites we develop a better understanding of the physical properties of each of the objects with implications for the formation of Haumea, its moons, and its collisional family.

  19. Diffusion of helium in the Sun

    Energy Technology Data Exchange (ETDEWEB)

    Noerdlinger, P D [Michigan State Univ., East Lansing (USA). Dept. of Astronomy and Astrophysics; Amsterdam Univ. (Netherlands). Sterrenkundig Instituut)

    1977-05-01

    I have reduced the set of diffusion and flow equations developed by Burgers for a multi-component gas to a workable scheme for the actual evaluation of the relative diffusion of hydrogen and helium in stars. Previous analyses have used the Aller and Chapman equations, which apply only to trace constitutents and whose coefficients are not believed to be as accurate as Burgers'. Furthermore, the resulting equations have been combined consistently with Paczynski's stellar evolution code to demonstrate small but significant effects in the Sun, from the thermal and gravitational settling of Helium. The core helium content of a 1 M star goes up about 0.04 and the surface helium content down by about -0.03 in 4.5 10/sup 9/ years. The results are still somewhat uncertain because of uncertainties in the underlying plasma physics, and further research is suggested. In any case, the diffusion process speeds up with time, due to increased temperature gradient, and it will be of interest to follow the process in older stars and in later stellar evolution.

  20. New Moon water, exploration, and future habitation

    CERN Document Server

    Crotts, Arlin

    2014-01-01

    Explore Earth's closest neighbor, the Moon, in this fascinating and timely book and discover what we should expect from this seemingly familiar but strange, new frontier. What startling discoveries are being uncovered on the Moon? What will these tell us about our place in the Universe? How can exploring the Moon benefit development on Earth? Discover the role of the Moon in Earth's past and present; read about the lunar environment and how it could be made more habitable for humans; consider whether continued exploration of the Moon is justified; and view rare Apollo-era photos and film still

  1. Stars of strange matter

    International Nuclear Information System (INIS)

    Bethe, H.A.; Brown, G.E.; Cooperstein, J.

    1987-01-01

    We investigate suggestions that quark matter with strangeness per baryon of order unity may be stable. We model this matter at nuclear matter densities as a gas of close packed Λ-particles. From the known mass of the Λ-particle we obtain an estimate of the energy and chemical potential of strange matter at nuclear densities. These are sufficiently high to preclude any phase transition from neutron matter to strange matter in the region near nucleon matter density. Including effects from gluon exchange phenomenologically, we investigate higher densities, consistently making approximations which underestimate the density of transition. In this way we find a transition density ρ tr > or approx.7ρ 0 , where ρ 0 is nuclear matter density. This is not far from the maximum density in the center of the most massive neutron stars that can be constructed. Since we have underestimated ρ tr and still find it to be ∝7ρ 0 , we do not believe that the transition from neutron to quark matter is likely in neutron stars. Moreover, measured masses of observed neutron stars are ≅1.4 M sun , where M sun is the solar mass. For such masses, the central (maximum) density is ρ c 0 . Transition to quark matter is certainly excluded for these densities. (orig.)

  2. Clustering of Sun Exposure Measurements

    OpenAIRE

    Have, Anna Szynkowiak; Larsen, Jan; Hansen, Lars Kai; Philipsen, Peter Alshede; Thieden, Elisabeth; Wulf, Hans Christian

    2002-01-01

    In a medically motivated Sun-exposure study, questionnaires concerning Sun-habits were collected from a number of subjects together with UV radiation measurements. This paper focuses on identifying clusters in the heterogeneous set of data for the purpose of understanding possible relations between Sun-habits exposure and eventually assessing the risk of skin cancer. A general probabilistic framework originally developed for text and Web mining is demonstrated to be useful for clustering of b...

  3. Formation of the Lunar Fossil Bulges and Its Implication for the Early Earth and Moon

    Science.gov (United States)

    Qin, Chuan; Zhong, Shijie; Phillips, Roger

    2018-02-01

    First recognized by Laplace over two centuries ago, the Moon's present tidal-rotational bulges are significantly larger than hydrostatic predictions. They are likely relics of a former hydrostatic state when the Moon was closer to the Earth and had larger bulges, and they were established when stresses in a thickening lunar lithosphere could maintain the bulges against hydrostatic adjustment. We formulate the first dynamically self-consistent model of this process and show that bulge formation is controlled by the relative timing of lithosphere thickening and lunar orbit recession. Viable solutions indicate that lunar bulge formation was a geologically slow process lasting several hundred million years, that the process was complete about 4 Ga when the Moon-Earth distance was less than 32 Earth radii, and that the Earth in Hadean was significantly less dissipative to lunar tides than during the last 4 Gyr, possibly implying a frozen hydrosphere due to the fainter young Sun.

  4. Optimal Target Stars in the Search for Life

    Science.gov (United States)

    Lingam, Manasvi; Loeb, Abraham

    2018-04-01

    The selection of optimal targets in the search for life represents a highly important strategic issue. In this Letter, we evaluate the benefits of searching for life around a potentially habitable planet orbiting a star of arbitrary mass relative to a similar planet around a Sun-like star. If recent physical arguments implying that the habitability of planets orbiting low-mass stars is selectively suppressed are correct, we find that planets around solar-type stars may represent the optimal targets.

  5. Materials refining on the Moon

    Science.gov (United States)

    Landis, Geoffrey A.

    2007-05-01

    Oxygen, metals, silicon, and glass are raw materials that will be required for long-term habitation and production of structural materials and solar arrays on the Moon. A process sequence is proposed for refining these materials from lunar regolith, consisting of separating the required materials from lunar rock with fluorine. The fluorine is brought to the Moon in the form of potassium fluoride, and is liberated from the salt by electrolysis in a eutectic salt melt. Tetrafluorosilane produced by this process is reduced to silicon by a plasma reduction stage; the fluorine salts are reduced to metals by reaction with metallic potassium. Fluorine is recovered from residual MgF and CaF2 by reaction with K2O.

  6. Stars and Star Myths.

    Science.gov (United States)

    Eason, Oliver

    Myths and tales from around the world about constellations and facts about stars in the constellations are presented. Most of the stories are from Greek and Roman mythology; however, a few Chinese, Japanese, Polynesian, Arabian, Jewish, and American Indian tales are also included. Following an introduction, myths are presented for the following 32…

  7. Physics of the sun

    CERN Document Server

    Holzer, Thomas; Mihalas, Dimitri; Ulrich, Roger

    1986-01-01

    This volume, together with its two companion volumes, originated in a study commis­ sioned by the United States National Academy of Sciences on behalf of the National Aeronautics and Space Administration. A committee composed of Tom Holzer, Dimitri Mihalas, Roger Ulrich and myself was asked to prepare a comprehensive review of current knowledge concerning the physics of the sun. We were fortunate in being able to persuade many distinguished scientists to gather their forces for the preparation of 21 separate chapters covering not only solar physics but also relevant areas of astrophysics and solar-terrestrial relations. It proved necessary to divide the chapters into three separate volumes that cover three different aspects of solar physics. Volumes 1 and 2 are concerned with 'The Solar Interior' and with 'The Solar Atmosphere'. This volume, devoted to 'Astrophysics and Solar-Terrestrial Relations', focuses on problems of solar physics from these two different but complementary perspectives. The emphasis thr...

  8. Sun light European Project

    Science.gov (United States)

    Soubielle, Marie-Laure

    2015-04-01

    2015 has been declared the year of light. Sunlight plays a major role in the world. From the sunbeams that heat our planet and feed our plants to the optical analysis of the sun or the modern use of sun particles in technologies, sunlight is everywhere and it is vital. This project aims to understand better the light of the Sun in a variety of fields. The experiments are carried out by students aged 15 to 20 in order to share their discoveries with Italian students from primary and secondary schools. The experiments will also be presented to a group of Danish students visiting our school in January. All experiments are carried out in English and involve teams of teachers. This project is 3 folds: part 1: Biological project = what are the mechanisms of photosynthesis? part 2: Optical project= what are the components of sunlight and how to use it? part 3: Technical project= how to use the energy of sunlight for modern devices? Photosynthesis project Biology and English Context:Photosynthesis is a process used by plants and other organisms to convert light energy, normally from the Sun, into chemical energy that can later fuel the organisms' activities. This chemical energy is stored in molecules which are synthesized from carbon dioxide and water. In most cases, oxygen is released as a waste product. Most plants perform photosynthesis. Photosynthesis maintains atmospheric oxygen levels and supplies all of the organic compounds and most of the energy necessary for life on Earth. Outcome: Our project consists in understanding the various steps of photosynthesis. Students will shoot a DVD of the experiments presenting the equipments required, the steps of the experiments and the results they have obtained for a better understanding of photosynthesis Digital pen project Electricity, Optics and English Context: Sunlight is a complex source of light based on white light that can be decomposed to explain light radiations or colours. This light is a precious source to create

  9. Post-giant evolution of helium stars

    International Nuclear Information System (INIS)

    Schoenberner, D.

    1977-01-01

    Extremely hydrogen deficient stars (helium stars and R Coronae Borealis variables) are considered to be remnants of double shell source stars (of the asymptotic giant branch). The evolution of stars with a condensed C/O-core and a helium envelope is followed numerically from the red giant stage to the white dwarf domain, crossing the regions of R CrB- and helium stars (so far analyzed). They have typically masses M/M(sun) = 0.7 and luminosities log L/L(sun) = 4.1. The time for crossing the helium star domain is some 10 3 years. The corresponding times in the R CrB-region amounts up to several 10 4 years. The lower limit of the death rate of helium stars is estimated to be 4 x 10 -14 pc -3 yr -1 . This value is only a factor of ten lower than the birth rate of all non-DA white dwarfs. It is therefore possible that the helium stars are the precursors of helium rich white dwarfs. As a consequence, a significant fraction of all stars which end their lives as white dwarfs should pass through the helium star phase. (orig.) [de

  10. Cosmic contamination: elemental clues to the sun's birth

    International Nuclear Information System (INIS)

    Richardson, S.M.; Willson, L.A.

    1980-01-01

    The anomalous isotope abundances in the carbonaceous chondrites can be explained easily by the hypothesis that the meteorites formed soon after a nearby supernova exploded. This seems to imply that the solar system was formed at the same time and place, because the ages of the meteorites are all the same, and that is the same age as our sun. Supporting evidence for this theory of solar system formation has been gathered from theoretical and observational astronomy. These are discussed in the article. The supernova-trigger theory and the Jean's theory of star formation are both studied and related to star formation in our galaxy

  11. SMART-1 leaves Earth on a long journey to the Moon

    Science.gov (United States)

    2003-09-01

    the X-ray Solar Monitor (XSM) will perform spectrometric observations of the Sun and provide calibration data to D-CIXS to compensate for solar variability. The SPEDE experiment used to monitor Solar Electric Primary Propulsion interactions with the environment will also study how the solar wind affects the Moon. The overall data collected by SMART-1 will provide new inputs for studies of the evolution of the Moon, its chemical composition and its geophysical processes, and also for comparative planetology in general. Paving the way for future space probes In addition to valuable lunar science, SMART-1’s payload will be involved in the mission’s technology demonstrations to prepare for future-generation deep space missions. For instance, the AMIE camera will be used to validate the On-Board Autonomous Navigation (OBAN) algorithm, which correlates data from sensors and star trackers to provide navigational data. It will also participate in a laser communication link experiment with ESA’s optical ground station at the Teide Observatory in Tenerife, Canary Islands, trying to detect an incoming laser beam from the ground. Using both AMIE and KaTE hardware, the Radio Science Investigation System (RSIS) experiment will demonstrate a new way of gauging the interiors of planets and their moons by detecting the well-known tilting motion of the Moon. This technology can be used later by ESA planetary missions. SMART-1 was developed for ESA by the Swedish Space Corporation, as prime contractor, with contributions from almost 30 contractors from 11 European countries and the United States. Despite its small size, the spacecraft carries 19 kg of science payload consisting in experiments led by Principal Investigators from Finland, Germany, Italy, Switzerland and the United Kingdom. Despite its relatively small budget and short development schedule, SMART-1 holds tremendous potential for future missions and is a clear illustration of Europe’s ambitions in the exploration of

  12. The Surprising History of Claims for Life on the Sun

    Science.gov (United States)

    Crowe, Michael J.

    2011-11-01

    Because astronomers are now convinced that it is impossible for life, especially intelligent life, to exist on the Sun and stars, it might be assumed that astronomers have always held this view. This paper shows that throughout most of the history of astronomy, some intellectuals, including a number of well-known astronomers, have advocated the existence of intelligent life on our Sun and thereby on stars. Among the more prominent figures discussed are Nicolas of Cusa, Giordano Bruno, William Whiston, Johann Bode, Roger Boscovich, William Herschel, Auguste Comte, Carl Gauss, Thomas Dick, John Herschel, and François Arago. One point in preparing this paper is to show differences between the astronomy of the past and that of the present.

  13. An Introduction to Waves and Oscillations in the Sun

    CERN Document Server

    Narayanan, A Satya

    2013-01-01

    Astrophysicists and others studying the Sun will find this expansive coverage of what we know about waves and oscillations in our nearest star an informative introduction to a hot contemporary topic. After a section summarizing the Sun's physical characteristics, the volume moves on to explore the basics of electrodynamics, which in turn facilitate a discussion of magnetohydrodynamics (MHD). The material also details the often complex nature of waves and oscillations in uniform and non-uniform media, before categorizing the observational signatures of oscillations and exploring the instabilities in fluid, dealing with a range of known forms. Lastly, a section on helioseismology explores our growing familiarity with the internal structure of the Sun. This book is a unified portal to a thorough grounding in solar waves that includes a wealth of explanatory vignettes demystifying concepts such as flux tubes, current-free and force-free magnetic fields, the prominences, and the relationship between the vorticity ...

  14. A SEARCH FOR ASTEROIDS, MOONS, AND RINGS ORBITING WHITE DWARFS

    International Nuclear Information System (INIS)

    Di Stefano, Rosanne; Howell, Steve B.; Kawaler, Steven D.

    2010-01-01

    Do white dwarfs host asteroid systems? Although several lines of argument suggest that white dwarfs may be orbited by large populations of asteroids, transits would provide the most direct evidence. We demonstrate that the Kepler mission has the capability to detect transits of white dwarfs by asteroids. Because white-dwarf asteroid systems, if they exist, are likely to contain many asteroids orbiting in a spatially extended distribution, discoveries of asteroid transits can be made by monitoring only a small number of white dwarfs, compatible with Kepler's primary mission, which is to monitor stars with potentially habitable planets. Possible future missions that survey 10 times as many stars with similar sensitivity and minute-cadence monitoring can establish the characteristics of asteroid systems around white dwarfs, such as the distribution of asteroid sizes and semimajor axes. Transits by planets would be more dramatic, but the probability that they will occur is lower. Ensembles of planetary moons and/or the presence of rings around planets can also produce transits detectable by Kepler. The presence of moons and rings can significantly increase the probability that Kepler will discover planets orbiting white dwarfs, even while monitoring only a small number of them.

  15. Optical region elemental abundance analyses of B and A stars

    International Nuclear Information System (INIS)

    Adelman, S.J.

    1984-01-01

    Abundance analyses using optical region data and fully line blanketed model atmospheres have been performed for six moderately sharplined middle to late B-type stars. The derived abundances have values similar to those of the Sun. (author)

  16. Astronomy: A small star with an Earth-like planet

    Science.gov (United States)

    Deming, Drake

    2015-11-01

    A rocky planet close in size to Earth has been discovered in the cosmic vicinity of our Sun. The small size and proximity of the associated star bode well for studies of the planet's atmosphere. See Letter p.204

  17. The Sun as you never saw it before

    Science.gov (United States)

    1997-02-01

    The remarkable images come from SOHO's visible-light coronagraph LASCO. It masks the intense rays from the Sun's surface in order to reveal the much fainter glow of the solar atmosphere, or corona. Operated with its widest field of view, in its C3 instrument, LASCO's unprecedented sensitivity enables it to see the thin ionized gas of the solar wind out to the edges of the picture, 22 million kilometres from the Sun's surface. Many stars are brighter than the gas, and they create the background scene. The results alter human perceptions of the Sun. Nearly 30 years ago, Apollo photographs of the Earth persuaded everyone of what until then they knew only in theory, that we live on a small planet. Similarly the new imagery shows our motion in orbit around the Sun, and depicts it as one star among - yet close enough to fill the sky emanations that engulf us. For many centuries even astrologers knew that the Sun was in Sagittarius in December and drifting towards the next zodiacal constellation, Capricornus. This was a matter of calculation only, because the Sun's own brightness prevented a direct view of the starfield. The SOHO-LASCO movie makes this elementary point of astronomy a matter of direct observation for the first time. The images are achievable only from a vantage point in space, because the blue glow of the Earth's atmosphere hides the stars during the day. A spacial allocation of observing time, and of data tranmission from the SOHO spacecraft, enabled the LASCO team to obtain large numbers of images over the period 22-28 December 1996. Since then, a sustained effort in image processing, frame by frame, has achieved a result of high technical and aesthetic quality. Only now is the leader of the LASCO team, Guenter Brueckner of the US Naval Research Laboratory, satisfied with the product and ready to authorize its release. "I spend my life examining the Sun," Brueckner says, "but this movie is a special thrill. For a moment I forget the years of effort that

  18. Our Place in Space: Exploring the Earth-Moon System and Beyond with NASA's CINDI E/PO Program

    Science.gov (United States)

    Urquhart, M. L.; Hairston, M. R.

    2010-12-01

    Where does space begin? How far is the Moon? How far is Mars? How does our dynamic star, the Sun, affect its family of planets? All of these questions relate to exploration of our Solar System, and are also part of the Education/Public Outreach (E/PO) Program for NASA’s CINDI project, a space weather mission of opportunity. The Coupled Ion Neutral Dynamics Investigation has been flying aboard the US Air Force Communication/Navigation Outage Forecast System (C/NOFS) satellite in the upper atmosphere of the Earth since April 2008. The Earth’s ionosphere, the part of the atmosphere CINDI studies, is also in space. The CINDI E/PO program uses this fact in lessons designed to help students in middle schools and introductory astronomy classes develop a sense of their place in space. In the activity "How High is Space?" students’ start by building an 8-page scale model of the Earth’s atmosphere with 100 km/page. The peak of Mount Everest, commercial airplanes, and the tops of thunderheads all appear at the bottom of the first page of the model, with astronaut altitude -where space begins- at the top of the same sheet of paper. In "Where Would CINDI Be?" the idea of scale is further developed by modeling the Earth-Moon system to scale first in size, then in distance, using half of standard containers of play dough. With a lowest altitude of about 400 km, similar to that of the International Space Station and orbiting Space Shuttle, CINDI is close to the Earth when compared with the nearly thousand times greater distance to the Moon. Comparing and combining the atmosphere and Earth-Moon system models help reinforce ideas of scale and build student understanding of how far away the Moon actually is. These scale models have also been adapted for use in Family Science Nights, and to include the planet Mars. In this presentation, we will show how we use CINDI’s scale modeling activities and others from our broader space sciences E/PO program in formal and informal

  19. Diffusion time scales and accretion in the sun

    International Nuclear Information System (INIS)

    Michaud, G.

    1977-01-01

    It is thought that surface abundances in the Sun could be due largely to accretion either of comets or grains, and it has been suggested that if surface convection zones were smaller than is usually indicated by model calculations, accretion would be especially important. Unless the zone immediately below the surface convection zone is sufficiently stable for diffusion to be important, other transport processes, such as turbulence and meridional circulation, more efficient than diffusion, will tend to homogenise the Sun. Diffusion is the slowest of the transport processes and will become important when other transport processes become inoperative. Using diffusion theory the minimum mass of the convection zone can be determined in order that transport processes at the bottom of the zone are not to influence abundances in the convection zone. If diffusion time scales are shorter than the life of the star (Sun) diffusion will modify the abundances in the convection zone. The mass in the convection zone for which diffusion time scales are equal to the life of the star on the main sequence then determines the minimum mass in the convection zone that justifies neglect of transport processes at the bottom of the convection zone. It is calculated here that, for the Sun, this mass is between 3 x 10 -3 and 10 -2 solar mass, and a general explosion is derived for the diffusion time scale as a function of the mass of the convection zone. (U.K.)

  20. Properties of the cold components of symbiotic stars

    International Nuclear Information System (INIS)

    Luud, L.; Leedyarv, L.

    1986-01-01

    The basic physical parameters of the cold components of symbiotic stars and comparison red giants have been determined from the data of infrared photometry by means of the Blackwell-Shallis method. It is found that the cold components of the symbiotic stars do not differ from normal red giants of the asymptotic branch. The masses of the cold components of the symbiotic stars are close to 3M. The red components of the symbiotic stars do not fill their Roche lobes. Among the cold components of the symbiotic stars, there are approximately ten times as many carbon stars as among the red giants in the neighborhood of the Sun

  1. An astrometric search for a stellar companion to the sun

    International Nuclear Information System (INIS)

    Perlmutter, S.

    1986-01-01

    A companion star within 0.8 pc of the Sun has been postulated to explain a possible 26 Myr periodicity in mass extinctions of species on the Earth. Such a star would already be catalogued in the Yale Bright Star catalogue unless it is fainter than m/sub nu/ = 6.5; this limits the possible stellar types for an unseen companion to red dwarfs, brown dwarfs, or compact objects. Red dwarfs account for about 75% of these possible stars. We describe here the design and development of an astrometric search for a nearby red dwarf companion with a six-month peak-to-peak parallax of ≥2.5 arcseconds. We are measuring the parallax of 2770 candidate faint red stars selected from the Dearborn Observatory catalogue. An automated 30-inch telescope and CCD camera system collect digitized images of the candidate stars, along with a 13' x 16' surrounding field of background stars. Second-epoch images, taken a few months later, are registered to the first epoch images using the background stars as fiducials. An apparent motion, m/sub a/, of the candidate stars is found to a precision of σ/sub m//sub a/ ≅ 0.08 pixel ≅ 0.2 arcseconds for fields with N/sub fiducial/ ≥ 10 fiducial stars visible above the background noise. This precision is sufficient to detect the parallactic motion of a star at 0.8 pc with a two month interval between the observation epochs. Images with fewer fiducial stars above background noise are observed with a longer interval between epochs. If a star is found with high parallactic motion, we will confirm its distance with further parallax measurements, photometry, and spectral studies, and will measure radial velocity and proper motion to establish its orbit. We have demonstrated the search procedure with observations of 41 stars, and have shown that none of these is a nearby star. 37 refs., 16 figs., 3 tabs

  2. Another Possibility for Boyajian's Star

    Science.gov (United States)

    Kohler, Susanna

    2017-07-01

    The unusual light curve of the star KIC 8462852, also known as Tabbys star or Boyajians star, has puzzled us since its discovery last year. A new study now explores whether the stars missing flux is due to internal blockage rather than something outside of the star.Mysterious DipsMost explanations for the flux dips of Boyajians star rely on external factors, like this illustrated swarm of comets. [NASA/JPL-Caltech]Boyajians star shows unusual episodes of dimming in its light curve by as much as 20%, each lasting a few to tens of days and separated by periods of typically hundreds of days. In addition, archival observations show that it has gradually faded by roughly 15% over the span of the last hundred years. What could be causing both the sporadic flux dips and the long-term fading of this odd star?Explanations thus far have varied from mundane to extreme. Alien megastructures, pieces of smashed planets or comets orbiting the star, and intervening interstellar medium have all been proposed as possible explanations but these require some object external to the star. A new study by researcher Peter Foukal proposes an alternative: what if the source of the flux obstruction is the star itself?Analogy to the SunDecades ago, researchers discovered that our own stars total flux isnt as constant as we thought. When magnetic dark spots on the Suns surface block the heat transport, the Suns luminosity dips slightly. The diverted heat is redistributed in the Suns interior, becoming stored as a very small global heating and expansion of the convective envelope. When the blocking starspot is removed, the Sun appears slightly brighter than it did originally. Its luminosity then gradually relaxes, decaying back to its original value.Model of a stars flux after a 1,000-km starspot is inserted at time t = 0 and removed at time t = ts at a depth of 10,000 km in the convective zone. The stars luminosity dips, then becomes brighter than originally, and then gradually decays. [Foukal

  3. Creating a Sun-Safe Camp.

    Science.gov (United States)

    Landrey, Ann

    1996-01-01

    Strategies for minimizing sun exposure of campers and staff include educating campers about the sun's effect on their skin, scheduling activities when the sun is less intense, creating shade at the camp site, incorporating sun protection into camp dress code, and training staff regarding sun protection. Addresses OSHA and liability issues. (LP)

  4. Constraining the Galaxy's dark halo with RAVE stars

    NARCIS (Netherlands)

    Piffl, T.; Binney, J.; McMillan, P. J.; Steinmetz, M.; Helmi, A.; Wyse, R. F. G.; Bienaymé, O.; Bland-Hawthorn, J.; Freeman, K.; Gibson, B.; Gilmore, G.; Grebel, E. K.; Kordopatis, G.; Navarro, J. F.; Parker, Q.; Reid, W. A.; Seabroke, G.; Siebert, A.; Watson, F.; Zwitter, T.

    2014-01-01

    We use the kinematics of ˜200 000 giant stars that lie within ˜1.5 kpc of the plane to measure the vertical profile of mass density near the Sun. We find that the dark mass contained within the isodensity surface of the dark halo that passes through the Sun ((6 ± 0.9) × 1010 M⊙), and the surface

  5. Lifestyle, sun worshipping and sun tanning - what about UV-A sun beds?

    International Nuclear Information System (INIS)

    Thune, P.

    1991-01-01

    This article considers the effects of ultraviolet (UV) light from the sun and UV-A sun beds on the skin. Sun worshipping and sun therapy has been en vogue for centuries, but in another way than used today. A changing lifestyle has led to an increase of various skin diseases, including skin cancer. Short wave UV-light (UV-B) in particular has been blamed for inducing not only erythema and pigmentation but also more chronic skin lesions. Long wave UV-light (UV-A) has been shown to be the cause of similar changes to the skin but the pigmentation is of another quality and affords less protection against the harmful effects of UV-B. A concept of sun reactive skin typing has been created. This is based on self-reported responses to an initial exposure to sun as regards tanning ability and erythema reaction. These two factors have certain practical consequences, not only for UV-phototherapy but also for a person's risk of developing skin cancer. Recently, several research groups and dermatologists have discouraged extensive use of UV-A sun beds because of side effects of varying degrees of seriousness. The possible implications of these side effects for the organism are not fully elucidated and may be more profound than known today. The British Photodermatology Group has issued more stringent rules for persons who, despite advice to the contrary, still wish to use UV-A sun beds. 14 refs., 1 tab

  6. Irregular Saturnian Moon Lightcurves from Cassini-ISS Observations: Update

    Science.gov (United States)

    Denk, Tilmann; Mottola, S.

    2013-10-01

    Cassini ISS-NAC observations of the irregular moons of Saturn revealed various physical information on these objects. 16 synodic rotational periods: Hati (S43): 5.45 h; Mundilfari (S25): 6.74 h; Suttungr (S23): ~7.4 h; Kari (S45): 7.70 h; Siarnaq (S29): 10.14 h; Tarvos (S21): 10.66 h; Ymir (S19, sidereal period): 11.92220 h ± 0.1 s; Skathi (S27): ~12 h; Hyrrokkin (S44): 12.76 h; Ijiraq (S22): 13.03 h; Albiorix (S26): 13.32 h; Bestla (S39): 14.64 h; Bebhionn (S37): ~15.8 h; Kiviuq (S24): 21.82 h; Thrymr (S30): ~27 h; Erriapus (S28): ~28 h. The average period for the prograde-orbiting moons is ~16 h, for the retrograde moons ~11½ h (includes Phoebe's 9.2735 h from Bauer et al., AJ, 2004). Phase-angle dependent behavior of lightcurves: The phase angles of the observations range from 2° to 105°. The lightcurves which were obtained at low phase (<40°) show the 2-maxima/ 2-minima pattern expected for this kind of objects. At higher phases, more complicated lightcurves emerge, giving rough indications on shapes. Ymir pole and shape: For satellite Ymir, a convex-hull shape model and the pole-axis orientation have been derived. Ymir's north pole points toward λ = 230°±180°, β = -85°±10°, or RA = 100°±20°, Dec = -70°±10°. This is anti-parallel to the rotation axes of the major planets, indicating that Ymir not just orbits, but also rotates in a retrograde sense. The shape of Ymir resembles a triangular prism with edge lengths of ~20, ~24, and ~25 km. The ratio between the longest 25 km) and shortest axis (pole axis, ~15 km) is ~1.7. Erriapus seasons: The pole direction of object Erriapus has probably a low ecliptic latitude. This gives this moon seasons similar to the Uranian regular moons with periods where the sun stands very high in the sky over many years, and with years-long periods of permanent night. Hati density: The rotational frequency of the fastest rotator (Hati) is close to the frequency where the object would lose material from the surface if

  7. Wave Star

    DEFF Research Database (Denmark)

    Kramer, Morten; Brorsen, Michael; Frigaard, Peter

    Denne rapport beskriver numeriske beregninger af forskellige flydergeometrier for bølgeenergianlæget Wave Star.......Denne rapport beskriver numeriske beregninger af forskellige flydergeometrier for bølgeenergianlæget Wave Star....

  8. Mapping and Naming the Moon

    Science.gov (United States)

    Whitaker, Ewen A.

    2003-12-01

    Preface; Introduction; Part I. First Era: From Prehistoric Images to Archetype Map: 1. Pre-telescopic lunar observations; 2. Early telescopic observations of the Moon; 3. Van Langren (Langrenus) and the birth of selenography; 4. Six more years of sporadic activity; Part II. Second Era: From Archetype to Maturity: 5. 140 years of sporadic activity; 6. A globe, tree rings, and a city; 7. Lunar cartography comes of age; Part III. Third Era: From proliferation to standardisation: 8. Lunar mapping in the Victorian period; 9. Nomenclature gets international attention; Part IV. The Space Age Demands Changes: 10. Setting up guidelines; 11. Planets and satellites set the rules. Appendices 1 - 22.

  9. Totality eclipses of the Sun

    CERN Document Server

    Littmann, Mark; Willcox, Ken

    2008-01-01

    A total eclipse of the Sun is the most awesome sight in the heavens. Totality: Eclipses of the Sun takes you to eclipses of the past, present, and future, and lets you see - and feel - why people travel to the ends of the Earth to observe them. - ;A total eclipse of the Sun is the most awesome sight in the heavens. Totality: Eclipses of the Sun takes you to eclipses of the past, present, and future, and lets you see - and feel - why people travel to the ends of the Earth to observe them. Totality: Eclipses of the Sun is the best guide and reference book on solar eclipses ever written. It explains: how to observe them; how to photograph and videotape them; why they occur; their history and mythology; and future eclipses - when and where to see them. Totality also tells the remarkable story of how eclipses shocked scientists, revealed the workings of the Sun, and made Einstein famous. And the book shares the experiences and advice of many veteran eclipse observers. Totality: Eclipses of the Sun is profusely ill...

  10. China (CNSA) views of the Moon

    Science.gov (United States)

    He, S.

    , the LM 3B can be upgraded to send 1.5-ton to 3-ton payloads into lunar orbit. The next generation rockets based on the Long March series currently being developed will meet the requirements for sample return and human missions. The development of the new launchers is expected to be completed within about six years. Launch centers: Two of the three existing centers, in Jiuquan and Xichang, can be used to launch missions to the Moon. In addition, Chinese space experts have been pushing for building the 4th launch center on Hainan island for new exploration missions and commercial satellite launch, which would be the embarkation point for China's future lunar missions. Tracking and control: The existing tracking and control network, including the TT&C stations in Swakopmund, Namibia and on Tarawa Atoll in Kiribati, and the Long View fleet of 4 tracking ships, can be used for lunar missions. However, a deep space tracking station needs to be built in either Kashi, Xinjiang or Beijing to improve efficiency. But the ground stations within China's territory can only track lunar probes for 8 hours daily. The global DSN needs to be utilized in order to ensure 24-hour tracking operation. Therefore, international cooperation is necessary. International Cooperation CNSA hopes to cooperate with foreign space agencies, using NASA's DSN stations in Madrid, Goldstone and Canberra to support its lunar expeditions. As compared to other space activities in LEO, lunar exploration, the Chinese reason, is basically scientific endeavour and is unrelated to military. Therefore, it is likely that other countries would cooperate with China. China has been cooperating with Russia in many areas. CNSA also has been closely working with ESA on the Double Star project. Most recently, NASA administrator Sean O'Keefe expressed that NASA was interested in China's participation in the ISS. If such cooperation materializes, joint efforts in lunar expeditions should be a logical extension, and the

  11. WAS THE SUN BORN IN A MASSIVE CLUSTER?

    International Nuclear Information System (INIS)

    Dukes, Donald; Krumholz, Mark R.

    2012-01-01

    A number of authors have argued that the Sun must have been born in a cluster of no more than several thousand stars, on the basis that, in a larger cluster, close encounters between the Sun and other stars would have truncated the outer solar system or excited the outer planets into eccentric orbits. However, this dynamical limit is in tension with meteoritic evidence that the solar system was exposed to a nearby supernova during or shortly after its formation; a several-thousand-star cluster is much too small to produce a massive star whose lifetime is short enough to have provided the enrichment. In this paper, we revisit the dynamical limit in the light of improved observations of the properties of young clusters. We use a series of scattering simulations to measure the velocity-dependent cross-section for disruption of the outer solar system by stellar encounters, and use this cross-section to compute the probability of a disruptive encounter as a function of birth cluster properties. We find that, contrary to prior work, the probability of disruption is small regardless of the cluster mass, and that it actually decreases rather than increases with cluster mass. Our results differ from prior work for three main reasons: (1) unlike in most previous work, we compute a velocity-dependent cross-section and properly integrate over the cluster mass-dependent velocity distribution of incoming stars; (2) we recognize that ∼90% of clusters have lifetimes of a few crossing times, rather than the 10-100 Myr adopted in many earlier models; and (3) following recent observations, we adopt a mass-independent surface density for embedded clusters, rather than a mass-independent radius as assumed many earlier papers. Our results remove the tension between the dynamical limit and the meteoritic evidence, and suggest that the Sun was born in a massive cluster. A corollary to this result is that close encounters in the Sun's birth cluster are highly unlikely to truncate the

  12. The Stars behind the Curtain

    Science.gov (United States)

    2010-02-01

    ESO is releasing a magnificent VLT image of the giant stellar nursery surrounding NGC 3603, in which stars are continuously being born. Embedded in this scenic nebula is one of the most luminous and most compact clusters of young, massive stars in our Milky Way, which therefore serves as an excellent "local" analogue of very active star-forming regions in other galaxies. The cluster also hosts the most massive star to be "weighed" so far. NGC 3603 is a starburst region: a cosmic factory where stars form frantically from the nebula's extended clouds of gas and dust. Located 22 000 light-years away from the Sun, it is the closest region of this kind known in our galaxy, providing astronomers with a local test bed for studying intense star formation processes, very common in other galaxies, but hard to observe in detail because of their great distance from us. The nebula owes its shape to the intense light and winds coming from the young, massive stars which lift the curtains of gas and clouds revealing a multitude of glowing suns. The central cluster of stars inside NGC 3603 harbours thousands of stars of all sorts (eso9946): the majority have masses similar to or less than that of our Sun, but most spectacular are several of the very massive stars that are close to the end of their lives. Several blue supergiant stars crowd into a volume of less than a cubic light-year, along with three so-called Wolf-Rayet stars - extremely bright and massive stars that are ejecting vast amounts of material before finishing off in glorious explosions known as supernovae. Using another recent set of observations performed with the SINFONI instrument on ESO's Very Large Telescope (VLT), astronomers have confirmed that one of these stars is about 120 times more massive than our Sun, standing out as the most massive star known so far in the Milky Way [1]. The clouds of NGC 3603 provide us with a family picture of stars in different stages of their life, with gaseous structures that are

  13. Sun exposure, sun protection and sunburn among Canadian adults.

    Science.gov (United States)

    Pinault, Lauren; Fioletov, Vitali

    2017-05-17

    Ultraviolet radiation (UVR) exposure and a history of sunburn are important risk factors for skin cancer. Sunburn is more common among men, younger age groups, and people in higher income households. Sun protection measures also vary by sex, age, and socioeconomic characteristics. Associations between ambient UVR and sunburn and sun safety measures have not been quantified. A total of 53,130 respondents aged 18 or older answered a Canadian Community Health Survey (CCHS) module on sun safety, which was administered in six provinces from 2005 to 2014. The module contained questions about sunburn, time in the sun, and sun protection. These respondents were linked to an ambient erythemal UVR dataset representing the June-to-August mean. Descriptive statistics and logistic regression were used to examine associations between population characteristics, sunburn, sun safety, time in the sun, and ambient UVR. Sunburn was reported by 33% of respondents and was more common among men, younger age groups, people who were not members of visible minorities, residents of higher income households, and individuals who were employed. On a typical summer day, a larger percentage of women than men sought shade and wore sunscreen, whereas a larger percentage of men wore a hat or long pants. As ambient summer UVR increased, women were more likely to apply sunscreen to their face, seek shade, or wear a hat (OR~1.02 to 1.09 per increase of 187 J/m² of erythemally-weighted UVR, or 5.4% of the mean); these associations were not observed among men. Findings related to sunburn and sun protection were similar to those of previous studies. The association between ambient UVR and women's precautionary measures suggests that information about UVR may influence their decision to protect their skin.

  14. Sun-Earth Day, 2001

    Science.gov (United States)

    Adams, Mitzi L.; Mortfield, P.; Hathaway, D. H.; Whitaker, Ann F. (Technical Monitor)

    2001-01-01

    To promote awareness of the Sun-Earth connection, NASA's Marshall Space Flight Center, in collaboration with the Stanford SOLAR Center, sponsored a one-day Sun-Earth Day event on April 27, 2001. Although "celebrated" on only one day, teachers and students from across the nation, prepared for over a month in advance. Workshops were held in March to train teachers. Students performed experiments, results of which were shared through video clips and an internet web cast. Our poster includes highlights from student experiments (grades 2 - 12), lessons learned from the teacher workshops and the event itself, and plans for Sun-Earth Day 2002.

  15. Clustering of Sun Exposure Measurements

    DEFF Research Database (Denmark)

    Have, Anna Szynkowiak; Larsen, Jan; Hansen, Lars Kai

    2002-01-01

    In a medically motivated Sun-exposure study, questionnaires concerning Sun-habits were collected from a number of subjects together with UV radiation measurements. This paper focuses on identifying clusters in the heterogeneous set of data for the purpose of understanding possible relations between...... Sun-habits exposure and eventually assessing the risk of skin cancer. A general probabilistic framework originally developed for text and Web mining is demonstrated to be useful for clustering of behavioral data. The framework combines principal component subspace projection with probabilistic...

  16. Sun protection policies of Australian primary schools in a region of high sun exposure.

    Science.gov (United States)

    Harrison, S L; Garzón-Chavez, D R; Nikles, C J

    2016-06-01

    Queensland, Australia has the highest rates of skin cancer globally. Predetermined criteria were used to score the comprehensiveness of sun protection policies (SPP) of primary schools across Queensland. SPP were sought for schools in 10 regions (latitude range 16.3°S-28.1°S) from 2011 to 2014. Of the 723 schools sampled, 90.9% had a written SPP available publicly. Total SPP scores were low {mean 3.6 [95% CI: 3.4-3.9]; median 2 [interquartile range (IQR) 2, 4]}, with only 3.2% of schools achieving the maximum score of 12. Median SPP scores were higher in Northern and Central Queensland [both 2 (IQR 2, 6) and (IQR 2, 5), respectively] than in Southern Queensland [2 (IQR 2, 3); P = 0.004]. Clothing and hat-wearing were addressed in most policies (96% and 89%) while few schools used their SPP to plan outdoor events (5.2%) or reschedule activities to minimize sun exposure (11.7%). The SunSmart Schools program has been operating in Queensland for 17 years, and while most primary schools now have a written SPP, most are not comprehensive. Incentive-based approaches (5-star-rating award scheme and grants) may assist in addressing this issue, to reduce sun exposure of students and teachers. These data provide a baseline from which improvements in the comprehensiveness of school SPPs can be evaluated. © The Author 2016. Published by Oxford University Press. All rights reserved. For permissions, please email: journals.permissions@oup.com.

  17. Taking Europe To The Moon

    Science.gov (United States)

    1998-03-01

    The first step in this ESA initiated programme is a unique project called 'Euromoon 2000' which is currently being studied by ESA engineers/ scientists and key European Space Industries. The project is intended to celebrate Europe's entry into the New Millennium; and to promote public awareness and interest in science, technology and space exploration. Euromoon 2000 has an innovative and ambitious implementation plan. This includes a 'partnership with industry' and a financing scheme based on raising part of the mission's budget from sponsorship through a dynamic public relations strategy and marketing programme. The mission begins in earnest with the small (approx. 100 kg) LunarSat orbiter satellite, to be designed and built by 50 young scientists and engineers from across Europe. Scheduled for launch in 2000 as a secondary payload on a European Ariane 5 rocket, it will then orbit the Moon, mapping the planned landing area in greater detail in preparation of the EuroMoon Lander in 2001. The Lander's 40 kg payload allocation will accommodate amongst others scientific instrumentation for in-situ investigation of the unique site. Elements of specific support to the publicity and fund-raising campaign will also be considered. The Lander will aim for the 'Peak of Eternal Light' on the rim of the 20 km-diameter, 3 km-deep Shackleton South Pole crater - a site uniquely suited for establishing a future outpost. This location enjoys almost continuous sunlight thus missions can rely on solar power instead of bulky batteries or costly and potentially hazardous nuclear power generation. As a consequence of the undulating South Pole terrain there are also permanently shadowed areas - amongst the coldest in the Solar System resulting in conditions highly favourable for the formation of frozen volatiles (as suggested by the Clementine mission in 1994). Earlier this year (7th January 1998), NASA launched its Lunar Prospector satellite which is currently performing polar lunar

  18. Discovery of a Makemakean Moon

    Science.gov (United States)

    Parker, Alex H.; Buie, Marc W.; Grundy, Will M.; Noll, Keith S.

    2016-01-01

    We describe the discovery of a satellite in orbit about the dwarf planet (136472) Makemake. This satellite, provisionally designated S/2015 (136472) 1, was detected in imaging data collected with the Hubble Space Telescope's Wide Field Camera 3 on UTC 2015 April 27 at 7.80 +/- 0.04 mag fainter than Makemake and at a separation of 0farcs57. It likely evaded detection in previous satellite searches due to a nearly edge-on orbital configuration, placing it deep within the glare of Makemake during a substantial fraction of its orbital period. This configuration would place Makemake and its satellite near a mutual event season. Insufficient orbital motion was detected to make a detailed characterization of its orbital properties, prohibiting a measurement of the system mass with the discovery data alone. Preliminary analysis indicates that if the orbit is circular, its orbital period must be longer than 12.4 days and must have a semimajor axis > or approx. = 21,000 km. We find that the properties of Makemake's moon suggest that the majority of the dark material detected in the system by thermal observations may not reside on the surface of Makemake, but may instead be attributable to S/2015 (136472) 1 having a uniform dark surface. This dark moon hypothesis can be directly tested with future James Webb Space Telescope observations. We discuss the implications of this discovery for the spin state, figure, and thermal properties of Makemake and the apparent ubiquity of trans-Neptunian dwarf planet satellites.

  19. Unique Moon Formation Model: Two Impacts of Earth and After Moon's Birth

    Science.gov (United States)

    Miura, Y.

    2018-04-01

    The Moon rocks are mixed with two impact-processes of Earth's impact breccias and airless Moon's impact breccias; discussed voids-rich texture and crust-like composition. The present model might be explained as cave-rich interior on the airless-and waterless Moon.

  20. Fly me to the Sun! ESA inaugurates the European Project on the Sun

    Science.gov (United States)

    2000-11-01

    In an initiative mounted by ECSITE (European Collaborative for Science, Industry and Technology Exhibitions) with funding from the European Commission and under the supervision, coordination and co-sponsorship of ESA, five teams of youngsters (16-18 years old) from Belgium, France, Germany, Italy and the Netherlands were selected and coordinated by European science museums from each of their countries (Musée des Sciences et des Techniques - Parentville, B; Cité de l'Espace - Toulouse, F; Deutsches Museum - Munich, D; Fondazione IDIS - Naples, I; Foundation Noordwijk Space Expo - Noordwijk, NL). The teams each focused on a theme related to solar research: "How does the Sun work?" (I), "The Sun as a star" (F), "Solar activity" (NL), "Observing the Sun" (D), "Humans and the Sun" (B), and built exhibition "modules" that they will present at the inauguration, in the context of European Science and Technology Week 2000 (6-10 November), promoted by the European Commission. During the two-day event, a jury of representatives of other European science and technology museums, ESA scientists, a science journalist, and two ESA astronauts (Frank de Winne and Andre Kuipers) will judge the youngsters' exhibition modules on the basis of their scientific correctness, their museological value and the commitment shown by the young "communication experts". The winning team will be officially announced on 9 November. The prize is a weekend at the Space Camp in Redu, Belgium. The objective of the European Project on the Sun is educational. It aims, through the direct and "fresh" involvement of youngsters, to heighten European citizens' awareness of space research in general and the Sun's influence on our daily lives in particular. The role of the European Space Agency as reference point in Europe for solar research has been fundamental to the project. From ESA's perspective, EPOS is part of this autumn's wider communication initiative called the Solar Season, which is highlighting ESA

  1. Aspects of long-term variability in sun and stars

    International Nuclear Information System (INIS)

    Skumanich, A.; Eddy, J.A.

    1981-01-01

    Evidence of long-term solar variability is reviewed, including historical data and the tree-ring record of radiocarbon. Epochs of suppressed activity like the Maunder Minimum are shown to be frequent occurences of the last several thousand years, but without no obvious period of recurrence. Weak evidence exists for the 11-year cycle as early as Medieval times, although with insufficient accuracy to establish long-term phase stability. (orig.)

  2. Methods and Strategies: The Sun Is a Star?!

    Science.gov (United States)

    Hutchison, Paul

    2013-01-01

    Children understand the natural world in ways that make sense to them before they learn any science in school. This column provides ideas and techniques to enhance science teaching. This month's issue helps students connect scientifically correct ideas to what makes sense to them.

  3. Star Maps, Planispheres, and Celestial Calendars : Engaging Students, Educators, and Communities with Multicultural STEM/STEAM Visual Resources

    Science.gov (United States)

    Lee, Annette S.; Wilson, William; Tibbetts, Jeffrey; Gawboy, Carl

    2017-06-01

    Aim:Designed by A. Lee, the Native Skywatchers initiative seeks to remember and revitalize indigenous star and earth knowledge, promoting the native voice as the lead voice. The overarching goal of Native Skywatchers is to communicate the knowledge that indigenous people practiced a sustainable way of living and sustainable engineering through a living and participatory relationship with the above and below, sky and earth. We aim to improve current inequities in education for native young people, to inspire increased cultural pride, and promote community wellness. We hope to inspire all participants towards a rekindling of the excitement and curiosity that causes us to look up at the sky in wonder generation after generation.Results:Presented here are several Native Skywatchers initiatives under the broad categories of: 1.) star maps, 2.) planispheres, and 3.) celestial calendars. In 2012 two indigenous star maps were created: the Ojibwe Giizhig Anung Masinaaigan-Ojibwe Sky Star Map (A. Lee, W. Wilson, C. Gawboy), and the D(L)akota star map, Makoce Wicanhpi Wowapi (A. Lee, J. Rock). More recently, a collaboration with W. Buck, science educator, at the Manitoba First Nations Resource Centre (MFNRC), in Winnipeg, Manitoba produced a third indigenous star map: Ininew Achakos Masinikan-Cree Star Map Book. Having star maps that are rooted in astronomical knowledge and cultural wisdoms has allowed communities multiple and ongoing opportunities for inclusive culture-based STEM learning. Next, planispheres were created based on the indigenous star maps. A learning and teaching hands-on tool, the planispheres, help partakers understand the patterns of motion in the night sky in addition to simply identifying the constellations. Most recently, calendar-paintings of the yearly motion of the Sun, the phases of the Moon, and the Venus-year have all been added to the growing list of Native Skywatchers resources. Working collaboratively with regional schools, educators, museums

  4. Properties of cold components of symbiotic stars

    International Nuclear Information System (INIS)

    Luud, L.; Leehdyarv, L.

    1986-01-01

    Using the Blackwell-Shallis method the luminosities, temperatures and radii for cold components of symbiotic stars and for a sample of field red giants have been determined by means of infrared photometric observations. It turned out that the cold components of symbiotic stars do not differ from the normal red giants of the asymptotic branch. The masses of cold components of symbiotic stars have been found to be close to 3 M* (M* is the solar mass).The cold components of symbiotic stars do not fill their Roche lobes. About 10 times more carbon stars than the normal value in the vicinity of the Sun have been found among the cold components of symbiotic stars

  5. Prototype of sun projector device

    Science.gov (United States)

    Ihsan; Dermawan, B.

    2016-11-01

    One way to introduce astronomy to public, including students, can be handled by solar observation. The widely held device for this purpose is coelostat and heliostat. Besides using filter attached to a device such as telescope, it is safest to use indirect way for observing the Sun. The main principle of the indirect way is deflecting the sun light and projecting image of the sun on a screen. We design and build a simple and low-cost astronomical device, serving as a supplement to increase public service, especially for solar observation. Without using any digital and intricate supporting equipment, people can watch and relish image of the Sun in comfortable condition, i.e. in a sheltered or shady place. Here we describe a design and features of our prototype of the device, which still, of course, has some limitations. In the future, this prototype can be improved for more efficient and useful applications.

  6. Protecting Yourself from Sun Exposure

    Science.gov (United States)

    Fast Facts Protecting Yourself from Sun Exposure Anyone working outdoors is exposed to the sun’s ultraviolet (UV) rays, even on cloudy ... nausea, and fatigue. In addition to the skin, eyes can become sunburned. Sunburned eyes become red, dry, ...

  7. As reliable as the sun

    Science.gov (United States)

    Leijtens, J. A. P.

    2017-11-01

    Fortunately there is almost nothing as reliable as the sun which can consequently be utilized as a very reliable source of spacecraft power. In order to harvest this power, the solar panels have to be pointed towards the sun as accurately and reliably as possible. To this extend, sunsensors are available on almost every satellite to support vital sun-pointing capability throughout the mission, even in the deployment and save mode phases of the satellites life. Given the criticality of the application one would expect that after more than 50 years of sun sensor utilisation, such sensors would be fully matured and optimised. In actual fact though, the majority of sunsensors employed are still coarse sunsensors which have a proven extreme reliability but present major issues regarding albedo sensitivity and pointing accuracy.

  8. There are days ... and moons. Self-poisoning is not lunacy.

    Science.gov (United States)

    Buckley, N A; Whyte, I M; Dawson, A H

    To determine whether there are significant circadian, weekly or lunar variations in self-poisoning presentations and whether patients' names or dates of birth have an influence on the likelihood of self-poisoning by analysing biorhythms, numerology and star sign. Hunter Valley, Australia. Consecutive adult patients admitted with self-poisoning between January 1987 and June 1993. There were 2215 patients admitted. There was a marked circadian variation. Over 6% of all admissions occurred in each of the hours between 6 p.m. and 1 a.m. compared with less than 2% per hour between 5 a.m. and 9 a.m. This pattern was not different for patients with a diagnosis of depression. Numerology, biorhythms and star signs had no significant correlations with self-poisoning, nor was there a significant weekly or yearly variation in presentations. There was a small but statistically significant sex difference in presentations analysed by lunar phases. At the new moon 60% of self-poisonings were in women, compared with 45% when the moon was full. The odds ratios (OR) for women to be admitted at full moon and at new moon were 1.27 (95% confidence interval [CI], 0.92-1.66; P value not significant) and 0.73 (95% CI, 0.57-0.92; P = 0.009) respectively. The mean illumination of the moon at the time of overdose was 50.63% +/- 0.91% for men, compared with 47.45% +/- 0.85% for women (P = 0.014). The circadian cycle (but not weekly, yearly or mystical cycles) should be taken into account when determining staffing levels for poison information and casualty services. The full moon is protective for women.

  9. One of the most massive stars in the Galaxy may have formed in isolation

    OpenAIRE

    Oskinova, L. M.; Steinke, M.; Hamann, W. -R.; Sander, A.; Todt, H.; Liermann, A.

    2013-01-01

    Very massive stars, 100 times heavier than the sun, are rare. It is not yet known whether such stars can form in isolation or only in star clusters. The answer to this question is of fundamental importance. The central region of our Galaxy is ideal for investigating very massive stars and clusters located in the same environment. We used archival infrared images to investigate the surroundings of apparently isolated massive stars presently known in the Galactic Center. We find that two such i...

  10. The sun and the neutrinos

    International Nuclear Information System (INIS)

    Forgacsne Dajka, E.

    2000-01-01

    A review of the solar neutrino puzzle is given. The main processes in the sun, the pp-chain and the CNO cycle are described. The solar neutrino puzzle, i.e. the fact that the detected amount of neutrinos coming from the sun is less than the amount predicted by the solar model is discussed. The first generation solar neutrino experiments are presented. (K.A.)

  11. Rotational velocities of low-mass stars

    International Nuclear Information System (INIS)

    Stauffer, J.B.; Hartmann, L.W.; Harvard-Smithsonian Center for Astrophysics, Cambridge, MA)

    1986-01-01

    The rotational velocities of stars provide important clues to how stars form and evolve. Yet until recently, studies of stellar rotation were limited to stars more massive than the sun. This is beginning to change, and an observational outline of the rotational velocity evolution of stars less massive than the sun can now be provided. Low-mass stars rotate slowly during the early stages of premain-sequence evolution, and spin up as they contract to the main sequence. This spin-up culminates in a brief period of very rapid rotation at an age of order 50 million years. Physical interpretation of this increase in rotation and the subsequent main-sequence spin-down are complicated by the possibility of differential internal rotation. The observed rapidity of spin-down among G dwarfs suggests that initially only the outer convective envelopes of these stars are slowed. The data suggest an intrinsic spread in angular momentum among young stars of the same mass and age, a spread which is apparently minimized by the angular-momentum loss mechanism in old low-mass stars. 83 references

  12. Taking the moon's internal temperature

    International Nuclear Information System (INIS)

    Duba, A.G.

    1976-01-01

    LLL geophysicists were instrumental in resolving a serious discrepancy between lunar magnetic-field data and melting studies of lunar basalts brought back from the Moon by Apollo astronauts. Estimates of the subsurface temperatures, based on lunar electrical conductivity measurements and laboratory experiments, were hundreds of degrees below those given by models using known melting points of various minerals. The work uncovered a basic flaw in previous measurements. New measurements under more realistic conditions brought the electrical-conductivity temperature estimates into agreement with temperatures derived from melting experiments. This same work also contributed to in situ coal gasification studies; to ERDA's dry, hot-rock geothermal effort; and to a program of monitoring for seismic evidence of clandestine nuclear testing. 4 figures

  13. The surface of the moon

    International Nuclear Information System (INIS)

    Langevin, Yves

    1982-01-01

    Knowledge of the history of the interplanetary environment is linked to that of the formation and evolution of the lunar regolith. The major importance of the various space flights was the collection of almost 400 kg of lunar soil and rock samples, the study of which, thanks to isotopic dating methods, enabled the main lines of the history of the moon to be retraced. Since the ending of magma activity (three thousand million years ago), only the impacts of meteorites have modified the appearance of the lunar surface; the data acquired on their flow provide the explanation of the essential characteristics of the lunar regolith. The processing of the core particles and the samples has contributed to the determination of the history of the flow of particles and matter in the interplanetary environment [fr

  14. Tracing the journey of the Sun and the Solar siblings through the Milky Way

    Science.gov (United States)

    Martínez-Barbosa, Carmen Adriana

    2016-04-01

    This thesis is focused on studying the motion of the Sun and the Solar siblings through the Galaxy. The Solar siblings are stars that were born with the Sun in the same molecular cloud 4.6 Gyr ago. In the first part of the thesis, we present an efficient method to calculate the evolution of small systems embedded in larger systems. Generalizations of this method are used to calculate the motion of the Sun and the Solar siblings in an analytical potential containing a central bar and spiral arms. By integrating the orbit of the Sun backwards in time, we determine its birth radius and the amount of radial migration experienced by our star. The birth radius of the Sun is used to investigate the evolution and disruption of the Sun's birth cluster. Depending on the Galaxy model parameters, the present-day phase-space distribution of the Solar siblings might be quite different. We used these data to predict the regions in the Galaxy where it will be more likely to search for So! lar siblings in the future. Finally, we compute the stellar encounters experienced by the Sun along its orbit and their role on the stability of the outer Solar System.

  15. DISCOVERY OF A MAKEMAKEAN MOON

    Energy Technology Data Exchange (ETDEWEB)

    Parker, Alex H.; Buie, Marc W. [Southwest Research Institute, 1050 Walnut Street, Suite 300, Boulder, CO 80302 (United States); Grundy, Will M. [Lowell Observatory, Flagstaff, AZ (United States); Noll, Keith S., E-mail: aparker@boulder.swri.edu [NASA Goddard Space Flight Center, Greenbelt, MD (United States)

    2016-07-01

    We describe the discovery of a satellite in orbit about the dwarf planet (136472) Makemake. This satellite, provisionally designated S/2015 (136472) 1, was detected in imaging data collected with the Hubble Space Telescope ’s Wide Field Camera 3 on UTC 2015 April 27 at 7.80 ± 0.04 mag fainter than Makemake and at a separation of 0.″57. It likely evaded detection in previous satellite searches due to a nearly edge-on orbital configuration, placing it deep within the glare of Makemake during a substantial fraction of its orbital period. This configuration would place Makemake and its satellite near a mutual event season. Insufficient orbital motion was detected to make a detailed characterization of its orbital properties, prohibiting a measurement of the system mass with the discovery data alone. Preliminary analysis indicates that if the orbit is circular, its orbital period must be longer than 12.4 days and must have a semimajor axis ≳21,000 km. We find that the properties of Makemake’s moon suggest that the majority of the dark material detected in the system by thermal observations may not reside on the surface of Makemake, but may instead be attributable to S/2015 (136472) 1 having a uniform dark surface. This “dark moon hypothesis” can be directly tested with future James Webb Space Telescope observations. We discuss the implications of this discovery for the spin state, figure, and thermal properties of Makemake and the apparent ubiquity of trans-Neptunian dwarf planet satellites.

  16. Life sciences on the moon

    Science.gov (United States)

    Horneck, G.

    Despite of the fact that the lunar environment lacks essential prerequisites for supporting life, lunar missions offer new and promising opportunities to the life sciences community. Among the disciplines of interest are exobiology, radiation biology, ecology and human physiology. In exobiology, the Moon offers an ideal platform for studies related to the understanding of the principles, leading to the origin, evolution and distribution of life. These include the analysis of lunar samples and meteorites in relatively pristine conditions, radioastronomical search for other planetary systems or Search for Extra-Terrestrial Intelligence (SETI), and studies on the role of radiation in evolutionary processes and on the environmental limits for life. For radiation biology, the Moon provides an unique laboratory with built-in sources for optical as well as ionising radiation to investigate the biological importance of the various components of cosmic and solar radiation. Before establishing a lunar base, precursor missions will provide a characterisation of the radiation field, determination of depth dose distributions in different absorbers, the installation of a solar flare alert system, and a qualification of the biological efficiency of the mixed radiation environment. One of the most challenging projects falls into the domain of ecology with the establishment for the first time of an artificial ecosystem on a celestial body beyond the Earth. From this venture, a better understanding of the dynamics regulating our terrestrial biosphere is expected. It will also serve as a precursor of bioregenerative life support systems for a lunar base. The establishment of a lunar base with eventually long-term human presence will raise various problems in the fields of human physiology and health care, psychology and sociology. Protection guidelines for living in this hostile environment have to be established.

  17. Star formation within OB subgroups: Implosion by multiple sources

    International Nuclear Information System (INIS)

    Klein, R.I.; Sanford, M.T. III; Whitaker, R.W.

    1983-01-01

    We present the results of new detailed two-dimensional radiation-hydrodynamical calculations of the effects of radiation-driven shock waves from two O stars on inhomogeneities embedded in molecular clouds. The calculations indicate the neutral primordial clumps of gas with 84 M/sub sun/ can be highly compressed in 3 x 10 4 yr with density enhancements greater than 170 over ambient densities and 40 M/sub sun/ remaining. Inhomogeneities that are compressed in this manner by stars in the range O7--B0 survive ionization evaporation and may rapidly form new stars. Low-mass objects would not survive, and there would be a natural cutoff of low-mass and high-mass stars. We present a scenario for hierarchical radiation-driven implosion as a potential, new highly efficient mechanismfor star formation that may explain aspects of recent observations of new star formation in ultracompact H II regions

  18. SOHO reveals violent action on the quiet Sun

    Science.gov (United States)

    1996-05-01

    SOHO's scientists are impressed by the vigorous action that they see going on every day, because the Sun is in the very quietest phase of its eleven-year cycle of activity. To ground-based observatories it appears extremely calm just now. The early indications of SOHO's performance amply justify the creation of a sungazing spacecraft capable of observing ultraviolet emissions that are blotted out by the Earth's atmosphere. Apart from the imager, two ultraviolet spectrometers and an ultraviolet coronagraph (an imager for the outer atmosphere) are busy analysing the violent processes at a wide range of wavelengths. Between them, these instruments should cure long-lasting ignorance concerning the Sun, especially about why the atmosphere is so hot and what drives the solar wind that blows non-stop into the Solar System. Scientists from other experimental teams use SOHO to explore the Sun from its deep interior to the far reaches of the solar wind. They have watched the supposedly quiet Sun belching huge masses of gas into space. They have mapped a hole burnt by the solar wind in a breeze of gas coming from the stars. And they have detected currents of gas flowing just below the visible surface. SOHO is a project of international cooperation between the European Space Agency and NASA. The spacecraft was built in Europe and instrumented by scientists on both sides of the Atlantic. NASA launched SOHO on 2 December 1995, and also provides the ground stations and an operations centre near Washington. The first results are the more remarkable because SOHO arrived at its vantage point 1,500,000 kilometres out in space only in February, and formally completed its commissioning on 16 April. It has a long life ahead of it. All scientific instruments are working well. The luminosity oscillation imager belonging to the VIRGO experiment had trouble with its lens cover. When opened, the cover rebounded on its hinges and closed again. Commands were devised that gave a shorter impulse

  19. Radio stars

    International Nuclear Information System (INIS)

    Hjellming, R.M.

    1976-01-01

    Any discussion of the radio emission from stars should begin by emphasizing certain unique problems. First of all, one must clarify a semantic confusion introduced into radio astronomy in the late 1950's when most new radio sources were described as radio stars. All of these early 'radio stars' were eventually identified with other galactic and extra-galactic objects. The study of true radio stars, where the radio emission is produced in the atmosphere of a star, began only in the 1960's. Most of the work on the subject has, in fact, been carried out in only the last few years. Because the real information about radio stars is quite new, it is not surprising that major aspects of the subject are not at all understood. For this reason this paper is organized mainly around three questions: what is the available observational information; what physical processes seem to be involved; and what working hypotheses look potentially fruitful. (Auth.)

  20. Fuel optimization for low-thrust Earth-Moon transfer via indirect optimal control

    Science.gov (United States)

    Pérez-Palau, Daniel; Epenoy, Richard

    2018-02-01

    The problem of designing low-energy transfers between the Earth and the Moon has attracted recently a major interest from the scientific community. In this paper, an indirect optimal control approach is used to determine minimum-fuel low-thrust transfers between a low Earth orbit and a Lunar orbit in the Sun-Earth-Moon Bicircular Restricted Four-Body Problem. First, the optimal control problem is formulated and its necessary optimality conditions are derived from Pontryagin's Maximum Principle. Then, two different solution methods are proposed to overcome the numerical difficulties arising from the huge sensitivity of the problem's state and costate equations. The first one consists in the use of continuation techniques. The second one is based on a massive exploration of the set of unknown variables appearing in the optimality conditions. The dimension of the search space is reduced by considering adapted variables leading to a reduction of the computational time. The trajectories found are classified in several families according to their shape, transfer duration and fuel expenditure. Finally, an analysis based on the dynamical structure provided by the invariant manifolds of the two underlying Circular Restricted Three-Body Problems, Earth-Moon and Sun-Earth is presented leading to a physical interpretation of the different families of trajectories.

  1. Star Wars?

    Science.gov (United States)

    Berry, John

    1981-01-01

    Likening the relationship of the ALA and its professional divisions to that of the sun and its planets, this editorial explores the organizational characteristics and stability of the present system and solicits opinions. (RAA)

  2. Kinematics and age of 15 stars-photometric solar analogs

    Science.gov (United States)

    Galeev, A. I.; Shimansky, V. V.

    2008-03-01

    The radial and space velocities are inferred for 15 stars that are photometric analogs of the Sun. The space velocity components (U, V, W) of most of these stars lie within the 10-60 km/s interval. The star HD 225239, which in our previous papers we classified as a subgiant, has a space velocity exceeding 100 km/s, and belongs to the thick disk. The inferred fundamental parameters of the atmospheres of solar analogs are combined with published evolutionary tracks to estimate the masses and ages of the stars studied. The kinematics of photometric analogs is compared to the data for a large group of solar-type stars.

  3. The Drifting Star

    Science.gov (United States)

    2008-04-01

    temperature is 6150 K, its mass is 1.25 times that of the Sun, and its age is 625 million years. Moreover, the star is found to be more metal-rich than the Sun by about 50%. ESO PR Photo 09b/08 ESO PR Photo 09b/08 Constellations "These results show the power of asteroseismology when using a very precise instrument such as HARPS," says Vauclair. "It also shows that Iota Horologii has the same metal abundance and age as the Hyades cluster and this cannot be a coincidence." The Hyades is an ensemble of stars that is seen with the unaided eye in the Northern constellation Taurus ("The Bull"). This open cluster, located 151 light-years away, contains stars that were formed together 625 million years ago. The star Iota Horologii must have thus formed together with the stars of the Hyades cluster but must have slowly drifted away, being presently more than 130 light-years away from its original birthplace. This is an important result to understand how stars move on the galactic highways of the Milky Way. This also means that the amount of metals present in the star is due to the original cloud from which it formed and not because it engulfed planetary material. "The chicken and egg question of whether the star got planets because it is metal-rich, or whether it is metal-rich because it made planets that were swallowed up is at least answered in one case," says Vauclair. More information The astronomers' study is being published as a Letter to the Editor in Astronomy and Astrophysics ("The exoplanet-host star iota Horologii: an evaporated member of the primordial Hyades cluster", by S. Vauclair et al.). The team is composed of Sylvie Vauclair, Marion Laymand, Gérard Vauclair, Alain Hui Bon Hoa, and Stéphane Charpinet (LATT, Toulouse, France), François Bouchy (IAP, Paris, France), and Michaël Bazot (University of Porto, Portugal).

  4. Shooting stars

    International Nuclear Information System (INIS)

    Maurette, M.; Hammer, C.

    1985-01-01

    A shooting star passage -even a star shower- can be sometimes easily seen during moonless black night. They represent the partial volatilization in earth atmosphere of meteorites or micrometeorites reduced in cosmic dusts. Everywhere on earth, these star dusts are searched to be gathered. This research made one year ago on the Greenland ice-cap is this article object; orbit gathering projects are also presented [fr

  5. DETERMINING STAR FORMATION RATES FOR INFRARED GALAXIES

    International Nuclear Information System (INIS)

    Rieke, G. H.; Weiner, B. J.; Perez-Gonzalez, P. G.; Donley, J. L.; Alonso-Herrero, A.; Blaylock, M.; Marcillac, D.

    2009-01-01

    We show that measures of star formation rates (SFRs) for infrared galaxies using either single-band 24 μm or extinction-corrected Paα luminosities are consistent in the total infrared luminosity = L(TIR) ∼ 10 10 L sun range. MIPS 24 μm photometry can yield SFRs accurately from this luminosity upward: SFR(M sun yr -1 ) = 7.8 x 10 -10 L(24 μm, L sun ) from L(TIR) = 5x 10 9 L sun to 10 11 L sun and SFR = 7.8 x 10 -10 L(24 μm, L sun )(7.76 x 10 -11 L(24)) 0.048 for higher L(TIR). For galaxies with L(TIR) ≥ 10 10 L sun , these new expressions should provide SFRs to within 0.2 dex. For L(TIR) ≥ 10 11 L sun , we find that the SFR of infrared galaxies is significantly underestimated using extinction-corrected Paα (and presumably using any other optical or near-infrared recombination lines). As a part of this work, we constructed spectral energy distribution templates for eleven luminous and ultraluminous purely star forming infrared galaxies and over the spectral range 0.4 μm to 30 cm. We use these templates and the SINGS data to construct average templates from 5 μm to 30 cm for infrared galaxies with L(TIR) = 5x 10 9 to 10 13 L sun . All of these templates are made available online.

  6. SunShot Initiative Portfolio Book 2014

    Energy Technology Data Exchange (ETDEWEB)

    Solar Energy Technologies Office

    2014-05-01

    The 2014 SunShot Initiative Portfolio Book outlines the progress towards the goals outlined in the SunShot Vision Study. Contents include overviews of each of SunShot’s five subprogram areas, as well as a description of every active project in the SunShot’s project portfolio as of May 2014.

  7. New planet hints at life in the stars

    CERN Multimedia

    Dalton, A W

    2002-01-01

    Astronomers have detected a distant planet 100 light years from Earth, circling Tau1 Gruis, its star, in the constellation of Grus (the crane). The planet, similar in appearance to Jupiter, is three times as far away from its star as the Earth is from the Sun and takes four years to revolve around the star, in a roughly circular orbit. Scientists believe this type of planetary orbit is the most promising for finding worlds that contain life (1 page).

  8. Rare White dwarf stars with carbon atmospheres

    OpenAIRE

    Dufour, P.; Liebert, James; Fontaine, G.; Behara, N.

    2007-01-01

    White dwarfs represent the endpoint of stellar evolution for stars with initial masses between approximately 0.07 msun and 8-10 msun, where msun is the mass of the Sun (more massive stars end their life as either black holes or neutron stars). The theory of stellar evolution predicts that the majority of white dwarfs have a core made of carbon and oxygen, which itself is surrounded by a helium layer and, for ~80 per cent of known white dwarfs, by an additional hydrogen layer. All white dwarfs...

  9. Evidence for a solar companion star

    International Nuclear Information System (INIS)

    Muller, R.A.

    1984-08-01

    Periodicity seen in both the mass extinctions and large impact cratering on earth can be explained if one postulates that the sun has a companion star, orbiting in a moderately eccentric orbit with a major axis of 2.8 light-years. No other explanations that have been suggested are compatible with known facts of physics and astronomy. If the companion is a red dwarf star, the most common kind in the galaxy, then no previous astronomical observations would have found it. A search for red objects with large parallax is now underway at Berkeley, and has a good chance of identifying the star in the near future

  10. Evidence for a solar companion star

    Energy Technology Data Exchange (ETDEWEB)

    Muller, R.A.

    1984-08-01

    Periodicity seen in both the mass extinctions and large impact cratering on earth can be explained if one postulates that the sun has a companion star, orbiting in a moderately eccentric orbit with a major axis of 2.8 light-years. No other explanations that have been suggested are compatible with known facts of physics and astronomy. If the companion is a red dwarf star, the most common kind in the galaxy, then no previous astronomical observations would have found it. A search for red objects with large parallax is now underway at Berkeley, and has a good chance of identifying the star in the near future.

  11. Sun Exposure and Psychotic Experiences

    Directory of Open Access Journals (Sweden)

    Izabela Pilecka

    2017-06-01

    Full Text Available ObjectiveSun exposure is considered the single most important source of vitamin D. Vitamin D deficiency has been suggested to play a role in the etiology of psychotic disorders. The aim of the present study was to evaluate the association between sun exposure and psychotic experiences (PEs in a general population sample of Swedish women.MethodsThe study population included participants from The Swedish Women’s Lifestyle and Health cohort study. The 20-item community assessment of psychic experiences (CAPEs was administered between ages 30 and 50 to establish PEs. Sun exposure as measured by (1 sunbathing holidays and (2 history of sunburn was measured between ages 10 and 39. The association between sun exposure and PEs was evaluated by quantile regression models.Results34,297 women were included in the analysis. Women who reported no sunbathing holidays and 2 or more weeks of sunbathing holidays scored higher on the CAPE scale than women exposed to 1 week of sunbathing holidays across the entire distribution, when adjusting for age and education. Similarly, compared with women who reported a history of one sunburn, the women with none or two or more sunburns showed higher scores on the CAPE scale.ConclusionThe results of the present study suggest that, in a population-based cohort of middle aged women, both low and high sun exposure is associated with increased level of positive PEs.

  12. Can the Full Moon and the Sun Be Observed on the Same Side of the Sky?

    Science.gov (United States)

    Susman, Katarina; Cepic, Mojca

    2010-01-01

    An ordinary flight became an interesting and amusing event when a look through the window of the plane revealed unusual light spots on the winglet. This article discusses the occurance we saw. Two possible explanations are presented. (Contains 8 figures.)

  13. VIS-NIR Lightweight Spectrometer for the Sun and the Moon, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — EPIR Inc. and Brimrose Technology Corporation propose a miniaturized spectrometer covering the 0.35 to 2.3um wavelength range by integrating a Hg1-xCdxTe (MCT) -...

  14. Flare stars in Pleiades. 6

    International Nuclear Information System (INIS)

    Mirzoyan, L.V.; Chavushyan, O.S.; Oganyan, G.B.; Ambaryan, V.V.; Garibdzhanyan, A.T.; Melikyan, N.D.; Natsvlishvili, R.Sh.; AN Gruzinskoj SSR, Abastumani. Abastumanskaya Astrofizicheskaya Observatoriya)

    1981-01-01

    The results of photographic observations of stellar flares in the Pleiades region carried out at the Byurakan and Abastumani astrophysical observatories during 1976-1979 are given. On the basis of these observations 17 new flare stars have been found. Total number of all known flare stars in the Pleiades region on 1 June 1980 reached 524, and the number of all flares-1244. The observational data on distribution of flare stars according to the observed flares is satisfactorily represented by the average frequency function introduced by V.A.Ambartsumian. The total number of the flare stars in the Pleiades is of the order of 1100. Using three telescopes, synchronous photographic observations of stellar flares in Pleiades in U, B, V, system are carried out. The colour indices U-B and B-V of stellar flares in periods including the maximum of the flare slightly differ from that of photoelectrically defined for flares of UV Ceti type stars, which testifies the physical relationship of flare stars in Pleiades and in the vicinity of the Sun [ru

  15. On the signatures of flare-induced global waves in the Sun: GOLF and VIRGO observations

    Science.gov (United States)

    Kumar, Brajesh; Mathur, Savita; García, Rafael A.; Jiménez, Antonio

    2017-11-01

    Recently, several efforts have been made to identify the seismic signatures of flares and magnetic activity in the Sun and Sun-like stars. In this work, we have analysed the disc-integrated velocity and intensity observations of the Sun obtained from the Global Oscillations at Low Frequencies (GOLF) and Variability of solar IRradiance and Gravity Oscillations/Sun photometers (VIRGO/SPM) instruments, respectively, on board the Solar and Heliospheric Observatory space mission covering several successive flare events, for the period from 2011 February 11 to 2011 February 17, of which 2011 February 11 remained a relatively quiet day and served as a `null test' for the investigation. Application of the spectral analysis to these disc-integrated Sun-as-a-star velocity and intensity signals indicates that there is enhanced power of the global modes of oscillations in the Sun during the flares, as compared to the quiet day. The GOLF instrument obtains velocity observations using the Na I D lines which are formed in the upper solar photosphere, while the intensity data used in our analysis are obtained by VIRGO/SPM instrument at 862 nm, which is formed within the solar photosphere. Despite the fact that the two instruments sample different layers of the solar atmosphere using two different parameters (velocity versus intensity), we have found that both these observations show the signatures of flare-induced global waves in the Sun. These results could suffice in identifying the asteroseismic signatures of stellar flares and magnetic activity in the Sun-like stars.

  16. SU(N) Irreducible Schwinger Bosons

    OpenAIRE

    Mathur, Manu; Raychowdhury, Indrakshi; Anishetty, Ramesh

    2010-01-01

    We construct SU(N) irreducible Schwinger bosons satisfying certain U(N-1) constraints which implement the symmetries of SU(N) Young tableaues. As a result all SU(N) irreducible representations are simple monomials of $(N-1)$ types of SU(N) irreducible Schwinger bosons. Further, we show that these representations are free of multiplicity problems. Thus all SU(N) representations are made as simple as SU(2).

  17. The validated sun exposure questionnaire

    DEFF Research Database (Denmark)

    Køster, B; Søndergaard, J; Nielsen, J B

    2017-01-01

    Few questionnaires used in monitoring sun-related behavior have been tested for validity. We established criteria validity of a developed questionnaire for monitoring population sun-related behavior. During May-August 2013, 664 Danes wore a personal electronic UV-dosimeter for one week...... that measured the outdoor time and dose of erythemal UVR exposure. In the following week, they answered a questionnaire on their sun-related behavior in the measurement week. Outdoor time measured by dosimetry correlated strongly with both outdoor time and the developed exposure scale measured...... in the questionnaire. Exposure measured in SED by dosimetry correlated strongly with the exposure scale. In a linear regression model of UVR (SED) received, 41 percent of the variation was explained by skin type, age, week of participation and the exposure scale, with the exposure scale as the main contributor...

  18. Nuclear astrophysics of the sun

    International Nuclear Information System (INIS)

    Kocharov, G.E.

    1980-01-01

    In the first chapter we will discuss the problem of nuclear reactions in the interior of the sun and consider the modern aspects of the neutrino astrophysics of the Sun. The second chapter is devoted to the high energy interactions in the solar atmosphere during the flares. Among a great number of events during the solar flares we shall consider mainly the nuclear reactions. Special attention will be paid to the genetic connection between the different components of solar electromagnetic and corpuscular radiation. The idea of the unity of processes in different parts of the Sun, from hot and dense interior up to the rare plasma of the solar corona will be the main line of the book. (orig./WL) 891 WL/orig.- 892 HIS

  19. Torsional oscillations of the sun

    International Nuclear Information System (INIS)

    Snodgrass, H.B.; Howard, R.; National Solar Observatory, Tucson, AZ)

    1985-01-01

    The sun's differential rotation has a cyclic pattern of change that is tightly correlated with the sunspot, or magnetic activity, cycle. This pattern can be described as a torsional oscillation, in which the solar rotation is periodically sped up or slowed down in certain zones of latitude while elsewhere the rotation remains essentially steady. The zones of anomalous rotation move on the sun in wavelike fashion, keeping pace with and flanking the zones of magnetic activity. It is uncertain whether this torsional oscillation is a globally coherent ringing of the sun or whether it is a local pattern caused by and causing local changes in the magnetic fields. In either case, it may be an important link in the connection between the rotation and the cycle that is widely believed to exist but is not yet understood. 46 references

  20. Towards A Moon Village: Vision and Opportunities

    Science.gov (United States)

    Foing, Bernard

    2016-04-01

    The new DG of ESA, Jan Wörner, has expressed from the very beginning of his duty a clear ambition towards a Moon Village, where Europe could have a lead role. The concept of Moon Village is basically to start with a robotic lunar village and then develop a permanent station on the Moon with different countries and partners that can participate and contribute with different elements, experiments, technologies, and overall support. ESA's DG has communicated about this programme and invited inputs from all the potential stakeholders, especially member states, engineers, industry, scientists, innovators and diverse representatives from the society. In order to fulfill this task, a series of Moon Village workshops have been organized first internally at ESA and then at international community events, and are also planned for the coming months, to gather stakeholders to present their ideas, their developments and their recommendations on how to put Moon Village into the minds of Europeans, international partners and prepare relevant actions for upcoming International Lunar Decade. Moon Village Workshop: The Moon Village Workshop in ESTEC on the 14th December was organized by ILEWG & ESTEC Staff Association in conjunction with the Moon 2020-2030 Symposium. It gathered people coming from all around the world, with many young professionals involved, as well as senior experts and representatives, with a very well gender balanced and multidisciplinary group. Engineers, business experts, managers, scientists, architects, artists, students presented their views and work done in the field of Lunar Exploration. Participants included colleagues from ESA, SGAC Space Generation Advisory Council, NASA, and industries such as OHB SE, TAS, Airbus DS, CGI, etc… and researchers or students from various Universities in Europe, America, and Asia. Working groups include: Moon Habitat Design, Science and Technology potentials on the Moon Village, and Engaging Stakeholders. The Moon

  1. Bulk yields of nucleosynthesis from massive stars

    International Nuclear Information System (INIS)

    Arnett, W.D.

    1978-01-01

    Preliminary estimates are made of the absolute yields of abundant nuclei synthesized in observed stars. The compositions of nine helium stars of mass 3 or =10M/sub sun/ is estimated. A variety of choices for the initial mass function (IMF) are used to calculate the yield per stellar generation. For standard choices of the (IMF) the absolute and relative yields of 12 C, 16 O, 20 Ne, 24 Mg, the Si to Ca group, and the iron group agree with solar system values, to the accuracy of the calculations. The relative yields are surprisingly insensitive to the slope of the IMF. In a second approach, using standard estimates (Ostriker, Richstone, and Thuan) for the current rate of stellar death, I find the present rate of nucleosynthesis in the solar neighborhood to be about 10%of the average rate over galactic history. This result is consistent with many standard models of galactic evolution (for example, the Schmidt model in which star formation goes as gas density squared). It appears that if the star formation rate is high enough to produce the stars we see around us, then the nucleosynthesis rate is large enough to produce the processed nuclei (except 4 He) seen in those stars. The typical nucleosynthesis source is massive (Mapprox. =30 M/sub sun/); the death rate of such stars is a small fraction (3-10%) of recent estimates of the total rate of supernovae

  2. Stars and Planets

    Science.gov (United States)

    Neta, Miguel

    2014-05-01

    'Estrelas e Planetas' (Stars and Planets) project was developed during the academic year 2009/2010 and was tested on three 3rd grade classes of one school in Quarteira, Portugal. The aim was to encourage the learning of science and the natural and physical phenomena through the construction and manipulation of materials that promote these themes - in this case astronomy. Throughout the project the students built a small book containing three themes of astronomy: differences between stars and planets, the solar system and the phases of the Moon. To each topic was devoted two sessions of about an hour each: the first to teach the theoretical aspects of the theme and the second session to assembly two pages of the book. All materials used (for theoretical sessions and for the construction of the book) and videos of the finished book are available for free use in www.miguelneta.pt/estrelaseplanetas. So far there is only a Portuguese version but soon will be published in English as well. This project won the Excellency Prize 2011 of Casa das Ciências, a portuguese site for teachers supported by the Calouste Gulbenkian Fundation (www.casadasciencias.org).

  3. SunBlock '99: Young Scientists Investigate the Sun

    Science.gov (United States)

    Walsh, R. W.; Pike, C. D.; Mason, H.; Young, P.; Ireland, J.; Galsgaard, K.

    1999-10-01

    SunBlock `99 is a Web-based Public Understanding of Science and educational project which seeks to present the very latest solar research as seen through the eyes of young British scientists. These ``solar guides'' discuss not only their scientific interests, but also their extra-curricular activities and the reasons they chose scientific careers; in other words the human face of scientific research. The SunBlock '99 pages gather a range of solar images and movies from current solar space observatories and discuss the underlying physics and its relationship to the school curriculum. The instructional level is pitched at UK secondary school children (aged 13-16 years). It is intended that the material should not only provide a visually appealing introduction to the study of the Sun, but that it should help bridge the often wide gap between classroom science lessons and the research scientist `out in the field'. SunBlock '99 is managed by a team from the Rutherford Appleton Laboratory and the Universities of St Andrews and Cambridge, together with educational consultants. The production has, in part, been sponsored by PPARC and the Millennium Mathematics Project. Web site addresss: http://www.sunblock99.org.uk

  4. Sun and Skin: The Dark Side of Sun Exposure

    Science.gov (United States)

    ... a toll on your skin and its underlying connective tissue. As a result, your skin may develop more wrinkles and lines. Too much sun exposure can also raise your risk for skin cancer, the most common type of cancer in the ...

  5. The sun and solar flares

    International Nuclear Information System (INIS)

    McKenna-Lawlor, S.

    1982-01-01

    The subject is discussed under the headings: the sun's core (thermonuclear reactions, energy transfer from core through radiation zone, convection zone, photosphere, chromosphere and corona); the photosphere (convection, granulation, sunspots, magnetic fields, solar cycle, rotation of the sun); solar variability and paleoclimatic records (correlation of low solar activity with increased 14 C production in atmosphere); the chromosphere and corona (turbulence, temperature, coronal streamers, energy transfer); solar flares (cosmic rays, aurorae, spectra, velocity of flares, prominences, mechanisms of flares); the solar wind. (U.K.)

  6. Star Polymers.

    Science.gov (United States)

    Ren, Jing M; McKenzie, Thomas G; Fu, Qiang; Wong, Edgar H H; Xu, Jiangtao; An, Zesheng; Shanmugam, Sivaprakash; Davis, Thomas P; Boyer, Cyrille; Qiao, Greg G

    2016-06-22

    Recent advances in controlled/living polymerization techniques and highly efficient coupling chemistries have enabled the facile synthesis of complex polymer architectures with controlled dimensions and functionality. As an example, star polymers consist of many linear polymers fused at a central point with a large number of chain end functionalities. Owing to this exclusive structure, star polymers exhibit some remarkable characteristics and properties unattainable by simple linear polymers. Hence, they constitute a unique class of technologically important nanomaterials that have been utilized or are currently under audition for many applications in life sciences and nanotechnologies. This article first provides a comprehensive summary of synthetic strategies towards star polymers, then reviews the latest developments in the synthesis and characterization methods of star macromolecules, and lastly outlines emerging applications and current commercial use of star-shaped polymers. The aim of this work is to promote star polymer research, generate new avenues of scientific investigation, and provide contemporary perspectives on chemical innovation that may expedite the commercialization of new star nanomaterials. We envision in the not-too-distant future star polymers will play an increasingly important role in materials science and nanotechnology in both academic and industrial settings.

  7. Wave Star

    DEFF Research Database (Denmark)

    Kramer, Morten; Brorsen, Michael; Frigaard, Peter

    Nærværende rapport beskriver numeriske beregninger af den hydrodynamiske interaktion mellem 5 flydere i bølgeenergianlægget Wave Star.......Nærværende rapport beskriver numeriske beregninger af den hydrodynamiske interaktion mellem 5 flydere i bølgeenergianlægget Wave Star....

  8. 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....

  9. Radio stars

    International Nuclear Information System (INIS)

    Hjellming, R.M.; Gibson, D.M.

    1985-01-01

    Studies of stellar radio emission became an important field of research in the 1970's and have now expanded to become a major area of radio astronomy with the advent of new instruments such as the Very Large Array in New Mexico and transcontinental telescope arrays. This volume contains papers from the workshop on stellar continuum radio astronomy held in Boulder, Colorado, and is the first book on the rapidly expanding field of radio emission from stars and stellar systems. Subjects covered include the observational and theoretical aspects of stellar winds from both hot and cool stars, radio flares from active double star systems and red dwarf stars, bipolar flows from star-forming regions, and the radio emission from X-ray binaries. (orig.)

  10. Development and validation of a learning progression for change of seasons, solar and lunar eclipses, and moon phases

    Science.gov (United States)

    Testa, Italo; Galano, Silvia; Leccia, Silvio; Puddu, Emanuella

    2015-12-01

    In this paper, we report about the development and validation of a learning progression about the Celestial Motion big idea. Existing curricula, research studies on alternative conceptions about these phenomena, and students' answers to an open questionnaire were the starting point to develop initial learning progressions about change of seasons, solar and lunar eclipses, and Moon phases; then, a two-tier multiple choice questionnaire was designed to validate and improve them. The questionnaire was submitted to about 300 secondary students of different school levels (14 to 18 years old). Item response analysis and curve integral method were used to revise the hypothesized learning progressions. Findings support that spatial reasoning is a key cognitive factor for building an explanatory framework for the Celestial Motion big idea, but also suggest that causal reasoning based on physics mechanisms underlying the phenomena, as light flux laws or energy transfers, may significantly impact a students' understanding. As an implication of the study, we propose that the teaching of the three discussed astronomy phenomena should follow a single teaching-learning path along the following sequence: (i) emphasize from the beginning the geometrical aspects of the Sun-Moon-Earth system motion; (ii) clarify consequences of the motion of the Sun-Moon-Earth system, as the changing solar radiation flow on the surface of Earth during the revolution around the Sun; (iii) help students moving between different reference systems (Earth and space observer's perspective) to understand how Earth's rotation and revolution can change the appearance of the Sun and Moon. Instructional and methodological implications are also briefly discussed.

  11. Water on the Moon Confirmed

    Science.gov (United States)

    Showstack, Randy

    2009-11-01

    When NASA's Lunar Crater Observation and Sensing Satellite (LCROSS) and a companion rocket purposely slammed into a crater at the Moon's south pole on 9 October, some observers on Earth lamented as anticlimactic the raised plumes of material that were partially blocked by a crater ridge and were difficult to see with backyard telescopes. However, it turns out that the projectiles struck it big. “Indeed, yes, we found water. We didn’t find just a little bit; we found a significant amount,” said Anthony Colaprete, LCROSS principal investigator with the NASA Ames Research Center, Moffett Field, Calif. At a 13 November news briefing, Colaprete lifted a 2-gallon plastic bucket and said preliminary results indicate that instruments detected about a dozen buckets' worth of water in parts of the two plumes, the first generated by the spent Centaur upper stage of the Atlas V launch vehicle at 1131 UTC and the second generated by LCROSS about 4 minutes later. NASA described the two plumes as a high-angle plume of vapor and fine dust and a lower-angle ejecta curtain of heavier material. LCROSS and the Centaur upper stage hit the permanently shadowed Cabeus crater.

  12. STARDUST FROM ASYMPTOTIC GIANT BRANCH STARS

    International Nuclear Information System (INIS)

    Gail, H.-P.; Zhukovska, S. V.; Hoppe, P.; Trieloff, M.

    2009-01-01

    1.5-4 M sun , in good agreement with what was inferred from the isotope data of presolar grains. The mass distribution of AGB stars that produce O-rich dust is essentially bimodal, with roughly equal contributions from stars in the ranges 1.3-2.5 M sun and ∼4-8 M sun . These model predictions are in conflict with the O-isotope data of presolar grains that indicate contributions essentially only from 1 to 2.5 M sun AGB stars.

  13. Ancient cults of the sun (German Title: Antike Sonnenkulte)

    Science.gov (United States)

    Hansen, Rahlf

    In ancient astronomy, the heliocentric system of Aristarchus of Samos did not meet universal approval. Contrary to that, the cult of the sun gained immense importance in the Roman Empire. Relics of this significance we still find e.g. in the meaning of the Sunday in the week and in the date of Christmas. The rise of the sun cults is characterised by the merging of different gods from various cultures. Already in classical Greece the god of the sun, Helios, almagated with the god of light, Apollo. The resulting entity was regarded as the harmonic guide of the visible universe, symbolized by Apoll. As well as he plays the lyre, he conducts the cosmos harmonically as the sun. Plato recommends to politicians to study musical harmonics and astronomy in order to get a feeling of the right way to rule the state. In consequence to the conquests of Alexander the Great, the Babylonian star religion was mingled with Greek cosmology and the concept of transmigration of souls. The astrology resulting therefrom spread out over the whole Hellenistic world and was very common in the Roman Empire. The calendar with its religious division of time as the days of the week, following the principle of the gods of the planets governing the hour, was well known. The god of the sun was graded up by the adoption of the calendar of the sun from Egypt by Caesar. Augustus chose Apoll as his guardian god and built with “his” sundial a symbol of the god of the sun, which was visible from a long distance. Augustus used more astral symbols as propaganda of leadership. During the competition with the Parthians, another large empire, for world domination the focus fell on an Iranian god: the Iranian god of light and contract - Mithras. Shortly before 100 A.D., a new cult of mysteries arose in the Roman Empire, called cult of Mithras, and spread quickly. It combined the attributes of a classical sun-god with a religion of salvation, guaranteed by baptism, communion and seven degrees to be passed

  14. Moon Prospective Energy and Material Resources

    CERN Document Server

    2012-01-01

    The Earth has limited material and energy resources. Further development of the humanity will require going beyond our planet for mining and use of extraterrestrial mineral resources and search of power sources. The exploitation of the natural resources of the Moon is a first natural step on this direction. Lunar materials may contribute to the betterment of conditions of people on Earth but they also may be used to establish permanent settlements on the Moon. This will allow developing new technologies, systems and flight operation techniques to continue space exploration.   In fact, a new branch of human civilization could be established permanently on Moon in the next century. But, meantime, an inventory and proper social assessment of Moon’s prospective energy and material resources is required. This book investigates the possibilities and limitations of various systems supplying manned bases on Moon with energy and other vital resources. The book collects together recent proposals and innovative optio...

  15. Yes, there was a moon race

    Science.gov (United States)

    Oberg, James E.

    1990-01-01

    Examination of newly disclosed evidence confirms that the Soviets were indeed striving to reach the moon before the U.S. in 1969. It is noted that a Soviet unmanned lunar probe crashed on the moon's surface only hours before the U.S. Apollo landing. Now confirmed openly are moon-exploration schedules that were competitive with Apollo plans, the names and histories of Soviet lunar boosters and landers, identities of the lunar cosmonauts; and even photos of manned lunar craft are available. Additional details on the troubled moon-probe program are presented: technical problems, continuous changes in goals, schedules, and planning, vehicle and personnel disasters, transfer of authority between ministries, and political power struggles in the scientific community.

  16. Effective Methods of Teaching Moon Phases

    Science.gov (United States)

    Jones, Heather; Hintz, E. G.; Lawler, M. J.; Jones, M.; Mangrubang, F. R.; Neeley, J. E.

    2010-01-01

    This research investigates the effectiveness of several commonly used methods for teaching the causes of moon phases to sixth grade students. Common teaching methods being investigated are the use of diagrams, animations, modeling/kinesthetics and direct observations of moon phases using a planetarium. Data for each method will be measured by a pre and post assessment of students understanding of moon phases taught using one of the methods. The data will then be used to evaluate the effectiveness of each teaching method individually and comparatively, as well as the method's ability to discourage common misconceptions about moon phases. Results from this research will provide foundational data for the development of educational planetarium shows for the deaf or other linguistically disadvantage children.

  17. Day the sun went out

    CERN Multimedia

    2007-01-01

    "A new british sci-fi movie envisages the death of the sun not in billions of years, but in decades. And, amazingly, the film's scientific adviser says this may not be so far from the truth..." (1/2 page)

  18. Teaching "Empire of the Sun."

    Science.gov (United States)

    Riet, Fred H. van

    1990-01-01

    A Dutch teacher presents reading, film viewing, and writing activities for "Empire of the Sun," J. G. Ballard's autobiographical account of life as a boy in Shanghai and in a Japanese internment camp during World War II (the subject of Steven Spielberg's film of the same name). Includes objectives, procedures, and several literature,…

  19. The Award Winning Black Suns

    Science.gov (United States)

    Holbrook, Jarita

    2018-01-01

    Black Suns: An Astrophysics Adventure is a documentary film focusing on the annular and total solar eclipses of 2012. We made a different kind of astronomy documentary showing the human aspects rather than just focusing on pretty astronomy pictures. The film combines personal stories with science. Our heroes are Hakeem Oluseyi and Alphonse Sterling, who valiantly travel to study the solar corona during total solar eclipses. The goals of the film included presenting three dimensional scientists, to show their paths to becoming astrophysicists, and to show them as they collect data and work as scientists. Drama and tension surround taking data during the small window of time during totality. The Black Suns was filmed in Tokyo, Cairns, Tucson, and Melbourne Florida. Uniquely, the film began through a Kickstarter campaign to fund travel and filming in Tokyo. Many American Astronomical Society members donated to the film! Black Suns won the Jury Prize at the 2017 Art of Brooklyn Film Festival. Black Suns will be screening in full on ???.

  20. The Moon: Resources, Future Development and Colonization

    Science.gov (United States)

    Schrunk, David; Sharpe, Burton; Cooper, Bonnie; Thangavelu, Madhu

    1999-07-01

    This unique, visionary and innovative book describes how the Moon could be colonised and developed as a platform for science, industrialization and exploration of our Solar System and beyond. Thirty years ago, the world waited with baited breath to watch history in the making, as man finally stepped onto the moon's surface. In the last few years, there has been growing interest in the idea of a return to the moon. This book describes the reasons why we should now start lunar development and settlement, and how this goal may be accomplished. The authors, all of whom are hugely experienced space scientists, consider the rationale and steps necessary for establishing permanent bases on the Moon. Their innovative and scientific-based analysis concludes that the Moon has sufficient resources for large-scale human development. Their case for development includes arguments for a solar-powered electric grid and railroad, creation of a utilities infrastructure, habitable facilities, scientific operations and the involvement of private enterprise with the public sector in the macroproject. By transferring and adapting existing technologies to the lunar environment, the authors argue that it will be possible to use lunar resources and solar power to build a global lunar infrastructure embracing power, communication, transportation, and manufacturing. This will support the migration of increasing numbers of people from Earth, and realization of the Moon's scientific potential. As an inhabited world, the Moon is an ideal site for scientific laboratories dedicated to geosciences, astronomy and life sciences, and most importantly, it would fulfil a role as a proving ground and launch pad for future Solar System exploration. The ten chapters in this book go beyond the theoretical and conceptual. With vision and foresight, the authors offer practical means for establishing permanent bases on the Moon. The book will make fascinating and stimulating reading for students in

  1. Moon Effect on Paciic Basin Stock Markets

    Directory of Open Access Journals (Sweden)

    Rayenda Khresna Brahman

    2014-08-01

    Full Text Available This is an empirical study on the inluences of moon on seven stock markets, which are Indonesia, Malaysia, United Kingdom, United States, Philippines, Japan, and Thailand. The period is from January 1999 until December 2009 in daily basis. This study investigates the relationship  between  moon  phase  and  market  returns.  We  divided  moon  phases  into  new moon  and  full  moon.  While  literature  mention  the  relationship  between  moon  phase  and market returns, our research reject the null hypothesis in regression analysis. However, the descriptive  catches  the  indication  and  conirmed  previous  research.  It  also  proposes  that the market is still rational and not moon-mood inluenced. This result is not contending the EMH theorem. Further research is needed in term of investigating the relationship between psychology  factors  (heuristic  bias,  information  ignorance,  and  other  factors  and  investor behavior. The effect of moon on certain anomalies has to examine speciically. ";} // -->activate javascript

  2. The Enigmatic Face of the Moon

    Science.gov (United States)

    Galles, C. D.; Gallagher, C. J.

    2011-06-01

    Whilst Man's only way of observing the Moon was with the naked eye, attempts at explaining the spots on her surface remained highly speculative. The telescopic observation by Galileo of previously unknown spots, differing from the earlier ones by their variability in time, was to signify a radical change to the hereto medieval ideas on the material composition of the Moon. And curiously enough, this new scenario was a revindication of Plutarch's hypothesis construed more than a millennium before.

  3. Nuclear technologies for Moon and Mars exploration

    International Nuclear Information System (INIS)

    Buden, D.

    1991-01-01

    Nuclear technologies are essential to successful Moon and Mars exploration and settlements. Applications can take the form of nuclear propulsion for transport of crews and cargo to Mars and the Moon; surface power for habitats and base power; power for human spacecraft to Mars; shielding and life science understanding for protection against natural solar and cosmic radiations; radioisotopes for sterilization, medicine, testing, and power; and resources for the benefits of Earth. 5 refs., 9 figs., 3 tabs

  4. Moon over Mauna Loa - a review of hypotheses of formation of earth's moon

    International Nuclear Information System (INIS)

    Wood, J.A.

    1986-01-01

    The present paper examines five models of lunar formation after considering the following constraints: (1) the large mass of the moon and the substantial prograde angular momentum of the earth-moon system; (2) the moon's depletion in volatile elements and iron, (3) the correspondence of oxygen isotope signatures in earth and moon, and (4) the lunar magma ocean. The models considered are: (1) capture from an independent heliocentric orbit, (2) coaccretion from a swarm of planetesimals in geocentric orbit, (3) fission from a rapidly rotating earth, (4) collisional ejection, and (5) disintegrative capture. 99 references

  5. Dwarf Star Erupts in Giant Flare

    Science.gov (United States)

    2005-01-01

    This movie taken by NASA'S Galaxy Evolution Explorer shows one of the largest flares, or star eruptions, ever recorded at ultraviolet wavelengths. The star, called GJ 3685A, just happened to be in the Galaxy Evolution Explorer's field of view while the telescope was busy observing galaxies. As the movie demonstrates, the seemingly serene star suddenly exploded once, then even more intensely a second time, pouring out in total about one million times more energy than a typical flare from our Sun. The second blast of light constituted an increase in brightness by a factor of at least 10,000. Flares are huge explosions of energy stemming from a single location on a star's surface. They are caused by the brief destruction of a star's magnetic fields. Many types of stars experience them, though old, small, rapidly rotating 'red dwarfs' like GJ 3685A tend to flare more frequently and dramatically. These stars, called flare stars, can experience powerful eruptions as often as every few hours. Younger stars, in general, also erupt more often. One of the reasons astronomers study flare stars is to gain a better picture and history of flare events taking place on the Sun. A preliminary analysis of the GJ 3685A flare shows that the mechanisms underlying stellar eruptions may be more complex than previously believed. Evidence for the two most popular flare theories was found. Though this movie has been sped up (the actual flare lasted about 20 minutes), time-resolved data exist for each one-hundredth of a second. These observations were taken at 2 p.m. Pacific time, April 24, 2004. In the still image, the time sequence starts in the upper left panel, continues in the upper right, then moves to the lower left and ends in the lower right. The circular and linear features that appear below and to the right of GJ 3685A during the flare event are detector artifacts caused by the extreme brightness of the flare.

  6. Moon. Prospective energy and material resources

    Energy Technology Data Exchange (ETDEWEB)

    Badescu, Viorel (ed.) [Polytechnic Univ. of Bucharest (Romania). Candida Oancea Inst.

    2012-07-01

    The Earth has limited material and energy resources. Further development of the humanity will require going beyond our planet for mining and use of extraterrestrial mineral resources and search of power sources. The exploitation of the natural resources of the Moon is a first natural step on this direction. Lunar materials may contribute to the betterment of conditions of people on Earth but they also may be used to establish permanent settlements on the Moon. This will allow developing new technologies, systems and flight operation techniques to continue space exploration. In fact, a new branch of human civilization could be established permanently on Moon in the next century. But, meantime, an inventory and proper social assessment of Moon's prospective energy and material resources is required. This book investigates the possibilities and limitations of various systems supplying manned bases on Moon with energy and other vital resources. The book collects together recent proposals and innovative options and solutions. It is a useful source of condensed information for specialists involved in current and impending Moon-related activities and a good starting point for young researchers. (orig.)

  7. Symbiotic stars

    International Nuclear Information System (INIS)

    Kafatos, M.; Michalitsianos, A.G.

    1984-01-01

    Among the several hundred million binary systems estimated to lie within 3000 light years of the solar system, a tiny fraction, no more than a few hundred, belong to a curious subclass whose radiation has a wavelength distribution so peculiar that it long defied explanation. Such systems radiate strongly in the visible region of the spectrum, but some of them do so even more strongly at both shorter and longer wavelengths: in the ultraviolet region and in the infrared and radio regions. This odd distribution of radiation is best explained by the pairing of a cool red giant star and an intensely hot small star that is virtually in contact with its larger companion. Such objects have become known as symbiotic stars. On photographic plate only the giant star can be discerned, but evidence for the existence of the hot companion has been supplied by satellite-born instruments capable of detecting ultraviolet radiation. The spectra of symbiotic stars indicate that the cool red giant is surrounded by a very hot ionized gas. Symbiotic stars also flared up in outbursts indicating the ejection of material in the form of a shell or a ring. Symbiotic stars may therefore represent a transitory phase in the evolution of certain types of binary systems in which there is substantial transfer of matter from the larger partner to the smaller

  8. Catching a Falling Star

    Science.gov (United States)

    2004-07-01

    -8, or nearly as bright as the first-quarter Moon. Although it is not possible to be sure from which shower this meteor belongs, a possible candidate is the Southern May Ophiuchid shower which appears from a direction just east of the bright star Antares. The shower contributes only one or two meteors per hour but was one of the stronger showers of that night. Telltale emissions ESO PR Photo 22b/04 ESO PR Photo 22b/04 Spectrum of a Meteor (FORS1/VLT) [Preview - JPEG: 426 x 400 pix - 91k] [Normal - JPEG: 851 x 800 pix - 232k] [Full Res - JPEG: 2567 x 2413 pix - 2.1M] ESO PR Photo 22c/04 ESO PR Photo 22c/04 Details of the Meteor Spectrum (FORS1/VLT) [Preview - JPEG: 1006 x 400 pix - 122k] [Normal - JPEG: 2011 x 800 pix - 236k] [Full Res - JPEG: 3414 x 1358 pix - 957k] Captions: ESO PR Photo 22b/04 shows the spectrum of a bright meteor, as observed serendipitously by the multi-mode FORS 1 instrument on the ESO Very Large Telescope during the night of May 12-13, 2002, in front of a photo of the VLT enclosures and with a meteor trail inserted in the sky (montage). The position of the meteor trail on the narrow slit of FORS (not to scale) is also indicated. The lower panel shows the spectrum of the meteor, following removal of the supernova spectrum and before (up) and after (down) removal of the spectrum of the night sky by image processing. Several emission lines from colliding Oxygen and Nitrogen atoms (sharp emissions) and molecules (broad emissions) are visible. ESO PR Photo 22c/04 illustrates details of the extracted VLT meteor spectrum (solid line): the intensity (in arbitrary units) is shown as a function of the wavelength. The dashed line is a theoretical model of the spectrum of air heated to a temperature of 4600 degrees at an altitude of 95 km. "At first, the bright trace across the supernova spectrum was a puzzle, but then I realized that the spectroscopic signature was that of our atmosphere being bombarded," says astronomer Remi Cabanac of the Catholic

  9. Life and death of the stars

    CERN Document Server

    Srinivasan, Ganesan

    2014-01-01

    This volume is devoted to one of the fascinating things about stars: how they evolve as they age. This evolution is different for stars of different masses. How stars end their lives when their supply of energy is exhausted also depends on their masses. Interestingly, astronomers conjectured about the ultimate fate of the stars even before the details of their evolution became clear. Part I of this book gives an account of the remarkable predictions made during the 1920s and 1930s concerning the ultimate fate of stars. Since much of this development hinged on quantum physics that emerged during this time, a detailed introduction to the relevant physics is included in the book. Part II is a summary of the life history of stars. This discussion is divided into three parts: low-mass stars, like our Sun, intermediate-mass stars, and massive stars. Many of the concepts of contemporary astrophysics were built on the foundation erected by Subrahmanyan Chandrasekhar in the 1930s. This book, written during his birth c...

  10. Observing the Sun with Coronado telescopes telescopes

    CERN Document Server

    Pugh, Philip

    2007-01-01

    The Sun provides amateur astronomers with one of the few opportunities for daytime astronomy. In order to see the major features of our nearest star, special telescopes that have a very narrow visible bandwidth are essential. The bandwidth has to be as narrow as 1 A- 10-10 m (1 Angstrom) and centred on the absorption line of neutral hydrogen. This makes many major features of the Suna (TM)s chromosphere visible to the observer. Such narrow-band "Fabry-Perot etalon filters" are high technology, and until the introduction of the Coronado range of solar telescopes, were too expensive for amateur use. The entry-level Coronado telescope, the PST (Personal Solar Telescope) costs under 500. Solar prominences (vast columns of plasma, best seen at the edge of the solar disk), filaments, flares, sunspots, plage and active regions are all visible and can be imaged to produce spectacular solar photographs. Philip Pugh has assembled a team of contributors who show just how much solar work can be done with Coronado telesco...

  11. A Novel Theory For The Origin And Evolution Of Stars And Planets, Including Earth, Which Asks, 'Was The Earth Once A Small Bright Star?'

    Science.gov (United States)

    Cimorelli, S. A.; Samuels, C.

    2001-12-01

    Improved prediction methods for earthquakes and volcanic activity will naturally follow from our theory, based on new concepts of the earth's interior composition, state and activity. In this paper we present a novel hypothesis for the formation and evolution of galaxies, stars (including black holes (BHs), neutron stars, giant, mid-size, dwarf, dying and dead stars), planets (including earth), and moons. Present day phenomenon will be used to substantiate the validity of this hypothesis. Every `body' is a multiple type of star, generated from modified pieces called particle proliferators, of a dislodged/expanded BH (of category 2 (c-2)) which explodes due to a collision with another expanded BH (or explodes on its own). This includes the sun, and the planet earth, which is a type of dead star. Such that, if we remove layers of the earth, starting with the crust, we will find evidence of each preceding star formation, from brown to blue, and the remains of the particle proliferator as the innermost core is reached. We show that the hypothesis is consistent with both the available astronomical data regarding stellar evolution and planetary formation; as well as the evolution of the earth itself, by considerations of the available geophysical data. Where data is not available, reasonably simple experiments are suggested to demonstrate further the consistency and viability of the hypothesis. Theories are presented to help define and explain phenomenon such as how two (or more) c-2 BHs expand and collide to form a small `big bang' (It is postulated that there was a small big bang to form each galaxy, similar to the big bang from a category 1 BH(s) that may have formed our universe. The Great Attractors would be massive c-2 BHs and act on galaxy clusters similar to the massive c-3 BHs at the center of Galaxies acting on stars.). This in turn afforded the material/matter to form all the galactic bodies, including the dark matter inside the galaxies that we catalogue as

  12. Theory for the Origin and Evolution of Stars and Planets, Including Earth

    Science.gov (United States)

    Cimorelli, S. A.; Samuels, C.

    2001-05-01

    In this paper we present a novel hypothesis for the formation and evolution of galaxies, stars (including black holes (BHs), giant, mid-size, dwarf, dying and dead stars), planets (including earth), and moons. Present day phenomenon will be used to substantiate the validity of this hypothesis. Every `body' is a multiple type of star, generated from pieces called particle proliferators, of a dislodged/expanded BH which explodes due to a collision with another expanded BH. This includes the sun, and the planet earth, which is a type of dead star. Such that, if we remove layers of the earth, starting with the crust, we will find evidence of each preceding star formation, such as a brown star, a red star, a white star, a blue star, and the remains of the particle proliferator as the innermost core is reached. We intend to show that the hypothesis is consistent with both the available astronomical data regarding stellar evolution and planetary formation; as well as the evolution of the earth itself, by considerations of the available geophysical data. Where data is not available, reasonably simple experiments will be suggested to demonstrate further the consistency and viability of the hypothesis. Theories are presented to help define and explain phenomenon such as how two (or more) BHs expand and collide to form a small `big bang' (it is postulated that there was a small big bang to form each galaxy). This in turn afforded the material/matter to form all the galactic bodies, including the dark matter. The start and development of the planet earth, initially as an emergent piece from the colliding BHs, is given special attention to explain the continuing expansion/growth that takes place in all stars and planets. Also, to explain the formation of the land, the growing/expanding earth (proportional to the ocean bed growth), the division of the continents, and the formation of the ocean beds (possibly long before the oceans existed). Attempts will be made to explain the

  13. Star formation

    International Nuclear Information System (INIS)

    Woodward, P.R.

    1978-01-01

    Theoretical models of star formation are discussed beginning with the earliest stages and ending in the formation of rotating, self-gravitating disks or rings. First a model of the implosion of very diffuse gas clouds is presented which relies upon a shock at the edge of a galactic spiral arm to drive the implosion. Second, models are presented for the formation of a second generation of massive stars in such a cloud once a first generation has formed. These models rely on the ionizing radiation from massive stars or on the supernova shocks produced when these stars explode. Finally, calculations of the gravitational collapse of rotating clouds are discussed with special focus on the question of whether rotating disks or rings are the result of such a collapse. 65 references

  14. Sun Exposure, Sun-Related Symptoms, and Sun Protection Practices in an African Informal Traditional Medicines Market.

    Science.gov (United States)

    Wright, Caradee Y; Reddy, Tarylee; Mathee, Angela; Street, Renée A

    2017-09-28

    Informal workers in African market trade have little formal protection against sun exposure. We aimed to examine sun exposure, sun-related symptoms, and sun protection practices in an informal occupational setting. Trained fieldworkers asked 236 workers in the Warwick Junction market about their workplace, skin and eye sensitivity and skin colour, symptoms faced at work during the summer due to heat, and preventive measures. Data were analyzed using univariate logistic regression to assess the effect of gender and the risk of experiencing symptoms to sun exposure in relation to pre-existing diseases and perception of sun exposure as a hazard. Of the 236 participants, 234 were Black African and 141 (59.7%) were female. Portable shade was the most commonly used form of sun protection (69.9%). Glare from the sun (59.7%) and excessive sweating (57.6%) were commonly reported sun-related health symptoms. The use of protective clothing was more prevalent among those who perceived sun exposure as a hazard ( p = 0.003). In an informal occupational setting, sun exposure was high. Protective clothing and portable shade to eliminate heat and bright light were self-implemented. Action by local authorities to protect informal workers should consider sun exposure to support workers in their efforts to cope in hot weather.

  15. Sun Exposure, Sun-Related Symptoms, and Sun Protection Practices in an African Informal Traditional Medicines Market

    Directory of Open Access Journals (Sweden)

    Caradee Y. Wright

    2017-09-01

    Full Text Available Informal workers in African market trade have little formal protection against sun exposure. We aimed to examine sun exposure, sun-related symptoms, and sun protection practices in an informal occupational setting. Trained fieldworkers asked 236 workers in the Warwick Junction market about their workplace, skin and eye sensitivity and skin colour, symptoms faced at work during the summer due to heat, and preventive measures. Data were analyzed using univariate logistic regression to assess the effect of gender and the risk of experiencing symptoms to sun exposure in relation to pre-existing diseases and perception of sun exposure as a hazard. Of the 236 participants, 234 were Black African and 141 (59.7% were female. Portable shade was the most commonly used form of sun protection (69.9%. Glare from the sun (59.7% and excessive sweating (57.6% were commonly reported sun-related health symptoms. The use of protective clothing was more prevalent among those who perceived sun exposure as a hazard (p = 0.003. In an informal occupational setting, sun exposure was high. Protective clothing and portable shade to eliminate heat and bright light were self-implemented. Action by local authorities to protect informal workers should consider sun exposure to support workers in their efforts to cope in hot weather.

  16. Wave Star

    DEFF Research Database (Denmark)

    Kramer, Morten; Frigaard, Peter

    Nærværende rapport beskriver modelforsøg udført på Aalborg Universitet, Institut for Byggeri og Anlæg med bølgeenergianlæget Wave Star.......Nærværende rapport beskriver modelforsøg udført på Aalborg Universitet, Institut for Byggeri og Anlæg med bølgeenergianlæget Wave Star....

  17. Wave Star

    DEFF Research Database (Denmark)

    Kramer, Morten; Andersen, Thomas Lykke

    Nærværende rapport beskriver modelforsøg udført på Aalborg Universitet, Institut for Vand, Jord og Miljøteknik med bølgeenergianlægget Wave Star.......Nærværende rapport beskriver modelforsøg udført på Aalborg Universitet, Institut for Vand, Jord og Miljøteknik med bølgeenergianlægget Wave Star....

  18. STARS no star on Kauai

    International Nuclear Information System (INIS)

    Jones, M.

    1993-01-01

    The island of Kuai, home to the Pacific Missile Range Facility, is preparing for the first of a series of Star Wars rocket launches expected to begin early this year. The Strategic Defense Initiative plans 40 launches of the Stategic Target System (STARS) over a 10-year period. The focus of the tests appears to be weapons and sensors designed to combat multiple-warhead ICBMs, which will be banned under the START II Treaty that was signed in January. The focus of this article is to express the dubious value of testing the STARS at a time when their application will not be an anticipated problem

  19. Flare stars

    International Nuclear Information System (INIS)

    Nicastro, A.J.

    1981-01-01

    The least massive, but possibly most numerous, stars in a galaxy are the dwarf M stars. It has been observed that some of these dwarfs are characterized by a short increase in brightness. These stars are called flare stars. These flare stars release a lot of energy in a short amount of time. The process producing the eruption must be energetic. The increase in light intensity can be explained by a small area rising to a much higher temperature. Solar flares are looked at to help understand the phenomenon of stellar flares. Dwarfs that flare are observed to have strong magnetic fields. Those dwarf without the strong magnetic field do not seem to flare. It is believed that these regions of strong magnetic fields are associated with star spots. Theories on the energy that power the flares are given. Astrophysicists theorize that the driving force of a stellar flare is the detachment and collapse of a loop of magnetic flux. The mass loss due to stellar flares is discussed. It is believed that stellar flares are a significant contributor to the mass of interstellar medium in the Milky Way

  20. Sun, UV Radiation and Your Eyes

    Science.gov (United States)

    ... Sunglasses Sun Smart UV Safety Infographic The Sun, UV Radiation and Your Eyes Leer en Español: El ... Aug. 28, 2014 Keep an Eye on Ultraviolet (UV) Safety Eye medical doctors (ophthalmologists) caution us that ...

  1. Our prodigal sun. [solar energy technology

    Science.gov (United States)

    1974-01-01

    Characteristics of the sun are reported indicating it as a source of energy. Data from several space missions are discussed, and the solar activity cycle is presented. The corona, flares, prominences, spots, and wind of the sun are also discussed.

  2. Tanel Padar & The Sun veab õhukitarri

    Index Scriptorium Estoniae

    2008-01-01

    Õhukitarri Eesti meistrivõistlustest 19. apr. Tallinnas Rock Cafés (võistluste eestvedajaks on ansambel Tanel Padar & The Sun, kes samas esitleb oma esimest ingliskeelset albumit "Here Comes The Sun")

  3. Essential Outdoor Sun Safety Tips for Winter

    Science.gov (United States)

    ... Weekend Warriors expand/collapse Vitamin D Essential Outdoor Sun Safety Tips for Winter Winter sports enthusiasts are ... skiing! Be Mindful of Time Spent in the Sun, Regardless of the Season If possible, ski early ...

  4. Micro technology based sun sensor

    DEFF Research Database (Denmark)

    Hales, Jan Harry; Pedersen, Martin; Fléron, René

    2003-01-01

    various payloads and platforms. The conventional and commercial actuators and attitude sensors are in most cases not suited for these satellites, which again lead to new design considerations. Another important property is the launch cost, which can be kept relatively low as a result of the concept....... This fact enables students to get hands-on experience with satellite systems design and project management. This paper describes the attitude control and determination system of a Danish student satellite (DTUsat), with main focus on the two-axis MOEMS sun sensor developed. On the magnetotorquer controlled...... DTUsat sun sensors are needed along with a magnetometer to obtain unambiguous attitude determination for the ACDS and the payloads - an electrodynamic tether and a camera. The accuracy needed was not obtainable by employing conventional attitude sensors. Hence a linear slit sensor was designed...

  5. Global Warming Blame the Sun

    CERN Document Server

    Calder, N

    1997-01-01

    Concern about climate change reaches a political peak at a UN conference in Kyoto, 1-10 December, but behind the scenes the science is in turmoil. A challenge to the hypothesis that greenhouse gases are responsible for global warming comes from the discovery that cosmic rays from the Galaxy are involved in making clouds (Svensmark and Friis-Christensen, 1997). During the 20th Century the wind from the Sun has grown stronger and the count of cosmic rays has diminished. With fewer clouds, the EarthÕs surface has warmed up. This surprising mechanism explains the link between the Sun and climate change that astronomers and geophysicists have suspected for 200 years.

  6. Caddo Sun Accounts across Time and Place

    Science.gov (United States)

    Gerona, Carla

    2012-01-01

    Billy Day, a Tunica/Biloxi, recently described the significance of the sun for Caddoan people. Day quoted an "old Caddo relative" of his who said: "I used to go outside and hold my hands up and bless myself with the sun--'a'hat.' Well, I can't do that anymore because they say we are sun worshipers. We didn't worship the sun. We worshiped what was…

  7. Can the Sun replace uranium

    International Nuclear Information System (INIS)

    Weinberg, A.M.

    1977-07-01

    Two asymptotic worlds, one based on solar energy, the other based on nuclear energy, are compared. The total energy demand in each case is 2,000 quads. Although the Sun can in principal supply this energy, it probably will be very expensive. If the energy were supplied entirely by breeders, the nuclear energy system would pose formidable systems problems--particularly safety and proliferation. It is suggested that in view of these possible difficulties, all options must be kept open

  8. Evolution of a blue supergiant with a neutron star companion immersed in its envelope

    International Nuclear Information System (INIS)

    Delgado, A.J.

    1980-01-01

    The evolution of a binary system consisting of 1 Msub(sun) neutron star and a 25 Msub(sun) blue supergiant through a phase of common envelope is investigated. We include the effects of an additional energy source on the supergiant's envelope, due to the presence of the neutron star, and variable mass loss from the system, taken as proportional to the total luminosity. The results indicate that, independently of the initial period, the system loses its whole envelope as a consequence of the common envelope phase, the final product of this being a detached system, consisting of a neutron star and a helium star. (orig.)

  9. Did Triton Destroy Neptune's First Moons?

    Science.gov (United States)

    Kohler, Susanna

    2017-11-01

    Neptunes moon system is not what we would expect for a gas giant in our solar system. Scientists have now explored the possibility that Neptune started its life with an ordinary system of moons that was later destroyed by the capture of its current giant moon, Triton.An Odd SystemOur current understanding of giant-planet formation predicts a period of gas accretion to build up the large size of these planets. According to models, the circumplanetary gas disks that surround the planets during this time then become the birthplaces of the giant planets satellite systems, producing systems of co-planar and prograde (i.e., orbiting in the same direction as the planets rotation) satellites similar to the many-moon systems of Jupiter or Saturn.Tritons orbit is tilted relative to the inner Neptunian satellite orbits. [NASA, ESA, and A. Feild (STScI)]Neptune, however, is quirky. This gas giant has surprisingly few satellites only 14 compared to, say, the nearly 70 moons of Jupiter and most of them are extremely small. One of Neptunes moons is an exception to this, however: Triton, which contains 99.7% of the mass of Neptunes entire satellite system!Tritons orbit has a number of unusual properties. The orbit is retrograde Triton orbits in the opposite direction as Neptunes rotation which is unique behavior among large moons in our solar system. Tritons orbit is also highly inclined, and yet the moons path is nearly circular and lies very close to Neptune.The distribution of impact velocities in the authors simulations for primordial satellite interactions with Triton, in three cases of different satellite mass ratios. In the low-mass case a third of the mass ratio of the Uranian satellite system 88% of simulations ended with Triton surviving on its high-inclination orbit. The survival rate was only 12% in the high-mass case. [Adapted from Rufu et al. 2017]How did this monster of a satellite get its strange properties, and why is Neptunes system so odd compared to what we

  10. The difficult births of sunlike stars

    International Nuclear Information System (INIS)

    Stahler, S.; Comins, N.

    1988-01-01

    Over 4.5 billion years ago a small region deep inside an enormous cloud of interstellar gas and dust, located in an outer spiral arm of the Milky Way, gradually contracted until it became gravitationally unstable. When the density in this region of the cloud became great enough to allow gravity to overcome all other forces acting on it, the region collapsed. Materials swirled inward, condensed, heated up, radiated energy, and eventually settled down to form the Sun and our solar system. What properties did that original unstable region have when it began to shrink? Astronomers know it rotated, because its angular momentum manifests itself today mostly in the orbital motions of the planets. But that alone cannot help us answer even the most fundamental questions we have about how stars like the Sun form. To find out more, astronomers are studying similar collapsing regions of interstellar gas and dust in the Milky Way known as cold cores, which are even now in the process of becoming solar-type stars. Astronomers want to answer three specific questions: What qualities do these cold cores have that allow stars like the Sun to form from them? What exactly happens during the collapse process? And how do newly formed stars evolve?

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

    Science.gov (United States)

    1996-01-01

    ADONIS Observes Pandora, S/1995 S6 and Others How many moons has Saturn, the second-largest planet in the solar system ? Until recently, the best answer was eighteen, ranging from innermost Pan that circles the planet 75,000 km above the cloud tops in a little less than 14 hours, to distant Phoebe , 13 million km away in a reverse (`retrograde') 550-day orbit [1]. Now the situation is less clear. New observations have become available which raise some questions about the actual number and nature of small `moons' near this planet. In particular, there is now evidence that some of the recent sightings may in fact refer to temporary condensations of material (dust clouds) in the inner rings rather than solid bodies. Most of these observations have been made with the Hubble Space Telescope (HST), but important supplementary data [2] was also obtained with the high-resolution ADONIS camera at the ESO 3.6-m telescope. When the Sun and Earth Cross the Plane of the Rings Saturn is surrounded by a spectacular ring system in which a large number of small (probably cm- to m-size) icy bodies are moving. Soon after the invention of the telescope in the early 17th century, it was found to consist of an inner B- and an outer A-ring, separated by the dark `Cassini division'. The faint F-ring was discovered further out by the Pioneer 11 spacecraft in 1979; it is separated from the A-ring by the 3000-km wide `Pioneer division'. All of these rings are very flat and quite thin. They are apparently no more than 2 kilometres thick in a global sense, and probably much less locally (10 - 100 metres). They all lie in the same plane which is inclined by 26.7 degrees, relative to the planet's orbital plane. One revolution of Saturn around the Sun lasts 29.455 years and twice during each orbital period, i.e. once about every 15 years, the Sun is situated exactly in this ring plane. This happened most recently on November 19, 1995. Astronomers refer to these relatively rare events as solar

  12. Integrable multi parametric SU(N) chain

    International Nuclear Information System (INIS)

    Foerster, Angela; Roditi, Itzhak; Rodrigues, Ligia M.C.S.

    1996-03-01

    We analyse integrable models associated to a multi parametric SU(N) R-matrix. We show that the Hamiltonians describe SU(N) chains with twisted boundary conditions and that the underlying algebraic structure is the multi parametric deformation of SU(N) enlarged by the introduction of a central element. (author). 15 refs

  13. Sun Tracker Operates a Year Between Calibrations

    Science.gov (United States)

    Berdahl, C. M.

    1984-01-01

    Low-cost modification of Sun tracker automatically compensates equation of time and seasonal variations in declination of Sun. Output of Scotch Yoke drive mechanism adjusted through proper sizing of crank, yoke and other components and through choice of gear ratios to approximate seasonal northand south motion of Sun. Used for industrial solar-energy monitoring and in remote meteorological stations.

  14. Sun tracker for clear or cloudy weather

    Science.gov (United States)

    Scott, D. R.; White, P. R.

    1979-01-01

    Sun tracker orients solar collector so that they absorb maximum possible sunlight without being fooled by bright clouds, holes in cloud cover, or other atmospheric conditions. Tracker follows sun within 0.25 deg arc and is accurate within + or - 5 deg when sun is hidden.

  15. Launching to the Moon, Mars, and Beyond

    Science.gov (United States)

    Dumbacher, Daniel L.

    2006-01-01

    The U.S. Vision for Space Exploration, announced in 2004, calls on NASA to finish constructing the International Space Station, retire the Space Shuttle, and build the new spacecraft needed to return to the Moon and go on the Mars. By exploring space, America continues the tradition of great nations who mastered the Earth, air, and sea, and who then enjoyed the benefits of increased commerce and technological advances. The progress being made today is part of the next chapter in America's history of leadership in space. In order to reach the Moon and Mars within the planned timeline and also within the allowable budget, NASA is building upon the best of proven space transportation systems. Journeys to the Moon and Mars will require a variety of vehicles, including the Ares I Crew Launch Vehicle, the Ares V Cargo Launch Vehicle, the Orion Crew Exploration Vehicle, and the Lunar Surface Access Module. What America learns in reaching for the Moon will teach astronauts how to prepare for the first human footprints on Mars. While robotic science may reveal information about the nature of hydrogen on the Moon, it will most likely tale a human being with a rock hammer to find the real truth about the presence of water, a precious natural resource that opens many possibilities for explorers. In this way, the combination of astronauts using a variety of tools and machines provides a special synergy that will vastly improve our understanding of Earth's cosmic neighborhood.

  16. Revival of the "Sun Festival": An educational and outreach project

    Science.gov (United States)

    Montabone, Luca

    2016-10-01

    In ancient times, past civilisations used to celebrate both the winter and summer solstices, which represented key moments in the periodical cycle of seasons and agricultural activities. In 1904, the French astronomer Camille Flammarion, the engineer Gustave Eiffel, the science writer Wilfrid de Fonvielle and the Spanish astronomer Josep Comas i Solà decided to celebrate the summer solstice with a festival of science, art and astronomical observations opened to the public at the Eiffel tower in Paris. For ten consecutive years (1904-1914) on the day of the summer solstice, the "Sun Festival" (Fête du Soleil in French) included scientific and technological lectures and demostrations, celestial observations, music, poetry, danse, cinema, etc. This celebration was interrupted by the First World War, just to resume in Barcelona, Spain, between 1915 and 1937, and in Marseille, France, in the 1930s. It was the founders' dream to extend this celebration to all cities in France and elsewhere.It is only during the International Year of Astronomy in 2009, to our knowledge, that the "Sun Festival" was given another chance in France, thanks to the joint effort of several scientific and cultural centers (Centres de Culture Scientifique, Technique et Industrielle, CCSTI) and the timely support of the European Space Agency (ESA). In this occasion again, the festival was characterized by the combination of science, art and technological innovation around a common denominator: our Sun!We have recently revived the idea of celebrating the summer solstice with a "Sun Festival" dedicated to scientific education and outreach about our star and related topics. This project started last year in Aix-les-Bains, France, with the "Sun and Light Festival" (2015 was the International Year of Light), attended by about 100 people. This year's second edition was in Le Bourget-du-Lac, France. Following the COP21 event, the specific theme was the "Sun and Climate Festival", and we had about 250

  17. Seeing Stars - Intensity Interferometry in the Laboratory & on the Ground

    Science.gov (United States)

    Carlile, Colin; Dravins, Dainis

    2018-04-01

    In many ways it is a golden age for astronomy. Spectacular new discoveries, for example the detection of gravitational waves, are very dependent upon instrumental development. The specific instrument development we propose, Intensity Interferometry (II), aims toimprove the spatial resolution of optical telescopes by 100x to 50µas [1]. This is impractical to achieve by increasing the size of telescopes or by extending the capabilities of phase interferometry. II, if implemented on the Cherenkov Telescope Array (CTA) currently being installed in La Palma and Paranal, would record the light intensity – the photon train - from many different telescopes, up to 2 km apart, on a nanosecond timescale and compare them. The signal from the many pairs of telescopes would quantify the degree of correlation by extracting the second-order correlation function, and thus create an image. This is not a real space image. However we can invert the data by Fourier Transform and create a real image. The more telescopes, the better resolved and more physical is the image, enabling the study of sunspots on nearby stars; orbiting binary stars; or exoplanets traversing the disc of their own star. We understand the Sun well but we have little experimental knowledge of how representative it is of main sequence stars. To test the II method, at Lund Observatory we have set up a laboratory analogue comprising ten small telescopes observing an artificial star created by light from a laser. The method has been shown to work [2] and the telescope array has now been extended to two dimensions. We are in discussion with other groups to explore the possibility of implementing this method on real telescopes observing actual stars. We plan to do this with the prototype Small Size Telescopes being built by groups in Europe, and ultimately with the CTA itself. A Science Working Group for II has now been set up within the CTA Consortium, of which Lund University is an integral part. A Letter of Intent

  18. "A Nightmare Land, a Place of Death": An Exploration of the Moon as a Motif in Herge's "Destination Moon" (1953) and "Explorers on the Moon" (1954)

    Science.gov (United States)

    Beauvais, Clementine

    2010-01-01

    This article analyses the symbolic meaning of the Moon in two "bande dessinee" books from the Tintin series, Herge's "Destination Moon" ("Objectif Lune," 1953) and its sequel "Explorers on the Moon" ("On a Marche sur la Lune," 1954). It argues that these two volumes stand out in the series for their graphic, narrative and philosophical emphasis on…

  19. Effects of back warming in cocoon stars

    International Nuclear Information System (INIS)

    Donnison, J.R.; Williams, I.P.

    1976-01-01

    It is stated that dust shells frequently surround young stars, and attempts have been made to determine some of the properties of these shells. It is probable that the dust absorbs the outgoing radiation from the star and re-emits it in the infrared. If the dust shell does absorb radiation both its inner and outer surfaces will re-emit a certain proportion and some radiation will return to the central star, causing what amounts to 'warming of its own back'. It is interesting to consider how such a star evolves, compared with evolution of a normal pre-main-sequence star. A model for a contracting star that is receiving radiation from an external source has been developed by the authors in connection with the evolution of Jupiter within the radiation field of the Sun (Astrophys. Space Sci., 29:387 (1974)), and this model is here applied to the situation just described. It is emphasised that the discussion is concerned only with the evolution of the central star, the dust being regarded merely as a means of redirecting radiation back on to the surface of this star. Amongst conclusions reached is that a thin shell will cause no significant change in the structure and evolution of the central star, whilst the presence of a thick shell has a substantial effect on the star, slowing down is evolution. Whilst a dust shell is present the star cannot be seen, but only the dust shell emitting in the infrared, but once the dust shell clears the star is seen in a position and with an age that differs considerably from what it would have had if it had evolved without 'back warming' from the dust shell. (U.K.)

  20. Unusual Metals in Galactic Center Stars

    Science.gov (United States)

    Hensley, Kerry

    2018-03-01

    Far from the galactic suburbs where the Sun resides, a cluster of stars in the nucleus of the Milky Way orbits a supermassive black hole. Can chemical abundance measurements help us understand the formation history of the galactic center nuclear star cluster?Studying Stellar PopulationsMetallicity distributions for stars in the inner two degrees of the Milky Way (blue) and the central parsec (orange). [Do et al. 2018]While many galaxies host nuclear star clusters, most are too distant for us to study in detail; only in the Milky Way can we resolve individual stars within one parsec of a supermassive black hole. The nucleus of our galaxy is an exotic and dangerous place, and its not yet clear how these stars came to be where they are were they siphoned off from other parts of the galaxy, or did they form in place, in an environment rocked by tidal forces?Studying the chemical abundances of stars provides a way to separate distinct stellar populations and discern when and where these stars formed. Previous studies using medium-resolution spectroscopy have revealed that many stars within the central parsec of our galaxy have very high metallicities possibly higher than any other region of the Milky Way. Can high-resolution spectroscopy tell us more about this unusual population of stars?Spectral Lines on DisplayTuan Do (University of California, Los Angeles, Galactic Center Group) and collaborators performed high-resolution spectroscopic observations of two late-type giant starslocated half a parsec from the Milky Ways supermassive black hole.Comparison of the observed spectra of the two galactic center stars (black) with synthetic spectra with low (blue) and high (orange) [Sc/Fe] values. Click to enlarge. [Do et al. 2018]In order to constrain the metallicities of these stars, Do and collaborators compared the observed spectra to a grid of synthetic spectra and used a spectral synthesis technique to determine the abundances of individual elements. They found that

  1. A new view of the Sun from space

    CERN Document Server

    Bonnet, Roger Maurice

    2001-01-01

    Artificial Satellites are providing new tools for the observation of our star. The European Space Agency, ESA, in cooperation with NASA has programmed and developed three important space missions: SOHO, ULYSSES, and CLUSTER which offer new opportunities to study the Sun and how it influences the Earth's environment. SOHO in particular, thanks to an unprecedented stability together with a very complete set of instruments, has responded to several of the most fundamental questions concerning the behaviour and the running of our star. It is now possible to probe its interior down to the very core where the thermonuclear reactions occur and to deduce the physical conditions which exist therein. It is also possible to understand better the origin of the solar wind and why is the solar corona so hot. These two questions have been at the core of a large number of observations and theoretical studies for a long time. Thanks to ULYSSES which observes the Sun from a unique vantage point, outside the ecliptic plane wher...

  2. Guaranteeing Pointing Performance of the SDO Sun-Pointing Controllers in Light of Nonlinear Effects

    Science.gov (United States)

    Starin, Scott R.; Bourkland, Kristin L.

    2007-01-01

    The Solar Dynamics Observatory (SDO) mission is the first Space Weather Research Network mission, part of NASA s Living With a Star program.1 This program seeks to understand the changing Sun and its effects on the Solar System, life, and society. To this end, the SDO spacecraft will carry three Sun-observing instruments to geosynchronous orbit: Helioseismic and Magnetic Imager (HMI), led by Stanford University; Atmospheric Imaging Assembly (AIA), led by Lockheed Martin Space and Astrophysics Laboratory; and Extreme Ultraviolet Variability Experiment (EVE), led by the University of Colorado. Links describing the instruments in detail may be found through the SDO web site.2 The basic mission goals are to observe the Sun for a very high percentage of the 5-year mission (10-year goal) with long stretches of uninterrupted observations and with constant, high-data-rate transmission to a dedicated ground station. These goals guided the design of the spacecraft bus that will carry and service the three-instrument payload. At the time of this publication, the SDO spacecraft bus is well into the integration and testing phase at the NASA Goddard Space Flight Center (GSFC). A three-axis stabilized attitude control system (ACS) is needed both to point at the Sun accurately and to keep the roll about the Sun vector correctly positioned. The ACS has four reaction wheel modes and 2 thruster actuated modes. More details about the ACS in general and the control modes in particular can be found in Refs. [3-6]. All four of SDO s wheel-actuated control modes involve Sun-pointing controllers, as might be expected from such a mission. Science mode, during which most science data is collected, uses specialized guide telescopes to point accurately at the Sun. Inertial mode has two sub-modes, one tracks a Sun-referenced target orientation, and another maintains an absolute (star-referenced) target orientation, that both employ a Kalman filter to process data from a digital Sun sensor and

  3. Nystagmus in Laurence-Moon-Biedl Syndrome

    Directory of Open Access Journals (Sweden)

    A. Bruce Janati

    2015-01-01

    Full Text Available Introduction. Laurence-Moon-Biedl (LMB syndrome is a rare autosomal-recessive ciliopathy with manifold symptomatology. The cardinal clinical features include retinitis pigmentosa, obesity, intellectual delay, polydactyly/syndactyly, and hypogenitalism. In this paper, the authors report on three siblings with Laurence-Moon-Biedl syndrome associated with a probable pseudocycloid form of congenital nystagmus. Methods. This was a case study conducted at King Khaled Hospital. Results. The authors assert that the nystagmus in Laurence-Moon-Biedl syndrome is essentially similar to idiopathic motor-defect nystagmus and the nystagmus seen in optic nerve hypoplasia, ocular albinism, and bilateral opacities of the ocular media. Conclusion. The data support the previous hypothesis that there is a common brain stem motor abnormality in sensory-defect and motor-defect nystagmus.

  4. Magnetism and the history of the moon

    Science.gov (United States)

    Strangway, D. W.; Gose, W. A.; Pearce, G. W.; Carnes, J. G.

    1973-01-01

    All lunar samples measured to date contain a weak but stable remanent magnetization of lunar origin. The magnetization is carried by metallic iron and is considered to be caused by cooling from above the Curie point in the presence of a magnetic field. Although at present the moon does not have a global field, the remanent magnetization of the rock samples and the presence of magnetic anomalies, both on the near and far side of the moon, imply that the moon experienced a magnetic field during some portion of its history. The field could have been generated in a liquid iron core sustaining a self-exciting dynamo, but there are some basic thermal and geochemical objections that need to be resolved.

  5. Symbiotic stars

    Science.gov (United States)

    Kafatos, M.; Michalitsianos, A. G.

    1984-01-01

    The physical characteristics of symbiotic star systems are discussed, based on a review of recent observational data. A model of a symbiotic star system is presented which illustrates how a cool red-giant star is embedded in a nebula whose atoms are ionized by the energetic radiation from its hot compact companion. UV outbursts from symbiotic systems are explained by two principal models: an accretion-disk-outburst model which describes how material expelled from the tenuous envelope of the red giant forms an inwardly-spiralling disk around the hot companion, and a thermonuclear-outburst model in which the companion is specifically a white dwarf which superheats the material expelled from the red giant to the point where thermonuclear reactions occur and radiation is emitted. It is suspected that the evolutionary course of binary systems is predetermined by the initial mass and angular momentum of the gas cloud within which binary stars are born. Since red giants and Mira variables are thought to be stars with a mass of one or two solar mass, it is believed that the original cloud from which a symbiotic system is formed can consist of no more than a few solar masses of gas.

  6. Relative amounts of stars and interstellar matter in the local Milky Way

    International Nuclear Information System (INIS)

    Jura, M.

    1987-01-01

    This paper considers the balance between star formation and mass loss from evolved stars in the region within 1 kpc of the sun. There is considerably more mass in stars than in the interstellar medium, and more material is being incorporated into new stars than is being returned by evolved stars. In the simplest interpretation of the data, it appears that unless there is some infall of new interstellar gas, the era of substantial star formation out of interstellar gas will be over in a few (perhaps 3) billion years. 34 references

  7. Sunwatchers Across Time: Sun-Earth Day from Ancient and Modern Solar Observatories

    Science.gov (United States)

    Hawkins, I.; Vondrak, R.

    Humans across all cultures have venerated, observed, and studied the Sun for thousands of years. The Sun, our nearest star, provides heat and energy, is the cause of the seasons, and causes space weather effects that influence our technology-dependent society. The Sun is also part of indigenous tradition and culture. The Inca believed that the Sun had the power to make things grow, and it does, providing us with the heat and energy that are essential to our survival. From a NASA perspective, Sun-Earth Connection research investigates the effects of our active Sun on the Earth and other planets, namely, the interaction of the solar wind and other dynamic space weather phenomena with the solar system. We present plans for Sun-Earth Day 2005, a yearly celebration of the Sun-Earth Connection sponsored by the NASA Sun-Earth Connection Education Forum (SECEF). SECEF is one of four national centers of space science education and public outreach funded by NASA Office of Space Science. Sun-Earth Day involves an international audience of schools, science museums, and the general public in activities and events related to learning about the Sun-Earth Connection. During the year 2005, the program will highlight cultural and historical perspectives, as well as NASA science, through educational and public outreach events intended to involve diverse communities. Sun-Earth Day 2005 will include a series of webcasts from solar observatories produced by SECEF in partnership with the San Francisco Exploratorium. Webcasts from Chaco Culture National Historical Park in New Mexico, USA, and from Chichen Itza, Mexico, will be accessed by schools and the public. Sun-Earth Day will also feature NASA Sun-Earth Connection research, missions, and the people who make it possible. One of the goals of this talk is to inform and engage COSPAR participants in these upcoming public events sponsored by NASA. Another goal is to share best practices in public event programming, and present impact

  8. New upper limit to the coronal line emission from the T Tauri star RU Lupi

    Energy Technology Data Exchange (ETDEWEB)

    Gahm, G F [Stockholm Observatory (Sweden); Lago, M T.V.T. [Universidade do Porto (Portugal). Grupo de Matematica Aplicada; Penston, M V [ESTEC, European Space Agency, Villafranca Satellite Tracking Station, Madrid, (Spain)

    1981-05-01

    A high dispersion AAT spectrogram sets an upper limit on the (Fe x) emission line lambda 6374.5 A in the T Tauri star RU Lupi. The intensity of any 10/sup 6/ K corona in this star is less than 600 times that of the Sun compared to a chromosphere and transition region of 3 x 10/sup 3/ to 2 x 10/sup 5/ K gas 10/sup 6/ times stronger than the Sun's. The important theoretical implications are noted.

  9. The HOSTS Survey—Exozodiacal Dust Measurements for 30 Stars

    Science.gov (United States)

    Ertel, S.; Defrère, D.; Hinz, P.; Mennesson, B.; Kennedy, G. M.; Danchi, W. C.; Gelino, C.; Hill, J. M.; Hoffmann, W. F.; Rieke, G.; Shannon, A.; Spalding, E.; Stone, J. M.; Vaz, A.; Weinberger, A. J.; Willems, P.; Absil, O.; Arbo, P.; Bailey, V. P.; Beichman, C.; Bryden, G.; Downey, E. C.; Durney, O.; Esposito, S.; Gaspar, A.; Grenz, P.; Haniff, C. A.; Leisenring, J. M.; Marion, L.; McMahon, T. J.; Millan-Gabet, R.; Montoya, M.; Morzinski, K. M.; Pinna, E.; Power, J.; Puglisi, A.; Roberge, A.; Serabyn, E.; Skemer, A. J.; Stapelfeldt, K.; Su, K. Y. L.; Vaitheeswaran, V.; Wyatt, M. C.

    2018-05-01

    The Hunt for Observable Signatures of Terrestrial Systems survey searches for dust near the habitable zones (HZs) around nearby, bright main-sequence stars. We use nulling interferometry in the N band to suppress the bright stellar light and to probe for low levels of HZ dust around the 30 stars observed so far. Our overall detection rate is 18%, including four new detections, among which are the first three around Sun-like stars and the first two around stars without any previously known circumstellar dust. The inferred occurrence rates are comparable for early-type and Sun-like stars, but decrease from {60}-21+16% for stars with previously detected cold dust to {8}-3+10% for stars without such excess, confirming earlier results at higher sensitivity. For completed observations on individual stars, our sensitivity is five to ten times better than previous results. Assuming a lognormal excess luminosity function, we put upper limits on the median HZ dust level of 13 zodis (95% confidence) for a sample of stars without cold dust and of 26 zodis when focusing on Sun-like stars without cold dust. However, our data suggest that a more complex luminosity function may be more appropriate. For stars without detectable Large Binocular Telescope Interferometer (LBTI) excess, our upper limits are almost reduced by a factor of two, demonstrating the strength of LBTI target vetting for future exo-Earth imaging missions. Our statistics are limited so far, and extending the survey is critical to informing the design of future exo-Earth imaging surveys.

  10. Moon Zoo - Examples of Interesting Lunar Morphology

    Science.gov (United States)

    Cook, A. C.; Wilkinson, J.

    2012-09-01

    The MoonMappers citizen science project is part of CosmoQuest, a virtual research facility designed for the public. CosmoQuest seeks to take the best aspects of a research center - research, seminars, journal clubs, and community discussions - and provide them to a community of citizen scientists through a virtual facility. MoonMappers was the first citizen science project within CosmoQuest, and is being used to define best practices in getting the public to effectively learn and do science.

  11. Protecting the Moon for research: ILEWG report

    Science.gov (United States)

    Foing, Bernard H.

    We give a report on recommendations with emphasis on environment protection, and since last COSPAR from ILEWG International conferences Exploration and Utilisation of the Moon on held at Cape Canaveral in 2008 (ICEUM10), and in Beijing in May 2010 with IAF (GLUC -ICEUM11). We discuss the different rationale for Moon exploration, as debated at ILEWG. ILEWG Science task group has listed priorities for scientific investigations: clues on the formation and evolution of rocky planets, accretion and bombardment in the inner solar system, comparative planetology processes (tectonic, volcanic, impact cratering, volatile delivery), records astrobiology, survival of organics; past, present and future life; sciences from a biology lunar laboratory. We discuss how to preserve Moon research potential in these areas while operating with instruments, landers, rover during a cooperative robotic village, and during the transition form lunar human outpost to permanent sustainable human base. We discuss how Moon-Mars Exploration can inspire solutions to global Earth sustained development with the trade-off of In-Situ Utilisation of resources; Establishment of permanent robotic infrastructures, Environmental and planetary protection aspects and lessons for Mars; Life sciences laboratories, and support to human exploration. Co-authors: ILEWG Task Groups on Science, Technology and Human Lunar Bases ILEWG Reference documents: http://sci.esa.int/ilewg -10th ILEWG Conference on Exploration and Utilisation of the Moon, NASA Lunar Ex-ploration Analysis Group-PSace Resources Roundtable, Cape Canaveral October 2008, pro-gramme online at http://sci.esa.int/ilewg/ -9th ILEWG Conference on Exploration and Utilisation of the Moon, ICEUM9 Sorrento 2007, programme online at http://sci.esa.int/ilewg/ -8th ILEWG Conference on Exploration and Utilisation of the Moon, Beijing July 2006, programme online at http://sci.esa.int/ilewg/ -The Moon and Near Earth Objects (P. Ehrenfreund , B.H. Foing, A

  12. Dark stars

    DEFF Research Database (Denmark)

    Maselli, Andrea; Pnigouras, Pantelis; Nielsen, Niklas Grønlund

    2017-01-01

    to the formation of compact objects predominantly made of dark matter. Considering both fermionic and bosonic (scalar φ4) equations of state, we construct the equilibrium structure of rotating dark stars, focusing on their bulk properties and comparing them with baryonic neutron stars. We also show that these dark......Theoretical models of self-interacting dark matter represent a promising answer to a series of open problems within the so-called collisionless cold dark matter paradigm. In case of asymmetric dark matter, self-interactions might facilitate gravitational collapse and potentially lead...... objects admit the I-Love-Q universal relations, which link their moments of inertia, tidal deformabilities, and quadrupole moments. Finally, we prove that stars built with a dark matter equation of state are not compact enough to mimic black holes in general relativity, thus making them distinguishable...

  13. The Sun Radio Imaging Space Experiment (SunRISE) Mission

    Science.gov (United States)

    Kasper, J. C.; Lazio, J.; Alibay, F.; Amiri, N.; Bastian, T.; Cohen, C.; Landi, E.; Hegedus, A. M.; Maksimovic, M.; Manchester, W.; Reinard, A.; Schwadron, N.; Cecconi, B.; Hallinan, G.; Krupar, V.

    2017-12-01

    Radio emission from coronal mass ejections (CMEs) is a direct tracer of particle acceleration in the inner heliosphere and potential magnetic connections from the lower solar corona to the larger heliosphere. Energized electrons excite Langmuir waves, which then convert into intense radio emission at the local plasma frequency, with the most intense acceleration thought to occur within 20 R_S. The radio emission from CMEs is quite strong such that only a relatively small number of antennas is required to detect and map it, but many aspects of this particle acceleration and transport remain poorly constrained. Ground-based arrays would be quite capable of tracking the radio emission associated with CMEs, but absorption by the Earth's ionosphere limits the frequency coverage of ground-based arrays (nu > 15 MHz), which in turn limits the range of solar distances over which they can track the radio emission (concept: A constellation of small spacecraft in a geostationary graveyard orbit designed to localize and track radio emissions in the inner heliosphere. Each spacecraft would carry a receiving system for observations below 25 MHz, and SunRISE would produce the first images of CMEs more than a few solar radii from the Sun. Part of this research was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration.

  14. The Glory of a Nearby Star

    Science.gov (United States)

    2001-08-01

    Optical Light from a Hot Stellar Corona Detected with the VLT Summary The solar corona is a beautiful sight during total solar eclipses . It is the uppermost region of the extended solar atmosphere and consists of a very hot (over 1 million degrees), tenuous plasma of highly ionised elements that emit strong X-ray radiation. There is also a much weaker coronal emission in the optical part of the spectrum . The Sun is a normal star and X-ray observations from rockets and orbiting X-ray telescopes have shown that many other stars also possess coronae . But due to observational limits of the telescopes available so far, the much fainter optical emission from stellar coronae had never been detected. Now, however, an optical coronal line from iron ions that have lost 12 electrons (Fe XIII) has for the first time been observed in a star other than the Sun . The object, a cool star named CN Leonis , is located at a distance of 8 light-years. This impressive observational feat was performed with the UV-Visual Echelle Spectrograph (UVES) on the VLT 8.2-m KUEYEN telescope at the ESO Paranal Observatory , within a programme by German astronomer Jürgen Schmitt and his collaborators at the University of Hamburg Observatory. The possibility to observe stellar coronae with ground-based telescopes opens up new and exciting research opportunities, including the detailed study of stellar cycles , similar to the 11-year solar period. PR Photo 24a/01 : The solar corona during the August 11, 1999, solar eclipse. PR Photo 24b/01 : The nearby star CN Leonis . PR Photo 24c/01 : Ultraviolet spectrum of CN Leonis , obtained with UVES at VLT KUEYEN. PR Photo 24d/01 : The coronal Fe XIII emission line at 3388 Ångstrom in CN Leonis . The 'coronium' mystery ESO PR Photo 24a/01 ESO PR Photo 24a/01 [Preview - JPEG: 450 x 400 pix - 26k] [Normal - JPEG: 899 x 800 pix - 328k] [HiRes - JPEG: 3000 x 2669 pix - 3.1Mk] Caption : Photo of the solar corona, obtained by Philippe Duhoux (ESO) on August 11

  15. Environments of T Tauri stars

    International Nuclear Information System (INIS)

    Chevalier, R.A.

    1983-01-01

    The environments of T Tauri stars are probably determined by the interaction of a stellar wind with matter which is falling toward a newly formed star. As shown by Ulrich, the steady infall of cool gas with angular momentum toward the star leads to a density distribution with rhoproportionalr/sup -1/2/ inside a radius r/sub d/ and rhoproportionalr/sup -3/2/ outside r/sub d/. The radius r/sub d/ is determined by the angular momentum of the infalling gas. The expansion of the wind into this medium depends on the parameter α = M/sub w/v/sub w//M/sub in/v/sub in/(r/sub d/), where v/sub in/(r/sub d/) is the free-fall velocity at r/sub d/, M/sub in/ is the mass accretion rate, v/sub w/ is the wind velocity, and M/sub w/ is the mass loss rate. For α 14 cm, v/sub w/ = 150 km s -1 , M/sub in/ = 10 -7 M/sub sun/ yr -1 , and M/sub w/ = 3 x 10 -8 M/sub sun/ yr -1 . The inflow is clumpy. The shocked wind gives the radio emission and nebular emission from T Tauri, and dust within the clumps gives the infrared emission. T Tauri is in a transitory phase in which most of the wind has only recently propagated beyond r/sub d/. The model naturally predicts variable obscuration of T Tauri stars because the infalling clumps move on nonradial trajectories. The infrared emission can vary either because of structural changes in the circumstellar gas or because of variations in the stellar luminosity. Infrared variability should be small at short time scales because of light-travel time effects

  16. ASTRO-ENTOMOLOGY? ANT-LIKE SPACE STRUCTURE PREVIEWS DEATH OF OUR SUN

    Science.gov (United States)

    2002-01-01

    From ground-based telescopes, the so-called 'ant nebula' (Menzel 3, or Mz 3) resembles the head and thorax of a garden-variety ant. This dramatic NASA/ESA Hubble Space Telescope image, showing 10 times more detail, reveals the 'ant's' body as a pair of fiery lobes protruding from a dying, Sun-like star. The Hubble images directly challenge old ideas about the last stages in the lives of stars. By observing Sun-like stars as they approach their deaths, the Hubble Heritage image of Mz 3 -- along with pictures of other planetary nebulae -- shows that our Sun's fate probably will be more interesting, complex, and striking than astronomers imagined just a few years ago. Though approaching the violence of an explosion, the ejection of gas from the dying star at the center of Mz 3 has intriguing symmetrical patterns unlike the chaotic patterns expected from an ordinary explosion. Scientists using Hubble would like to understand how a spherical star can produce such prominent, non-spherical symmetries in the gas that it ejects. One possibility is that the central star of Mz 3 has a closely orbiting companion that exerts strong gravitational tidal forces, which shape the outflowing gas. For this to work, the orbiting companion star would have to be close to the dying star, about the distance of the Earth from the Sun. At that distance the orbiting companion star wouldn't be far outside the hugely bloated hulk of the dying star. It's even possible that the dying star has consumed its companion, which now orbits inside of it, much like the duck in the wolf's belly in the story 'Peter and the Wolf.' (See http://oposite.stsci.edu/pubinfo/qt/ssudec.mov for an animation that shows how this might work.) A second possibility is that, as the dying star spins, its strong magnetic fields are wound up into complex shapes like spaghetti in an eggbeater. Charged winds moving at speeds up to 1000 kilometers per second from the star, much like those in our sun's solar wind but millions of

  17. MASSIVE STARS IN THE Cl 1813-178 CLUSTER: AN EPISODE OF MASSIVE STAR FORMATION IN THE W33 COMPLEX

    International Nuclear Information System (INIS)

    Messineo, Maria; Davies, Ben; Figer, Donald F.; Trombley, Christine; Kudritzki, R. P.; Valenti, Elena; Najarro, F.; Michael Rich, R.

    2011-01-01

    Young massive (M > 10 4 M sun ) stellar clusters are a good laboratory to study the evolution of massive stars. Only a dozen of such clusters are known in the Galaxy. Here, we report about a new young massive stellar cluster in the Milky Way. Near-infrared medium-resolution spectroscopy with UIST on the UKIRT telescope and NIRSPEC on the Keck telescope, and X-ray observations with the Chandra and XMM satellites, of the Cl 1813-178 cluster confirm a large number of massive stars. We detected 1 red supergiant, 2 Wolf-Rayet stars, 1 candidate luminous blue variable, 2 OIf, and 19 OB stars. Among the latter, twelve are likely supergiants, four giants, and the faintest three dwarf stars. We detected post-main-sequence stars with masses between 25 and 100 M sun . A population with age of 4-4.5 Myr and a mass of ∼10, 000 M sun can reproduce such a mixture of massive evolved stars. This massive stellar cluster is the first detection of a cluster in the W33 complex. Six supernova remnants and several other candidate clusters are found in the direction of the same complex.

  18. Our explosive sun a visual feast of our source of light and life

    CERN Document Server

    Brekke, Pal

    2012-01-01

    The center of our Solar System is a star, one among billions of stars in our own galaxy. This star, which we call the Sun, gives rise to all life on Earth, is the driver of the photosynthesis in plants, and is the source of all food, energy, and fossil fuels on Earth. For us humans, the Sun as seen with the naked eye appears as a static and quiet yellow disk in the sky. However, it is in fact a stormy and variable star and contributes much more than only light and heat. It is the source of the beautiful northern and southern lights and can affect our technology-based society in many ways. The Sun is, like astronomy in general, a good entrance to natural science, since it affects us in so many ways and connects us to many other fields of science, such as physics, chemistry, biology, and meteorology. The book includes additional material on Springer Extras, a large number of animations and video material. A PowerPoint presentation of the book is also included there as a useful resource for teachers.

  19. SU(N,1) inflation

    International Nuclear Information System (INIS)

    Ellis, J.; Enqvist, K.; Nanopoulos, D.V.; Olive, K.A.; Srednicki, M.

    1985-01-01

    We present a simple model for primordial inflation in the context of SU(N, 1) no-scale n=1 supergravity. Because the model at zero temperature very closely resembles global supersymmetry, minima with negative cosmological constants do not exist, and it is easy to have a long inflationary epoch while keeping density perturbations of the right magnitude and satisfying other cosmological constraints. We pay specific attention to satisfying the thermal constraint for inflation, i.e. the existence of a high temperature minimum at the origin. (orig.)

  20. Isotopic evolution of the protoplanetary disk and the building blocks of Earth and the Moon

    Science.gov (United States)

    Schiller, Martin; Bizzarro, Martin; Fernandes, Vera Assis

    2018-03-01

    Nucleosynthetic isotope variability among Solar System objects is often used to probe the genetic relationship between meteorite groups and the rocky planets (Mercury, Venus, Earth and Mars), which, in turn, may provide insights into the building blocks of the Earth–Moon system. Using this approach, it has been inferred that no primitive meteorite matches the terrestrial composition and the protoplanetary disk material from which Earth and the Moon accreted is therefore largely unconstrained. This conclusion, however, is based on the assumption that the observed nucleosynthetic variability of inner-Solar-System objects predominantly reflects spatial heterogeneity. Here we use the isotopic composition of the refractory element calcium to show that the nucleosynthetic variability in the inner Solar System primarily reflects a rapid change in the mass-independent calcium isotope composition of protoplanetary disk solids associated with early mass accretion to the proto-Sun. We measure the mass-independent 48Ca/44Ca ratios of samples originating from the parent bodies of ureilite and angrite meteorites, as well as from Vesta, Mars and Earth, and find that they are positively correlated with the masses of their parent asteroids and planets, which are a proxy of their accretion timescales. This correlation implies a secular evolution of the bulk calcium isotope composition of the protoplanetary disk in the terrestrial planet-forming region. Individual chondrules from ordinary chondrites formed within one million years of the collapse of the proto-Sun reveal the full range of inner-Solar-System mass-independent 48Ca/44Ca ratios, indicating a rapid change in the composition of the material of the protoplanetary disk. We infer that this secular evolution reflects admixing of pristine outer-Solar-System material into the thermally processed inner protoplanetary disk associated with the accretion of mass to the proto-Sun. The identical calcium isotope composition of Earth

  1. John Bauer: Painter of a Star-Spangled Fairy-Tale World

    Science.gov (United States)

    Sundin, M.; Roslund, C.

    Several generations of Swedish children have become acquainted with the world of fairy-tales through illustrations by the painter John Bauer in the Christmas magazine Goblins and Trolls. Next to his portrayal of grotesque but humorous trolls, his paintings of the Moon and the starry sky are among those best remembered. These pictures have inspired very many Swedes to take pleasure in the beauty of the stars and the movement of the Moon.

  2. COLORFUL FIREWORKS FINALE CAPS A STAR'S LIFE

    Science.gov (United States)

    2002-01-01

    Glowing gaseous streamers of red, white, and blue -- as well as green and pink -- illuminate the heavens like Fourth of July fireworks. The colorful streamers that float across the sky in this photo taken by NASA's Hubble Space Telescope were created by one of the biggest firecrackers seen to go off in our galaxy in recorded history, the titanic supernova explosion of a massive star. The light from the exploding star reached Earth 320 years ago, nearly a century before our United States celebrated its birth with a bang. The dead star's shredded remains are called Cassiopeia A, or 'Cas A' for short. Cas A is the youngest known supernova remnant in our Milky Way Galaxy and resides 10,000 light-years away in the constellation Cassiopeia, so the star actually blew up 10,000 years before the light reached Earth in the late 1600s. This stunning Hubble image of Cas A is allowing astronomers to study the supernova's remains with great clarity, showing for the first time that the debris is arranged into thousands of small, cooling knots of gas. This material eventually will be recycled into building new generations of stars and planets. Our own Sun and planets are constructed from the debris of supernovae that exploded billions of years ago. This photo shows the upper rim of the supernova remnant's expanding shell. Near the top of the image are dozens of tiny clumps of matter. Each small clump, originally just a small fragment of the star, is tens of times larger than the diameter of our solar system. The colors highlight parts of the debris where chemical elements are glowing. The dark blue fragments, for example, are richest in oxygen; the red material is rich in sulfur. The star that created this colorful show was a big one, about 15 to 25 times more massive than our Sun. Massive stars like the one that created Cas A have short lives. They use up their supply of nuclear fuel in tens of millions of years, 1,000 times faster than our Sun. With their fuel exhausted, heavy

  3. "Wonderful" Star Reveals its Hot Nature

    Science.gov (United States)

    2005-04-01

    For the first time an X-ray image of a pair of interacting stars has been made by NASA's Chandra X-ray Observatory. The ability to distinguish between the interacting stars - one a highly evolved giant star and the other likely a white dwarf - allowed a team of scientists to observe an X-ray outburst from the giant star and find evidence that a bridge of hot matter is streaming between the two stars. "Before this observation it was assumed that all the X-rays came from a hot disk surrounding a white dwarf, so the detection of an X-ray outburst from the giant star came as a surprise," said Margarita Karovska of the Harvard-Smithsonian Center for Astrophysics in Cambridge, Mass., and lead author article in the latest Astrophysical Journal Letters describing this work. An ultraviolet image made by the Hubble Space Telescope was a key to identifying the location of the X-ray outburst with the giant star. X-ray studies of this system, called Mira AB, may also provide better understanding of interactions between other binary systems consisting of a "normal" star and a collapsed star such as a white dwarf, black hole or a neutron star, where the stellar objects and gas flow cannot be distinguished in an image. HST Ultraviolet Image of Mira HST Ultraviolet Image of Mira The separation of the X-rays from the giant star and the white dwarf was made possible by the superb angular resolution of Chandra, and the relative proximity of the star system at about 420 light years from Earth. The stars in Mira AB are about 6.5 billion miles apart, or almost twice the distance of Pluto from the Sun. Mira A (Mira) was named "The Wonderful" star in the 17th century because its brightness was observed to wax and wane over a period of about 330 days. Because it is in the advanced, red giant phase of a star's life, it has swollen to about 600 times that of the Sun and it is pulsating. Mira A is now approaching the stage where its nuclear fuel supply will be exhausted, and it will collapse

  4. Destruction of a Magnetized Star

    Science.gov (United States)

    Kohler, Susanna

    2017-01-01

    What happens when a magnetized star is torn apart by the tidal forces of a supermassive black hole, in a violent process known as a tidal disruption event? Two scientists have broken new ground by simulating the disruption of stars with magnetic fields for the first time.The magnetic field configuration during a simulation of the partial disruption of a star. Top left: pre-disruption star. Bottom left: matter begins to re-accrete onto the surviving core after the partial disruption. Right: vortices form in the core as high-angular-momentum debris continues to accrete, winding up and amplifying the field. [Adapted from Guillochon McCourt 2017]What About Magnetic Fields?Magnetic fields are expected to exist in the majority of stars. Though these fields dont dominate the energy budget of a star the magnetic pressure is a million times weaker than the gas pressure in the Suns interior, for example they are the drivers of interesting activity, like the prominences and flares of our Sun.Given this, we can wonder what role stars magnetic fields might play when the stars are torn apart in tidal disruption events. Do the fields change what we observe? Are they dispersed during the disruption, or can they be amplified? Might they even be responsible for launching jets of matter from the black hole after the disruption?Star vs. Black HoleIn a recent study, James Guillochon (Harvard-Smithsonian Center for Astrophysics) and Michael McCourt (Hubble Fellow at UC Santa Barbara) have tackled these questions by performing the first simulations of tidal disruptions of stars that include magnetic fields.In their simulations, Guillochon and McCourt evolve a solar-mass star that passes close to a million-solar-mass black hole. Their simulations explore different magnetic field configurations for the star, and they consider both what happens when the star barely grazes the black hole and is only partially disrupted, as well as what happens when the black hole tears the star apart

  5. WHAT IS THE SOURCE OF QUIET SUN TRANSITION REGION EMISSION?

    Energy Technology Data Exchange (ETDEWEB)

    Schmit, D. J.; De Pontieu, Bart [Lockheed-Martin Solar and Astrophysics Laboratory, Palo Alto, CA 94304 (United States)

    2016-11-10

    Dating back to the first observations of the on-disk corona, there has been a qualitative link between the photosphere’s magnetic network and enhanced transition-temperature plasma emission. These observations led to the development of a general model that describes emission structures through the partitioning of the atmospheric volume with different magnetic loop geometries that exhibit different energetic equilibria. Does the internetwork produce transition-temperature emission? What fraction of network flux connects to the corona? How does quiet Sun emission compare with low-activity Sun-like stars? In this work, we revisit the canonical model of the quiet Sun, with high-resolution observations from the Interface Region Imaging Spectrograph ( IRIS ) and HMI in hand, to address those questions. We use over 900 deep exposures of Si iv 1393 Å from IRIS along with nearly simultaneous HMI magnetograms to quantify the correlation between transition-temperature emission structures and magnetic field concentrations through a number of novel statistics. Our observational results are coupled with analysis of the Bifrost MHD model and a large-scale potential field model. Our results paint a complex portrait of the quiet Sun. We measure an emission signature in the distant internetwork that cannot be attributed to network contribution. We find that the dimmest regions of emission are not linked to the local vertical magnetic field. Using the MHD simulation, we categorize the emission contribution from cool mid-altitude loops and high-altitude coronal loops and discuss the potential emission contribution of spicules. Our results provide new constraints on the coupled solar atmosphere so that we can build on our understanding of how dynamic thermal and magnetic structures generate the observed phenomena in the transition region.

  6. Hybrid stars

    Indian Academy of Sciences (India)

    Hybrid stars. AsHOK GOYAL. Department of Physics and Astrophysics, University of Delhi, Delhi 110 007, India. Abstract. Recently there have been important developments in the determination of neutron ... number and the electric charge. ... available to the system to rearrange concentration of charges for a given fraction of.

  7. Pulsating stars

    CERN Document Server

    Catelan, M?rcio

    2014-01-01

    The most recent and comprehensive book on pulsating stars which ties the observations to our present understanding of stellar pulsation and evolution theory.  Written by experienced researchers and authors in the field, this book includes the latest observational results and is valuable reading for astronomers, graduate students, nuclear physicists and high energy physicists.

  8. Variable stars

    International Nuclear Information System (INIS)

    Feast, M.W.; Wenzel, W.; Fernie, J.D.; Percy, J.R.; Smak, J.; Gascoigne, S.C.B.; Grindley, J.E.; Lovell, B.; Sawyer Hogg, H.B.; Baker, N.; Fitch, W.S.; Rosino, L.; Gursky, H.

    1976-01-01

    A critical review of variable stars is presented. A fairly complete summary of major developments and discoveries during the period 1973-1975 is given. The broad developments and new trends are outlined. Essential problems for future research are identified. (B.R.H. )

  9. Astronomy from the Moon and International Lunar Observatory Missions

    Science.gov (United States)

    Durst, S.; Takahashi, Y. D.

    2018-04-01

    Astronomy from the Moon provides a promising new frontier for 21st century astrophysics and related science activity. International Lunar Observatory Association is an enterprise advancing missions to the Moon for observation and communication.

  10. Origin of the Earth–Moon system

    Indian Academy of Sciences (India)

    However, during the course of time some incon- sistencies of the impact hypothesis have surfaced. It is not the ... At the same time, there are some important differences between the composition of the Earth and that of ... primitive carbonaceous chondrites but to a much lesser degree. At first glance, depletion of the Moon in ...

  11. Mr.Seah Moon Ming Leadership & Management

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    @@ Life and Work Philosophy Seah Moon Ming considers life a continuous journey of learning,adaptation and attainment of goals.He believes that as long as there are changes,you will need to learn - to learn to adapt and to play a useful role in a dynamic and ever-changing world.

  12. Telerobotic exploration and development of the Moon

    Indian Academy of Sciences (India)

    There has been a debate for the last thirty years about the relative merits of human versus robotic systems and we argue here that both are essential components for successful lunar exploration and development.We examine the role of robots in the next phases of exploration and human development of the Moon.

  13. Europe over the moon with new satellite

    CERN Document Server

    2002-01-01

    ESA has taken delivery of a 3kg device that it plans to use to complete the first high-resolution map of the moon. The D-CIXS (Demonstration of a Compact Imaging X-Ray Spectrometer) will be aboard the SMART-1 satellite to be launched from French Guyana in South America next February (1/2 page).

  14. Sketching the moon an astronomical artist's guide

    CERN Document Server

    Handy, Richard; McCague, Thomas; Rix, Erika; Russell, Sally

    2012-01-01

    Soon after you begin studying the sky through your small telescope or binoculars, you will probably be encouraged by others to make sketches of what you see. Sketching is a time-honored tradition in amateur astronomy and dates back to the earliest times, when telescopes were invented. Even though we have lots of new imaging technologies nowadays, including astrophotography, most observers still use sketching to keep a record of what they see, make them better observers, and in hopes of perhaps contributing something to the body of scientific knowledge about the Moon. Some even sketch because it satisfies their artistic side. The Moon presents some unique challenges to the astronomer-artist, the Moon being so fond of tricks of the light. Sketching the Moon: An Astronomical Artist’s Guide, by five of the best lunar observer-artists working today, will guide you along your way and help you to achieve really high-quality sketches. All the major types of lunar features are covered, with a variety of sketching te...

  15. Space architecture for MoonVillage

    Science.gov (United States)

    Sherwood, Brent

    2017-10-01

    The concept of a multinational MoonVillage, as proposed by Jan Wörner of ESA, is analyzed with respect to diverse factors affecting its implementation feasibility: potential activities and scale as a function of location, technology, and purpose; potential participants and their roles; business models for growth and sustainability as compared to the ISS; and implications for the field of space architecture. Environmental and operations constraints that govern all types of MoonVillage are detailed. Findings include: 1) while technically feasible, a MoonVillage would be more distributed and complex a project than the ISS; 2) significant and distinctive opportunities exist for willing participants, at all evolutionary scales and degrees of commercialization; 3) the mixed-use space business park model is essential for growth and permanence; 4) growth depends on exporting lunar material products, and the rate and extent of growth depends on export customers including terrestrial industries; 5) industrial-scale operations are a precondition for lunar urbanism, which goal in turn dramatically drives technology requirements; but 6) industrial viability cannot be discerned until significant in situ operations occur; and therefore 7) government investment in lunar surface operations is a strictly enabling step. Because of the resources it could apply, the U.S. government holds the greatest leverage on growth, no matter who founds a MoonVillage. The interplanetary business to be built may because for engagement.

  16. 7Li production in bouncing supermassive stars

    International Nuclear Information System (INIS)

    Norgaard, H.; Fricke, K.J.

    1976-01-01

    Nucleosynthesis in detailed models for bouncing supermassive stars is investigated. We consider a non-rotating 5.2 x 10 5 M(sun) and a rotating 3 x 10 6 M (sun) star and follow the time evolution of the abundances throughout the quasistatic contraction phase as well as through the implosion-explosion. Our numerical network integrations show that explosions of such objects cause predominantly the enrichment of 7 Li. Typical enhancement factors for 7 Li with respect to the 'universal' value of Cameron (1973) are of the order of 1,000, whereas those of 13 C, 15 N and 17 O are of the order of 100 or less. (orig./WL) [de

  17. STAR FORMATION IN THE TAURUS FILAMENT L 1495: FROM DENSE CORES TO STARS

    International Nuclear Information System (INIS)

    Schmalzl, Markus; Kainulainen, Jouni; Henning, Thomas; Launhardt, Ralf; Quanz, Sascha P.; Alves, Joao; Goodman, Alyssa A.; Pineda, Jaime E.; Roman-Zuniga, Carlos G.

    2010-01-01

    We present a study of dense structures in the L 1495 filament in the Taurus Molecular Cloud and examine its star-forming properties. In particular, we construct a dust extinction map of the filament using deep near-infrared observations, exposing its small-scale structure in unprecedented detail. The filament shows highly fragmented substructures and a high mass-per-length value of M line = 17 M sun pc -1 , reflecting star-forming potential in all parts of it. However, a part of the filament, namely B 211, is remarkably devoid of young stellar objects. We argue that in this region the initial filament collapse and fragmentation is still taking place and star formation is yet to occur. In the star-forming part of the filament, we identify 39 cores with masses from 0.4 to 10 M sun and preferred separations in agreement with the local Jeans length. Most of these cores exceed the Bonnor-Ebert critical mass, and are therefore likely to collapse and form stars. The dense core mass function follows a power law with exponent Γ = 1.2 ± 0.2, a form commonly observed in star-forming regions.

  18. Star Masses and Star-Planet Distances for Earth-like Habitability.

    Science.gov (United States)

    Waltham, David

    2017-01-01

    This paper presents statistical estimates for the location and duration of habitable zones (HZs) around stars of different mass. The approach is based upon the assumption that Earth's location, and the Sun's mass, should not be highly atypical of inhabited planets. The results support climate-model-based estimates for the location of the Sun's HZ except models giving a present-day outer-edge beyond 1.64 AU. The statistical approach also demonstrates that there is a habitability issue for stars smaller than 0.65 solar masses since, otherwise, Earth would be an extremely atypical inhabited world. It is difficult to remove this anomaly using the assumption that poor habitability of planets orbiting low-mass stars results from unfavorable radiation regimes either before, or after, their stars enter the main sequence. However, the anomaly is well explained if poor habitability results from tidal locking of planets in the HZs of small stars. The expected host-star mass for planets with intelligent life then has a 95% confidence range of 0.78 M ⊙ planets with at least simple life is 0.57 M ⊙  < M < 1.64 M ⊙ . Key Words: Habitability-Habitable zone-Anthropic-Red dwarfs-Initial mass function. Astrobiology 17, 61-77.

  19. Towards a Moon Village : Community Workshops Highlights

    Science.gov (United States)

    Foing, Bernard H.

    2016-07-01

    A series of Moon Village Workshops were organised at ESTEC and at ILEWG community events in 2015 and 2016. They gathered a multi-disciplinary group of professionals from all around the world to discuss their ideas about the concept of a Moon Village, the vision of ESA's Director General (DG) Jan Woerner of a permanent lunar base within the next decades [1]. Three working groups focused on 1) Moon Habitat Design; 2) science and technology potentials of the Moon Village, and 3) engaging stake-holders [2-3]. Their results and recommendations are presented in this abstract. The Moon Habitat Design group identified that the lunar base design is strongly driven by the lunar environment, which is characterized by high radiation, meteoroids, abrasive dust particles, low gravity and vacuum. The base location is recommended to be near the poles to provide optimized illumination conditions for power generation, permanent communication to Earth, moderate temperature gradients at the surface and interesting subjects to scientific investigations. The abundance of nearby available resources, especially ice at the dark bottoms of craters, can be exploited in terms of In-Situ Resources Utilization (ISRU). The identified infrastructural requirements include a navigation, data- & commlink network, storage facilities and sustainable use of resources. This involves a high degree of recycling, closed-loop life support and use of 3D-printing technology, which are all technologies with great potential for terrestrial spin-off applications. For the site planning of the Moon Village, proven ideas from urban planning on Earth should be taken into account. A couple of principles, which could improve the quality of a long-term living milieu on the Moon, are creating spacious environments, visibility between interior and exterior spaces, areas with flora, such as gardens and greenhouses, establishing a sustainable community and creating social places for astronauts to interact and relax. The

  20. Star Products and Applications

    OpenAIRE

    Iida, Mari; Yoshioka, Akira

    2010-01-01

    Star products parametrized by complex matrices are defined. Especially commutative associative star products are treated, and star exponentials with respect to these star products are considered. Jacobi's theta functions are given as infinite sums of star exponentials. As application, several concrete identities are obtained by properties of the star exponentials.