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. The sky-disk of Nebra - sun, moon and stars (German Title: Die Himmelsscheibe von Nebra - Sonne, Mond und Sterne)

    Science.gov (United States)

    Schlosser, Wolfhard

    No prehistorical find anywhere shows such a clear proof for the interest of prehistoric mankind in cosmic events as does the Nebra sky-disk. With an almost 100 percent probability, the (originally) 32 centimeter-size gold plates represent stars. According to astronomical analysis, the group of seven closely arranged plates represent the Pleiades (The Seven Sisters). Statistical research strengthens the view that the remaining 25 gold plates cannot be assigned to individual constellations, but represent the general starry night sky. Without much restriction, the two lateral arcs (added at a later time) can be assigned to those horizon regions which are accessible to the sun over the year for the geographic latitude of Saxe-Anhalt. A slight asymmetry of these arcs with respect to the center of the disk makes it possible that the upper solar limb was observed. The lower pinnate arc with an interior drawing - also a later addition - can be interpreted as the solar barque, which, because of the above-mentioned asymmetry, indicates the southern direction of the sky-disk. An investigation of the visibilities of the Pleiades for the finding spot of the Mittelberg indicates that only their last evening visibility (March 10 of our calendar) and their first morning setting (October 17) were of calendary use in the early Bronze Age. At these times, the Pleiades were found in those parts of the sky which are the domain of the young crescent shortly after new moon (March) and of the full moon (October). This would make possible a suitable assignment of the sky-disk's crescent- and round object to both these phases of the moon. The said dates describe quite well the beginning and the end of the agricultural year for the region where the sky-disk was found. Such a working hypothesis (‘rural year’) is not at all unique, but is supported by numerous peasant-rules referring to the Pleiades from antiquity up to the present time. In particular, Lithuanian peasants observed until

  3. 'My Sun' and 'Guided by the Moon'

    Directory of Open Access Journals (Sweden)

    Rebecca Baillie

    2013-07-01

    Full Text Available My Sun and Guided by the Moon (2012 show the heavily pregnant artist with her swollen belly covered in gold and silver leaf. The work is suggestive that the connectivity experienced by an expectant mother, extends outwards, even as far as her relationship with the cosmos. The 'sun' portrait was taken on a bright September morning, and its partner image, the following October, on the night of a full moon. Female cycles and the importance of time passing during a pregnancy are referenced. Interestingly, bearing in mind that the artist gave birth to a son in November, creating the 'moon' portrait felt like a familiar, empowering and yet isolated expression of selfhood, whilst the 'sun/son' version exuded the energy of a collaboration, and stimulated feelings of joy, liberation and potentiality. By seeming contradiction, the boy was born on a full moon, exactly a month to the day that Guided by the Moon was taken.

  4. Stars resembling the Sun

    Science.gov (United States)

    Cayrel de Strobel, G.

    This review is primarily directed to the question whether photometric solar analogues remain such when subjected to detailed spectroscopic analyses and interpreted with the help of internal stucture models. In other words, whether the physical parameters: mass, chemical composition, age (determining effective temperature and luminosity), chromospheric activity, equatorial rotation, lithium abundance, velocity fields etc., we derive from the spectral analysis of a photometric solar analogue, are really close to those of the Sun. We start from 109 photometric solar analogues extracted from different authors. The stars selected had to satisfy three conditions: i) their colour index (B-V) must be contained in the interval: Δ (B-V) = 0.59-0.69, ii) they must possess a trigonometric parallax, iii) they must have undergone a high resolution detailed spectroscopic analysis. First, this review presents photometric and spectrophotometric researches on solar analogues and recalls the pionneering work on these stars by the late Johannes Hardorp. After a brief discussion on low and high resolution spectroscopic researches, a comparison is made between effective temperatures as obtained, directly, from detailed spectral analyses and those obtained, indirectly, from different photometric relations. An interesting point in this review is the discussion on the tantalilizing value of the (B-V)solar of the Sun, and the presentation of a new reliable value of this index. A short restatement of the kinematic properties of the sample of solar analogues is also made. And, finally, the observational ( T eff, M bol) diagram, obtained with 99 of the initially presented 109 analogues, is compared to a theoretical ( T eff, M bol) diagram. This latter has been constructed with a grid of internal structure models for which, (very important for this investigation), the Sun was used as gauge. In analysing the position, with respect to the Sun, of each star we hoped to find a certain number of

  5. The sun, moon and stars of the southern Levant at Gezer and Megiddo: Cultural astronomy in Chalcolithic/Early and Middle Bronze Ages

    Science.gov (United States)

    Gardner, Sara Lee

    Astronomical images are found on monumental structures and decorative art, and metaphorically in seasonal myths, and are documented by calendars. In Israel and the southern Levant, images of the sun, the moon, and the stars were common decorating motifs. They were found on walls, pottery, and seals and date to as early as the Chalcolithic period; for example, the wall painting of a star at Teleilat Ghassul (North 1961). This dissertation establishes that the people of the Levant were aware of the apparent movement of the sun, and this will be discussed in Chapter 4. They began recording through representation drawings, astronomical phenomena no later than the Chalcolithic/Early Bronze Age and continued to do so late into the Middle Bronze Age. The argument moves beyond the simple use of symbols to the use of images to represent constellations, with the focus on the constellation Leo in Chapter 5. Furthermore, the use of astronomy as a power and political tool is also suggested in Chapter 6. Nonetheless, the primary purpose that is addressed here is the tendency in Syro-Palestinian archaeology has been to attribute technological evidence found in the northern and southern Levant as diffused from Egypt or Assyria, particularly astronomy. This dissertation firmly establishes that astronomy was used in the southern Levant before any significant contact with the civilizations of Egypt or Assyria.

  6. 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.

  7. The sun, our star

    Science.gov (United States)

    Noyes, R. W.

    Observational data, analytical models, and instrumentation used to study the sun and its evolution are detailed, and attention is given to techniques for converting solar energy to useful power on earth. The star ignited when the mutual gravitational attractions of dust and vapor in a primordial cloud in the Galaxy caused an in-rush of accelerating particles which eventually became dense enough to ignite. The heat grew until inward rushing matter was balanced by outward moving radiative forces. The planets formed from similar debris, and solar radiation is suggested to have triggered the chemical reactions giving rise to life on earth. Visual, spectroscopic, coronagraphic, and UV observations of the sun from the ground and from spacecraft, particularly Skylab, are described, together with features of the solar surface, magnetic field, sunspots, and coronal loops. Models for the processes that occur in the solar interior are explored, as are the causes of solar flares. Attention is given to solar cells, heliostat arrays, wind turbines, and water turbines as means to convert, either directly or indirectly, the earth-bound solar energy to electrical and thermal power. Finally, the life cycle of the sun, about 9 billion yr in duration, is summarized, noting the current status of midlife.

  8. Haloes around the Moon and the Sun

    Science.gov (United States)

    Gaina, Alex; Gaina, Danielle A.

    2008-10-01

    The authors observations of the Haloes around the Moon and the Sun during few last years are reported. A Historical review of the phenomenon is given since the observations by Benvenuto Cellini and Gaston Tissandier is given. A photograph (from eight available) of the Halo around the Sun observed in Chisinau on 21 May 2007 is included. The Halo from 21 May 2007 occured after a very fast increasing of the air temperature during one day by more than 15 Deg. The authors consider, that the phenomenon is due to scattering of light on Cirri clouds(7 km altitude), present on the sky during that day. They formed due to very fast heating.

  9. The Sun: Our Nearest Star

    Science.gov (United States)

    Adams, M. L.; Six, N. Frank (Technical Monitor)

    2002-01-01

    We have in our celestial backyard, a prime example of a variable star. The Sun, long thought to be "perfect" and unvarying, began to reveal its cycles in the early 1600s as Galileo Galilei and Christoph Scheiner used a telescope to study sunspots. For the past four hundred years, scientists have accumulated data, showing a magnetic cycle that repeats, on average, every eleven (or twenty-two) years. In addition, modern satellites have shown that the energy output at radio and x-ray wavelengths also varies with this cycle. This talk will showcase the Sun as a star and discuss how solar studies may be used to understand other stars.

  10. Earth, Moon, Sun, and CV Accretion Disks

    CERN Document Server

    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 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 differential rotation and effects on the disk by the accretion stream must be addressed. Our a...

  11. The Impact of Stars on Moons

    Science.gov (United States)

    Kohler, Susanna

    2017-01-01

    . The black dotted line shows how the critical semimajor axis for stability evolves with time as the planet loses mass. [Yang et al. 2016]Yang and collaborators find that the photoevaporation process has a critical impact on whether or not the moons remain in stable orbits. As the photoevaporation drives mass loss of the planet, the planets gravitational influence shrinks and the orbits of its exomoons expand and become more eccentric. Eventually these orbits can reach critical values where theyre no longer stable, often resulting in systems with only one or no surviving moons.The team finds that even in the best-case scenario of only small moons, no more than roughly a quarter of them survive the simulation still in orbit around their planet. In simulations that include larger moons further out, the system is even more likely to become unstable as the planet loses mass, with more moons ultimately escaping.What happens to the moons that escape? Some leave the planetmoon system to become planet-like objects that remain in orbit around the host star. Others are smashed to bits when they collide with other moons or with the planet. And some can even escape their entire solar system to become a free-floating object in the galaxy!Based on their simulations, the authors speculate that exomoons are less common around planets that are close to their host stars (0.1 AU). Furthermore, exomoons are likely less common in solar systems around especially X-ray-luminous stars (e.g., M dwarfs) that can more easily drive photoevaporation. For these reasons, our best chances for finding exomoons in future missions will be aroundstars that are more Sun-like, orbitingplanets that arent too close to their hosts.CitationMing Yang et al 2016 ApJ 833 7. doi:10.3847/0004-637X/833/1/7

  12. 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.

  13. 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.

  14. 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...

  15. 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

  16. The skylight gradient of luminance helps sandhoppers in sun and moon identification.

    Science.gov (United States)

    Ugolini, Alberto; Galanti, Giuditta; Mercatelli, Luca

    2012-08-15

    To return to the ecologically optimal zone of the beach, the sandhopper Talitrus saltator (Montagu) maintains a constant sea-land direction based on the sun and moon compasses. In this study, we investigated the role of the skylight gradient of luminance in sun and moon identification under natural and artificial conditions of illumination. Clock-shifted (inverted) sandhoppers tested under the sun (during their subjective night) and under the full moon (during their subjective day) exhibit orientation in accordance with correct identification of the sun and the moon at night. Tested in artificial conditions of illumination at night without the artificial gradient of luminance, the artificial astronomical cue is identified as the moon even when the conditions of illumination allow sun compass orientation during the day. When the artificial gradient of luminance is added, the artificial astronomical cue is identified as the sun. The role of the sky gradient of luminance in sun and moon identification is discussed on the basis of present and past findings.

  17. The Association of the Moon and the Sun with Large Earthquakes

    CERN Document Server

    Chiou, Lyndie

    2012-01-01

    The role of the moon in triggering earthquakes has been studied since the early 1900s. Theory states that as land tides swept by the moon cross fault lines, stress in the Earth's plates intensifies, increasing the likelihood of small earthquakes. This paper studied the association of the moon and sun with larger magnitude earthquakes (magnitude 5 and greater) using a worldwide dataset from the USGS. Initially, the positions of the moon and sun were considered separately. The moon showed a reduction of 1.74% (95% confidence) in earthquakes when it was 10 hours behind a longitude on earth and a 1.62% increase when it was 6 hours behind. The sun revealed even weaker associations (<1%). Binning the data in 6 hours quadrants (matching natural tide cycles) reduced the associations further. However, combinations of moon-sun positions displayed significant associations. Cycling the moon and sun in all possible quadrant permutations showed a decrease in earthquakes when they were paired together on the East and Wes...

  18. A search for connections of gravitational influence of the Moon and the Sun with earthquakes of Carpathian region of Ukraine

    Science.gov (United States)

    Kazantsev, A. M.; Kazantseva, L.

    2016-05-01

    If there is an influence of the Moon and Sun on the occurrence of earthquakes, the physical nature of such influence can only be the gravitational. A possible gravitational influence is caused by the resultant tidal forces of the Moon and the Sun, but not by their separate actions. The calculations algorithm for the tidal forces of the Sun and Moon and for their resultant is described. Relative changes of these forces for different zones on the earth's surface in time and at various depths are presented. Preliminary recommendations for searching of connections of gravitational influence of the Moon and the Sun with earthquakes was made.

  19. Simple transfer calibration method for a Cimel Sun-Moon photometer: calculating lunar calibration coefficients from Sun calibration constants.

    Science.gov (United States)

    Li, Zhengqiang; Li, Kaitao; Li, Donghui; Yang, Jiuchun; Xu, Hua; Goloub, Philippe; Victori, Stephane

    2016-09-20

    The Cimel new technologies allow both daytime and nighttime aerosol optical depth (AOD) measurements. Although the daytime AOD calibration protocols are well established, accurate and simple nighttime calibration is still a challenging task. Standard lunar-Langley and intercomparison calibration methods both require specific conditions in terms of atmospheric stability and site condition. Additionally, the lunar irradiance model also has some known limits on its uncertainty. This paper presents a simple calibration method that transfers the direct-Sun calibration constant, V0,Sun, to the lunar irradiance calibration coefficient, CMoon. Our approach is a pure calculation method, independent of site limits, e.g., Moon phase. The method is also not affected by the lunar irradiance model limitations, which is the largest error source of traditional calibration methods. Besides, this new transfer calibration approach is easy to use in the field since CMoon can be obtained directly once V0,Sun is known. Error analysis suggests that the average uncertainty of CMoon over the 440-1640 nm bands obtained with the transfer method is 2.4%-2.8%, depending on the V0,Sun approach (Langley or intercomparison), which is comparable with that of lunar-Langley approach, theoretically. In this paper, the Sun-Moon transfer and the Langley methods are compared based on site measurements in Beijing, and the day-night measurement continuity and performance are analyzed.

  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, wit

  2. "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…

  3. 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…

  4. AsteroFLAG - from the Sun to the stars

    Energy Technology Data Exchange (ETDEWEB)

    Chaplin, W J; Elsworth, Y [School of Physics and Astronomy, University of Birmingham, Edgbaston, Birmingham, B15 2TT (United Kingdom); Appourchaux, T; Baudin, F [Institut d' Astrophysique Spatiale (IAS), Batiment 121, F-91405, Orsay Cedex (France); Arentoft, T; Christensen-Dalsgaard, J; Kjeldsen, H [Department of Physics and Astronomy, University of Aarhus, DK-8000 Aarhus C (Denmark); Ballot, J [Max-Planck-Institut fuer Astrophysik, Karl-Schwarzschild-Str. 1, Postfach 1317, 85741, Garching (Germany); Bazot, M [Centro de AstrofIsica Universidade do Porto, 4150-762 Porto (Portugal); Bedding, T R [School of Physics, University of Sydney, Sydney, NSW 2006 (Australia); Creevey, O L [High Altitude Observatory, National Center for Atmospheric Research, Boulder, CO 80301 (United States); Duez, V; Garcia, R A [DAPNIA/CEA, CE Saclay, FR-91191 Gif-sur-Yvette Cedex (France); Fletcher, S T [Faculty of Arts, Computing, Engineering and Sciences, Sheffield Hallam University, Sheffield S1 1WB (United Kingdom); Gough, D O; Houdek, G [Institute of Astronomy, University of Cambridge, Cambridge CB3 0HA (United Kingdom); Jimenez, A; Jimenez-Reyes, S J [Instituto de Astrofisica de Canarias, E-38200, La Laguna, Tenerife (Spain); Lazrek, M [LPHEA, Faculte des Sciences Semlalia, Universite Cadi Ayyad, Marrakech (Morocco); Leibacher, J W, E-mail: w.j.chaplin@bham.ac.uk (and others)

    2008-10-15

    We stand on the threshold of a critical expansion of asteroseismology of Sun-like stars, the study of stellar interiors by observation and analysis of their global acoustic modes of oscillation. The Sun-like oscillations give a very rich spectrum allowing the internal structure and dynamics to be probed down into the stellar cores to very high precision. Asteroseismic observations of many stars will allow multiple-point tests of crucial aspects of stellar evolution and dynamo theory. The aims of the asteroFLAG collaboration are to help the community to refine existing, and to develop new, methods for analysis of the asteroseismic data on the Sun-like oscillators.

  5. Visualizing Sun-Earth-Moon Relationships through Hands-On Modeling

    Science.gov (United States)

    Morton, Abby

    2013-04-01

    "Tell me and I forget, teach me and I may remember, involve me and I learn." -Benjamin Franklin Understanding the spatial relationships between the sun, Earth and Moon is fundamental to any basic earth science education. Since both of the following concepts involve shadows on three-dimensional spheres, seeing them on paper is not often conducive to understanding. In the first activity, students use five Styrofoam balls painted to look like the sun and the four positions of the earth in each season. Students position the Earth-balls in their correct order around the sun and translate what they are seeing onto paper. In the second activity, students hold up a Styrofoam ball painted half white, half black. A picture of the sun is projected at the front of the classroom. They move the ball around their heads as if they were the Earth, keeping the lit side of the moon always facing the sun. They then draw the phases of the moon as they see them.

  6. Grand Challenges in the Physics of the Sun and Sun-like Stars

    CERN Document Server

    Thompson, Michael J

    2014-01-01

    The study of stellar structure and evolution is one of the main building blocks of astrophysics, and the Sun has an importance both as the star that is most amenable to detailed study and as the star that has by far the biggest impact on the Earth and near-Earth environment through its radiative and particulate outputs. Over the past decades, studies of stars and of the Sun have become somewhat separate. But in recent years, the rapid advances in asteroseismology, as well as the quest to better understand solar and stellar dynamos, have emphasized once again the synergy between studies of the stars and the Sun. In this article I have selected two "grand challenges" both for their crucial importance and because I thnk that these two problems are tractable to significant progress in the next decade. They are (i) understanding how solar and stellar dynamos generate magnetic field, and (ii) improving the predictability of geo-effective space weather.

  7. The Sun: A Star at the Center of Our Solar System

    Science.gov (United States)

    Adams, Mitzi L.

    2016-01-01

    There is a star at the center of our solar system! But what is a star? How do stars work? What are the characteristics of our Sun and how are these traits different from other stars? How does the Sun compare to stars such as Betelgeuse and Rigel? "Will the Sun end its life with a bang or a whimper?"

  8. Two sun-like superflare stars rotating as slow as the Sun*

    Science.gov (United States)

    Nogami, Daisaku; Notsu, Yuta; Honda, Satoshi; Maehara, Hiroyuki; Notsu, Shota; Shibayama, Takuya; Shibata, Kazunari

    2014-04-01

    We report on the results of high dispersion spectroscopy of two "superflare stars," KIC 9766237 and KIC 9944137 with Subaru/HDS. Superflare stars are G-type main sequence stars, but show gigantic flares compared to the Sun, which have recently been discovered in the data obtained with the Kepler spacecraft. Though most of these stars are thought to have a rotation period shorter than 10 d on the basis of photometric variabilities, the two targets of the present paper are estimated to have rotation periods of 21.8 d and 25.3 d. Our spectroscopic results clarified that these stars have stellar parameters similar to those of the Sun in terms of the effective temperature, surface gravity, and metallicity. The projected rotational velocities derived by us are consistent with the photometric rotation period, indicating a fairly high inclination angle. The average strength of the magnetic field on the surface of these stars are estimated to be 1-20 G, by using the absorption line of Ca II 8542. We could not detect any hint of binarity in our spectra, although more data are needed to firmly rule out the presence of an unseen low-mass companion. These results claim that the spectroscopic properties of these superflare stars are very close to those of the Sun, and support the hypothesis that the Sun might cause a superflare.

  9. Photometric Variations In The Sun And Solar-Type Stars

    Science.gov (United States)

    Giampapa, Mark

    The rich array of solar magnetic field-related phenomena we see occurs not only on stellar counterparts of our Sun but in stars that represent significant departures in their fundamental parameters from those of the Sun. Though these phenomena appear energetically negligible when compared to the total luminosity of stars, they nevertheless govern the angular momentum evolution and modulate the radiative and particle output of the Sun and late-type stars. The term "The Solar-Stellar Connection" has been coined to describe the solar-stellar synergisms in the investigation of the generation, emergence and coupling of magnetic fields with the outer solar-stellar atmosphere to produce what we broadly refer to as magnetic activity. With the discovery of literally thousands of planets beyond our solar system, the Solar-Stellar-Planet Connection is quickly emerging as a new area of investigation of the impacts of magnetic activity on exoplanet atmospheres. In parallel with this rapid evolution in our perspectives is the advent of transformative facilities for the study of the Sun and the dynamic Universe. The primary focus of this invited talk will be on photometric variations in solar-type stars and the Sun. These brightness variations are associated with thermal homogeneities typically defined by magnetic structures that are also spatially coincident with key radiative proxies. Photometric variability in solar-type stars and the Sun includes transient brightening, rotational modulation by cool spots and cycle-related variability, each with a characteristic signature in time and wavelength. The emphasis of this presentation will be on the relationship between broadband photometric variations and magnetic field-related activity in solar-type stars and the Sun. Facets of this topic will be discussed both retrospectively and prospectively as we enter a revolutionary, new era for astronomy.

  10. New Suns in the Cosmos II: Differential rotation in $Kepler$ Sun-like stars

    CERN Document Server

    Chagas, M L Das; Costa, A D; Lopes, C E Ferreira; Sobrinho, R Silva; Paz-Chinchón, F; Leão, I C; Valio, A; de Freitas, D B; Martins, B L Canto; Lanza, A F; De Medeiros, J R

    2016-01-01

    The present study reports the discovery of Sun-like stars, namely main-sequence stars with $T_{\\rm eff}$, $\\log g$ and rotation periods $P_{rot}$ similar to solar values, presenting evidence of surface differential rotation. An autocorrelation of the time series was used to select stars presenting photometric signal stability from a sample of 881 stars with light curves collected by the $Kepler$ space-borne telescope, in which we have identified 17 stars with stable signals. A simple two-spot model together with a Bayesian information criterion were applied to these stars in the search for indications of differential rotation; in addition, for all 17 stars, it was possible to compute the spot rotation period $P$, the mean values of the individual spot rotation periods and their respective colatitudes, and the relative amplitude of the differential rotation.

  11. New Suns in the Cosmos II: differential rotation in Kepler Sun-like stars

    Science.gov (United States)

    Das Chagas, M. L.; Bravo, J. P.; Costa, A. D.; Ferreira Lopes, C. E.; Silva Sobrinho, R.; Paz-Chinchón, F.; Leão, I. C.; Valio, A.; de Freitas, D. B.; Canto Martins, B. L.; Lanza, A. F.; De Medeiros, J. R.

    2016-12-01

    The present study reports the discovery of Sun-like stars, namely main-sequence stars with Teff, log g and rotation periods Prot similar to solar values, presenting evidence of surface differential rotation (DR). An autocorrelation of the time series was used to select stars presenting photometric signal stability from a sample of 881 stars with light curves collected by the Kepler space-borne telescope, in which we have identified 17 stars with stable signals. A simple two-spot model together with a Bayesian information criterion were applied to these stars in the search for indications of DR; in addition, for all 17 stars, it was possible to compute the spot rotation period P, the mean values of the individual spot rotation periods and their respective colatitudes, and the relative amplitude of the DR.

  12. 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

  13. Study of the Shadows of the Moon and the Sun with VHE Cosmic Rays

    CERN Document Server

    Atkins, R; Berley, D; Chen, M L; Coyne, D G; Delay, R S; Dingus, B L; Dorfan, D E; Ellsworth, R W; Evans, D; Falcone, A D; Fleysher, L; Fleysher, R; Gisler, G; Goodman, J A; Haines, T J; Hoffman, C M; Hugenberger, S; Kelley, L A; Leonor, I; Macri, J R; McConnell, M; McCullough, J F; McEnery, J E; Miller, R S; Mincer, A I; Morales, M F; Némethy, P; Ryan, J M; Schneider, M; Shen, B; Shoup, A L; Sinnis, G; Smith, A J; Sullivan, G W; Thompson, T N; Tümer, T O; Wang, K; Wascko, M O; Westerhoff, S; Williams, D A; Yang, T; Yodh, G B

    1999-01-01

    Milagrito, a prototype for the Milagro detector, operated for 15 months in 1997-8 and collected 8.9 billion events. It was the first extensive air shower (EAS) array sensitive to showers intiated by primaries with energy below 1 TeV. The shadows of the sun and moon observed with cosmic rays can be used to study systematic pointing shifts and measure the angular resolution of EAS arrays. Below a few TeV, the paths of cosmic rays coming toward the earth are bent by the helio- and geo-magnetic fields. This is expected to distort and displace the shadows of the sun and the moon. The moon shadow, offset from the nominal (undeflected) position, has been observed with high statistical significance in Milagrito. This can be used to establish energy calibrations, as well as to search for the anti-matter content of the VHE cosmic ray flux. The shadow of the sun has also been observed with high significance.

  14. Are the majority of Sun-like stars single?

    CERN Document Server

    Whitworth, A P

    2015-01-01

    It has recently been suggested that, in the field, $\\sim\\!\\!56\\%$ of Sun-like stars ($0.8\\,{\\rm M}_{_\\odot}\\lesssim M_\\star\\lesssim 1.2\\,{\\rm M}_{_\\odot}$) are single. We argue here that this suggestion may be incorrect, since it appears to be based on the multiplicity frequency of systems with Sun-like primaries, and therefore takes no account of Sun-like stars that are secondary (or higher-order) components in multiple systems. When these components are included in the reckoning, it seems likely that only $\\sim\\!46\\%$ of Sun-like stars are single. This estimate is based on a model in which the system mass function has the form proposed by Chabrier, with a power-law Salpeter extension to high masses; there is a flat distribution of mass ratios; and the probability that a system of mass $M$ is a binary is $\\,0.50 + 0.46\\log_{_{10}}\\!\\left(M/{\\rm M}_{_\\odot}\\right)\\,$ for $\\,0.08\\,{\\rm M}_{_\\odot}\\leq M\\leq 12.5\\,{\\rm M}_{_\\odot}$, $\\,0\\,$ for $\\,M12.5\\,{\\rm M}_{_\\odot}$. The constants in this last relation ar...

  15. The Sun. A typical star in the solar neighborhood?

    CERN Document Server

    Melendez, Jorge

    2013-01-01

    The Sun is used as the fundamental standard in chemical abundance studies, thus it is important to know whether the solar abundance pattern is representative of the solar neighborhood. Albeit at low precision (0.05 - 0.10 dex) the Sun seems to be a typical solar-metallicity disk star, at high precision (0.01 dex) its abundance pattern seems abnormal when compared to solar twins. The Sun shows a deficiency of refractory elements that could be due to the formation of terrestrial planets. The formation of giant planets may also introduce a signature in the chemical composition of stars. We discuss both planet signatures and also the enhancement of neutron-capture elements in the solar twin 18 Sco.

  16. Description of the Sun as a Star: General Physical Characteristics

    Science.gov (United States)

    Kucera, Theresa; Crannell, Carol Jo

    2000-01-01

    Numerical parameters characterizing the size and energy output of the sun are presented. These values are the standard yardstick by which other stars are measured. The large number of significant digits tabulated here serve mainly to illustrate the precision to which these parameters are known. Also listed are parameters characterizing the earth's orbit around the sun and the intensity of the sun's radiation at the mean orbital distance. The appearance of the sun depends critically on how it is observed. Each type of radiation observed carries specific information about the physical processes at work on the sun. Special types of instruments reveal aspects otherwise invisible. Coronagraphs reveal the dimmer outer regions of the sun's atmosphere otherwise visible only during total solar eclipses. Spectroscopy can reveal motions, magnetic field strengths, temperatures and densities. In situ measurements have revealed the characteristics of the solar wind and extended our knowledge of the solar magnetic field both near the earth and beyond the orbits of the planets. As an example, the sun's disk observed almost simultaneously in six different wavelengths of light is shown. In visible light we can see the white disk of the sun with the dark spots known as sunspots. By analyzing the spectral lines produced by the sun we can measure the strength of the sun's magnetic field at its surface, producing a magnetogram. This magnetogram reveals that the sunspots are regions of intense magnetic field. Further images of the sun reveal that the sunspot regions are just the bases of systems of hot loops which emit radio-waves, ultraviolet light and X-rays. The sun imaged in a spectral line of hydrogen known as "H alpha" is shown. In this line we also see the long dark "filaments". These filaments form in long channels between areas of opposing magnetic field. Such channels can be seen in the ultraviolet image. Data concerning the sun are obtained with many different kinds of

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

    Energy Technology Data Exchange (ETDEWEB)

    Adamson, P.; /Fermilab; Andreopoulos, C.; /Rutherford /Athens U.; Ayres, D.S.; /Argonne; Backhouse, C.; /Oxford U.; Barr, G.; /Oxford U.; Barrett, W.L.; /Western Washington U.; Bishai, M.; /Brookhaven; Blake, A.; /Cambridge U.; Bock, B.; /Minnesota U., Duluth; Bock, G.J.; /Fermilab; Boehnlein, D.J.; /Fermilab /Fermilab

    2010-08-01

    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 {sigma} level and the shadow of the sun at the 3.8 {sigma} 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{sup o}. Hints of Interplanetary Magnetic Field effects were observed in both the sun and moon shadow.

  18. Two Sun-like Superflare Stars Rotating as Slow as the Sun

    CERN Document Server

    Nogami, Daisaku; Honda, Satoshi; Maehara, Hiroyuki; Notsu, Shota; Shibayama, Takuya; Shibata, Kazunari

    2014-01-01

    We report on the results of high dispersion spectroscopy of two `superflare stars', KIC 9766237, and KIC 9944137 with Subaru/HDS. Superflare stars are G-type main sequence stars, but show gigantic flares compared to the Sun, which have been recently discovered in the data obtained with the Kepler spacecraft. Though most of these stars are thought to have a rotation period shorter than 10 days on the basis of photometric variabilities, the two targets of the present paper are estimated to have a rotation period of 21.8 d, and 25.3 d. Our spectroscopic results clarified that these stars have stellar parameters similar to those of the Sun in terms of the effective temperature, surface gravity, and metallicity. The projected rotational velocities derived by us are consistent with the photometric rotation period, indicating a fairy high inclination angle. The average strength of the magnetic field on the surface of these stars are estimated to be 1-20 G, by using the absorption line of Ca II 8542. We could not det...

  19. The Colorful Demise of a Sun-like Star

    Science.gov (United States)

    2007-01-01

    This image, taken by NASA's Hubble Space Telescope, shows the colorful 'last hurrah' of a star like our Sun. The star is ending its life by casting off its outer layers of gas, which formed a cocoon around the star's remaining core. Ultraviolet light from the dying star makes the material glow. The burned-out star, called a white dwarf, is the white dot in the center. Our Sun will eventually burn out and shroud itself with stellar debris, but not for another 5 billion years. Our Milky Way Galaxy is littered with these stellar relics, called planetary nebulae. The objects have nothing to do with planets. Eighteenth- and nineteenth-century astronomers named them planetary nebulae because through small telescopes they resembled the disks of the distant planets Uranus and Neptune. The planetary nebula in this image is called NGC 2440. The white dwarf at the center of NGC 2440 is one of the hottest known, with a surface temperature of nearly 400,000 degrees Fahrenheit (200,000 degrees Celsius). The nebula's chaotic structure suggests that the star shed its mass episodically. During each outburst, the star expelled material in a different direction. This can be seen in the two bow tie-shaped lobes. The nebula also is rich in clouds of dust, some of which form long, dark streaks pointing away from the star. NGC 2440 lies about 4,000 light-years from Earth in the direction of the constellation Puppis. The image was taken Feb. 6, 2007 with Hubble's Wide Field Planetary Camera 2. The colors correspond to material expelled by the star. Blue corresponds to helium; blue-green to oxygen; and red to nitrogen and hydrogen.

  20. Nocturnal aerosol optical thickness measured with a sun/moon photometer developed by improving the Prede Sky-radiometer

    Science.gov (United States)

    Shiobara, Masataka; Kobayashi, Hiroshi; Hishida, Kosuke; Uchiyama, Akihiro

    2017-04-01

    Sun photometry to obtain the aerosol optical thickness (AOT) needs the sun. Since the moon must be another source of light instead of the sun during night-time, a moon photometer was developed by improving the Prede POM-02 Sky-radiometer to measure the spectral lunar irradiance. The original POM-02 model has an electric dynamic range of 109 to measure both of direct- and circum-solar radiation. The electronics of POM-02 was upgraded to include a 1011 dynamic range for better performance to measure the direct lunar irradiance at the visible range as well as the sun and sky measurements with a single instrument. A CCD-based position sensor was newly developed to track the moon as well as the sun continuously. The position of the moon/sun is determined with accuracy of better than 0.01° by a real-time processing system using the CCD imager. Test measurements with the improved POM-02 instrument were performed for the half to full moon conditions, and showed a good performance for lunar photometry to obtain the nocturnal AOTs.

  1. 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.

  2. 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

  3. 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

  4. Aristarchus's On the Sizes and Distances of the Sun and the Moon: Greek and Arabic Texts

    Science.gov (United States)

    Berggren, J. L.; Sidoli, N.

    2007-05-01

    In the 1920s, T. L. Heath pointed out that historians of mathematics have "given too little attention to Aristarchus". This is still true today. The Greek text of Aristarchus's On the Sizes and Distances of the Sun and the Moon has received little attention; the Arabic editions virtually none. Much of what this text has to tell us about ancient and medieval mathematics and the mathematical sciences has gone unnoticed. It should be taken as an important source for our understanding of the mathematical sciences of the early Hellenistic period.

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

    CERN Document Server

    Lanza, A F; Monaco, L; Haywood, R D

    2016-01-01

    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. 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 programs. We use the Moon, the Galilean satellites, and several asteroids as reflectors to measure the radial velocity of the Sun as a star and correlate it 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. We find that the radial velocity of the Sun as a star is positively correlated with the level of its chromospheric activity at about 95 percent significance level. The amplitude of the long-term variation measured in the 2006-2...

  6. Photometric Variability in Kepler Target Stars: The Sun Among Stars -- A First Look

    CERN Document Server

    Basri, Gibor; Batalha, Natalie; Gilliland, Ronald L; Jenkins, Jon; Borucki, William J; Koch, David; Caldwell, Doug; 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 lightcurves 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 vary similar to rather different stellar properties, at a wide variety of ages. Although Kepler data is 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 t...

  7. HARPS-N observes the Sun as a star

    CERN Document Server

    Dumusque, Xavier; Phillips, David F; Buchschacher, Nicolas; Cameron, Andrew Collier; Cecconi, Massimo; Charbonneau, David; Cosentino, Rosario; Ghedina, Adriano; Latham, David W; Li, Chih-Hao; Lodi, Marcello; Lovis, Christophe; Molinari, Emilio; Pepe, Francesco; Udry, Stephane; Sasselov, Dimitar; Szentgyorgyi, Andrew; Walsworth, Ronald

    2015-01-01

    Radial velocity 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 radial velocity changes. Over seven days of observing in 2014, we show an average 50\\cms radial velocity rms over a few hours of observation. After correcting observed radial velocities for spot and...

  8. Magnetic cycles of Sun-like stars with different levels of coronal and chromospheric activity — comparison with the Sun

    Science.gov (United States)

    Shimanovskaya, Elena; Bruevich, Vasiliy; Bruevich, Elena

    2016-09-01

    The atmospheric activity of the Sun and Sun-like stars is analyzed involving observations from the HK-project at the Mount Wilson Observatory, the California and Carnegie Planet Search Program at the Keck and Lick Observatories and the Magellan Planet Search Program at the Las Campanas Observatory. We show that for stars of F, G and K spectral classes, the cyclic activity, similar to the 11-yr solar cycle, is different: it becomes more prominent in K-stars. Comparative study of Sun-like stars with different levels of chromospheric and coronal activity confirms that the Sun belongs to stars with a low level of chromospheric activity and stands apart among these stars by its minimum level of coronal radiation and minimum level of variations in photospheric flux.

  9. Magnetic cycles of Sun-like stars with different levels of coronal and chromospheric activity -- comparison with the Sun

    CERN Document Server

    Bruevich, E A; Shimanovskaya, E V

    2016-01-01

    The atmospheric activity of the Sun and Sun-like stars is analyzed involving observations from HK-project at the Mount Wilson Observatory, the California and Carnegie Planet Search Program at the Keck and Lick Observatories and the Magellan Planet Search Program at the Las Campanas Observatory. We show that for stars of F, G and K spectral classes, the cyclic activity, similar to the 11-yr solar cycles, is different: it becomes more prominent in K-stars. Comparative study of Sun-like stars with different levels of the chromospheric and coronal activity confirms that the Sun belongs to stars with the low level of the chromospheric activity and stands apart among these stars by the minimum level of its coronal radiation and the minimum level of its variations of the photospheric flux.

  10. Challenges for asteroseismic analysis of Sun-like stars

    CERN Document Server

    Chaplin, W J; Appourchaux, T; Elsworth, Y; New, R; Toutain, T

    2008-01-01

    Asteroseismology of Sun-like stars is undergoing rapid expansion with, for example, new data from the CoRoT mission and continuation of ground-based campaigns. There is also the exciting upcoming prospect of NASA's Kepler mission, which will allow the asteroseismic study of several hundred Sun-like targets, in some cases for periods lasting up to a few years. The seismic mode parameters are the input data needed for making inference on stars and their internal structures. In this paper we discuss the ease with which it will be possible to extract estimates of individual mode parameters, dependent on the mass, age, and visual brightness of the star. Our results are generally applicable; however, we look at mode detectability in the context of the upcoming Kepler observations. To inform our discussions we make predictions of various seismic parameters. To do this we use simple empirical scaling relations and detailed pulsation computations of the stochastic excitation and damping characteristics of the Sun-like...

  11. Astrobiologically Interesting Stars within 10 parsecs of the Sun

    CERN Document Server

    De Mello, G F P; Ghezzi, L

    2006-01-01

    The existence of life based on carbon chemistry and water oceans relies upon planetary properties, chiefly climate stability, and stellar properties, such as mass, age, metallicity and Galactic orbits. The latter can be well constrained with present knowledge. We present a detailed, up-to-date compilation of the atmospheric parameters, chemical composition, multiplicity and degree of chromospheric activity for the astrobiologically interesting solar-type stars within 10 parsecs of the Sun. We determine their state of evolution, masses, ages and space velocities, and produce an optimized list of candidates that merit serious scientific consideration by the future space-based interferometry probes aimed at directly detecting Earth-sized extrasolar planets and seeking spectroscopic infrared biomarkers as evidence of photosynthetic life. The initially selected stars number 33 solar-type within the population of 182 stars (excluding late M-dwarfs) closer than 10 pc. A comprehensive and detailed data compilation fo...

  12. 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.

  13. Catastrophic rotational braking among Sun-like stars. A model of the Sun's rotation evolution

    Science.gov (United States)

    Gondoin, P.

    2017-03-01

    Context. Observations of young open clusters show a bimodal distribution of stellar rotation. In those clusters, Sun-like stars group into two main populations of fast and slow rotators. Beyond an age of approximately 600 Myr, the two populations converge towards a single sequence of slow rotators. Aims: The present study addresses the origin of this bimodal distribution and the cause of its observed evolution. Methods: New prescriptions of mass-loss rate and Alfven radius dependences on Rossby number suggested by observations are implemented in a phenomenological model of angular-momentum loss and redistribution. The obtained model is used to calculate the time evolution of a rotation-period distribution of solar-mass stars similar to that observed in the 5 Myr-old NGC 2362 open cluster. The simulated distributions at subsequent ages are compared with those of h Per, the Pleiades, M 50, M 35, and M 37. Results: The model is able to reproduce the appearance and disappearance of a bimodal rotation-period distribution in open clusters providing that a brief episode of large-angular-momentum loss is included in the early evolution of Sun-like stars. Conclusions: I argue that a transitory episode of large-angular-momentum loss occurs on Sun-like stars with Rossby numbers between 0.13 and 0.3. This phenomenon of enhanced magnetic braking by stellar wind would be mainly driven by a rapid increase of mass loss at a critical rotation rate. This scenario accounts for the bimodal distribution of stellar rotation in open clusters with ages between 20-30 Myr and approximately 600 Myr. The mass-loss rate increase could account for a significant fraction of the X-ray luminosity decay of Sun-like stars in the 0.13-0.3 Rossby number range where a transition from the saturated to the non-saturated regime of X-ray emission is observed. Observed correlations between Li abundance and rotation sequences in the Pleiades and M 34 clusters support this scenario.

  14. 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

  15. Detection of Planetary Transits Across a Sun-like Star

    CERN Document Server

    Charbonneau, D; Latham, D W; Mayor, M; Charbonneau, David; Brown, Timothy M.; Latham, David W.; Mayor, Michel

    1999-01-01

    We report high precision, high cadence photometric measurements of the star HD 209458, which is known from radial velocity measurements to have a planetary mass companion in a close orbit. We detect two separate transit events at times that are consistent with the radial velocity measurements. In both cases, the detailed shape of the transit curve due to both the limb darkening of the star and the finite size of the planet is clearly evident. Assuming stellar parameters of 1.1 R_Sun and 1.1 M_Sun, we find that the data are best interpreted as a gas giant with a radius of 1.27 +/- 0.02 R_Jup in an orbit with an inclination of 87.1 +/- 0.2 degrees. We present values for the planetary surface gravity, escape velocity, and average density, and discuss the numerous observations that are warranted now that a planet is known to transit the disk of its parent star.

  16. High-energy irradiances of Sun-like stars

    Science.gov (United States)

    Sanz-Forcada, Jorge; Ribas, Ignasi

    2015-07-01

    Research on exoplanetary atmospheres has developed an increasing interest. Astrobiology has put its eyes on the effects that stellar irradiance may have on the atmosphere of planets, and on the early development of life. The high energy (XUV and UV) part of the spectrum is of special interest for this purpose. Part of this spectral range, the EUV is of no access to current telescopes, hampering the studies that intend to model planetary atmospheres. A program was developed to to circumvent this problem, and to provide with spectral energy distributions of stars hosting exoplanets (X-exoplanets) in the XUV range. We present here a work in which we develop further this program to create a semiempirical grid of models of emission of Sun-like stars, based on real data and coronal models, covering the XUV and UV ranges. These models will represent a great improvement with respect to currently used models of the solar irradiance at different ages, and intend to be the reference for the years to come. These models will be of special interest to reproduce the conditions of the Earth and solar system planets during different stages of the evolution, and can be safely exported to exoplanets orbiting Sun-like stars.

  17. Understanding Space Weather: The Sun as a Variable Star

    Science.gov (United States)

    Strong, Keith; Saba, Julia; Kucera, Therese

    2012-01-01

    The Sun is a complex system of systems and until recently, less than half of its surface was observable at any given time and then only from afar. New observational techniques and modeling capabilities are giving us a fresh perspective of the solar interior and how our Sun works as a variable star. This revolution in solar observations and modeling provides us with the exciting prospect of being able to use a vastly increased stream of solar data taken simultaneously from several different vantage points to produce more reliable and prompt space weather forecasts. Solar variations that cause identifiable space weather effects do not happen only on solar-cycle timescales from decades to centuries; there are also many shorter-term events that have their own unique space weather effects and a different set of challenges to understand and predict, such as flares, coronal mass ejections, and solar wind variations.

  18. The pulsations of the Sun and the stars

    CERN Document Server

    Rozelot, Jean-Pierre

    2011-01-01

    This volume of lecture notes brings together the knowledge on pulsations of the Sun and the stars, with a particular emphasis on recent observations and modelling, and on the influence of pulsations of other physical processes. The book begins with an extensive introduction to helioseismology. The solar cycle and gravity modes are discussed before the focus is widened from helioseismology to asteroseismology which is detailed in a series of specific chapters. Based on courses given at a graduate school, these tutorial lecture notes will be of interest and useful to a rather broad audience of scientists and students.

  19. On the Imminent Regional Seismic Activity Forecasting Using INTERMAGNET and Sun-Moon Tide Code Data

    CERN Document Server

    Mavrodiev, Strachimir Cht; Kikuashvili, Giorgi; Botev, Emil; Getsov, Petar; Mardirossian, Garo; Sotirov, Georgi; Teodossiev, Dimitar

    2016-01-01

    In this paper we present an approach for forecasting the imminent regional seismic activity by using geomagnetic data and Earth tide data. The time periods of seismic activity are the time periods around the Sun-Moon extreme of the diurnal average value of the tide vector module. For analyzing the geomagnetic data behaviour we use diurnal standard deviation of geomagnetic vector components F for calculating the time variance Geomag Signal. The Sun storm influence is avoided by using data for daily A-indexes (published by NOAA). The precursor signal for forecasting the incoming regional seismic activity is a simple function of the present and previous day Geomag Signal and A-indexes values. The reliability of the geomagnetic when, regional precursor is demonstrated by using statistical analysis of day difference between the times of predicted and occurred earthquakes. The base of the analysis is a natural hypothesis that the predicted earthquake is the one whose surface energy density in the monitoring point i...

  20. Sun and moon grinding to a halt: Exegetical remarks on Joshua 10:9-14 and related texts in Judges

    Directory of Open Access Journals (Sweden)

    H. J.A. Kruger

    1999-01-01

    Full Text Available Attempts to solve the enigma of the extended day may be classified into two groups. Several interpretations are based on the natural sciences. Recently, however, as far as the construction of the passage is concerned, renewed attention has been given to the possible role of religious customs, mythology and omens in connection with ancient military strategy. Against this background, the sun and moon are viewed as deities and told to remain passive in the battle. Omen texts from Mesopotamia related to warfare, and based on the "favourable" or "unfavourable" position of the sun and moon, seem to have impacted on the passage as well. Others have interpreted the sun in terms of mythical and/or theological categories. This paper avers that an interpretaion in terms of the mythical millwheel may help to explain the meaning ofthe passage.

  1. Astrometric jitter of the sun as a star

    CERN Document Server

    Makarov, V V; Ulrich, R K

    2010-01-01

    The daily variation of the solar photocenter over some 11 years is derived from the Mount Wilson data reprocessed by Ulrich et al. 2010 to closely match the surface distribution of solar irradiance. The standard deviations of astrometric jitter are 0.52 $\\mu$AU and 0.39 $\\mu$AU in the equatorial and the axial dimensions, respectively. The overall dispersion is strongly correlated with the solar cycle, reaching $0.91 \\mu$AU at the maximum activity in 2000. The largest short-term deviations from the running average (up to 2.6 $\\mu$AU) 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 $\\mu$AU 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.

  2. The Moon

    Institute of Scientific and Technical Information of China (English)

    范图雨

    2000-01-01

    The sun goes down in the west. The moon comes up in the east. Last week the moon was round. It is a half-moon this evening. A round moon loods like a big silver(银色)ball in the sky. A new moon looks like a comb(梳子)。

  3. Mass Ejection from Old and Young Stars and the Sun

    Science.gov (United States)

    Jatenco-Pereira, V.; Opher, R.

    1990-11-01

    RESUMEN. Para poder explicar: 1) la enorme cantidad de perdida de masa y la baja velocidad asint5tica de las estrellas gigantes de o, y 2) los flujos de masa observados en protoestrellas, se sugiere un modelo para Ia perdida de masa, en donde se usa un flujo de ondas de Alfvencomo un mecanismo de aceleraci6n para los vientos de estrellas de tipo y vientos en protoestrellas. Se estudian los mecanismos de disipaci5n de las ondas de Alfven: los amortiguamientos no lineal, de superficie reso- nante y turbulento. En nuestro modelo se usa una divergente A(r) = A(R0) (r/r0)5 (donde A(r) es el area a una distancia radial r, y (A(r)/r2)max/(A(ro)/r02 - 10). Tambien se sugiere un modelo para una de hoyo coronal en el Sol. Se muestra que para satisfacer los datos observacionales en el Sol, tomando en cuenta la deposici6n del momento de las ondas de Alfven sobre el viento, se necesita: (a) una divergencia lenta en un hoyo coronal hasta una altura de 0.01 - 0.1 R seguido de (b) una divergencia rap ida de hasta una altura aproximada de 1 R . ABSTRACT: In order to explain (1) a large mass-loss rate and a small asymptotic flow speed of late-type giant stars and (2) the observed protostellar mass outflows, we suggest a model for mass loss, where we use a flux of Alfven waves as a mechanism of acceleration for late-type giant star winds and protostellar winds. We study the Alfven wave dissipation mechanisms: nonlinear damping, resonant surface damping, and turbulent damping. In our model we use a diverging geometry A(r) = A(r0) (r I r )S (where A(r) is the cross sectional area of the geometry at a radial distance r, and(A(r) I r2)max/(A(r0)/r02) = 10). We also suggest a model for a coronal hole geometry in the sun. We show that in order to satisfy the observational data of the sun, taking into account Alfven wave momentum deposition in the wind, we need: (a) a slow divergence in a coronal hole up t6 a height of 0.01 - 0.1 followed by (b) a rapid divergence up to a height of

  4. Superflares on Sun-Like Stars: Bane of Habitability?

    Science.gov (United States)

    Ayres, T.

    2014-04-01

    A key aspect of planetary habitability is the existence of rare, but catastrophic events. One Earthly example is the attribution of several geological mass extinctions to asteroid collisions. Indeed, the Late Heavy Bombardment, during which the 600 Myr old Earth was pummeled persistently by impactors over a period of perhaps a hundred Myr, likely significantly delayed the permanent foothold of life on our planet. Another, less well known, example is the proposed existence of "superflares" on Sun-like stars. Although the quantity of energy in a superflare is negligible compared with the time-integrated X-ray dose from the quiescent multi-MK corona, the quality of the radiation (i.e., composition dominated by gamma rays) released from the transient, but extreme, outburst is what could be of concern to the survival of primitive lifeforms struggling for existence on a semi-habitable world. However, existing reports of superflares mainly involve interpretations of historical materials, such as long-term astronomical plate collections; there are very few concrete examples of such events observed by modern techniques at the most relevant wavelengths, namely ultraviolet or X-rays. The lack of good examples is mostly because these rare events are, well, rare. However, a recent HST Cosmic Origins Spectrograph program to record the ultraviolet spectrum of young (~50 Myr) solar analog EK Draconis, fortuitously captured a giant, hour-long FUV transient, in hot lines like the C IV 155 nm doublet (T~100,000 K), and very toasty Fe XXI 124 nm coronal forbidden line (~10 MK). If translated into the equivalent GOES 0.1-0.8 nm X-ray fluence, the event would correspond to an X25000-class flare (most extreme observed on the Sun might reach as high as a mere X50). The EK Dra giant flare, as viewed with the excellent wavelength resolution, broad coverage, and high sensitivity of COS, provides the opportunity to deduce properties of such events to help inform possible impacts on planetary

  5. Field chronobiology of a molluscan bivalve: how the moon and sun cycles interact to drive oyster activity rhythms.

    Science.gov (United States)

    Tran, Damien; Nadau, Arnaud; Durrieu, Gilles; Ciret, Pierre; Parisot, Jean-Paul; Massabuau, Jean-Charles

    2011-05-01

    The present study reports new insights into the complexity of environmental drivers in aquatic animals. The focus of this study was to determine the main forces that drive mollusc bivalve behavior in situ. To answer this question, the authors continuously studied the valve movements of permanently immersed oysters, Crassostrea gigas, during a 1-year-long in situ study. Valve behavior was monitored with a specially build valvometer, which allows continuously recording of up to 16 bivalves at high frequency (10 Hz). The results highlight a strong relationship between the rhythms of valve behavior and the complex association of the sun-earth-moon orbital positions. Permanently immersed C. gigas follows a robust and strong behavior primarily driven by the tidal cycle. The intensity of this tidal driving force is modulated by the neap-spring tides (i.e., synodic moon cycle), which themselves depend of the earth-moon distance (i.e., anomalistic moon cycle). Light is a significant driver of the oysters' biological rhythm, although its power is limited by the tides, which remain the predominant driver. More globally, depending where in the world the bivalves reside, the results suggest their biological rhythms should vary according to the relative importance of the solar cycle and different lunar cycles associated with tide generation. These results highlight the high plasticity of these oysters to adapt to their changing environment.

  6. New High-Precision Values of the Geodetic Rotation of the Major Planets, Pluto, the Moon and the Sun

    Science.gov (United States)

    Pashkevich, V. V.

    2016-06-01

    This investigation is continuation of our studies of the geodetic (relativistic) rotation of the Solar system bodies (Eroshkin and Pashkevich, 2007) and (Eroshkin and Pashkevich, 2009). For each body (the Moon, the Sun, the major planets and Pluto) the files of the values of the components of the angular velocity of the geodetic rotation are constructed over the time span from AD1000 to AD3000 with one day spacing, by using DE422/LE422 ephemeris (Folkner, 2011), with respect to the proper coordinate systems of the bodies (Seidelmann et al., 2005). For the first time in the perturbing terms of the physical librations for the Moon and in Euler angles for other bodies of the Solar system the most essential terms of the geodetic rotation are found by means of the least squares method and spectral analysis methods.

  7. ADVANCED BURNING STAGES AND FATE OF 8-10 M{sub Sun} STARS

    Energy Technology Data Exchange (ETDEWEB)

    Jones, S.; Hirschi, R. [Astrophysics Group, Lennard Jones Building, Keele University, Staffordshire ST5 5BG (United Kingdom); Nomoto, K. [Kavli Institute for the Physics and Mathematics of the Universe (WPI), University of Tokyo, Kashiwa, Chiba 277-8583 (Japan); Fischer, T.; Martinez-Pinedo, G. [GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, Planckstrasse 1, D-64291 Darmstadt (Germany); Timmes, F. X. [School of Earth and Space Exploration, University of Arizona, Tempe, AZ 85287 (United States); Herwig, F. [Joint Institute for Nuclear Astrophysics, University of Notre Dame, IN 46556 (United States); Paxton, B. [KITP and Department of Physics, University of California, Santa Barbara, CA 93106 (United States); Toki, H. [Research Center for Nuclear Physics (RCNP), Osaka University, Osaka 567-0047 (Japan); Suzuki, T. [Department of Physics, College of Humanities and Sciences, Nihon University Sakurajosui 3-25-40, Setagaya-ku, Tokyo 156-8550 (Japan); Lam, Y. H. [Institut fuer Kernphysik, Technische Universitaet Darmstadt, Schlossgartenstrasse 2, D-64289 Darmstadt (Germany); Bertolli, M. G., E-mail: s.w.jones@keele.ac.uk [Theoretical Division, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States)

    2013-08-01

    The stellar mass range 8 {approx}< M/M{sub Sun} {approx}< 12 corresponds to the most massive asymptotic giant branch (AGB) stars and the most numerous massive stars. It is host to a variety of supernova (SN) progenitors and is therefore very important for galactic chemical evolution and stellar population studies. In this paper, we study the transition from super-AGB (SAGB) star to massive star and find that a propagating neon-oxygen-burning shell is common to both the most massive electron capture supernova (EC-SN) progenitors and the lowest mass iron-core-collapse supernova (FeCCSN) progenitors. Of the models that ignite neon-burning off-center, the 9.5 M{sub Sun} star would evolve to an FeCCSN after the neon-burning shell propagates to the center, as in previous studies. The neon-burning shell in the 8.8 M{sub Sun} model, however, fails to reach the center as the URCA process and an extended (0.6 M{sub Sun }) region of low Y{sub e} (0.48) in the outer part of the core begin to dominate the late evolution; the model evolves to an EC-SN. This is the first study to follow the most massive EC-SN progenitors to collapse, representing an evolutionary path to EC-SN in addition to that from SAGB stars undergoing thermal pulses (TPs). We also present models of an 8.75 M{sub Sun} SAGB star through its entire TP phase until electron captures on {sup 20}Ne begin at its center and of a 12 M{sub Sun} star up to the iron core collapse. We discuss key uncertainties and how the different pathways to collapse affect the pre-SN structure. Finally, we compare our results to the observed neutron star mass distribution.

  8. 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....

  9. The Sun as a star: empirical estimates of stellar coronal mass ejection rates and properties

    Science.gov (United States)

    Aarnio, Alicia

    2017-05-01

    Our nearest star provides exquisite, up-close views of the physical processes driving energetic phenomena we observe on stars and cannot yet spatially resolve. Stars provide a statistical ensemble of solar analogs spanning a range of ages representing snapshots along our Sun's full life cycle. In this talk, I will share a project bringing the astronomer's large scale statistical approach to bear on solar data. Combining a decades' worth of solar flare and CME data, we characterize for the first time a relationship between flare and CME properties in order to extend analogy to readily observable stellar flares. We aim to better understand the properties and evolution of magnetic activity on Sun-like stars and exoweather on planets about distant Suns.

  10. 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....

  11. The variability of Sun-like stars: reproducing observed photometric trends

    CERN Document Server

    Shapiro, A I; Krivova, N A; Schmutz, W K; Ball, W T; Knaack, R; Rozanov, E V; Unruh, Y C

    2014-01-01

    The Sun and stars with low magnetic activity levels, become photometrically brighter when their activity increases. Magnetically more active stars display the opposite behaviour and get fainter when their activity increases. We reproduce the observed photometric trends in stellar variations with a model that treats stars as hypothetical Suns with coverage by magnetic features different from that of the Sun. The presented model attributes the variability of stellar spectra to the imbalance between the contributions from different components of the solar atmosphere, such as dark starspots and bright faculae. A stellar spectrum is calculated from spectra of the individual components, by weighting them with corresponding disc area coverages. The latter are obtained by extrapolating the solar dependences of spot and facular disc area coverages on chromospheric activity to stars with different levels of mean chromospheric activity. We have found that the contribution by starspots to the variability increases faster...

  12. 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...

  13. 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...

  14. Spectrometer for Sky-Scanning Sun-Tracking Atmospheric Research (4STAR: Instrument Technology

    Directory of Open Access Journals (Sweden)

    Yohei Shinozuka

    2013-08-01

    Full Text Available 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/climate. Direct beam hyper-spectral 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 will 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. Technical challenges include compact optical collector design, radiometric dynamic range and stability, and broad spectral coverage. Test results establishing the performance of the instrument against the full range of operational requirements are presented, along with calibration, engineering flight test, and scientific field campaign data and results.

  15. Effectiveness of GeoWall Visualization Technology for Conceptualization of the Sun-Earth-Moon System

    Science.gov (United States)

    Turner, N. E.; Gray, C.; Mitchell, E. J.

    2004-12-01

    One persistent difficulty many introductory astronomy students face is the lack of a 3-dimensional mental model of the Earth-Moon system. Students without such a mental model can have a very hard time conceptualizing the geometric relationships that cause the cycle of lunar phases. The GeoWall is a recently developed and affordable projection mechanism for three-dimensional stereo visualization which is becoming a popular tool in classrooms and research labs. We present results from a study using a 3-D GeoWall with a simulated sunlit Earth-Moon system on undergraduate students' ability to understand the origins of lunar phases. We test students exposed to only in-class instruction, some with a laboratory exercise using the GeoWall Earth-Moon simulation, some students who were exposed to both, and some with an alternate activity involving lunar observations. Students are given pre and post tests using the a diagnostic test called the Lunar Phase Concept Inventory (LPCI). We discuss the effectiveness of this technology as a teaching tool for lunar phases.

  16. Capture of the Sun's Oort cloud from stars in its birth cluster.

    Science.gov (United States)

    Levison, Harold F; Duncan, Martin J; Brasser, Ramon; Kaufmann, David E

    2010-07-09

    Oort cloud comets are currently believed to have formed in the Sun's protoplanetary disk and to have been ejected to large heliocentric orbits by the giant planets. Detailed models of this process fail to reproduce all of the available observational constraints, however. In particular, the Oort cloud appears to be substantially more populous than the models predict. Here we present numerical simulations that show that the Sun captured comets from other stars while it was in its birth cluster. Our results imply that a substantial fraction of the Oort cloud comets, perhaps exceeding 90%, are from the protoplanetary disks of other stars.

  17. "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…

  18. On the Transfer and Control of Space Probes Around the L1 Point of the Sun-Earth+Moon System

    Science.gov (United States)

    Hou, Xi-Yun; Liu, Lin

    2008-01-01

    The motion around the collinear libration points in the restricted three body problem is unstable. But there exist conditionally stable periodic orbits around these points. Special-purpose space probes located in the vicinity of these points (e.g., ISEE-3, SOHO) can benefit from this dynamical property, in regard to maintaining the orbit in position and the energy required of placing the probe in position. As an example, we study in this paper the launch and orbital control of a space probe around the L1 libration point in the system consisting of the Sun and the Earth-Moon. We present some theoretical and numerical simulations' results, which may serve as a basis for the realization of such a space probe in future.

  19. Seismic constraints on rotation of Sun-like star and mass of exoplanet.

    Science.gov (United States)

    Gizon, Laurent; Ballot, Jérome; Michel, Eric; Stahn, Thorsten; Vauclair, Gérard; Bruntt, Hans; Quirion, Pierre-Olivier; Benomar, Othman; Vauclair, Sylvie; Appourchaux, Thierry; Auvergne, Michel; Baglin, Annie; Barban, Caroline; Baudin, Fréderic; Bazot, Michaël; Campante, Tiago; Catala, Claude; Chaplin, William; Creevey, Orlagh; Deheuvels, Sébastien; Dolez, Noël; Elsworth, Yvonne; García, Rafael; Gaulme, Patrick; Mathis, Stéphane; Mathur, Savita; Mosser, Benoît; Régulo, Clara; Roxburgh, Ian; Salabert, David; Samadi, Réza; Sato, Kumiko; Verner, Graham; Hanasoge, Shravan; Sreenivasan, Katepalli R

    2013-08-13

    Rotation is thought to drive cyclic magnetic activity in the Sun and Sun-like stars. Stellar dynamos, however, are poorly understood owing to the scarcity of observations of rotation and magnetic fields in stars. Here, inferences are drawn on the internal rotation of a distant Sun-like star by studying its global modes of oscillation. We report asteroseismic constraints imposed on the rotation rate and the inclination of the spin axis of the Sun-like star HD 52265, a principal target observed by the CoRoT satellite that is known to host a planetary companion. These seismic inferences are remarkably consistent with an independent spectroscopic observation (rotational line broadening) and with the observed rotation period of star spots. Furthermore, asteroseismology constrains the mass of exoplanet HD 52265b. Under the standard assumption that the stellar spin axis and the axis of the planetary orbit coincide, the minimum spectroscopic mass of the planet can be converted into a true mass of 1.85(-0.42)(+0.52)M(Jupiter), which implies that it is a planet, not a brown dwarf.

  20. Seismic constraints on rotation of Sun-like star and mass of exoplanet

    CERN Document Server

    Gizon, Laurent; Michel, Eric; Stahn, Thorsten; Vauclair, Gérard; Bruntt, Hans; Quirion, Pierre-Olivier; Benomar, Othman; Vauclair, Sylvie; Appourchaux, Thierry; Auvergne, Michel; Baglin, Annie; Barban, Caroline; Baudin, Fréderic; Bazot, Michaël; Campante, Tiago; Catala, Claude; Chaplin, William; Creevey, Orlagh; Deheuvels, Sébastien; Dolez, Noël; Elsworth, Yvonne; García, Rafael; Gaulme, Patrick; Mathis, Stéphane; Mathur, Savita; Mosser, Benoît; Régulo, Clara; Roxburgh, Ian; Salabert, David; Samadi, Réza; Sato, Kumiko; Verner, Graham; Hanasoge, Shravan; Sreenivasan, Katepalli R

    2013-01-01

    Rotation is thought to drive cyclic magnetic activity in the Sun and Sun-like stars. Stellar dynamos, however, are poorly understood owing to the scarcity of observations of rotation and magnetic fields in stars. Here, inferences are drawn on the internal rotation of a distant Sun-like star by studying its global modes of oscillation. We report asteroseismic constraints imposed on the rotation rate and the inclination of the spin axis of the Sun-like star HD 52265, a principal target observed by the CoRoT satellite that is known to host a planetary companion. These seismic inferences are remarkably consistent with an independent spectroscopic observation (rotational line broadening) and with the observed rotation period of star spots. Furthermore, asteroseismology constrains the mass of exoplanet HD 52265b. Under the standard assumption that the stellar spin axis and the axis of the planetary orbit coincide, the minimum spectroscopic mass of the planet can be converted into a true mass of 1.85 (+0.52,-0.42) M...

  1. Coupling of the Matched Gravity and Electromagnetic Fields of the Sun with Jupiter and its Moons Together in Nearest Portion of Jupiter's Orbit to the Sun as the Main Cause of the Peak of Approximately 11 Yearly Solar Cycles and Hazards from Solar Storms

    Science.gov (United States)

    Gholibeigian, Kazem; Gholibeigian, Hassan

    2016-04-01

    On March 13, 1989 the entire province of Quebec Blackout by solar storm during solar cycle 22. The solar storm of 1859, also known as the Carrington event, was a powerful geomagnetic solar storm during solar cycle 10. The solar storm of 2012 during solar cycle 24 was of similar magnitude, but it passed Earth's orbit without striking the plane. All of these solar storms occurred in the peak of 11 yearly solar cycles. In this way, the White House in its project which is focusing on hazards from solar system, in a new strategy and action plan to increase protection from damaging solar emissions, should focus on coupling of the matched Gravity and Electromagnetic Fields)GEFs) of the Sun with Jupiter and its moons together. On the other hand, in solar system, the Jupiter's gravity has largest effect to the Sun's core and its dislocation, because the gravity force between the Jupiter and the Sun is 11.834 times, In addition overlapping of the solar cycles with the Jupiter's orbit period is 11.856 years. These observable factors lead us to the effect of the Jupiter and Sun gravity fields coupling as the main cause of the approximately 11 years duration for solar cycles. Its peak in each cycle is when the Jupiter is in nearest portion to the Sun in its orbit. In this way, the other planets in their coupling with Sun help to the variations and strengthening solar cycles. [Gholibeigian, 7/24/2015http://adsabs.harvard.edu/abs/2014EGU]. In other words, the both matched GEFs are generating by the large scale forced convection system inside the stars and planets [Gholibeigian et. al, AGU Fall Meeting 2015]. These two fields are couple and strengthening each other. The Jupiter with its 67 moons generate the largest coupled and matched GEFs in its core and consequently strongest effect on the Sun's core. Generation and coupling of the Jupiter's GEFs with its moons like Europa, Io and Ganymede make this planet of thousands of times brighter and many times bigger than Earth as the

  2. Controlling a transfer trajectory with realistic impulses assumming perturbations in the Sun-Earth-Moon Quasi-Bicircular Problem

    Science.gov (United States)

    Leiva, A. M.; Briozzo, C. B.

    In a previous work we successfully implemented a control algorithm to stabilize unstable periodic orbits in the Sun-Earth-Moon Quasi-Bicircular Problem (QBCP). Applying the same techniques, in this work we stabilize an unstable trajectory performing fast transfers between the Earth and the Moon in a dynamical system similar to the QBCP but incorporating the gravitational perturbation of the planets Mercury, Venus, Mars, Jupiter, Saturn, Uranus, and Neptune, assumed to move on circular coplanar heliocentric orbits. In the control stage we used as a reference trajectory an unstable periodic orbit from the unperturbed QBCP. We performed 400 numerical experiments integrating the trajectories over time spans of ~40 years, taking for each one random values for the initial positions of the planets. In all cases the control impulses applied were larger than 20 cm/s, consistently with realistic implementations. The minimal and maximal yearly mean consumptions were ~10 m/s and ~71 m/s, respectively. FULL TEXT IN SPANISH

  3. Optimal design of near-Earth asteroid sample-return trajectories in the Sun-Earth-Moon system

    Science.gov (United States)

    He, Shengmao; Zhu, Zhengfan; Peng, Chao; Ma, Jian; Zhu, Xiaolong; Gao, Yang

    2016-08-01

    In the 6th edition of the Chinese Space Trajectory Design Competition held in 2014, a near-Earth asteroid sample-return trajectory design problem was released, in which the motion of the spacecraft is modeled in multi-body dynamics, considering the gravitational forces of the Sun, Earth, and Moon. It is proposed that an electric-propulsion spacecraft initially parking in a circular 200-km-altitude low Earth orbit is expected to rendezvous with an asteroid and carry as much sample as possible back to the Earth in a 10-year time frame. The team from the Technology and Engineering Center for Space Utilization, Chinese Academy of Sciences has reported a solution with an asteroid sample mass of 328 tons, which is ranked first in the competition. In this article, we will present our design and optimization methods, primarily including overall analysis, target selection, escape from and capture by the Earth-Moon system, and optimization of impulsive and low-thrust trajectories that are modeled in multi-body dynamics. The orbital resonance concept and lunar gravity assists are considered key techniques employed for trajectory design. The reported solution, preliminarily revealing the feasibility of returning a hundreds-of-tons asteroid or asteroid sample, envisions future space missions relating to near-Earth asteroid exploration.

  4. Optimal design of near-Earth asteroid sample-return trajectories in the Sun-Earth-Moon system

    Institute of Scientific and Technical Information of China (English)

    Shengmao He; Zhengfan Zhu; Chao Peng; Jian Ma; Xiaolong Zhu; Yang Gao

    2016-01-01

    In the 6th edition of the Chinese Space Trajec-tory Design Competition held in 2014, a near-Earth asteroid sample-return trajectory design problem was released, in which the motion of the spacecraft is modeled in multi-body dynamics, considering the gravitational forces of the Sun, Earth, and Moon. It is proposed that an electric-propulsion spacecraft initially parking in a circular 200-km-altitude low Earth orbit is expected to rendezvous with an asteroid and carry as much sample as possible back to the Earth in a 10-year time frame. The team from the Technology and Engi-neering Center for Space Utilization, Chinese Academy of Sciences has reported a solution with an asteroid sample mass of 328 tons, which is ranked first in the competition. In this article, we will present our design and optimization methods, primarily including overall analysis, target selec-tion, escape from and capture by the Earth–Moon system, and optimization of impulsive and low-thrust trajectories that are modeled in multi-body dynamics. The orbital res-onance concept and lunar gravity assists are considered key techniques employed for trajectory design. The reported solution, preliminarily revealing the feasibility of returning a hundreds-of-tons asteroid or asteroid sample, envisions future space missions relating to near-Earth asteroid explo-ration.

  5. Evolution of the cycles of magnetic activity of the Sun and Sun-like stars in time

    CERN Document Server

    Bruevich, E A; Artamonov, B P

    2016-01-01

    We applied the method of continuous wavelet-transform to the time-frequency analysis to the sets of observations of relative sunspot numbers, sunspot areas and to 6 Mount Wilson HK-project stars with well-defined magnetic cycles. Wavelet analysis of these data reveals the following pattern: at the same time there are several activity cycles whose periods vary widely from the quasi-biennial up to the centennial period for the Sun and vary significant during observations time of the HK-project stars. These relatively low-frequency periodic variations of the solar and stellar activity gradually change the values of periods of different cycles in time. This phenomenon can be observed in every cycles of activity

  6. The influence of the sun, moon, climate and economic conditions on crisis incidence.

    Science.gov (United States)

    Snoyman, P; Holdstock, T L

    1980-10-01

    Investigated the relationship between 2,344 cases of crisis incidence over a 1-year period (1976) and geophysical, climatic and seasonal conditions. Results revealed an intricate interactive effect between the variables of sex, nature of crisis, period of analysis, and environmental conditions. Males crisis became more likely, with downward economic trends or decreased solar activity. In contrast to female incidence of crisis, which peaked in spring, that of males peaked in autumn. Increased solar activity was related strongly to the incidence of crisis experienced by people who were retarded, abused drugs and were guilty of assault and/or rape. The waxing of the moon was related closely to cases of assault and/or rape, while retardates were influenced further by the moisture content in the air. Temporal considerations revealed a positive relationship between full moon and crisis incidence on alternate months only. Generally, the increased cloud cover, rainfall and temperature in summer, gave rise to more crisis consultations. Finally, geophysical, climatic and economic conditions also were seen to act in conjunction with each other to influence crisis incidence.

  7. Sun

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    @@ Sun Microsystems, Inc. is committed to open standards,a standardization system, and sharing within the information tech nology field, focusing not only on technical innovation, but also on new ideas, practices and future development.

  8. A Solar cycle correlation of coronal element abundances in Sun-as-a-star observations

    Science.gov (United States)

    Brooks, David H.; Baker, Deborah; van Driel-Gesztelyi, Lidia; Warren, Harry P.

    2017-08-01

    The elemental composition in the coronae of low-activity solar-like stars appears to be related to fundamental stellar properties such as rotation, surface gravity, and spectral type. Here we use full-Sun observations from the Solar Dynamics Observatory, to show that when the Sun is observed as a star, the variation of coronal composition is highly correlated with a proxy for solar activity, the F10.7 cm radio flux, and therefore with the solar cycle phase. Similar cyclic variations should therefore be detectable spectroscopically in X-ray observations of solar analogs. The plasma composition in full-disk observations of the Sun is related to the evolution of coronal magnetic field activity. Our observations therefore introduce an uncertainty into the nature of any relationship between coronal composition and fixed stellar properties. The results highlight the importance of systematic full-cycle observations for understanding the elemental composition of solar-like stellar coronae.

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

    Science.gov (United States)

    1987-02-19

    65 Eielson 112 32 Sells 88 34 Fayette 148 65 Fair barks 110 34 Show Low 88 35 Florence 146 64 Fort Greely 110 32 Sierra Vista 88 30 Foley 152 60...Stamps 120 37 Nariposa 106 40 Central City 92 34 Star City 120 3? Merced 102 39 Cheyenne Wells 92 35 Stuttgart 121 38 Modesto 108 39 Clifton 94 33

  10. Planet signatures in the chemical composition of Sun-like stars

    CERN Document Server

    Melendez, Jorge

    2016-01-01

    There are two possible mechanisms to imprint planet signatures in the chemical composition of Sun-like stars: i) dust condensation at the early stages of planet formation, causing a depletion of refractory elements in the gas accreted by the star in the late stages of its formation; ii) planet engulfment, enriching the host star in lithium and refractory elements. We discuss both planet signatures, the influence of galactic chemical evolution, and the importance of binaries composed of stellar twins as laboratories to verify abundance anomalies imprinted by planets.

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

    Science.gov (United States)

    Lopes, Ilídio; Silk, Joseph

    2017-07-01

    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 1-103 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.

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

    CERN Document Server

    Garcia, Rafael A

    2016-01-01

    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.

  13. Transport Phenomena and Light Element Abundances in the Sun and Solar Type Stars

    CERN Document Server

    Vauclair, S

    2000-01-01

    The observations of light elements in the Sun and Solar type stars givespecial clues for understanding the hydrodynamical processes at work in stellarinteriors. In the Sun 7Li is depleted by 140 while 3He has not increased bymore than 10 0n 3 Gyrs. Meanwhile the inversion of helioseismic modes lead toa precision on the sound velocity of about .1The mixing processes below thesolar convection zone are constrained by these observations. Lithium isdepleted in most Pop I solar type stars. In halo stars however, the lithiumabundance seems constant in the "spite plateau" with no observed dispersion,which is difficult to reconcile with the theory of diffusion processes. In thepresent paper, the various relevant observations will be discussed. It will beshown that the mu-gradients induced by element settling may help solving the"lithium paradox".

  14. Spectral magnetohydrodynamic simulations of the sun and stars

    Science.gov (United States)

    Brun, A. S.

    The purpose of this lecture is two fold: first, to describe a powerful numerical technic, namely the spectral method, to solve the compressible (anelastic) magnetohydrodynamic (MHD) equations in spherical geometry and then to discuss some recent numerical applications to study stellar dynamics and magnetism. We thus start by describing the semi-implicit, anelastic spherical harmonic (ASH) code. In this code, the main field variables are projected into spherical harmonics for their horizontal dimensions and into Chebyshev polynomials for their radial direction. We then present, high resolution 3 D MHD simulations of the convective region of A- and G-type stars in spherical shells. We have chosen to model A and G-type stars because they represent good proxies to study and understand stellar dynamics and magnetism given their strikingly different internal “up-side-down” structure and magnetic activity level. In particular, we discuss the nonlinear interactions between turbulent convection, rotation and magnetic fields and the possibility for such flows and fields to lead to dynamo action. We find that both core and envelope turbulent convective zones are efficient at inducing strong mostly non-axisymmetric fields near equipartition but at the expense of damping the differential rotation present in the purely hydrodynamic progenitor solutions.

  15. 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.

  16. The First Focused Hard X-ray Images of the Sun with NuSTAR

    CERN Document Server

    Grefenstette, Brian W; Krucker, Säm; Hudson, Hugh; Hannah, Iain G; Smith, David M; Vogel, Julia K; White, Stephen M; Madsen, Kristin K; Marsh, Andrew J; Caspi, Amir; Chen, Bin; Shih, Albert; Kuhar, Matej; Boggs, Steven E; Christensen, Finn E; Craig, William W; Forster, Karl; Hailey, Charles J; Harrison, Fiona A; Miyasaka, Hiromasa; Stern, Daniel; Zhang, William W

    2016-01-01

    We present results from the the first campaign of dedicated solar observations undertaken by the \\textit{Nuclear Spectroscopic Telescope ARray} ({\\em NuSTAR}) hard X-ray telescope. Designed as an astrophysics mission, {\\em NuSTAR} nonetheless has the capability of directly imaging the Sun at hard X-ray 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 \\textit{NuSTAR} will make major improvements on existing solar measurements. We report on the techniques used to observe the Sun with \\textit{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, hard X-ray emission from high in the solar corona, and full-disk hard X-ray images of the Sun.

  17. Phasing Delta-V for transfers from Sun-Earth halo orbits to the Moon

    Science.gov (United States)

    Chen, Hongru; Kawakatsu, Yasuhiro; Hanada, Toshiya

    2016-10-01

    Inspired by successful extended missions such as the ISEE-3, an investigation for the extended mission that involves a lunar encounter following a Sun-Earth halo orbit mission is considered valuable. Most previous studies present the orbit-to-orbit transfers where the lunar phase is not considered. Intended for extended missions, the present work aims to solve for the minimum phasing ∆V for various initial lunar phases. Due to the solution multiplicity of the two-point boundary value problem, the general constrained optimization algorithm that does not identify multiple feasible solutions is shown to miss minima. A two-step differential corrector with a two-body Lambert solver is developed for identifying multiple solutions. The minimum ∆V associated with the short-way and long-way approaches can be recovered. It is acquired that the required ∆V to cover all initial lunar phases is around 45 m/s for the halo orbit with out-of-plane amplitude Az greater than 3.5×105 km, and 14 m/s for a small halo orbit with Az=1×105 km. In addition, the paper discusses the phasing planning based on the ∆V result and the shift of lunar phase with halo orbit revolution.

  18. The stability of tidal equilibrium for hierarchical star-planet-moon systems

    Science.gov (United States)

    Adams, Fred C.; Bloch, Anthony M.

    2016-11-01

    Motivated by the current search for exomoons, this paper 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. Because of the lack of a closed form solution for the full three-body problem, however, we must 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. These results suggest that star-planet-moon systems have no viable long-term stable states analogous to those found for two-body systems.

  19. Spectral variability of photospheric radiation due to faculae. I. The Sun and Sun-like stars

    Science.gov (United States)

    Norris, Charlotte M.; Beeck, Benjamin; Unruh, Yvonne C.; Solanki, Sami K.; Krivova, Natalie A.; Yeo, Kok Leng

    2017-09-01

    Context. Stellar spectral variability on timescales of a day and longer, arising from magnetic surface features such as dark spots and bright faculae, is an important noise source when characterising extra-solar planets. Current 1D models of faculae do not capture the geometric properties and fail to reproduce observed solar facular contrasts. Magnetoconvection simulations provide facular contrasts accounting for geometry. Aims: We calculate facular contrast spectra from magnetoconvection models of the solar photosphere with a view to improve (a) future parameter determinations for planets with early G type host stars and (b) reconstructions of solar spectral variability. Methods: Regions of a solar twin (G2, log g = 4.44) atmosphere with a range of initial average vertical magnetic fields (100 to 500 G) were simulated using a 3D radiation-magnetohydrodynamics code, MURaM, and synthetic intensity spectra were calculated from the ultraviolet (149.5 nm) to the far infrared (160 000 nm) with the ATLAS9 radiative transfer code. Nine viewing angles were investigated to account for facular positions across most of the stellar disc. Results: Contrasts of the radiation from simulation boxes with different levels of magnetic flux relative to an atmosphere with no magnetic field are a complicated function of position, wavelength and magnetic field strength that is not reproduced by 1D facular models. Generally, contrasts increase towards the limb, but at UV wavelengths a saturation and decrease are observed close to the limb. Contrasts also increase strongly from the visible to the UV; there is a rich spectral dependence, with marked peaks in molecular bands and strong spectral lines. At disc centre, a complex relationship with magnetic field was found and areas of strong magnetic field can appear either dark or bright, depending on wavelength. Spectra calculated for a wide variety of magnetic fluxes will also serve to improve total and spectral solar irradiance

  20. Rotation period distribution of CoRoT and Kepler Sun-like stars

    Science.gov (United States)

    Leão, I. C.; Pasquini, L.; Ferreira Lopes, C. E.; Neves, V.; Valcarce, A. A. R.; de Oliveira, L. L. A.; Freire da Silva, D.; de Freitas, D. B.; Canto Martins, B. L.; Janot-Pacheco, E.; Baglin, A.; De Medeiros, J. R.

    2015-10-01

    Aims: We study the distribution of the photometric rotation period (Prot), which is a direct measurement of the surface rotation at active latitudes, for three subsamples of Sun-like stars: one from CoRoT data and two from Kepler data. For this purpose, we identify the main populations of these samples and interpret their main biases specifically for a comparison with the solar Prot. Methods: Prot and variability amplitude (A) measurements were obtained from public CoRoT and Kepler catalogs, which were combined with public data of physical parameters. Because these samples are subject to selection effects, we computed synthetic samples with simulated biases to compare with observations, particularly around the location of the Sun in the Hertzsprung-Russel (HR) diagram. Publicly available theoretical grids and empirical relations were used to combine physical parameters with Prot and A. Biases were simulated by performing cutoffs on the physical and rotational parameters in the same way as in each observed sample. A crucial cutoff is related with the detectability of the rotational modulation, which strongly depends on A. Results: The synthetic samples explain the observed Prot distributions of Sun-like stars as having two main populations: one of young objects (group I, with ages younger than ~1 Gyr) and another of main-sequence and evolved stars (group II, with ages older than ~1 Gyr). The proportions of groups I and II in relation to the total number of stars range within 64-84% and 16-36%, respectively. Hence, young objects abound in the distributions, producing the effect of observing a high number of short periods around the location of the Sun in the HR diagram. Differences in the Prot distributions between the CoRoT and Kepler Sun-like samples may be associated with different Galactic populations. Overall, the synthetic distribution around the solar period agrees with observations, which suggests that the solar rotation is normal with respect to Sun

  1. Spectrometer for Sky-Scanning, Sun-Tracking Atmospheric Research (4STAR) Instrument Improvements

    Science.gov (United States)

    Dunagan, Stephen E.; Redemann, Jens; Chang, Cecilia; Dahlgren, Robert; Fahey, Lauren; Flynn, Connor; Johnson, Roy; Kacenelenbogen, Meloe; Leblanc, Samuel; Liss, Jordan; text-decoration: none; " href="javascript:void(0); " onClick="displayelement('author_20170005591'); toggleEditAbsImage('author_20170005591_show'); toggleEditAbsImage('author_20170005591_hide'); "> hide

    2017-01-01

    The Spectrometer for Sky-Scanning, Sun-Tracking Atmospheric Research (4STAR) combines airborne sun tracking and sky scanning with grating spectroscopy to improve knowledge of atmospheric constituents and their links to air-pollution and climate. Hyper-spectral measurements of direct-beam solar irradiance provide retrievals of gas constituents, aerosol optical depth, and aerosol and thin cloud optical properties. Sky radiance measurements in the principal and almucantar planes enhance retrievals of aerosol absorption, aerosol type, and size mode distribution. Zenith radiance measurements are used to retrieve cloud properties and phase, which in turn are used to quantify the radiative transfer below cloud layers. These airborne measurements tighten the closure between satellite and ground-based measurements. In contrast to the Ames Airborne Tracking Sunphotometer (AATS-14) predecessor instrument, new technologies for each subsystem have been incorporated into 4STAR. In particular, 4STAR utilizes a modular sun-trackingsky-scanning optical head with fiber optic signal transmission to rack mounted spectrometers, permitting miniaturization of the external optical head, and spectrometerdetector configurations that may be tailored for specific scientific objectives. This paper discusses technical challenges relating to compact optical collector design, radiometric dynamic range and stability, and broad spectral coverage at high resolution. Test results benchmarking the performance of the instrument against the AATS-14 standard and emerging science requirements are presented.

  2. No Sun-like dynamo on the active star ζ Andromedae from starspot asymmetry.

    Science.gov (United States)

    Roettenbacher, R M; Monnier, J D; Korhonen, H; Aarnio, A N; Baron, F; Che, X; Harmon, R O; Kővári, Zs; Kraus, S; Schaefer, G H; Torres, G; Zhao, M; ten Brummelaar, T A; Sturmann, J; Sturmann, L

    2016-05-12

    Sunspots are cool areas caused by strong surface magnetic fields that inhibit convection. Moreover, strong magnetic fields can alter the average atmospheric structure, degrading our ability to measure stellar masses and ages. Stars that are more active than the Sun have more and stronger dark spots than does the Sun, including on the rotational pole. Doppler imaging, which has so far produced the most detailed images of surface structures on other stars, cannot always distinguish the hemisphere in which the starspots are located, especially in the equatorial region and if the data quality is not optimal. This leads to problems in investigating the north-south distribution of starspot active latitudes (those latitudes with more starspot activity); this distribution is a crucial constraint of dynamo theory. Polar spots, whose existence is inferred from Doppler tomography, could plausibly be observational artefacts. Here we report imaging of the old, magnetically active star ζ Andromedae using long-baseline infrared interferometry. In our data, a dark polar spot is seen in each of two observation epochs, whereas lower-latitude spot structures in both hemispheres do not persist between observations, revealing global starspot asymmetries. The north-south symmetry of active latitudes observed on the Sun is absent on ζ And, which hosts global spot patterns that cannot be produced by solar-type dynamos.

  3. A Spatially Resolved X-ray Image of a Star Like the Sun.

    Science.gov (United States)

    Schmitt, J H; Kürster, M

    1993-10-08

    Observations made with the x-ray satellite ROSAT (Roentgen Satellite) have produced the first spatially resolved x-ray image of a corona around a star like our sun. The star is the secondary in the eclipsing binary system alpha Coronae Borealis (CrB), which consists of one star of spectral type A0V and one of type G5V. The x-ray light curve of alpha CrB shows a total x-ray eclipse during secondary optical minimum, with the G star behind the A star. The totality of the eclipse demonstrates that the A-type component in alpha CrB is x-ray dark and that the x-ray flux arises exclusively from the later-type companion. The x-ray eclipse ingress and egress are highly asymmetric compared with the optical eclipse, indicating a highly asymmetric x-ray intensity distribution on the surface of the G star. From a detailed modeling of the ingress and egress of the x-ray light curve, an eclipse map of the G star was constructed by a method based on an optimization by simulated annealing.

  4. 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

  5. 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.

  6. Contributions to Proceedings from the NATO Advanced Research Workshop on the Seismology of the Sun and the Distant Stars

    Science.gov (United States)

    1985-01-01

    Advanced research results on the seismology of the Sun and distant stars is presented. Topics presented include: (1) detection of global convective wave flows; (2) observation of low degree p-mode oscillations; and (3) techniques for spectral deconvolution.

  7. 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.

  8. Prevalence of Earth-size Planets Orbiting Sun-like Stars

    Science.gov (United States)

    Petigura, Erik Ardeshir

    2015-04-01

    In this thesis, I explore two topics in exoplanet science. The first is the prevalence of Earth-size planets in the Milky Way Galaxy. To determine the occurrence of planets having different sizes, orbital periods, and other properties, I conducted a survey of extrasolar planets using data collected by NASA's Kepler Space Telescope. This project involved writing new algorithms to analyze Kepler data, finding planets, and conducting follow-up work using ground-based telescopes. I found that most stars have at least one planet at or within Earth's orbit and that 26% of Sun-like stars have an Earth-size planet with an orbital period of 100 days or less. The second topic is the connection between the properties of planets and their host stars. The precise characterization of exoplanet hosts helps to bring planet properties like mass, size, and equilibrium temperature into sharper focus and probes the physical processes that form planets. I studied the abundance of carbon and oxygen in over 1000 nearby stars using optical spectra taken by the California Planet Search. I found a large range in the relative abundance of carbon and oxygen in this sample, including a handful of carbon-rich stars. I also developed a new technique called SpecMatch for extracting fundamental stellar parameters from optical spectra. SpecMatch is particularly applicable to the relatively faint planet-hosting stars discovered by Kepler.

  9. A New Association of Post-T Tauri Stars Near The Sun

    CERN Document Server

    Torres, C A O; Quast, G R; De la Reza, R; Jilinski, E; Torres, Carlos A. O.; Silva, Licio da; Quast, Germano R.; Reza, Ramiro de la; Jilinski, Evgueni

    2000-01-01

    Observing ROSAT sources in 20 x 25 deg centered at the high latitude active star ER Eri, we found evidences for a new young nearby association (~30Myr at~60pc), the Horologium Association (HorA), formed by at least 10 probable and 6 possible members, some being Post-T Tauri stars. We examine several requirements that characterize a young association and they, together, create a strong evidence for the reality of the HorA. In fact, the Li line intensities are between those of the oldest classical T Tauri stars and the ones of the Local Association stars. The space velocities of the HorA relative to the Sun, U= -9.5+/-1.0, V = -20.9 +/- 1.1, W = -2.1 +/- 1.9, are not far from those of the Local Association. We suggest that some hotter and non-X-ray active stars, with similar space velocities, could be massive members of the HorA, among them, the nearby Be star Achernar. The maximum of the mass distribution function of the HorA is around 0.8 solar masses. At its distance, the projected size of the HorA, ~50 pc, ...

  10. The Solar Twin Planet Search: IV. The Sun as a typical rotator and evidence for a new rotational braking law for Sun-like stars

    CERN Document Server

    Santos, Leonardo A dos; Nascimento, José-Dias do; Bedell, Megan; Ramírez, Iván; Bean, Jacob L; Asplund, Martin; Spina, Lorenzo; Dreizler, Stefan; Alves-Brito, Alan; Casagrande, Luca

    2016-01-01

    It is still unclear how common the Sun is when compared to other similar stars in regards to some of its physical properties, such as rotation. Considering that gyrochronology relations are widely used today to estimate ages of stars in the main sequence, and that the Sun is used to calibrate it, it is crucial to assess if these procedures are acceptable. We analyze the rotational velocities -- limited by the unknown rotation axis inclination angle -- of an unprecedented large sample of solar twins in order to study the rotational evolution of Sun-like stars, and assess if the Sun is a typical rotator. We use high-resolution ($R = 115000$) spectra obtained with the HARPS spectrograph and ESO's 3.6 m telescope at La Silla Observatory. The projected rotational velocities for 82 solar twins are estimated by line profile fitting with synthetic spectra. Macroturbulence velocities are inferred from a prescription that accurately reflects their dependence with effective temperature and luminosity of the stars. Our s...

  11. Asteroseismology from multi-month Kepler photometry: the evolved Sun-like stars KIC 10273246 and KIC 10920273

    NARCIS (Netherlands)

    T.L. Campante; R. Handberg; S. Mathur; T. Appourchaux; T.R. Bedding; W.J. Chaplin; B. Mosser; O. Benomar; A. Bonanno; E. Corsaro; S.T. Fletcher; P. Gaulme; S. Hekker; C. Karoff; D. Salabert; G.A. Verner; T.R. White; G. Houdek; I.M. Brandao; O.L. Creevey; G. Dogan; M. Bazot; J. Christensen-Dalsgaard; M.S. Cunha; Y. Elsworth; D. Huber; H. Kjeldsen; M. Lundkvist; J. Molenda-Zakowicz; M.J.P.F.G. Monteiro; D. Stello; B.D. Clarke; F.R. Girouard; J.R. Hall; R.A. Garcia; C. Regulo

    2011-01-01

    Context. The evolved main-sequence Sun-like stars KIC 10273246 (F-type) and KIC 10920273 (G-type) were observed with the NASA Kepler satellite for approximately ten months with a duty cycle in excess of 90%. Such continuous and long observations are unprecedented for solar-type stars other than the

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

    CERN Document Server

    Petigura, Erik A; 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 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 $11\\pm4%$ 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 $\\sim200$ d. Extrapolating, one finds $5.7^{+1.7}_{-2.2}%$ of Sun-like s...

  13. Magnetic fields on young, moderately rotating Sun-like stars II. EK Draconis (HD 129333)

    CERN Document Server

    Waite, Ian; Carter, Brad; Petit, Pascal; Jeffers, Sandra; Morin, Julien; Vidotto, Aline; Donati, Jean-Francois

    2016-01-01

    The magnetic fields, activity and dynamos of young solar-type stars can be empirically studied using time-series of spectropolarimetric observations and tomographic imaging techniques such as Doppler imaging and Zeeman Doppler imaging. In this paper we use these techniques to study the young Sun-like star EK Draconis (Sp-Type: G1.5V, HD 129333) using ESPaDOnS at the Canada-France-Hawaii Telescope and NARVAL at the T\\`elescope Bernard Lyot. This multi-epoch study runs from late 2006 until early 2012. We measure high levels of chromospheric activity indicating an active, and varying, chromosphere. Surface brightness features were constructed for all available epochs. The 2006/7 and 2008 data show large spot features appearing at intermediate-latitudes. However, the 2012 data indicate a distinctive polar spot. We observe a strong, almost unipolar, azimuthal field during all epochs that is similar to that observed on other Sun-like stars. Using magnetic features, we determined an average equatorial rotational vel...

  14. Conditions for water ice lines and Mars-mass exomoons around accreting super-Jovian planets at 1 - 20 AU from Sun-like stars

    CERN Document Server

    Heller, René

    2015-01-01

    Exomoon detections might be feasible with NASA's Kepler or ESA's upcoming PLATO mission or the ground-based E-ELT. To use observational resources most efficiently we need to know where the largest, most easily detected moons can form. We explore the possibility of large exomoons by following the movement of water (H2O) ice lines in the accretion disks around young super-Jovian planets. We want to know how different heating sources in those disks affect the H2O ice lines. We simulate 2D rotationally symmetric accretion disks in hydrostatic equilibrium around super-Jovian exoplanets. The energy terms in our semi-analytical model -- (1) viscous heating, (2) planetary illumination, (3) accretional heating, and (4) stellar illumination -- are fed by precomputed planet evolution tracks. We consider planets accreting 1 to 12 Jupiter masses at distances between 1 and 20 AU to a Sun-like star. Accretion disks around Jupiter-mass planets closer than ~4.5 AU to Sun-like stars do not feature H2O ice lines, but the most m...

  15. Young Stars and Planets Near the Sun in 2015: Five Takeaways and Five Predictions

    CERN Document Server

    Liu, Michael C

    2016-01-01

    I present a highly biased and skewed summary of IAU Symposium 314, "Young Stars and Planets Near the Sun," held in Atlanta. This summary includes takeaway thoughts about the rapidly evolving state of the field, as well as crowd-sourced predictions for progress over the next ~10 years. We predict the elimination of 1-2 of the currently recognized young moving groups, the addition of 3 or more new moving groups within 100 pc, the continued lack of a predictive theory of stellar mass, robust measurements of the gas and dust content of circumstellar disks, and an ongoing struggle to achieve a consensus definition for a planet.

  16. 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.

  17. Mass Gathering Emergency Medicine: A Review of the Taiwan Experience of Long-distance Swimming Across Sun-Moon Lake

    Directory of Open Access Journals (Sweden)

    Wen-Han Chang

    2010-06-01

    Full Text Available Once a year during the festival of Sun-Moon Lake in Nan-Tou County, Taiwan, a long-distance swimming mass gathering (LDSMG event takes place. This event, in which participants swim an estimated 30 km, is very popular; the total number of spectators and participants at the 2002 festival was 15,189. This study, the first pertaining to the LDSMG, aimed to review the effect of the environmental factors at this particular mass gathering event, with mass being defined here as more than 1,000 people, upon the event's patient presentation rate (PPR. This was done to provide improved medical services at this event in future years The study also aimed to collect patient data from the two medical stations (one upstream and one downstream and analyze the differences between them. In 2002, the number of patients requiring first aid treatment was determined from data gathered on-site. A total of 63 presented at on-site medical stations (PPR, 4.15 per 1,000 attendees, where 14 patients presented to a downstream medical station and 49 to an upstream medical station. The mean age of the patients was 35.46 ± 15.14 years; ages ranged from 1 to 65 years. Forty-nine of the patients (78% were male. Fifty-nine patients were treated with medication (3.88 per 1,000 attendees, and two were taken to hospital (0.13 per 1,000 attendees. Injuries sustained included trauma (71%, such as impact, fall, sprain, stabbed laceration and burn, hypothermia (5%, and foreign bodies (3%. The PPR at the LDSMG was related to factors including the presence or absence of seating, whether the event was outdoors or indoors, mobility of the crowd, whether the activity was contained within a boundary, attendance figures, and humidity level. The weather, particularly the relative humidity (81%, was also positively correlated with an increase in the number of presentations at the medical stations.

  18. Worlds Without Moons

    Science.gov (United States)

    Kohler, Susanna

    2017-04-01

    Many of the exoplanets that weve discovered lie in compact systems with orbits very close to their host star. These systems are especially interesting in the case of cool stars where planets lie in the stars habitable zone as is the case, for instance, for the headline-making TRAPPIST-1 system.But other factors go into determining potential habitability of a planet beyond the rough location where water can remain liquid. One possible consideration: whether the planets have moons.Supporting HabitabilityLocations of equality between the Hill and Roche radius for five different potential moon densities. The phase space allows for planets of different semi-major axes and stellar host masses. Two example systems are shown, Kepler-80 and TRAPPIST-1, with dots representing the planets within them. [Kane 2017]Earths Moon is thought to have been a critical contributor to our planets habitability. The presence of a moon stabilizes its planets axial tilt, preventing wild swings in climate as the stars radiation shifts between the planets poles and equator. But what determines if a planet can have a moon?A planet can retain a moon in a stable orbit anywhere between an outer boundary of the Hill radius (beyond which the planets gravity is too weak to retain the moon) and an inner boundary of the Roche radius (inside which the moon would be torn apart by tidal forces). The locations of these boundaries depend on both the planets and moons properties, and they can be modified by additional perturbative forces from the host star and other planets in the system.In a new study, San Francisco State University scientist Stephen R. Kane modeled these boundaries for planets specifically in compact systems, to determine whether such planets can host moons to boost their likelihood of habitability.Allowed moon density as a function of semimajor axis for the TRAPPIST-1 system, for two different scenarios with different levels of perturbations. The vertical dotted lines show the locations

  19. A photometric and spectroscopic survey of solar twin stars within 50 parsecs of the Sun: I. Atmospheric parameters and color similarity to the Sun

    CERN Document Server

    de Mello, G F Porto; da Silva, L; de Nader, R V

    2013-01-01

    Solar twins and analogs are fundamental in the characterization of the Sun's place in the context of stellar measurements, as they are in understanding how typical the solar properties are in its neighborhood. They are also important for representing sunlight observable in the night sky for diverse photometric and spectroscopic tasks, besides being natural candidates for harboring planetary systems similar to ours and possibly even life-bearing environments. We report a photometric and spectroscopic survey of solar twin stars within 50 pc of the Sun. Hipparcos absolute magnitudes and (B-V)_Tycho colors were used to define a 2 sigma box around the solar values, where 133 stars were considered. Additional stars resembling the solar UBV colors in a broad sense, plus stars present in the lists of Hardorp, were also selected. All objects were ranked by a color-similarity index with respect to the Sun, defined by uvby and BV photometry. Moderately high-resolution, high-S/N spectra were used for a subsample of equat...

  20. Prevalence of Earth-size Planets Orbiting Sun-like Stars

    CERN Document Server

    Petigura, Erik Ardeshir

    2015-01-01

    In this thesis, I explore two topics in exoplanet science. The first is the prevalence of Earth-size planets in the Milky Way Galaxy. To determine the occurrence of planets having different sizes, orbital periods, and other properties, I conducted a survey of extrasolar planets using data collected by NASA's Kepler Space Telescope. This project involved writing new algorithms to analyze Kepler data, finding planets, and conducting follow-up work using ground-based telescopes. I found that most stars have at least one planet at or within Earth's orbit and that 26% of Sun-like stars have an Earth-size planet with an orbital period of 100 days or less. The second topic is the connection between the properties of planets and their host stars. The precise characterization of exoplanet hosts helps to bring planet properties like mass, size, and equilibrium temperature into sharper focus and probes the physical processes that form planets. I studied the abundance of carbon and oxygen in over 1000 nearby stars using ...

  1. 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

  2. Toroidal vs. poloidal magnetic fields in Sun-like stars: a rotation threshold

    CERN Document Server

    Petit, P; Solanki, SK; Donati, J-F; Aurière, M; Lignières, F; Morin, J; Paletou, F; Ramírez, J; Catala, C; Fares, R

    2008-01-01

    From a set of stellar spectropolarimetric observations, we report the detection of surface magnetic fields in a sample of four solar-type stars, namely HD 73350, HD 76151, HD 146233 and HD 190771. Assuming that the observed variability of polarimetric signal is controlled by stellar rotation, we establish the rotation periods of our targets, with values ranging from 8.8 d (for HD 190771) to 22.7 d (for HD 146233). Apart from rotation, fundamental parameters of the selected objects are very close to the Sun's, making this sample a practical basis to investigate the specific impact of rotation on magnetic properties of Sun-like stars. We reconstruct the large-scale magnetic geometry of the targets as a low-order (l<10) spherical harmonics expansion of the surface magnetic field. From the set of magnetic maps, we draw two main conclusions. (a) The magnetic energy of the large-scale field increases with rotation rate. The increase of chromospheric emission with the mean magnetic field is flatter than observed ...

  3. Dynamical systems for modeling evolution of the magnetic field of the Sun, stars and planets

    Science.gov (United States)

    Popova, E.

    2016-12-01

    The magnetic activity of the Sun, stars and planets are connected with a dynamo process based on the combined action of the differential rotation and the alpha-effect. Application of this concept allows us to get different types of solutions which can describe the magnetic activity of celestial bodies. We investigated the dynamo model with the meridional circulation by the low-mode approach. This approach is based on an assumption that the magnetic field can be described by non-linear dynamical systems with a relatively small number of parameters. Such non-linear dynamical systems are based on the equations of dynamo models. With this method dynamical systems have been built for media which contains the meridional flow and thickness of the spherical shell where dynamo process operates. It was shown the possibility of coexistence of quiasi-biennial oscillations, 22-year cycle, and grand minima of magnetic activity which is consistent with the observational data for the solar activity. We obtained different regimes (oscillations, vacillations, dynamo-bursts) depending on a value of the dynamo-number, the meridional circulation, and thickness of the spherical shell. We discuss features of these regimes and compare them with the observed features of the magnetic fields of the Sun, stars and Earth. We built theoretical paleomagnetic time scale and butterfly-diagrams for the helicity and toroidal magnetic field for different regimes.

  4. Interactions between brown-dwarf binaries and Sun-like stars

    CERN Document Server

    Kaplan, M; Whitworth, A P

    2012-01-01

    Several mechanisms have been proposed for the formation of brown dwarfs, but there is as yet no consensus as to which -- if any -- are operative in nature. Any theory of brown dwarf formation must explain the observed statistics of brown dwarfs. These statistics are limited by selection effects, but they are becoming increasingly discriminating. In particular, it appears (a) that brown dwarfs that are secondaries to Sun-like stars tend to be on wide orbits, $a\\ga 100\\,{\\rm AU}$ (the Brown Dwarf Desert), and (b) that these brown dwarfs have a significantly higher chance of being in a close ($a\\la 10\\,{\\rm AU}$) binary system with another brown dwarf than do brown dwarfs in the field. This then raises the issue of whether these brown dwarfs have formed {\\it in situ}, i.e. by fragmentation of a circumstellar disc; or have formed elsewhere and subsequently been captured. We present numerical simulations of the purely gravitational interaction between a close brown-dwarf binary and a Sun-like star. These simulatio...

  5. High Precision Full Stokes Spectropolarimetry of the Sun as a star-Instrument design aspects

    CERN Document Server

    Bose, Souvik

    2016-01-01

    The magnetic field plays a major role in governing the dynamics of the sun. Many interesting features like sunspots, flares, prominences, and Coronal Mass Ejections (CMEs) occur on its surface due to the dynamics associated with the magnetic fields. The magnetic activity exhibits spatial scales ranging from very fine scale (below the resolution limit of the current largest telescope) to large scale such as sunspots, active regions and the spatial scales as large as the sun itself. While the major efforts in building large telescopes is going on towards the goal of resolving smallest structure possible we propose here to measure the magnetic field on the global scale. For this purpose we propose an instrument to carryout high precision and high accurate spectropolarimetry of sun-as-a-star. In this thesis, we explore various instrumental design aspects that are necessary to make such observations. As part of the design consideration we have analysed a major noise source i.e. seeing induced cross-talk through si...

  6. Ancient Black Hole Speeds Through Sun's Galactic Neighborhood, Devouring Companion Star

    Science.gov (United States)

    2001-09-01

    Astronomers using the National Science Foundation's Very Long Baseline Array (VLBA) radio telescope have found an ancient black hole speeding through the Sun's Galactic neighborhood, devouring a small companion star as the pair travels in an eccentric orbit looping to the outer reaches of our Milky Way Galaxy. The scientists believe the black hole is the remnant of a massive star that lived out its brief life billions of years ago and later was gravitationally kicked from its home star cluster to wander the Galaxy with its companion. "This discovery is the first step toward filling in a missing chapter in the history of our Galaxy," said Felix Mirabel, an astrophysicist at the Institute for Astronomy and Space Physics of Argentina and French Atomic Energy Commission. "We believe that hundreds of thousands of very massive stars formed early in the history of our Galaxy, but this is the first black hole remnant of one of those huge primeval stars that we've found." "This also is the first time that a black hole's motion through space has been measured," Mirabel added. A black hole is a dense concentration of mass with a gravitational pull so strong that not even light can escape it. The research is reported in the Sept. 13 issue of the scientific journal Nature. XTE J1118+480 The object is called XTE J1118+480 and was discovered by the Rossi X-Ray satellite on March 29, 2000. Later observations with optical and radio telescopes showed that it is about 6,000 light-years from Earth and that it is a "microquasar" in which material sucked by the black hole from its companion star forms a hot, spinning disk that spits out "jets" of subatomic particles that emit radio waves. Most of the stars in our Milky Way Galaxy are within a thin disk, called the plane of the Galaxy. However, there also are globular clusters, each containing hundreds of thousands of the oldest stars in the Galaxy which orbit the Galaxy's center in paths that take them far from the Galaxy's plane. XTE J

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

    CERN Document Server

    Adams, Fred C

    2016-01-01

    Motivated by the current search for exomoons, this paper 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 tha...

  8. `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 and night, Moon phases and seasons. These modules were used in a science and literacy unit for 35 second graders at an urban elementary school in Midwestern USA. Data included pre- and post-interviews, audio-taped lessons and classroom observations. Post-interviews demonstrated that children's knowledge of the shapes and the movements of the Earth and Moon, alternation of day and night, the occurrence of the seasons, and Moon's changing appearance increased. Second graders reported that they enjoyed expanding their knowledge through hands-on experiences; through its reality effect, 3D visualization enabled them to observe the space objects that move in the virtual space. The teachers noted that 3D visualization stimulated children's interest in space and that using 3D visualization in combination with other teaching methods-literacy experiences, videos and photos, simulations, discussions, and presentations-supported student learning. The teachers and the students still experienced challenges using 3D visualization due to technical problems with 3D vision and time constraints. We conclude that 3D visualization offers hands-on experiences for challenging science concepts and may support young children's ability to view phenomena that would typically be observed through direct, long-term observations in outer space. Results imply a reconsideration of assumed capabilities of young children to understand astronomical phenomena.

  9. Metallicity of Sun-like G-stars that have Exoplanets

    Indian Academy of Sciences (India)

    Shashanka R. Gurumath; K. M. Hiremath; V. Ramasubramanian

    2017-06-01

    By considering the physical and orbital characteristics of G type stars and their exoplanets, we examine the association between stellar mass and its metallicity that follows a power law. Similar relationship is also obtained in case of single and multiplanetary stellar systems suggesting that, Sun′s present mass is about 1% higher than the estimated value for its metallicity. Further, for all the stellar systems with exoplanets, association between the planetary mass and the stellar metallicity is investigated, that suggests planetary mass is independent of stellar metallicity. Interestingly, in case of multiplanetary systems, planetary mass is linearly dependent on the stellar absolute metallicity, that suggests, metal rich stars produce massive (≥1 Jupiter mass) planets compared to metal poor stars. This study also suggests that there is a solar system planetary missing mass of ∼0.8 Jupiter mass. It is argued that probably 80% of missing mass is accreted onto the Sun and about 20% of missing mass might have been blown off to the outer solar system (beyond the present Kuiper belt) during early history of solar system formation. We find that, in case of single planetary systems, planetary mass is independent of stellar metallicity with an implication of their non-origin in the host star’s protoplanetary disk and probably are captured from the space. Final investigation of dependency of the orbital distances of planets on the host stars metallicity reveals that inward migration of planets is dominant in case of single planetary systems supporting the result that most of the planets in single planetary systems are captured from the space.

  10. HAT-P-55b: A Hot Jupiter Transiting a Sun-like Star

    CERN Document Server

    Juncher, D; Hartman, J D; Bakos, G Á; Bieryla, A; Kovács, T; Boisse, I; Latham, D W; Kovács, G; Bhatti, W; Csubry, Z; Penev, K; de Val-Borro, M; Falco, E; Torres, G; Noyes, R W; Lázár, J; Papp, I; Sári, P

    2015-01-01

    We report the discovery of a new transiting extrasolar planet, HAT-P-55b. The planet orbits a V = 13.207 +/- 0.039 sun-like star with a mass of 1.013 +/- 0.037 solar masses, a radius of 1.011 +/- 0.036 solar radii and a metallicity of -0.03 +/- 0.08. The planet itself is a typical hot Jupiter with a period of 3.5852467 +/- 0.0000064 days, a mass of 0.582 +/- 0.056 Jupiter masses and a radius of 1.182 +/- 0.055 Jupiter radii. This discovery adds to the increasing sample of transiting planets with measured bulk densities, which is needed to put constraints on models of planetary structure and formation theories.

  11. 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)

  12. 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…

  13. On the rotation period distribution of CoRoT and Kepler Sun-like stars

    CERN Document Server

    Leao, I C; Lopes, C E Ferreira; Neves, V; Valcarce, A A R; de Oliveira, L L A; da Silva, D Freire; de Freitas, D B; Martins, B L Canto; Janot-Pacheco, E; Baglin, A; De Medeiros, J R

    2015-01-01

    We study the distribution of the photometric rotation period (Prot), which is a direct measurement of the surface rotation at active latitudes, for three subsamples of Sun-like stars: one from CoRoT data and two from Kepler data. We identify the main populations of these samples and interpret their main biases particularly for a comparison with the solar Prot. Prot and variability amplitude (A) measurements were obtained from public CoRoT and Kepler catalogs, which were combined with public data of physical parameters. Because these samples are subject to selection effects, we computed synthetic samples with simulated biases to compare with observations, particularly around the Sun's HR-diagram location. Theoretical grids and empirical relations were used to combine physical parameters with Prot and A. Biases were simulated by performing cutoffs on the physical and rotational parameters in the same way as in each observed sample. A crucial cutoff is related with the detectability of the rotational modulation,...

  14. Spectrometers for Sky-Scanning, Sun-Tracking Atmospheric Research (4STAR) Upgrade to Full Sun-Sky-Cloud-Trace Gas Spectrometry Capability for Airborne Science

    Science.gov (United States)

    Dunagan, S. E.; Flynn, C. J.; Johnson, R. R.; Kacenelenbogen, M. S.; Knobelspiesse, K. D.; LeBlanc, S. E.; Livingston, J. M.; Redemann, J.; Russell, P. B.; Schmid, B.; Segal-Rosenhaimer, M.; Shinozuka, Y.

    2014-12-01

    The Spectrometers for Sky-Scanning, Sun-Tracking Atmospheric Research (4STAR) instrument has been developed at NASA Ames in collaboration with Pacific Northwest National Laboratory (PNNL) and NASA Goddard, supported substantially since 2009 by NASA's Radiation Science Program and Earth Science Technology Office. It combines grating spectrometers with fiber optic links to a tracking, scanning head to enable sun tracking, sky scanning, and zenith viewing. 4STAR builds on the long and productive heritage of the NASA Ames Airborne Tracking Sunphotometers (AATS-6 and -14), which have yielded more than 100 peer-reviewed publications and extensive archived data sets in many NASA Airborne Science campaigns from 1986 to the present. The baseline 4STAR instrument has provided extensive data supporting the TCAP (Two Column Aerosol Project, July 2012 & Feb. 2013), SEAC4RS (Studies of Emissions, Atmospheric Composition, Clouds and Climate Coupling by Regional Surveys, 2013), and ARISE (Arctic Radiation - IceBridge Sea and Ice Experiment, 2014), field campaigns.This poster presents plans and progress for an upgrade to the 4STAR instrument to achieve full science capability, including (1) direct-beam sun tracking measurements to derive aerosol optical depth spectra, (2) sky radiance measurements to retrieve aerosol absorption and type (via complex refractive index and mode-resolved size distribution), (3) cloud properties via zenith radiance, and (4) trace gas spectrometry. Technical progress in context with the governing physics is reported on several upgrades directed at improved light collection and usage, particularly as related to spectrally and radiometrically stable propagation through the collection light path. In addition, improvements to field calibration and verification, and flight operability and reliability are addressed.

  15. 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

  16. Ionization balance of Ti in the photospheres of the Sun and four late-type stars

    CERN Document Server

    Bergemann, Maria

    2011-01-01

    In this paper we investigate statistical equilibrium of Ti in the atmospheres of late-type stars. The Ti I/Ti II level populations are computed with available experimental atomic data, except for photoionization and collision induced transition rates, for which we have to rely on theoretical approximations. For the Sun, the NLTE line formation with adjusted H I inelastic collision rates and MAFAGS-OS model atmosphere solve the long-standing discrepancy between Ti I and Ti II lines. The NLTE abundances determined from both ionization stages agree within $0.01$ dex with each other and with the Ti abundance in C I meteorites. The Ti NLTE model does not perform similarly well for the metal-poor stars, overestimating NLTE effects in the atmospheres of dwarfs, but underestimating overionization for giants. Investigating different sources of errors, we find that only [Ti/Fe] ratios based on Ti II and Fe II lines can be safely used in studies of Galactic chemical evolution. To avoid spurious abundance trends with met...

  17. High resolution spectroscopy of two young active late type stars within 20 parsecs of the Sun

    Institute of Scientific and Technical Information of China (English)

    Hui-Juan Wang; Jian-Yan Wei

    2009-01-01

    We present high-resolution optical echell spectroscopy of HIP 544 and HIP 46843, two nearby solar like stars. The discovery of these young stars at such a close distance to the Sun is really a surprising phenomenon. It will help us to have a better understanding of the structure and evolutionary history of the Milky Way. The radial ve-locities (RV) of HIP 544 and HIP 46843 are measured to be -6.88±0.13km s-1 and 8.30±0.16km s-1, respectively, which are more accurate than before. The equivalent widths (EW) of the Li I 6707.8 A absorption line of HIP 544 and HIP 46843 are mea-sured to be 110±5mA and 195±5mA respectively. Based on these properties, HIP 544 is estimated to be 100-800Myr old and HIP 46843 30-100Myr old using three relatively creditable methods.

  18. The influence of the magnetic topology on the wind braking of sun-like stars.

    Science.gov (United States)

    Réville, V.; Brun, A. S.; Matt, S. P.; Strugarek, A.; Pinto, R.

    2014-12-01

    Stellar winds are thought to be the main process responsible for the spin down of main-sequence stars. The extraction of angular momentum by a magnetized wind has been studied for decades, leading to several formulations for the resulting torque. However, previous studies generally consider simple dipole or split monopole stellar magnetic topologies. Here we consider in addition to a dipolar stellar magnetic field, both quadrupolar and octupolar configurations, while also varying the rotation rate and the magnetic field strength. 60 simulations made with a 2.5D, cylindrical and axisymmetric set-up and computed with the PLUTO code were used to find torque formulations for each topology. We further succeed to give a unique law that fits the data for every topology by formulating the torque in terms of the amount of open magnetic flux in the wind. We also show that our formulation can be applied to even more realistic magnetic topologies, with examples of the Sun in its minimum and maximum phase as observed at the Wilcox Solar Observatory, and of a young K-star (TYC-0486-4943-1) whose topology has been obtained by Zeeman-Doppler Imaging (ZDI).

  19. Activity and Magnetic Field Structure of the Sun-Like Planet Hosting Star HD 1237

    CERN Document Server

    Alvarado-Gómez, J D; Grunhut, J; Fares, R; Donati, J -F; Alecian, E; Kochukhov, O; Oksala, M; Morin, J; Redfield, S; Cohen, O; Drake, J J; Jardine, M; Matt, S; Petit, P; Walter, F M

    2015-01-01

    We analyse the magnetic activity characteristics of the planet hosting Sun-like star, HD 1237, using HARPS spectro-polarimetric time-series data. We find evidence of rotational modulation of the magnetic longitudinal field measurements consistent with our ZDI analysis, with a period of 7 days. We investigate the effect of customising the LSD mask to the line depths of the observed spectrum and find that it has a minimal effect on shape of the extracted Stokes V profile but does result in a small increase in the S/N ($\\sim$ 7%). We find that using a Milne-Eddington solution to describe the local line profile provides a better fit to the LSD profiles in this slowly rotating star, which also impacts the recovered ZDI field distribution. We also introduce a fit-stopping criterion based on the information content (entropy) of the ZDI maps solution set. The recovered magnetic field maps show a strong (+90 G) ring-like azimuthal field distribution and a complex radial field dominating at mid latitudes ($\\sim$45 degr...

  20. Dust discs around intermediate mass and Sun-like stars in the 16 Myr old NGC 1960 open cluster

    CERN Document Server

    Smith, R

    2011-01-01

    We present an analysis of Spitzer IRAC (3.6--8um) and MIPS (24um) imaging of members of the 16(+10/-5)Myr old open cluster NGC 1960 (M36). Models of terrestrial planet formation indicate that rocky planets are likely to achieve their final masses at around 10-30Myr, and thus this cluster is at an interesting epoch for planet formation. We find 21 B-F5 type stars and 14 F6-K9 type stars which have 24um excess emission, and thus determine that >30% of B-F5 type stars and >23% of F6-K9 type stars in this cluster have 24um excess emission. These excess frequencies are similar to those observed in other clusters of similar age. Three early type stars have excesses at near-infrared wavelengths. Analysis of their SEDs confirms that these are true debris discs and not remnant primordial or transitional discs. None of the 61 sun-like stars have confirmed near-infrared excess, and we can place a limit on the frequency of 8um excess emission around sun-like stars of <7%. All of the detected excesses are consistent wi...

  1. On the Observations of the Sun in Polynesia

    CERN Document Server

    Rjabchikov, Sergei

    2014-01-01

    The role of the Polynesian sun god Tagaloa has been studied. The Polynesian characters Maui-tikitiki, Tane and Tiki were related to the sun as well. The solar data of Easter Island are essential indeed. The rongorongo text on the Santiago staff about the solar eclipse of December 20, 1805 A.D. has been decoded. The Mataveri calendar was probably incised on a rock in 1775 A.D. So, a central event during the bird-man festval was the day of vernal equinox. The priests-astronomers watched not only the sun and the moon, but also some stars of the zodiacal constellations and other bright stars.

  2. 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

  3. The Earth transiting the Sun as seen from Jupiter's moons: detection of an inverse Rossiter-McLaughlin effect produced by the Opposition Surge of the icy Europa

    CERN Document Server

    Molaro, Paolo; Monaco, Lorenzo; Zaggia, Simone; Lovis, Christophe

    2015-01-01

    We report on a multi-wavelength observational campaign which followed the Earth's transit on the Sun as seen from Jupiter on 5 Jan the 2014. Simultaneous observations of Jupiter's moons Europa and Ganymede obtained with HARPS from La Silla, Chile, and HARPS-N from La Palma, Canary Islands, were performed to measure the Rossiter-McLaughlin effect due to the Earth's passage using the same technique successfully adopted for the 2012 Venus Transit (Molaro et al 2013). The expected modulation in radial velocities was of about 20 cm/s but an anomalous drift as large as 38 m/s, i.e. more than two orders of magnitude higher and opposite in sign, was detected instead. The consistent behaviour of the two spectrographs rules out instrumental origin of the radial velocity drift and BiSON observations rule out the possible dependence on the Sun's magnetic activity. We suggest that this anomaly is produced by the Opposition Surge on Europa's icy surface, which amplifies the intensity of the solar radiation from a portion o...

  4. The influence of the magnetic topology on the braking of sun-like stars

    CERN Document Server

    Réville, Victor; Matt, Sean; Strugarek, Antoine; Pinto, Rui

    2014-01-01

    Stellar winds are thought to be the main process responsible for the spin down of main-sequence stars. The extraction of angular momentum by a magnetized wind has been studied for decades, leading to several formulations for the resulting torque. However, previous studies generally consider simple dipole or split monopole stellar magnetic topologies. Here we consider in addition to a dipolar stellar magnetic field, both quadrupolar and octupolar configurations, while also varying the rotation rate and the magnetic field strength. 60 simulations made with a 2.5D, cylindrical and axisymmetric set-up and computed with the PLUTO code were used to find torque formulations for each topology. We further succeed to give a unique law that fits the data for every topology by formulating the torque in terms of the amount of open magnetic flux in the wind. We also show that our formulation can be applied to even more realistic magnetic topologies, with examples of the Sun in its minimum and maximum phase as observed at t...

  5. Wide companions to Hipparcos stars within 67 pc of the Sun

    CERN Document Server

    Tokovinin, Andrei

    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" < \\rho < 1800", relative proper motion between the two components less than 25 mas/yr, 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 \\"Opik's law. We find that Solar-mass dwarfs have no less than 4.4% +/- 0.3% companions with separations l...

  6. Kepler-9: A System of Multiple Planets Transiting a Sun-Like Star, Confirmed by Timing Variations

    Science.gov (United States)

    Holman, Matthew J.; Fabrycky, Daniel C.; Ragozzine, Darin; Ford, Eric B.; Steffen, Jason H.; Welsh, William F.; Lissauer, Jack J.; Latham, David W.; Marcy, Geoffrey W.; Walkowicz, Lucianne M.; Batalha, Natalie M.; Jenkins, Jon M.; Rowe, Jason F.; Cochran, William D.; Fressin, Francois; Torres, Guillermo; Buchhave, Lars A.; Sasselov, Dimitar D.; Borucki, William J.; Koch, David G.; Basri, Gibor; Brown, Timothy M.; Caldwell, Douglas A.; Charbonneau, David; Dunham, Edward W.; Gautier, Thomas N.; Geary, John C.; Gilliland, Ronald L.; Haas, Michael R.; Howell, Steve B.; Ciardi, David R.; Endl, Michael; Fischer, Debra; Fürész, Gábor; Hartman, Joel D.; Isaacson, Howard; Johnson, John A.; MacQueen, Phillip J.; Moorhead, Althea V.; Morehead, Robert C.; Orosz, Jerome A.

    2010-10-01

    The Kepler spacecraft is monitoring more than 150,000 stars for evidence of planets transiting those stars. We report the detection of two Saturn-size planets that transit the same Sun-like star, based on 7 months of Kepler observations. Their 19.2- and 38.9-day periods are presently increasing and decreasing at respective average rates of 4 and 39 minutes per orbit; in addition, the transit times of the inner body display an alternating variation of smaller amplitude. These signatures are characteristic of gravitational interaction of two planets near a 2:1 orbital resonance. Six radial-velocity observations show that these two planets are the most massive objects orbiting close to the star and substantially improve the estimates of their masses. After removing the signal of the two confirmed giant planets, we identified an additional transiting super-Earth-size planet candidate with a period of 1.6 days.

  7. Kepler-9: a system of multiple planets transiting a Sun-like star, confirmed by timing variations.

    Science.gov (United States)

    Holman, Matthew J; Fabrycky, Daniel C; Ragozzine, Darin; Ford, Eric B; Steffen, Jason H; Welsh, William F; Lissauer, Jack J; Latham, David W; Marcy, Geoffrey W; Walkowicz, Lucianne M; Batalha, Natalie M; Jenkins, Jon M; Rowe, Jason F; Cochran, William D; Fressin, Francois; Torres, Guillermo; Buchhave, Lars A; Sasselov, Dimitar D; Borucki, William J; Koch, David G; Basri, Gibor; Brown, Timothy M; Caldwell, Douglas A; Charbonneau, David; Dunham, Edward W; Gautier, Thomas N; Geary, John C; Gilliland, Ronald L; Haas, Michael R; Howell, Steve B; Ciardi, David R; Endl, Michael; Fischer, Debra; Fürész, Gábor; Hartman, Joel D; Isaacson, Howard; Johnson, John A; MacQueen, Phillip J; Moorhead, Althea V; Morehead, Robert C; Orosz, Jerome A

    2010-10-01

    The Kepler spacecraft is monitoring more than 150,000 stars for evidence of planets transiting those stars. We report the detection of two Saturn-size planets that transit the same Sun-like star, based on 7 months of Kepler observations. Their 19.2- and 38.9-day periods are presently increasing and decreasing at respective average rates of 4 and 39 minutes per orbit; in addition, the transit times of the inner body display an alternating variation of smaller amplitude. These signatures are characteristic of gravitational interaction of two planets near a 2:1 orbital resonance. Six radial-velocity observations show that these two planets are the most massive objects orbiting close to the star and substantially improve the estimates of their masses. After removing the signal of the two confirmed giant planets, we identified an additional transiting super-Earth-size planet candidate with a period of 1.6 days.

  8. A super-Earth-sized planet orbiting in or near the habitable zone around Sun-like star

    CERN Document Server

    Barclay, Thomas; Howell, Steve B; Rowe, Jason F; Huber, Daniel; Isaacson, Howard; Jenkins, Jon M; Kolbl, Rea; Marcy, Geoffrey W; Quintana, Elisa V; Still, Martin; Twicken, Joseph D; Bryson, Stephen T; Borucki, William J; Caldwell, Douglas A; Ciardi, David; Clarke, Bruce D; Christiansen, Jessie L; Coughlin, Jeffrey L; Fischer, Debra A; Li, Jie; Haas, Michael R; Hunter, Roger; Lissauer, Jack J; Mullally, Fergal; Sabale, Anima; Seader, Shawn E; Smith, Jeffrey C; Tenenbaum, Peter; Uddin, AKM Kamal; Thompson, Susan E

    2013-01-01

    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 three-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 >99.1%. The inner planet, Kepler-69b, has a radius of 2.24+/-0.4 Rearth and orbits the host star every 13.7 days. The outer planet, Kepler-69c, is a super-Earth-size object with a radius of 1.7+/-0.3 Rearth 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 habitable zone of a Sun-like star and represents an important step on the path to finding the first true Earth ...

  9. Spectrometers for Sky-Scanning, Sun-Tracking Atmospheric Research (4STAR): Airborne Concepts and Ground Prototype Measurements

    Science.gov (United States)

    Russell, P. B.; Schmid, B.; Flynn, C.; Dunagan, S. E.; Johnson, R. R.; Redemann, J.; Livingston, J.

    2007-12-01

    A collaboration between NASA Ames Research Center and Battelle Pacific Northwest Division is exploring new instrument concepts that combine sky scanning and spectroscopy with the direct sun transmission measurement capabilities of previous instruments like the NASA Ames Airborne Tracking Sunphotometers (AATS). Additional technical goals are to reduce instrument size, weight, and power requirements while increasing autonomy, so as to permit operation on a wider range of aircraft, including unmanned aerial vehicles (UAVs). The overall science goal for the new instruments is to improve knowledge of atmospheric constituents and their links to climate using a variety of airborne measurement approaches including satellite validation. 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 sunphotometry alone. The spectroscopic capability will improve measurements of gas constituents (e.g., H2O, O3, NO2, SO2) . Concepts explored to date for an airborne Spectrometer for Sky-Scanning, Sun-Tracking Atmospheric Research (4STAR-Air) include using fiber optics to link a spectrometer inside the aircraft to optical entrance ports in a relatively small tracking/scanning head outside the aircraft. 4STAR feasibility depends on overcoming three technological hurdles: 1. Maintaining calibration to 1% stability over a period of months. 2. Demonstrating stray light rejection to permit measuring skylight within a few degrees of the sun. 3. Devising a fiber optic coupling that maintains 1% calibration stability with as many as possible of the following desirable characteristics: detachable during assembly before calibration; detachable between calibration and scientific measurements; rotatable during measurements. To investigate ways to overcome these hurdles we have developed a ground-based prototype, 4STAR-Ground. To date 4STAR-Ground has been

  10. Basal Chromospheric Flux and Maunder Minimum-type Stars: The quiet-Sun Chromosphere as a Universal Phenomenon

    CERN Document Server

    Schroeder, K -P; Martinez, M I Perez; Cuntz, M; Schmitt, J H M M

    2012-01-01

    Aims: We demonstrate the universal character of the quiet-Sun chromosphere among inactive stars (solar-type and giants). By assessing the main physical processes, we shed new light on some common observational phenomena. Methods: We discuss measurements of the solar Mt. Wilson S-index, obtained by the Hamburg Robotic Telescope around the extreme minimum year 2009, and compare the established chromospheric basal Ca II K line flux to the Mt. Wilson S-index data of inactive ("flat activity") stars, including giants. Results: During the unusually deep and extended activity minimum of 2009, the Sun reached S-index values considerably deeper than in any of its previously observed minima. In several brief periods, the Sun coincided exactly with the S-indices of inactive ("flat", presumed Maunder Minimum-type) solar analogues of the Mt. Wilson sample; at the same time, the solar visible surface was also free of any plages or remaining weak activity regions. The corresponding minimum Ca II K flux of the quiet Sun and ...

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

    Energy Technology Data Exchange (ETDEWEB)

    Volkamer, Klaus E-mail: dr.volkamer@t-online.de

    2003-07-01

    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 {center_dot} {radical}((h{center_dot}c)/((2 {center_dot} {pi} {center_dot} G))) = n 0 21.77 {mu}g, 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 &apos

  12. 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.

  13. Development of the effective teaching material of the science unit "the Moon and the Sun" of the elementary school of Japan. - Method for understanding of the movement of the celestial sphere

    Science.gov (United States)

    Taketa, I.; Matsumoto, I.

    2014-12-01

    In general, elementary school teacher relatively poor at the science field about "earth and universe". There is the science unit "the Moon and the Sun" in the sixth grader in elementary school in Japan. In this study, we developed the effective teaching material that is both student is easy understanding and teacher is easy treating. The teaching material that we developed is the Movement of the Moon and the Sun using about 30-cm turntable and a USB Camera. As for the previous teaching materials, every student was checking (see) the moon and the sun spatial relationship, and the shape of the moon to each. The developed teaching material have the advantage that all student in the class can check the same phenomenon on a Video screen, by using a USB Camera. And we carried the questionnaire survey to student of attached elementary school of Shimane University. The result checked that such teaching materials were useful to a student's understanding of the movement of the celestial sphere.

  14. A unified normal mode approach to dynamic tides and its application to rotating Sun-like stars

    CERN Document Server

    Ivanov, P B; Chernov, S V

    2013-01-01

    We determine the response of a uniformly rotating star to tidal perturbations due to a companion. General periodic orbits and parabolic flybys are considered. We evaluate energy and angular momentum exchange rates as a sum of contributions from normal modes allowing for dissipative processes. We consider the case when the response is dominated by the contribution of an identifiable regular spectrum of low frequency modes, such as gravity modes and evaluate it in the limit of very weak dissipation. Our formalism may be applied both to Sun-like stars with radiative cores and convective envelopes and to more massive stars with convective cores and radiative envelopes. We provide general expressions for transfer of energy and angular momentum valid for an orbit with any eccentricity. Detailed calculations are made for Sun-like stars in the slow rotation regime where centrifugal distortion is neglected in the equilibrium and the traditional approximation is made for the normal modes. We use both a WKBJ procedure a...

  15. The Earth transiting the Sun as seen from Jupiter's moons: detection of an inverse Rossiter-McLaughlin effect produced by the opposition surge of the icy Europa

    Science.gov (United States)

    Molaro, P.; Barbieri, M.; Monaco, L.; Zaggia, S.; Lovis, C.

    2015-10-01

    We report on a multiwavelength observational campaign which followed the Earth's transit on the Sun as seen from Jupiter on 2014 January 2014. Simultaneous observations of Jupiter's moons Europa and Ganymede obtained with high accuracy radial velocity planetary searcher (HARPS) from La Silla, Chile and HARPS-N from La Palma, Canary Islands were performed to measure the Rossiter-McLaughlin effect due to the Earth's passage using the same technique successfully adopted for the 2012 Venus Transit. The expected modulation in radial velocities was of ≈20 cm s-1 but an anomalous drift as large as ≈38 m s-1, i.e. more than two orders of magnitude higher and opposite in sign, was detected instead. The consistent behaviour of the two spectrographs rules out instrumental origin of the radial velocity drift and Birmingham Solar Oscillations Network observations rule out the possible dependence on the Sun's magnetic activity. We suggest that this anomaly is produced by the opposition surge on Europa's icy surface, which amplifies the intensity of the solar radiation from a portion of the solar surface centred around the crossing Earth which can then be observed as a sort of inverse Rossiter-McLaughlin effect. in fact, a simplified model of this effect can explain in detail most features of the observed radial velocity anomalies, namely the extensions before and after the transit, the small differences between the two observatories and the presence of a secondary peak closer to Earth passage. This phenomenon, observed here for the first time, should be observed every time similar Earth alignments occur with rocky bodies without atmospheres. We predict that it should be observed again during the next conjunction of Earth and Jupiter in 2026.

  16. Cool stars, stellar systems, and the sun; Proceedings of the 6th Cambridge Workshop, Seattle, WA, Sept. 18-21, 1989

    Science.gov (United States)

    Wallerstein, George (Editor)

    1990-01-01

    The present conference on cool stars, stellar systems, and the sun encompasses stellar chromospheres and coronae, binary stars, the stellar evolution of contracting stars and red giants, stellar evolution abundances of the elements, mass loss and envelopes, and stellar pulsation. Specific issues addressed include theories regarding the acoustic and magnetic heating of stellar chromospheres and coronae, stellar granulation, wave heating in magnetic flux tubes, observations of the solar Ca-II lines, longitudinal-transverse magnetic tube waves in the solar atmosphere, radio emission from rapidly rotating cool giant stars, and spot temperatures and area coverages on active dwarf stars. Also addressed are the optical and UV spectra of RS-CVn stars, emission lines from T-Tauri stars, the spectroscopy of HR1614 group stars, red giants in external galaxies, the rotation of evolved stars, the transition from red giant to planetary nebula, and radiative transfer in the dynamic atmospheres of variable stars.

  17. 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 rocky 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

  18. 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.

  19. 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.

  20. 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...

  1. TENTATIVE EVIDENCE FOR RELATIVISTIC ELECTRONS GENERATED BY THE JET OF THE YOUNG SUN-LIKE STAR DG Tau

    Energy Technology Data Exchange (ETDEWEB)

    Ainsworth, Rachael E.; Ray, Tom P.; Taylor, Andrew M. [Dublin Institute for Advanced Studies, 31 Fitzwilliam Place, Dublin 2 (Ireland); Scaife, Anna M. M. [School of Physics and Astronomy, University of Southampton, Highfield, Southampton, SO17 1BJ (United Kingdom); Green, David A.; Buckle, Jane V., E-mail: rainsworth@cp.dias.ie [Cavendish Laboratory, J J Thomson Avenue, Cambridge, CB3 0HE (United Kingdom)

    2014-09-01

    Synchrotron emission has recently been detected in the jet of a massive protostar, providing further evidence that certain jet formation characteristics for young stars are similar to those found for highly relativistic jets from active galactic nuclei. We present data at 325 and 610 MHz taken with the Giant Metrewave Radio Telescope of the young, low-mass star DG Tau, an analog of the Sun soon after its birth. This is the first investigation of a low-mass young stellar object at such low frequencies. We detect emission with a synchrotron spectral index in the proximity of the DG Tau jet and interpret this emission as a prominent bow shock associated with this outflow. This result provides tentative evidence for the acceleration of particles to relativistic energies due to the shock impact of this otherwise very low-power jet against the ambient medium. We calculate the equipartition magnetic field strength B {sub min} ≈ 0.11 mG and particle energy E {sub min} ≈ 4 × 10{sup 40} erg, which are the minimum requirements to account for the synchrotron emission of the DG Tau bow shock. These results suggest the possibility of low energy cosmic rays being generated by young Sun-like stars.

  2. Pulsation models for the 0.26M_sun star mimicking RR Lyrae pulsator. Model survey for the new class of variable stars

    CERN Document Server

    Smolec, R; Graczyk, D; Pilecki, B; Gieren, W; Thompson, I; Stepien, K; Karczmarek, P; Konorski, P; Gorski, M; Suchomska, K; Bono, G; Moroni, P G Prada; Nardetto, N

    2012-01-01

    We present non-linear hydrodynamic pulsation models for OGLE-BLG-RRLYR-02792 - a 0.26M_sun pulsator, component of the eclipsing binary system, analysed recently by Pietrzynski et al. The star's light and radial velocity curves mimic that of classical RR Lyrae stars, except for the bump in the middle of the ascending branch of the radial velocity curve. We show that the bump is caused by the 2:1 resonance between the fundamental mode and the second overtone - the same mechanism that causes the Hertzsprung bump progression in classical Cepheids. The models allow to constrain the parameters of the star, in particular to estimate its absolute luminosity (approx 33L_sun) and effective temperature (approx 6970K, close to the blue edge of the instability strip). We conduct a model survey for the new class of low mass pulsators similar to OGLE-BLG-RRLYR-02792 - products of evolution in the binary systems. We compute a grid of models with masses corresponding to half (and less) of the typical mass of RR Lyrae variable...

  3. 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

  4. 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

  5. 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

  6. 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

  7. Full moon and crime.

    Science.gov (United States)

    Thakur, C P; Sharma, D

    The incidence of crimes reported to three police stations in different towns (one rural, one urban, one industrial) was studied to see if it varied with the day of the lunar cycle. The period of the study covered 1978-82. The incidence of crimes committed on full moon days was much higher than on all other days, new moon days, and seventh days after the full moon and new moon. A small peak in the incidence of crimes was observed on new moon days, but this was not significant when compared with crimes committed on other days. The incidence of crimes on equinox and solstice days did not differ significantly from those on other days, suggesting that the sun probably does not influence the incidence of crime. The increased incidence of crimes on full moon days may be due to "human tidal waves" caused by the gravitational pull of the moon.

  8. Kepler-63b: A Giant Planet in a Polar Orbit around a Young Sun-like Star

    CERN Document Server

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

    2013-01-01

    We present the discovery and characterization of a giant planet orbiting the young Sun-like star Kepler-63 (KOI-63, $m_{\\rm Kp} = 11.6$, $T_{\\rm eff} = 5576$ K, $M_\\star = 0.98\\, M_\\odot$). The planet transits every 9.43 days, with apparent depth variations and brightening anomalies caused by large starspots. The planet's radius is $6.1 \\pm 0.2 R_{\\earth}$, 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 we can place a rough upper bound of $120 M_{\\earth}$ (3$\\sigma$). The host star has a high obliquity ($\\psi$ = $104^{\\circ}$), 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-cross...

  9. Modeling the exchange of comets between the Sun and passing stars in a low stellar density environment

    Science.gov (United States)

    Levine, Stephen; Gosmeyer, Catherine

    2016-10-01

    We investigated the importance of close encounters between our Sun and its Oort cloud and passing stars with similar Oort clouds in the low stellar density environment of the outer portion of our Galaxy. By constructing a set of interaction cross-sections that describe the interchange of material between the two passing Oort clouds, and then randomly computing sets of encounters that a star would have during its orbit in the Galaxy over a period of time equivalent to the life of the Sun after the dissolution of its birth cluster, we have examined how the ensemble of passing encounters could impact the evolution of our Oort cloud. From the set of 1,000 possible realizations of the interactions over a solar lifetime, we find that the resulting solar Oort cloud is likely to be significantly eroded as a result of the set of encounters, and is also likely today to contain a significant amount of material that was formed in passing extra-solar systems.

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

    CERN Document Server

    Marcy, Geoffrey W; 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 R_e planets that receive 1-4x the incident stellar flux that warms our Earth. These Earth-size planets are sprinkled uniformly with orbital distance (logarithmically) out to 0.4 AU, and probably beyond. Mass measurements for 33 transiting planets of 1-4 R_e show that the smallest of them, R < 1.5 R_e, have the density expected for rocky planets. Their densities increase with increasing radius, likely caused by gravitational compression. Including solar system planets yields a relation: rho = 2.32 + 3.19 R/R_e [g/cc]. ...

  11. solarFLAG hare and hounds: estimation of p-mode frequencies from Sun-as-star helioseismology data

    CERN Document Server

    Jiménez-Reyes, S J; García, R A; Appourchaux, T; Baudin, F; Boumier, P; Elsworth, Y; Fletcher, S T; Lazrek, M; Leibacher, J W; Lochard, J; New, R; Regulo, C; Salabert, D; Toutain, T; Verner, G A; Wachter, R

    2008-01-01

    We report on the results of the latest solarFLAG hare-and-hounds exercise, which was concerned with testing methods for extraction of frequencies of low-degree solar p modes from data collected by Sun-as-a-star observations. We have used the new solarFLAG simulator, which includes the effects of correlated mode excitation and correlations with background noise, to make artificial timeseries data that mimic Doppler velocity observations of the Sun as a star. The correlations give rise to asymmetry of mode peaks in the frequency power spectrum. Ten members of the group (the hounds) applied their ``peak bagging'' codes to a 3456-day dataset, and the estimated mode frequencies were returned to the hare (who was WJC) for comparison. Analysis of the results reveals a systematic bias in the estimated frequencies of modes above approximately 1.8 mHz. The bias is negative, meaning the estimated frequencies systematically underestimate the input frequencies. We identify two sources that are the dominant contributions t...

  12. High-mass star formation at high luminosities: W31 at >10^6 L_sun

    CERN Document Server

    Beuther, H; Henning, Th; Bik, A; Wyrowski, F; Schuller, F; Schilke, P; Thorwirth, S; Kim, K -T

    2011-01-01

    Context: High-mass star formation has been a very active field over the last decade, however, most studies targeted regions of luminosities between 10^4 and 10^5 L_sun. Methods: We selected the W31 star-forming complex with a total luminosity of ~6x10^6 L_sun for a multi-wavelength spectral line and continuum study covering wavelengths from the near- and mid-infrared via (sub)mm wavelength observations to radio data in the cm regime. Results: While the overall structure of the multi-wavelength continuum data resembles each other well, there are several intriguing differences. The 24mum emission stemming largely from small dust grains follows tightly the spatial structure of the cm emission tracing the ionized free-free emission. Hence warm dust resides in regions that are spatially associated with the ionized hot gas (~10^4 K) of the HII regions. Furthermore, we find several evolutionary stages within the same complexes, ranging from infrared-observable clusters, via deeply embedded regions associated with ac...

  13. The Sun as a planet-host star: Proxies from SDO images for HARPS radial-velocity variations

    CERN Document Server

    Haywood, R D; Unruh, Y C; Lovis, C; Lanza, A F; Llama, J; Deleuil, M; Fares, R; Gillon, M; Moutou, C; Pepe, F; Pollacco, D; Queloz, D; Segransan, D

    2016-01-01

    The Sun is the only star whose surface can be directly resolved at high resolution, and therefore constitutes an excellent test case to explore the physical origin of stellar radial-velocity (RV) variability. We present HARPS observations of sunlight scattered off the bright asteroid 4/Vesta, from which we deduced the Sun's activity-driven RV variations. In parallel, the HMI instrument onboard the Solar Dynamics Observatory provided us with simultaneous high spatial resolution magnetograms, Dopplergrams, and continuum images of the Sun in the Fe I 6173A line. We determine the RV modulation arising from the suppression of granular blueshift in magnetised regions and the flux imbalance induced by dark spots and bright faculae. The rms velocity amplitudes of these contributions are 2.40 m/s and 0.41 m/s, respectively, which confirms that the inhibition of convection is the dominant source of activity-induced RV variations at play, in accordance with previous studies. We find the Doppler imbalances of spot and pl...

  14. Sun's rap song

    Science.gov (United States)

    Hogan, M.; Lee, W.

    1995-07-01

    We present a rap song composed for the Sun, our star. This Sun's Rap Song can be utilized in classroom teaching to spark the students' interest and facilitate the students' learning of the relevant subjects.

  15. 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.

  16. The Sun-as-a-star As Seen By Hinode XRT

    Science.gov (United States)

    Saar, Steven H.; DeLuca, E. E.

    2007-05-01

    We study full disk images of the Sun taken in multiple filters with the Hinode XRT during the current low state of the solar cycle (late 2006). Taking advantage of the wide temperature sensitivity of the XRT, we construct spatially averaged emission measure (EM) curves for each of several solar region types, including coronal holes, quiet Sun, bright points, and active regions of various description. These are used to determine the relative contribution of the various features to the total solar EM, as a starting point for a program to investigate their time variation. We also explore use of the average EM curves for understanding spatially unresolved stellar spectra and their correlation with underlying magnetic fields. The US XRT team is supported by a contract from NASA to SAO. Hinode is an international project supported by JAXA, NASA, PPARC and ESA. We are grateful to the Hinode team for all their efforts in the design, development and operation of the mission.

  17. A STAR-FORMING RING AROUND κ Ori 250 pc FROM THE SUN

    Energy Technology Data Exchange (ETDEWEB)

    Pillitteri, I.; Wolk, S. J. [Harvard-Smithsonian Center for Astrophysics, Cambridge, MA 02138 (United States); Megeath, S. T., E-mail: ipillitt@cfa.harvard.edu [Ritter Astrophysical Research Center, Department of Physics and Astronomy, University of Toledo, Toledo, OH (United States)

    2016-04-01

    X-rays are a powerful probe of activity in early stages of star formation. They allow us to identify young stars even after they have lost the IR signatures of circumstellar disks and provide constraints on their distance. Here, we report on XMM-Newton observations that detect 121 young stellar objects (YSOs) in two fields between L1641 S and κ Ori. These observations extend the Survey of Orion A with XMM and Spitzer (SOXS). The YSOs are contained in a ring of gas and dust apparent at millimeter wavelengths, and in far-IR and near-IR surveys. The X-ray luminosity function of the YSOs detected in the two fields indicates a distance of 250–280 pc, much closer than the Orion A cloud and similar to distance estimates of κ Ori. We propose that the ring is a 5–8 pc diameter shell that has been swept up by κ Ori. This ring contains several groups of stars detected by Spitzer and WISE including one surrounding the Herbig Ae/Be stars V1818 Ori. In this interpretation, the κ Ori ring is one of several shells swept up by massive stars within the Orion Eridanus Superbubble and is unrelated to the southern portion of Orion A/L1641 S.

  18. Asteroseismic determination of fundamental parameters of Sun-like stars using multilayered neural networks

    Science.gov (United States)

    Verma, Kuldeep; Hanasoge, Shravan; Bhattacharya, Jishnu; Antia, H. M.; Krishnamurthi, Ganapathy

    2016-10-01

    The advent of space-based observatories such as Convection, Rotation and planetary Transits (CoRoT) and Kepler has enabled the testing of our understanding of stellar evolution on thousands of stars. Evolutionary models typically require five input parameters, the mass, initial helium abundance, initial metallicity, mixing length (assumed to be constant over time), and the age to which the star must be evolved. Some of these parameters are also very useful in characterizing the associated planets and in studying Galactic archaeology. How to obtain these parameters from observations rapidly and accurately, specifically in the context of surveys of thousands of stars, is an outstanding question, one that has eluded straightforward resolution. For a given star, we typically measure the effective temperature and surface metallicity spectroscopically and low-degree oscillation frequencies through space observatories. Here we demonstrate that statistical learning, using artificial neural networks, is successful in determining the evolutionary parameters based on spectroscopic and seismic measurements. Our trained networks show robustness over a broad range of parameter space, and critically, are entirely computationally inexpensive and fully automated. We analyse the observations of a few stars using this method and the results compare well to inferences obtained using other techniques. This method is both computationally cheap and inferentially accurate, paving the way for analysing the vast quantities of stellar observations from past, current, and future missions.

  19. 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

  20. The velocity fields of gas and stars within five KPC of the sun

    Science.gov (United States)

    Ovenden, M. W.; Pryce, M. H. L.; Shuter, W. L. H.

    A mathematical expression is considered for the most probable value of the line of sight velocity, Vr, of an element at a certain galactic longitude and a certain distance projected onto the plane of the galactic disk. Attention is given to the velocity field of O and B stars, the velocity field for idealized circular motion, the velocity field of 112 kinematically distinct H II regions, and the velocity field of nearby 21 cm emission. It is found that the velocity field describing the O and B stars is very close to pure circular motion. On the basis of plots presented in the investigation and an extensive statistical error analysis conducted by Pryce (1983), it is seen that the velocity fields for the nearby gas and H II regions and that of the stars are different.

  1. A star forming ring around Kappa Ori 250 pc from the Sun

    CERN Document Server

    Pillitteri, I; Megeath, S T

    2016-01-01

    X-rays are a powerful probe of activity in early stages of star formation. They allow us to identify young stars even after they have lost the IR signatures of circumstellar disks and provide constraints on their distance. Here we report on XMM-Newton observations which detect 121 young stellar objects (YSOs) in two fields between L1641S and $\\kappa$ Ori. These observations extend the Survey of Orion A with XMM and Spitzer (SOXS). The YSOs are contained in a ring of gas and dust apparent at millimeter wavelengths, and in far-IR and near-IR surveys. The X-ray luminosity function of the young stellar objects detected in the two fields indicates a distance of 250-280 pc, much closer than the Orion A cloud and similar to distance estimates of $\\kappa$ Ori. We propose that the ring is a 5-8 pc diameter shell that has been swept up by $\\kappa$ Ori. This ring contains several groups of stars detected by Spitzer and WISE including one surrounding the Herbig Ae/Be stars V1818 Ori. In this interpretation, the $\\kappa$ ...

  2. 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 ar

  3. Research on Non-radial Oscillations of the Sun and Stars in the Early 1970s

    Science.gov (United States)

    Osaki, Y.

    2013-12-01

    I describe some historical background of helio- and astero-seismology research in the early 1970s from my personal recollection, particularly on how our Tokyo research group on non-radial oscillations of stars got started. I also describe my recent research on the super-outburst mechanism of SU UMa-type dwarf novae.

  4. A Precise Asteroseismic Age and Radius for the Evolved Sun-like Star KIC 11026764

    DEFF Research Database (Denmark)

    Metcalfe, Travis S.; Monteiro, Mario J.P.F.G.; Thompson, Michael J.

    2010-01-01

    that attempt to match the asteroseismic and spectroscopic constraints simultaneously. We determine both the radius and the age of KIC 11026764 with a precision near 1%, and an accuracy near 2% for the radius and 15% for the age. Continued observations of this star promise to reveal additional oscillation...

  5. Stellar Activity on the Young Suns of Orion: COUP Observations of K5-7 Pre-Main Sequence Stars

    CERN Document Server

    Wolk, S J; Micela, G; Favata, F; Glassgold, A E; Shang, H; Feigelson, E D

    2005-01-01

    In January 2003, the Chandra Orion Ultradeep Project (COUP) detected about 1400 young stars during a 13.2 day observation of the Orion Nebula Cluster (ONC). This paper studies a well-defined sample of 28 solar-mass COUP sources to characterize the magnetic activity of analogs of the young Sun and thereby to improve understanding of the effects of solar X-rays on the solar nebula during the era of planet formation. We find that active young Suns spend 70% of their time in a characteristic state with relatively constant flux and magnetically confined plasma with temperatures kT_2 = 2.1 * kT_1. During characteristic periods, the 0.5-8 keV X-ray luminosity is about 0.03% of the bolometric luminosity. One or two powerful flares per week with peak luminosities logL_x ~ 30-32 erg/s are typically superposed on this characteristic emission accompanied by heating of the hot plasma component from ~2.4 keV to ~7 keV at the flare peak. The energy distribution of flares superposed on the characteristic emission level follo...

  6. Completing the census of young stars near the Sun with the FunnelWeb spectroscopic survey

    Science.gov (United States)

    Lawson, Warrick; Murphy, Simon; Tinney, Christopher G.; Ireland, Michael; Bessell, Michael S.

    2016-06-01

    From late 2016, the Australian FunnelWeb survey will obtain medium-resolution (R~2000) spectra covering the full optical range for 2 million of the brightest stars (ITESS) and radial velocity exoplanet studies. In this poster contribution we introduce the FunnelWeb survey, its science goals and input catalogue, as well as provide an update on the status of the fibre positioner and spectrograph commissioning at Siding Spring.

  7. Formation and Evolution of Planetary Systems: Cold Outer Disks Associated with Sun-like stars

    CERN Document Server

    Kim, J S; Backman, D E; Hillenbrand, L A; Meyer, M R; Rodmann, J; Moro-Martin, A; Carpenter, J M; Silverstone, M D; Bouwman, J; Mamajek, E E; Wolf, S; Malhotra, R; Pascucci, I; Najita, J; Padgett, D L; Henning, T; Brooke, T Y; Cohen, M; Strom, S E; Stobie, E B; Engelbracht, C W; Gordon, K D; Misselt, K; Morrison, J E; Muzerolle, J; Su, K Y L; Kim, Jinyoung Serena; Hines, Dean C.; Backman, Dana E.; Hillenbrand, Lynne A.; Meyer, Michael R.; Rodmann, Jens; Moro-Martin, Amaya; Carpenter, John M.; Silverstone, Murray D.; Bouwman, Jeroen; Mamajek, Eric E.; Wolf, Sebastian; Malhotra, Renu; Pascucci, Ilaria; Najita, Joan; Padgett, Deborah L.; Henning, Thomas; Brooke, Timothy Y.; Cohen, Martin; Strom, Stephen E.; Stobie, Elizabeth B.; Engelbracht, Charles W.; Gordon, Karl D.; Misselt, Karl; Morrison, Jane E.; Muzerolle, James; Su, Kate Y. L.

    2005-01-01

    We present the discovery of debris systems around three solar mass stars based upon observations performed with the Spitzer Space Telescope as part of a Legacy Science Program, ``the Formation and Evolution of Planetary Systems'' (FEPS). We also confirm the presence of debris around two other stars. All the stars exhibit infrared emission in excess of the expected photospheres in the 70 micron band, but are consistent with photospheric emission at <= 33 micron. This restricts the maximum temperature of debris in equilibrium with the stellar radiation to T < 70 K. We find that these sources are relatively old in the FEPS sample, in the age range 0.7 - 3 Gyr. Based on models of the spectral energy distributions, we suggest that these debris systems represent materials generated by collisions of planetesimal belts. We speculate on the nature of these systems through comparisons to our own Kuiper Belt, and on the likely planet(s) responsible for stirring the system and ultimately releasing dust through coll...

  8. 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.; Hori, Y.; Suzuki, R.; Burrows, A.; Henning, T.; Turner, E. L.; McElwain, M. W.; Moro-Martin, A.; Suenaga, T.; Takahashi, Y. H.; Kwon, J.; Lucas, P.; Abe, L.; Brandner, W.; Grady, C. A.; Serabyn, E.

    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.

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

    CERN Document Server

    Kuzuhara, M; Kudo, T; Janson, M; Kandori, R; Brandt, T D; Thalmann, C; Spiegel, D; Biller, B; Carson, J; Hori, Y; Suzuki, R; Burrows, A; Henning, T; Turner, E L; McElwain, M W; Moro-Martin, A; Suenaga, T; Takahashi, Y H; Kwon, J; Lucas, P; Abe, L; Brandner, W; Egner, S; Feldt, M; Fujiwara, H; Goto, M; Grady, C A; Guyon, O; Hashimoto, J; Hayano, Y; Hayashi, M; Hayashi, S S; Hodapp, K W; Ishii, M; Iye, M; Knapp, G R; Matsuo, T; Mayama, S; Miyama, S; Morino, J -I; Nishikawa, J; Nishimura, T; Kotani, T; Kusakabe, N; Pyo, T -S; Serabyn, E; Suto, H; Takami, M; Takato, N; Terada, H; Tomono, D; Watanabe, M; Wisniewski, J P; Yamada, T; Takami, H; Usuda, T

    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 ...

  10. Patrol of the short wavelength activity and flares of Sun as star

    Science.gov (United States)

    Afanasiev, I.; Avakyan, S.; Leonov, N.; Serova, A.; Voronin, N.

    Monitoring of the spectral range which most affects solar-terrestrial relationship - soft X-ray and extreme UV-radiations allows to solve ? problem of solar activity influence on all aspects of the Sun - Earth ties and to select the most important precursors of solar flares and the solar events related with a flare (such as proton events, high-velocity plasma streams in the solar wind, shock waves, coronal mass ejection and, the most important, the beginning of principal magnetic storms). Solar activity is constantly monitored at present (in the USA) only in two sections of the spectrum of ionizing radiation: 115 (119) nm. However, so far there has been no monitoring of the flux in the most geoeffective region of the spectrum (0.8-115 nm) from the entire disk of the sun; this region completely monitors the main part of the ionosphere of the earth and the ionosphere of the other planets of the solar system, including the formation and status of the main ionospheric maxima. This occurs solely because of technical and methodological difficulties in performing the measurements and calibration in this spectral range on spacecraft, because it is necessity to use only windowless optics. At the present the solar the optical - electronic equipment (OEE) is testing and there are plans to launch OEE of Space Solar Patrol (SSP) consisting of solar radiometers and spectrometers at the Russian Module of the International Space Station. So the solving the problem of the permanent monitoring-patrol of ionizing radiation from the full disk of the Sun appears in the main tasks of fundamental scientific studies in space. The results of this monitoring can be contribution in development of simultaneous studies in several sciences, such as: - solar astrophysics (state of all solar atmospheric regions), - meteorology, physics of atmosphere (the influence of solar activity on global changes, climate and weather including the effects of atmo s pheric electricity), - aeronomy, astronautics

  11. How Dry is the Brown Dwarf Desert?: Quantifying the Relative Number of Planets, Brown Dwarfs and Stellar Companions around Nearby Sun-like Stars

    CERN Document Server

    Grether, D; Grether, Daniel; Lineweaver, Charles H.

    2004-01-01

    Sun-like stars have stellar, brown dwarf and planetary companions. To help constrain their formation and migration scenarios, we analyse the close companions (orbital period 2 M_Solar respectively. However, we find no evidence that companion mass scales with host mass in general. Approximately 16% of Sun-like stars have close (P < 5 years) companions more massive than Jupiter: 11% are stellar, 1% are brown dwarf and 4% are giant planets. The companion mass function in the brown dwarf and stellar mass range, has a different shape than the initial mass function of individual stars and free-floating brown dwarfs. This suggests either a different spectrum of gravitational fragmentation in the formation environment or post-formation migratory processes disinclined to leave brown dwarfs in close orbits.

  12. Long-term magnetic field monitoring of the Sun-like star Ksi Boo A

    CERN Document Server

    Morgenthaler, A; Saar, S; Solanki, S K; Auriere, M; Dintrans, B; Fares, R; Gastine, T; Lanoux, J; Lignieres, F; Marsden, S C; Morin, J; Paletou, F; Velez, J C Ramirez; Theado, S; Van Grootel, V

    2011-01-01

    Aims. We aim at investigating the long-term temporal evolution of the magnetic field of the solar-type star Ksi Boo A, both from direct magnetic field measurements and from the simultaneous estimate of indirect activity indicators. Methods. We use 7 time-series of high-resolution, circularly-polarized spectra obtained with the NARVAL spectropolarimeter between 2007 and 2011, for a total of 76 spectra. Using about 6,100 photospheric spectral lines covering the visible domain, we employ a cross-correlation procedure to compute, from each spectrum, a mean polarized line profile. We model the large-scale photospheric magnetic field of the star by means of Zeeman-Doppler Imaging and follow the year-to-year evolution of the reconstructed magnetic topology. Simultaneously, we monitor the width of several magnetically-sensitive spectral lines, the radial velocity and line asymmetry of intensity line profiles and the chromospheric emission in the cores of the Ca II H and Halpha lines. Results. During the highest obser...

  13. Searching for IR excesses in Sun-like stars observed by WISE

    CERN Document Server

    de Miera, Fernando Cruz-Saenz; Bertone, Emanuele; Vega, Olga

    2013-01-01

    We present the results of a search of infrared excess candidates in a comprehensive (29\\,000 stars) magnitude limited sample of dwarf stars, spanning the spectral range F2-K0, and brighter than V$=$15 mag. We searched the sample within the {\\em WISE} all sky survey database for objects within 1 arcsecond of the coordinates provided by SIMBAD database and found over 9\\,000 sources detected in all {\\em WISE} bands. This latter sample excludes objects that are flagged as extended sources and those images which are affected by various optical artifacts. For each detected object, we compared the observed W4/W2 (22$\\mu$m/4.6$\\mu$m) flux ratio with the expected photospheric value and identified 197 excess candidates at 3$\\sigma$. For the vast majority of candidates, the results of this analysis represent the first reported evidence of an IR excess. Through the comparison with a simple black-body emission model, we derive estimates of the dust temperature, as well as of the dust fractional luminosities. For more than...

  14. ENSEMBLE EMPIRICAL MODE DECOMPOSITION OF THE MAGNETIC FIELD OF THE SUN AS A STAR

    Energy Technology Data Exchange (ETDEWEB)

    Xiang, N. B. [Yunnan Observatories, Chinese Academy of Sciences, Kunming 650011 (China); Qu, Z. N., E-mail: znqu@ynao.ac.cn [Department of Physics, School of Science, Sichuan University of Science and Engineering, Zigong 643000 (China)

    2016-03-15

    The ensemble empirical mode decomposition (EEMD) analysis is utilized to extract the intrinsic mode functions (IMFs) of the solar mean magnetic field (SMMF) observed at the Wilcox Solar Observatory of Stanford University from 1975 to 2014, and then we analyze the periods of these IMFs as well as the relation of IMFs (SMMF) with some solar activity indices. The two special rotation cycles of 26.6 and 28.5 days should be derived from different magnetic flux elements in the SMMF. The rotation cycle of the weak magnetic flux element in the SMMF is 26.6 days, while the rotation cycle of the strong magnetic flux element in the SMMF is 28.5 days. The two rotation periods of the structure of the interplanetary magnetic field near the ecliptic plane are essentially related to weak and strong magnetic flux elements in the SMMF, respectively. The rotation cycle of weak magnetic flux in the SMMF did not vary over the last 40 years because the weak magnetic flux element derived from the weak magnetic activity on the full disk is not influenced by latitudinal migration. Neither the internal rotation of the Sun nor the solar magnetic activity on the disk (including the solar polar fields) causes the annual variation of SMMF. The variation of SMMF at timescales of a solar cycle is more related to weak magnetic activity on the full solar disk.

  15. The magnetic field vector of the Sun-as-a-star

    CERN Document Server

    Vidotto, A A

    2016-01-01

    Direct comparison between stellar and solar magnetic maps are hampered by their dramatic differences in resolution. Here, we present a method to filter out the small-scale component of vector fields, in such a way that comparison between solar and stellar (large-scale) magnetic field vector maps can be directly made. Our approach extends the technique widely used to decompose the radial component of the solar magnetic field to the azimuthal and meridional components as well. For that, we self-consistently decompose the three-components of the vector field using spherical harmonics of different $l$ degrees. By retaining the low $l$ degrees in the decomposition, we are able to calculate the large-scale magnetic field vector. Using a synoptic map of the solar vector field at Carrington Rotation CR2109, we derive the solar magnetic field vector at a similar resolution level as that from stellar magnetic images. We demonstrate that the large-scale field of the Sun is not purely radial, as often assumed -- at CR210...

  16. The Sun among stars. IV - Albedos of Uranus and Neptune and the solar color

    Science.gov (United States)

    Hardorp, J.

    1981-01-01

    Geometric albedos in 48 adjacent 50 A bands from 3250 to 5600 A have been derived from observations of Uranus and Neptune. The solar analog found in earlier papers (Hardorp 1978, 1980) was chosen for these reductions, so these albedos are more reliable systematically than earlier ones and allow a choice among the scattering models of Savage et al. (1980). Green methane bands are stronger on Neptune. Strong solar absorption lines are found to be partially filled in by Raman-scattering. Neglect of this effect caused Croft et al. (1972) to find a solar color that is too blue. It probably also affected the classification of G-type stars in the Michigan Spectral Catalogue as well as Garrison's (1979) interpretation of IUE observations.

  17. Looking for Stars and Finding the Moon: Effects of Lunar Gamma-ray Emission on Fermi LAT Light Curves

    CERN Document Server

    Corbet, Robin; Kerr, Matthew; Ray, Paul S

    2013-01-01

    We are conducting a search for new gamma-ray binaries by making high signal-to-noise light curves of all cataloged Fermi LAT sources and searching for periodic variability using appropriately weighted power spectra. The light curves are created using a variant of aperture photometry where photons are weighted by the probability that they came from the source of interest. From this analysis we find that the light curves of a number of sources near the ecliptic plane are contaminated by gamma-ray emission from the Moon. This shows itself as modulation on the Moon's sidereal period in the power spectra. We demonstrate that this contamination can be removed by excluding times when the Moon was too close to a source. We advocate that this data screening should generally be used when analyzing LAT data from a source located close to the path of the Moon.

  18. New Suns in the Cosmos. IV. The Multifractal Nature of Stellar Magnetic Activity in Kepler Cool Stars

    Science.gov (United States)

    de Freitas, D. B.; Nepomuceno, M. M. F.; Gomes de Souza, M.; Leão, I. C.; Das Chagas, M. L.; Costa, A. D.; Canto Martins, B. L.; De Medeiros, J. R.

    2017-07-01

    In the present study, we investigate the multifractal nature of a long-cadence time series observed by the Kepler mission for a sample of 34 M dwarf stars and the Sun in its active phase. Using the Multifractal Detrending Moving Average algorithm, which enables the detection of multifractality in nonstationary time series, we define a set of multifractal indices based on the multifractal spectrum profile as a measure of the level of stellar magnetic activity. This set of indices is given by the (A, {{Δ }}α , C, H)-quartet, where A, {{Δ }}α , and C are related to geometric features from the multifractal spectrum and the global Hurst exponent H describes the global structure and memorability of time series dynamics. As a test, we measure these indices and compare them with a magnetic index defined as S ph and verify the degree of correlation among them. First, we apply the Poincaré plot method and find a strong correlation between the index and one of the descriptors that emerges from this method. As a result, we find that this index is strongly correlated with long-term features of the signal. From the multifractal perspective, the index is also strongly linked to the geometric properties of the multifractal spectrum except for the H index. Furthermore, our results emphasize that the rotation period of stars is scaled by the H index, which is consistent with Skumanich’s relationship. Finally, our approach suggests that the H index may be related to the evolution of stellar angular momentum and a star’s magnetic properties.

  19. 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 ...

  20. 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.

  1. 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

  2. Statistical Properties of Blue Horizontal Branch Stars in the Spheroid: Detection of a Moving Group approximately 50 kpc from the Sun

    Energy Technology Data Exchange (ETDEWEB)

    Harrigan, Matthew J.; Newberg, Heidi Jo; Newberg, Lee A.; /Rensselaer Poly.; Yanny, Brian; /Fermilab; Beers, Timothy C.; Lee, Young Sun; /Michigan State U.; Fiorentin, Paola Re; /Ljubljana U. /Heidelberg, Max Planck Inst. Astron.

    2010-02-01

    A new moving group comprising at least four Blue Horizontal Branch (BHB) stars is identified at (l; b) = (65{sup o}; 48{sup o}). The horizontal branch at g{sub 0} = 18.9 magnitude implies a distance of 50 kpc from the Sun. The heliocentric radial velocity is = -157 {+-} 4 km s{sup -1}, corresponding to V{sub gsr} = -10 km s{sup -1}; the dispersion in line-of-sight velocity is consistent with the instrumental errors for these stars. The mean metallicity of the moving group is [Fe/H] {approx} -2.4, which is significantly more metal poor than the stellar spheroid. We estimate that the BHB stars in the outer halo have a mean metallicity of [Fe/H]=-2.0, with a wide scatter and a distribution that does not change much as a function of distance from the Sun. We explore the systematics of SDSS DR7 surface gravity metallicity determinations for faint BHB stars, and present a technique for estimating the significance of clumps discovered in multidimensional data. This moving group cannot be distinguished in density, and highlights the need to collect many more spectra of Galactic stars to unravel the merger history of the Galaxy.

  3. On the Structure and Properties of Differentially Rotating Main-Sequence Stars in the 1-2 M_sun Range

    CERN Document Server

    MacGregor, K B; Skumanich, Andrew; Metcalfe, T S

    2007-01-01

    We conduct a systematic examination of the properties of models for chemically homogeneous, differentially rotating, main-sequence stars of mass 1-2 M_sun. The models were constructed using a code based on a reformulation of the self-consistent field method of computing the equilibrium stellar structure for a specified conservative internal rotation law. [abridged] Relative to nonrotating stars of the same mass, these models all have reduced luminosities and effective temperatures, and flattened photospheric shapes (i.e., decreased polar radii) with equatorial radii that can be larger or smaller, depending on the degree of differential rotation. For a fixed ratio of the axial rotation rate to the surface equatorial rotation rate, increasingly rapid rotation generally deepens convective envelopes, shrinks convective cores, and can lead to the presence of a convective core (envelope) in a 1 M_sun (2 M_sun) model, a feature that is absent in a nonrotating star of the same mass. The positions of differentially ro...

  4. Isotopes Tell Sun's Origin and Operation

    Science.gov (United States)

    Manuel, O.; Kamat, Sumeet A.; Mozina, Michael

    2006-03-01

    Modern versions of Aston's mass spectrometer enable measurements of two quantities - isotope abundances and masses - that tell the Sun's origin and operation. Isotope analyses of meteorites, the Earth, Moon, Mars, Jupiter, the solar wind, and solar flares over the past 45 years indicate that fresh, poorly-mixed, supernova debris formed the solar system. The iron-rich Sun formed on the collapsed supernova core and now itself acts as a magnetic plasma diffuser, as did the precursor star, separating ions by mass. This process covers the solar surface with lightweight elements and with the lighter isotopes of each element. Running difference imaging provides supporting evidence of a rigid, iron-rich structure below the Sun's fluid outer layer of lightweight elements. Mass measurements of all 2,850 known nuclides expose repulsive interactions between neutrons that trigger neutron-emission at the solar core, followed by neutron-decay and a series of reactions that collectively generate solar luminosity, solar neutrinos, the carrier gas for solar mass separation, and an outpouring of solar-wind hydrogen from the solar surface. Neutron-emission and neutron-decay generate ~ 65% of solar luminosity; H-fusion ~ 35%, and ~ 1% of the neutron-decay product survives to depart as solar-wind hydrogen. The energy source for the Sun and other ordinary stars seems to be neutron-emission and neutron-decay, with partial fusion of the decay product, rather than simple fusion of hydrogen into helium or heavier elements.

  5. Sixth-grade Indonesian student explanations of directions on flat maps and globes, of the Earth's rotation to cause night and day, and of the relative positions of the Earth, Moon, and Sun during an eclipse

    Science.gov (United States)

    Dimyati, Surachman

    The purpose of the study was to elicit and analyze sixth grade students' explanations concerning concepts taught in the national Indonesian sixth grade science curriculum. In this study, students were asked to identify the cardinal directions on flat maps and a globe, to describe what causes night and day on the earth, to identify the direction of the earth's rotation, and to identify the relative positions of the earth, sun, and moon during either a solar or lunar eclipse. The findings in the study can be summarized as follows (1) Eighty out of 88 students (91%) were able to explain what causes night and day. (2) Approximately 50% could identify the direction the earth rotates to cause night and day. (3) Using a solar system model, about 64% of the students could describe the relative position of the earth, sun, and moon during an eclipse. (4) Cultural differences affect student thinking. One student thought that Mecca had to be west of everywhere, not just west of Indonesia. (5) The way teachers teach seems to influence student thinking. It is easy for students to form the misconception that up is north. Most maps in classrooms are hung vertically. (6) Some students were confused by the globe. Teachers need to explain why the globe is tilted. Also, they need to help students understand how to determine the cardinal directions on a globe. More research is needed to determine what is needed to help students truly understand these concepts and to determine whether these concepts are best taught at the elementary level.

  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. Full Moon Feeling

    Science.gov (United States)

    Ortiz-Gil, A.; Ballesteros Roselló, F.; Fernández-Soto, A.; Lanzara, M.; Moya, M. J.

    2012-09-01

    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 to follow a different path to experience it too. Here we will show the process of designing and testing a tactile 3D Moon sphere whose goal is to reproduce on a tactile support the experience of observing the Moon visually. We have used imaging data obtained by NASA's mission Clementine, along with free image processing and 3D rendering software. This method is also useful to produce other artifacts that can be employed in the communication of astronomy to all kinds of public. The tactile Moon project for the blind has been funded partially by the 2011 Europlanet Outreach Funding Scheme.

  8. Moon Phases

    Science.gov (United States)

    Riddle, Bob

    2010-01-01

    When teaching Moon phases, the focus seems to be on the sequence of Moon phases and, in some grade levels, how Moon phases occur. Either focus can sometimes be a challenge, especially without the use of models and observations of the Moon. In this month's column, the author describes some of the lessons that he uses to teach the phases of the Moon…

  9. Formation and Evolution of Planetary Systems (FEPS): Primordial Warm Dust Evolution From 3-30 Myr around Sun-like Stars

    CERN Document Server

    Silverstone, M D; Mamajek, E E; Hines, D C; Hillenbrand, L A; Najita, J; Pascucci, I; Bouwman, J; Kim, J S; Carpenter, J M; Stauffer, J R; Backman, D E; Moro-Martin, A; Henning, T; Wolf, S; Brooke, T Y; Padgett, D L

    2006-01-01

    We present data obtained with the Infrared Array Camera (IRAC) aboard the Spitzer Space Telescope (Spitzer) for a sample of 74 young (t < 30 Myr old) Sun-like (0.7 < M(star)/M(Sun) < 1.5) stars. These are a sub-set of the observations that comprise the Spitzer Legacy science program entitled the Formation and Evolution of Planetary Systems (FEPS). Using IRAC we study the fraction of young stars that exhibit 3.6-8.0 micron infrared emission in excess of that expected from the stellar photosphere, as a function of age from 3-30 Myr. The most straightforward interpretation of such excess emission is the presence of hot (300-1000K) dust in the inner regions (< 3 AU) of a circumstellar disk. Five out of the 74 young stars show a strong infrared excess, four of which have estimated ages of 3-10 Myr. While we detect excesses from 5 optically thick disks, and photospheric emission from the remainder of our sample, we do not detect any excess emission from optically thin disks at these wavelengths. We comp...

  10. Statistical Properties of Blue Horizontal Branch Stars in the Spheroid: Detection of a Moving Group approximately 50 kpc from the Sun

    CERN Document Server

    Harrigan, Matthew J; Newberg, Lee A; Yanny, Brian; Beers, Timothy C; Lee, Young Sun; Fiorentin, Paola Re

    2010-01-01

    A new moving group comprising at least four Blue Horizontal Branch (BHB) stars is identified at (l,b) = (65 deg, 48 deg). The horizontal branch at g0=18.9 magnitude implies a distance of 50 kpc from the Sun. The heliocentric radial velocity is RV = -157 +/- 4 km/s, corresponding to V(gsr) = -10 km/s; the dispersion in line-of-sight velocity is consistent with the instrumental errors for these stars. The mean metallicity of the moving group is [Fe/H] approximately -2.4, which is significantly more metal poor than the stellar spheroid. We estimate that the BHB stars in the outer halo have a mean metallicity of [Fe/H] = -2.0, with a wide scatter and a distribution that does not change much as a function of distance from the Sun. We explore the systematics of SDSS DR7 surface gravity metallicity determinations for faint BHB stars, and present a technique for estimating the significance of clumps discovered in multidimensional data. This moving group cannot be distinguished in density, and highlights the need to c...

  11. Initial Assessment of the Spectrometer for Sky-Scanning, Sun-Tracking Atmospheric Research (4STAR-Based Aerosol Retrieval: Sensitivity Study

    Directory of Open Access Journals (Sweden)

    Alexander Sinyuk

    2012-10-01

    Full Text Available The Spectrometer for Sky-Scanning, Sun-Tracking Atmospheric Research (4STAR being developed for airborne measurements will offer retrievals of aerosol microphysical and optical properties from multi-angular and multi-spectral measurements of sky radiance and direct-beam sun transmittance. In this study, we assess the expected accuracy of the 4STAR-based aerosol retrieval and its sensitivity to major sources of anticipated perturbations in the 4STAR measurements. The major anticipated perturbations are (1 an apparent enhancement of sky radiance at small scattering angles associated with the necessarily compact design of the 4STAR and (2 an offset (i.e., uncertainty of sky radiance calibration independent of scattering angle. The assessment is performed through application of the operational AERONET aerosol retrieval and constructed synthetic 4STAR-like data. Particular attention is given to the impact of these perturbations on the broadband fluxes and the direct aerosol radiative forcing. The results from this study suggest that limitations in the accuracy of 4STAR-retrieved particle size distributions and scattering phase functions have diminished impact on the accuracy of retrieved bulk microphysical parameters, permitting quite accurate retrievals of properties including the effective radius (up to 10%, or 0.03, and the radiatively important optical properties, such as the asymmetry factor (up to 4%, or ±0.02 and single-scattering albedo (up to 6%, or ±0.04. Also, the obtained results indicate that the uncertainties in the retrieved aerosol optical properties are quite small in the context of the calculated fluxes and direct aerosol radiative forcing (up to 15%, or 3 W∙m−2.

  12. Regarding how Tycho Brahe noted the absurdity of the Copernican Theory regarding the Bigness of Stars, while the Copernicans appealed to God to answer that absurdity

    CERN Document Server

    Graney, Christopher M

    2011-01-01

    Tycho Brahe, the most prominent and accomplished astronomer of his era, made measurements of the apparent sizes of the Sun, Moon, stars, and planets. From these he showed that within a geocentric cosmos these bodies were of comparable sizes, with the Sun being the largest body and the Moon the smallest. He further showed that within a heliocentric cosmos, the stars had to be absurdly large - with the smallest star dwarfing even the Sun. (The results of Tycho's calculations are illustrated in this paper.) Various Copernicans responded to this issue of observation and geometry by appealing to the power of God: They argued that giant stars were not absurd because even such giant objects were nothing compared to an infinite God, and that in fact the Copernican stars pointed out the power of God to humankind. Tycho rejected this argument.

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

    DEFF Research Database (Denmark)

    Borucki, W.J.; Koch, D.G.; Batalha, N.

    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 astero......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 asteroseismic analysis of the Kepler photometry, leading to an estimated mass and radius of 0.970 ± 0.060 M sun and 0.979 ± 0.020 R sun. The depth of 492 ± 10 ppm for the three observed transits yields a radius of 2.38 ± 0.13 Re for the planet. The system passes a battery of tests for false positives, including...... masses, thus earning the designation Kepler-22b. The radiative equilibrium temperature is 262 K for a planet in Kepler-22b's orbit. Although there is no evidence that Kepler-22b is a rocky planet, it is the first confirmed planet with a measured radius to orbit in the habitable zone of any star other...

  14. The Sun in Time: Activity and Environment

    CERN Document Server

    Güdel, M

    2007-01-01

    (abridged) 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...

  15. Water ice lines and the formation of giant moons around super-Jovian planets

    CERN Document Server

    Heller, René

    2014-01-01

    Most of the exoplanets with known masses at Earth-like distances to Sun-like stars are heavier than Jupiter, which raises the question of whether such planets are accompanied by detectable, possibly habitable moons. Here we simulate the accretion disks around super-Jovian planets and find that giant moons with masses similar to Mars can form. Our results suggest that the Galilean moons formed during the final stages of accretion onto Jupiter, when the circumjovian disk was sufficiently cool. But in contrast to other studies, we show that Jupiter was still feeding from the circumsolar disk and that its principal moons cannot have formed after the complete photoevaporation of the circumsolar nebula. To counteract the steady loss of moons into the planet due to type I migration, we propose that the water ice line around Jupiter and super-Jovian exoplanets acted as a migration trap for moons. Heat transitions, however, cross the disk during the gap opening within 10^4 yr, which makes them inefficient as moon trap...

  16. A non-LTE study of neutral and singly-ionized iron line spectra in 1D models of the Sun and selected late-type stars

    CERN Document Server

    Mashonkina, L; Shi, J -R; Korn, A J; Grupp, F

    2011-01-01

    A comprehensive model atom for Fe with more than 3000 energy levels is presented. As a test and first application of this model atom, Fe abundances are determined for the Sun and five stars with well determined stellar parameters and high-quality observed spectra. Non-LTE leads to systematically depleted total absorption in the Fe I lines and to positive abundance corrections in agreement with the previous studies, however, the magnitude of non-LTE effect is smaller compared to the earlier results. Non-LTE corrections do not exceed 0.1 dex for the solar metallicity and mildly metal-deficient stars, and they vary within 0.21 dex and 0.35 dex in the very metal-poor stars HD 84937 and HD 122563, respectively, depending on the assumed efficiency of collisions with hydrogen atoms. Based on the analysis of the Fe I/Fe II ionization equilibrium in these two stars, we recommend to apply the Drawin formalism in non-LTE studies of Fe with a scaling factor of 0.1. For the Fe II lines, non-LTE corrections do not exceed 0...

  17. 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.

  18. Kepler-22b: A 2.4 EARTH-RADIUS PLANET IN THE HABITABLE ZONE OF A SUN-LIKE STAR

    Energy Technology Data Exchange (ETDEWEB)

    Borucki, William J.; Koch, David G.; Bryson, Stephen T.; Howell, Steve B.; Lissauer, Jack J. [NASA-Ames Research Center, Moffett Field, CA 94035-0001 (United States); Batalha, Natalie [Department of Physics and Astronomy, San Jose State University, San Jose, CA, 95192 (United States); Rowe, Jason; Caldwell, Douglas A.; DeVore, Edna; Jenkins, Jon M. [SETI Institute, Mountain View, CA 94043 (United States); Fressin, Francois; Torres, Guillermo; Geary, John C.; Latham, David W. [Harvard-Smithsonian Center for Astrophysics, Cambridge, MA 02138 (United States); Christensen-Dalsgaard, Jorgen [Department of Physics and Astronomy, Aarhus University, DK-8000 Aarhus C (Denmark); Cochran, William D. [McDonald Observatory, University of Texas at Austin, Austin, TX 78712 (United States); Gautier, Thomas N. [Jet Propulsion Laboratory, California Institute of Technology, Pasadena CA, 91109 (United States); Gilliland, Ronald [Space Telescope Science Institute, Baltimore, MD 21218 (United States); Gould, Alan [Lawrence Hall of Science, University of California, Berkeley, CA 94720 (United States); Marcy, Geoffrey W., E-mail: William.J.Borucki@nasa.gov [Department of Astronomy, University of California, Berkeley, CA 94720 (United States); and others

    2012-02-01

    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 asteroseismic analysis of the Kepler photometry, leading to an estimated mass and radius of 0.970 {+-} 0.060 M{sub Sun} and 0.979 {+-} 0.020 R{sub Sun }. The depth of 492 {+-} 10 ppm for the three observed transits yields a radius of 2.38 {+-} 0.13 Re for the planet. The system passes a battery of tests for false positives, including reconnaissance spectroscopy, high-resolution imaging, and centroid motion. A full BLENDER analysis provides further validation of the planet interpretation by showing that contamination of the target by an eclipsing system would rarely mimic the observed shape of the transits. The final validation of the planet is provided by 16 radial velocities (RVs) obtained with the High Resolution Echelle Spectrometer on Keck I over a one-year span. Although the velocities do not lead to a reliable orbit and mass determination, they are able to constrain the mass to a 3{sigma} upper limit of 124 M{sub Circled-Plus }, safely in the regime of planetary masses, thus earning the designation Kepler-22b. The radiative equilibrium temperature is 262 K for a planet in Kepler-22b's orbit. Although there is no evidence that Kepler-22b is a rocky planet, it is the first confirmed planet with a measured radius to orbit in the habitable zone of any star other than the Sun.

  19. The squint Moon and the witch ball

    Science.gov (United States)

    Berry, M. V.

    2015-06-01

    A witch ball is a reflecting sphere of glass. Looking into the disk that it subtends, the whole sky can be seen at one glance. This feature can be exploited to see and photograph the squint Moon illusion, in which the direction normal to the illuminated face of the Moon—its ‘attitude vector’—does not appear to point towards the Sun. The images of the Sun and Moon in the disk, the geodesic connecting them, the Moon’s attitude, and the squint angle (distinct from the tilt), can be calculated and simulated, for all celestial configurations and viewing inclinations. The Moon direction antipodal to the Sun, corresponding to full Moon, is a singularity of the attitude vector field, with index +1. The main features of the witch ball images also occur in other ways of imaging the squint Moon.

  20. ULTRA-DEEP HUBBLE SPACE TELESCOPE IMAGING OF THE SMALL MAGELLANIC CLOUD: THE INITIAL MASS FUNCTION OF STARS WITH M {approx}< 1 M {sub Sun}

    Energy Technology Data Exchange (ETDEWEB)

    Kalirai, Jason S.; Anderson, Jay; Dotter, Aaron; Reid, I. Neill [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Richer, Harvey B. [Department of Physics and Astronomy, University of British Columbia, Vancouver, BC (Canada); Fahlman, Gregory G. [National Research Council, Herzberg Institute of Astrophysics, Victoria, BC (Canada); Hansen, Brad M. S.; Rich, R. Michael [Division of Astronomy and Astrophysics, University of California at Los Angeles, Los Angeles, CA 90095 (United States); Hurley, Jarrod [Center for Astrophysics and Supercomputing, Swinburne University of Technology, Hawthorn VIC 3122 (Australia); Shara, Michael M., E-mail: jkalirai@stsci.edu, E-mail: jayander@stsci.edu, E-mail: dotter@stsci.edu, E-mail: richer@astro.ubc.ca, E-mail: greg.fahlman@nrc-cnrc.gc.ca, E-mail: hansen@astro.ucla.edu, E-mail: rmr@astro.ucla.edu, E-mail: jhurley@swin.edu.au, E-mail: mshara@amnh.org [Department of Astrophysics, American Museum of Natural History, Central Park West and 79th Street, New York, NY 10024 (United States)

    2013-02-15

    We present a new measurement of the stellar initial mass function (IMF) based on ultra-deep, high-resolution photometry of >5000 stars in the outskirts of the Small Magellanic Cloud (SMC) galaxy. The Hubble Space Telescope (HST) Advanced Camera for Surveys observations reveal this rich, cospatial population behind the foreground globular cluster 47 Tuc, which we targeted for 121 HST orbits. The stellar main sequence of the SMC is measured in the F606W, F814W color-magnitude diagram down to {approx}30th magnitude, and is cleanly separated from the foreground star cluster population using proper motions. We simulate the SMC population by extracting stellar masses (single and unresolved binaries) from specific IMFs and converting those masses to luminosities in our bandpasses. The corresponding photometry for these simulated stars is drawn directly from a rich cloud of 4 million artificial stars, thereby accounting for the real photometric scatter and completeness of the data. Over a continuous and well-populated mass range of M = 0.37-0.93 M {sub Sun} (e.g., down to a {approx}75% completeness limit at F606W = 28.7), we demonstrate that the IMF is well represented by a single power-law form with slope {alpha} = -1.90 ({sup +0.15} {sub -0.10}) (3{sigma} error) (e.g., dN/dM{proportional_to} M {sup {alpha}}). This is shallower than the Salpeter slope of {alpha} = -2.35, which agrees with the observed stellar luminosity function at higher masses. Our results indicate that the IMF does not turn over to a more shallow power-law form within this mass range. We discuss implications of this result for the theory of star formation, the inferred masses of galaxies, and the (lack of a) variation of the IMF with metallicity.

  1. 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.

  2. Immersive Virtual Moon Scene System Based on Panoramic Camera Data of Chang'E-3

    Science.gov (United States)

    Gao, X.; Liu, J.; Mu, L.; Yan, W.; Zeng, X.; Zhang, X.; Li, C.

    2014-12-01

    The system "Immersive Virtual Moon Scene" is used to show the virtual environment of Moon surface in immersive environment. Utilizing stereo 360-degree imagery from panoramic camera of Yutu rover, the system enables the operator to visualize the terrain and the celestial background from the rover's point of view in 3D. To avoid image distortion, stereo 360-degree panorama stitched by 112 images is projected onto inside surface of sphere according to panorama orientation coordinates and camera parameters to build the virtual scene. Stars can be seen from the Moon at any time. So we render the sun, planets and stars according to time and rover's location based on Hipparcos catalogue as the background on the sphere. Immersing in the stereo virtual environment created by this imaged-based rendering technique, the operator can zoom, pan to interact with the virtual Moon scene and mark interesting objects. Hardware of the immersive virtual Moon system is made up of four high lumen projectors and a huge curve screen which is 31 meters long and 5.5 meters high. This system which take all panoramic camera data available and use it to create an immersive environment, enable operator to interact with the environment and mark interesting objects contributed heavily to establishment of science mission goals in Chang'E-3 mission. After Chang'E-3 mission, the lab with this system will be open to public. Besides this application, Moon terrain stereo animations based on Chang'E-1 and Chang'E-2 data will be showed to public on the huge screen in the lab. Based on the data of lunar exploration,we will made more immersive virtual moon scenes and animations to help the public understand more about the Moon in the future.

  3. 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.

  4. 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.

  5. New Rare Earth Element Abundance Distributions for the Sun and Five r-Process-Rich Very Metal-Poor Stars

    CERN Document Server

    Sneden, Christopher; Cowan, John J; Ivans, Inese I; Hartog, Elizabeth A Den

    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.

  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. Project Practice of Sun Moon Light Centre Underground Complex in Shanghai%上海日月光中心地下综合体工程实践

    Institute of Scientific and Technical Information of China (English)

    谢炯; 贾坚; 杨科

    2012-01-01

    上海地区结合轨道交通车站开发的地下综合体是一种能充分利用轨道交通资源的地下空间开发模式.在系统分析城市地下综合体开发的经济效益、社会效益和环境效益的基础上,结合地铁车站、隧道与地块开发建筑共建的上海日月光中心这一地下综合体工程的成功实践,对软土地区建造大型地下综合体所面临的岩土工程问题及工程技术对策进行了分析总结,可为软土地基中结合轨道交通建设大力发展城市地下空间开发的区域综合工程提供工程借鉴和交流.%In Shanghai, the development of underground complex combined with rail transit station is an underground space development mode which can make full use of rail transit resources. To promote the application of this development mode, this paper discussed economic, social and environmental benefits of the urban underground complex firstly. And then, some geotechnical engineering problems and engineering technical countermeasures faced for large underground complex construction, were analysed combined with underground complex engineering practice, the project Sun Moon Light Centre in Luwan district, Shanghai. The success of the project, subway station, tunnel and high-building built altogether, can provide engineering reference for integrated regional project of the urban underground space development combined with orbit transportation in soft soil area.

  8. Improved Ni I log(gf) Values and Abundance Determinations in the Photospheres of the Sun and Metal-poor Star HD 84937

    CERN Document Server

    Wood, M P; Sneden, C; Cowan, J J

    2014-01-01

    Atomic transition probability measurements for 371 Ni I lines in the UV through near IR are reported. Branching fractions from data recorded using a Fourier transform spectrometer and a new echelle spectrograph are combined with published radiative lifetimes to determine these transition probabilities. Generally good agreement is found in comparisons to previously reported Ni I transition probability measurements. Use of the new echelle spectrograph, independent radiometric calibration methods, and independent data analysis routines enable a reduction of systematic errors and overall improvement in transition probability uncertainty over previous measurements. The new Ni I data are applied to high resolution visible and UV spectra of the Sun and metal-poor star HD 84937 to derive new, more accurate Ni abundances. Lines covering a wide range of wavelength and excitation potential are used to search for non-LTE effects.

  9. Two-dimensional hydrodynamic core-collapse supernova simulations with spectral neutrino transport. I. Numerical method and results for a 15 M_sun star

    CERN Document Server

    Buras, R; Janka, H T; Kifonidis, K

    2005-01-01

    Supernova models with a full spectral treatment of the neutrino transport are presented, employing the Prometheus/Vertex neutrino-hydrodynamics code with a ``ray-by-ray plus'' approximation for treating two- (or three-) dimensional problems. The method is described in detail and critically assessed with respect to its capabilities, limitations, and inaccuracies in the context of supernova simulations. In this first paper of a series, 1D and 2D core-collapse calculations for a (nonrotating) 15 M_sun star are discussed, uncertainties in the treatment of the equation of state -- numerical and physical -- are tested, Newtonian results are compared with simulations using a general relativistic potential, bremsstrahlung and interactions of neutrinos of different flavors are investigated, and the standard approximation in neutrino-nucleon interactions with zero energy transfer is replaced by rates that include corrections due to nucleon recoil, thermal motions, weak magnetism, and nucleon correlations. Models with t...

  10. Improved V II log($gf$) Values, Hyperfine Structure Constants, and Abundance Determinations in the Photospheres of the Sun and Metal-poor Star HD 84937

    CERN Document Server

    Wood, M P; Hartog, E A Den; Sneden, C; Cowan, J J

    2014-01-01

    New experimental absolute atomic transition probabilities are reported for 203 lines of V II. Branching fractions are measured from spectra recorded using a Fourier transform spectrometer and an echelle spectrometer. The branching fractions are normalized with radiative lifetime measurements to determine the new transition probabilities. Generally good agreement is found between this work and previously reported V II transition probabilities. Use of two spectrometers, independent radiometric calibration methods, and independent data analysis routines enables a reduction in systematic uncertainties, in particular those due to optical depth errors. In addition, new hyperfine structure constants are measured for selected levels by least squares fitting line profiles in the FTS spectra. The new V II data are applied to high resolution visible and UV spectra of the Sun and metal-poor star HD 84937 to determine new, more accurate V abundances. Lines covering a range of wavelength and excitation potential are used t...

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

    NARCIS (Netherlands)

    Kuzuhara, M.; et al., [Unknown; Thalmann, C.

    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 (<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 mo

  12. Improved Cr II log(gf) Values and Abundance Determinations in the Photospheres of the Sun and Metal-poor Star HD 84937

    Science.gov (United States)

    Lawler, J. E.; Sneden, C.; Nave, G.; Den Hartog, E. A.; Emrahoğlu, N.; Cowan, J. J.

    2017-01-01

    New emission branching fraction (BF) measurements for 183 lines of the second spectrum of chromium (Cr ii) and new radiative lifetime measurements from laser-induced fluorescence for 8 levels of Cr+ are reported. The goals of this study are to improve transition probability measurements in Cr ii and reconcile solar and stellar Cr abundance values based on Cr i and Cr ii lines. Eighteen spectra from three Fourier Transform Spectrometers supplemented with ultraviolet spectra from a high-resolution echelle spectrometer are used in the BF measurements. Radiative lifetimes from this study and earlier publications are used to convert the BFs into absolute transition probabilities. These new laboratory data are applied to determine the Cr abundance log ε in the Sun and metal-poor star HD 84937. The mean result in the Sun is = 5.624 ± 0.009 compared to = 5.644 ± 0.006 on a scale with the hydrogen abundance log ε(H) = 12 and with the uncertainty representing only line-to-line scatter. A Saha (ionization balance) test on the photosphere of HD 84937 is also performed, yielding = 3.417 ± 0.006 and 0 eV)> = 3.374 ± 0.011 for this dwarf star. We find a correlation of Cr with the iron-peak element Ti, suggesting an associated nucleosynthetic production. Four iron-peak elements (Cr along with Ti, V, and Sc) appear to have a similar (or correlated) production history—other iron-peak elements appear not to be associated with Cr.

  13. Improved Cr II log(gf)s and Cr Abundances in the Photospheres of the Sun and Metal-Poor Star HD 84937

    Science.gov (United States)

    Lawler, James E.; Sneden, Chris; Nave, Gillian; Den Hartog, Elizabeth; Emrahoglu, Nuri; Cowan, John J.

    2017-01-01

    New laser induced fluorescence (LIF) data for eight levels of singly ionized chromium (Cr) and emission branching fraction (BF) measurements for 183 lines of the second spectrum of chromium (Cr II) are reported. A goal of this study is to reconcile Solar and stellar Cr abundance values based on Cr I and Cr II lines. Analyses of eighteen spectra from three Fourier Transform Spectrometers supplemented with ultraviolet spectra from a high resolution echelle spectrometer yield the BF measurements. Radiative lifetimes from LIF measurements are used to convert the BFs to absolute transition probabilities. These new laboratory data are applied to determine the Cr abundance log eps in the Sun and metal-poor star HD 84937. The mean result in the Sun is = 5.624 ± 0.009 compared to = 5.644 ± 0.006 on a scale with the H abundance log eps(H) = 12. Similarily the photosphere of HD 84937 is found to be in Saha balance with = 3.417 ± 0.006 and 0 eV) > = 3.374 ± 0.011 for this dwarf star. The resonance (E.P. = 0 eV) lines of Cr I reveal overionization of the ground level of neutral Cr. We find a correlation of Cr with the iron-peak element Ti, suggesting an associated or related nucleosynthetic production. Four iron-peak elements (Cr along with Ti, V and Sc) appear to have a similar (or correlated) production history - other iron-peak elements appear not to be associated with Cr.This work is supported in part by NASA grant NNX16AE96G (J.E.L.), by NSF grant AST-1516182 (J.E.L. & E.D.H.), by NASA interagency agreement NNH10AN381 (G.N.), and NSF grant AST-1211585 (C.S.). Postdoctoral research support for N. E. is from the Technological and Scientific Research Council of Turkey (TUBITAK).

  14. 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

  15. IMPROVED V I log(gf) VALUES AND ABUNDANCE DETERMINATIONS IN THE PHOTOSPHERES OF THE SUN AND METAL-POOR STAR HD 84937

    Energy Technology Data Exchange (ETDEWEB)

    Lawler, J. E.; Wood, M. P.; Den Hartog, E. A.; Feigenson, T. [Department of Physics, University of Wisconsin, Madison, WI 53706 (United States); Sneden, C. [Department of Astronomy and McDonald Observatory, University of Texas, Austin, TX 78712 (United States); Cowan, J. J., E-mail: jelawler@wisc.edu, E-mail: mpwood@wisc.edu, E-mail: eadenhar@wisc.edu, E-mail: tfeigenson@wisc.edu, E-mail: chris@verdi.as.utexas.edu, E-mail: cowan@nhn.ou.edu [Homer L. Dodge Department of Physics and Astronomy, University of Oklahoma, Norman, OK 73019 (United States)

    2015-01-01

    New emission branching fraction measurements for 836 lines of the first spectrum of vanadium (V I) are determined from hollow cathode lamp spectra recorded with the National Solar Observatory 1 m Fourier transform spectrometer (FTS) and a high-resolution echelle spectrometer. The branching fractions are combined with recently published radiative lifetimes from laser-induced fluorescence measurements to determine accurate absolute atomic transition probabilities for the 836 lines. The FTS data are also used to extract new hyperfine structure A coefficients for 26 levels of neutral vanadium. These new laboratory data are applied to determine the V abundance in the Sun and metal-poor star HD 84937, yielding log ε(V) = 3.956 ± 0.004 (σ = 0.037) based on 93 V I lines and log ε(V) = 1.89 ± 0.03 (σ = 0.07) based on nine V I lines, respectively, using the Holweger-Müller 1D model. These new V I abundance values for the Sun and HD 84937 agree well with our earlier determinations based upon V II.

  16. solarFLAG hare and hounds: on the extraction of rotational p-mode splittings from seismic, Sun-as-a-star data

    CERN Document Server

    Chaplin, W J; Baudin, F; Boumier, P; Elsworth, Y; Fletcher, S T; Fossat, E; García, R A; Isaak, G R; Jiménez, A; Jiménez-Reyes, S J; Lazrek, M; Leibacher, J W; Lochard, J; New, R; Pallé, P L; Regulo, C; Salabert, D; Seghouani, N; Toutain, T; Wachter, R

    2006-01-01

    We report on results from the first solar Fitting at Low-Angular degree Group (solar FLAG) hare-and-hounds exercise. The group is concerned with the development of methods for extracting the parameters of low-l solar p mode data (`peak bagging'), collected by Sun-as-a-star observations. Accurate and precise estimation of the fundamental parameters of the p modes is a vital pre-requisite of all subsequent studies. Nine members of the FLAG (the `hounds') fitted an artificial 3456-d dataset. The dataset was made by the `hare' (WJC) to simulate full-disc Doppler velocity observations of the Sun. The rotational frequency splittings of the l=1, 2 and 3 modes were the first parameter estimates chosen for scrutiny. Significant differences were uncovered at l=2 and 3 between the fitted splittings of the hounds. Evidence is presented that suggests this unwanted bias had its origins in several effects. The most important came from the different way in which the hounds modeled the visibility ratio of the different rotati...

  17. Blue moons and Martian sunsets.

    Science.gov (United States)

    Ehlers, Kurt; Chakrabarty, Rajan; Moosmüller, Hans

    2014-03-20

    The familiar yellow or orange disks of the moon and sun, especially when they are low in the sky, and brilliant red sunsets are a result of the selective extinction (scattering plus absorption) of blue light by atmospheric gas molecules and small aerosols, a phenomenon explainable using the Rayleigh scattering approximation. On rare occasions, dust or smoke aerosols can cause the extinction of red light to exceed that for blue, resulting in the disks of the sun and moon to appear as blue. Unlike Earth, the atmosphere of Mars is dominated by micron-size dust aerosols, and the sky during sunset takes on a bluish glow. Here we investigate the role of dust aerosols in the blue Martian sunsets and the occasional blue moons and suns on Earth. We use the Mie theory and the Debye series to calculate the wavelength-dependent optical properties of dust aerosols most commonly found on Mars. Our findings show that while wavelength selective extinction can cause the sun's disk to appear blue, the color of the glow surrounding the sun as observed from Mars is due to the dominance of near-forward scattering of blue light by dust particles and cannot be explained by a simple, Rayleigh-like selective extinction explanation.

  18. The Lick-Carnegie Exoplanet Survey: HD32963 -- A New Jupiter Analog Orbiting a Sun-like Star

    CERN Document Server

    Rowan, Dominick; Laughlin, Gregory; Vogt, Steven S; Butler, R Paul; Burt, Jennifer; Wang, Songhu; Holden, Brad; Hanson, Russell; Arriagada, Pamela; Keiser, Sandy; Teske, Johanna; Diaz, Matias

    2015-01-01

    We present a set of 109 new, high-precision Keck/HIRES radial velocity (RV) observations for the solar-type star HD 32963. Our dataset reveals a candidate planetary signal with a period of 6.49 $\\pm$ 0.07 years and a corresponding minimum mass of 0.7 $\\pm$ 0.03 Jupiter masses. Given Jupiter's crucial role in shaping the evolution of the early Solar System, we emphasize the importance of long-term radial velocity surveys. Finally, using our complete set of Keck radial velocities and correcting for the relative detectability of synthetic planetary candidates orbiting each of the 1,122 stars in our sample, we estimate the frequency of Jupiter analogs across our survey at approximately 3%.

  19. 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.

  20. MagAO Imaging of Long-period Objects (MILO). II. A Puzzling White Dwarf around the Sun-like Star HD 11112

    CERN Document Server

    Rodigas, Timothy J; Simon, Amelie; Arriagada, Pamela; Faherty, Jackie; Anglada-Escude, Guillem; Mamajek, Eric E; Weinberger, Alycia; Butler, R Paul; Males, Jared R; Morzinski, Katie; Close, Laird M; Hinz, Philip M; Bailey, Jeremy; Carter, Brad; Jenkins, James S; Jones, Hugh; O'Toole, Simon; Tinney, C G; Wittenmyer, Rob; Debes, John

    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\\fasec 2 (100 AU) at multiple wavelengths spanning 0.6-4 \\microns ~and show that it is most likely a gravitationally-bound cool white dwarf. Modeling its spectral energy distribution (SED) suggests that its mass is 0.9-1.1 \\msun, which corresponds to very high-eccentricity, near edge-on orbits from Markov chain Monte Carlo analysis of the RV and imaging data together. The total age of the white dwarf is $>2\\sigma$ 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 ...

  1. IMPROVED Co i log(gf) VALUES AND ABUNDANCE DETERMINATIONS IN THE PHOTOSPHERES OF THE SUN AND METAL-POOR STAR HD 84937

    Energy Technology Data Exchange (ETDEWEB)

    Lawler, J. E. [Department of Physics, University of Wisconsin-Madison, 1150 University Ave., Madison, WI 53706 (United States); Sneden, C. [Department of Astronomy and McDonald Observatory, University of Texas, Austin, TX 78712 (United States); Cowan, J. J., E-mail: jelawler@wisc.edu, E-mail: chris@verdi.as.utexas.edu, E-mail: jjcowan1@ou.edu [Homer L. Dodge Department of Physics and Astronomy, University of Oklahoma, Norman, OK 73019 (United States)

    2015-09-15

    New emission branching fraction measurements for 898 lines of the first spectrum of cobalt (Co i) are determined from hollow cathode lamp spectra recorded with the National Solar Observatory 1 m Fourier transform spectrometer on Kitt Peak, AZ and a high-resolution echelle spectrometer. Published radiative lifetimes from laser induced fluorescence measurements are combined with the branching fractions to determine accurate absolute atomic transition probabilities for the 898 lines. Hyperfine structure (hfs) constants for levels of neutral Co in the literature are surveyed and selected values are used to generate complete hfs component patterns for 195 transitions of Co i. These new laboratory data are applied to determine the Co abundance in the Sun and metal-poor star HD 84937, yielding log ϵ(Co) = 4.955 ± 0.007 (σ = 0.059) based on 82 Co i lines and log ϵ(Co) = 2.785 ± 0.008 (σ = 0.065) based on 66 Co i lines, respectively. A Saha or ionization balance test on the photosphere of HD 84937 is performed using 16 UV lines of Co ii, and good agreement is found with the Co i result in this metal-poor ([Fe i/H] = −2.32, [Fe ii/H] = −2.32) dwarf star. The resulting value of [Co/Fe] = +0.14 supports a rise of Co/Fe at low metallicity that has been suggested in other studies.

  2. The stability of tightly-packed, evenly-spaced systems of Earth-mass planets orbiting a Sun-like star

    Science.gov (United States)

    Obertas, Alysa; Van Laerhoven, Christa; Tamayo, Daniel

    2017-09-01

    Many of the multi-planet systems discovered to date have been notable for their compactness, with neighbouring planets closer together than any in the Solar System. Interestingly, planet-hosting stars have a wide range of ages, suggesting that such compact systems can survive for extended periods of time. We have used numerical simulations to investigate how quickly systems go unstable in relation to the spacing between planets, focusing on hypothetical systems of Earth-mass planets on evenly-spaced orbits (in mutual Hill radii). In general, the further apart the planets are initially, the longer it takes for a pair of planets to undergo a close encounter. We recover the results of previous studies, showing a linear trend in the initial planet spacing between 3 and 8 mutual Hill radii and the logarithm of the stability time. Investigating thousands of simulations with spacings up to 13 mutual Hill radii reveals distinct modulations superimposed on this relationship in the vicinity of first and second-order mean motion resonances of adjacent and next-adjacent planets. We discuss the impact of this structure and the implications on the stability of compact multi-planet systems. Applying the outcomes of our simulations, we show that isolated systems of up to five Earth-mass planets can fit in the habitable zone of a Sun-like star without close encounters for at least 109 orbits.

  3. Moon Bound

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    China’s first lunar probe,Chang’e-1, blasts off aboard a Long March 3A carrier rocket at 6:05 p.m.(10:05 GMT)from the Xichang Satellite Launch Center in Sichuan Province. Chang’e-1,named after a legendary Chinese goddess of the moon,is expected to experience four accelerations and enter earth-moon transfer orbit on October 31,arriving in the moon’s orbit on November 5 for a yearlong scientific exploration. The launch of the circumlunar satellite marked the start of China’s ambitious three-phase moon mission.Scientists have planned a moon landing and release of a moon rover around 2012 in the second phase.In the third phase,another rover will land on the moon and return to earth with lunar soil and stone samples for scientific research around 2017. Inset:Staff at the Beijing Aerospace Control Center applaud the successful launch of Chang’e-1.

  4. Feasibility for p+/p- intensity-ratio evaluation in the 0.5 - 1.5 TeV primary energy range, based on Moon-shadow muon measurements, to be carried out in the Pyramid of the Sun, Teotihuacan, Experiment

    Science.gov (United States)

    Grabski, V.; Morales, A.; Reche, R.; Orozco, O.

    Several experimental works demonstrate the possibility of observation of shadows of the Moon and the Sun for the mean energy of primaries higher than 1 TeV. Calculations are presented to demonstrate the feasibility of Moon shadow observations for mean primary energies in the region 0.5-1 TeV in a muon detector operating under the Pyramid of the Sun at Teotihuacan, Mexico. Due to the relatively small height of that monument (65 m), the experiment is capable of providing considerably high statistics, but with deterioration in the angular accuracy for primary particle direction reconstruction. Our estimates are based on simulations of muon production and transport in the atmosphere by CORSICA, while the transport along the body of the pyramid is simulated using GEANT4. The deflection of primaries in magnetic field of the earth is calculated using the IGRF model. The analysis aims at discriminating between positively and negatively charged primaries traveling along directions corresponding to the Moon shadow region. The statistics for antiproton shadow observations, which depends on different factors affecting the accuracy of the primary particle direction reconstruction, is analyzed in detail.

  5. Global Seismology of the Sun

    CERN Document Server

    Basu, Sarbani

    2016-01-01

    The seismic study of the Sun and other stars offers a unique window into the interior of these stars. Thanks to helioseismology, we know the structure of the Sun to admirable precision. In fact, our knowledge is good enough to use the Sun as a laboratory. We have also been able to study the dynamics of the Sun in great detail. Helioseismic data also allow us to probe the changes that take place in the Sun as solar activity waxes and wanes. The seismic study of stars other than the Sun is a fairly new endeavour, but we are making great strides in this field. In this review I discuss some of the techniques used in helioseismic analyses and the results obtained using those techniques. In this review I focus on results obtained with global helioseismology, i.e., the study of the Sun using its normal modes of oscillation. I also briefly touch upon asteroseismology, the seismic study of stars other than the Sun, and discuss how seismic data of others stars are interpreted.

  6. 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

  7. 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.

  8. 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.

  9. A Helicity-Based Method to Infer the CME Magnetic Field Magnitude in Sun and Geospace: Generalization and Extension to Sun-Like and M-Dwarf Stars and Implications for Exoplanet Habitability

    Science.gov (United States)

    Patsourakos, S.; Georgoulis, M. K.

    2017-07-01

    Patsourakos et al. ( Astrophys. J. 817, 14, 2016) and Patsourakos and Georgoulis ( Astron. Astrophys. 595, A121, 2016) introduced a method to infer the axial magnetic field in flux-rope coronal mass ejections (CMEs) in the solar corona and farther away in the interplanetary medium. The method, based on the conservation principle of magnetic helicity, uses the relative magnetic helicity of the solar source region as input estimates, along with the radius and length of the corresponding CME flux rope. The method was initially applied to cylindrical force-free flux ropes, with encouraging results. We hereby extend our framework along two distinct lines. First, we generalize our formalism to several possible flux-rope configurations (linear and nonlinear force-free, non-force-free, spheromak, and torus) to investigate the dependence of the resulting CME axial magnetic field on input parameters and the employed flux-rope configuration. Second, we generalize our framework to both Sun-like and active M-dwarf stars hosting superflares. In a qualitative sense, we find that Earth may not experience severe atmosphere-eroding magnetospheric compression even for eruptive solar superflares with energies {≈} 104 times higher than those of the largest Geostationary Operational Environmental Satellite (GOES) X-class flares currently observed. In addition, the two recently discovered exoplanets with the highest Earth-similarity index, Kepler 438b and Proxima b, seem to lie in the prohibitive zone of atmospheric erosion due to interplanetary CMEs (ICMEs), except when they possess planetary magnetic fields that are much higher than that of Earth.

  10. After Apollo: Fission Origin of the Moon

    Science.gov (United States)

    O'Keefe, John A.

    1973-01-01

    Presents current ideas about the fission process of the Moon, including loss of mass. Saturnian rings, center of the Moon, binary stars, and uniformitarianism. Indicates that planetary formation may be best explained as a destructive, rather than a constructive process. (CC)

  11. Lessons from the Sun

    Directory of Open Access Journals (Sweden)

    Robitaille P.-M.

    2011-07-01

    Full Text Available In this brief note, the implications of a condensed Sun will be examined. A celestial body composed of liquid metallic hydrogen brings great promise to astronomy, relative to understanding thermal emission and solar structure. At the same time, as an incom- pressible liquid, a condensed Sun calls into question virtually everything which is cur- rently believed with respect to the evolution and nature of the stars. Should the Sun be condensed, then neutron stars and white dwarfs will fail to reach the enormous densities they are currently believed to possess. Much of cosmology also falls into question, as the incompressibility of matter curtails any thought that a primordial atom once existed. Aging stars can no longer collapse and black holes will know no formative mechanism. A condensed Sun also hints that great strides must still be made in understanding the nature of liquids. The Sun has revealed that liquids possess a much greater potential for lattice order than previously believed. In addition, lessons may be gained with regards to the synthesis of liquid metallic hydrogen and the use of condensed matter as the basis for initiating fusion on Earth.

  12. Exotic World Blisters Under the Sun

    Science.gov (United States)

    2006-01-01

    This artist's concept shows a Jupiter-like planet soaking up the scorching rays of its nearby 'sun.' NASA's Spitzer Space Telescope used its heat-seeking infrared eyes to figure out that a gas-giant planet like the one depicted here is two-faced, with one side perpetually in the cold dark, and the other forever blistering under the heat of its star. The illustration portrays how the planet would appear to infrared eyes, showing temperature variations across its surface. The planet, called Upsilon Andromedae b, was first discovered in 1996 around the star Upsilon Andromedae, located 40 light-years away in the constellation Andromeda. This star also has two other planets orbiting farther out. Upsilon Andromedae b is what's known as a 'hot-Jupiter' planet, because it is made of gas like our Jovian giant, and it is hot, due to its tight, 4.6-day-long jaunt around its star. The toasty planet orbits at one-sixth the distance of Mercury from our own sun. It travels in a plane that is seen neither edge- nor face-on from our solar system, but somewhere in between. Scientists do not know how fast Upsilon Andromedae b is spinning on its axis, but they believe that it is tidally locked to its star, just as our locked moon forever hides its 'dark side' from Earth's view. Spitzer observed Upsilon Andromedae b at five points during the planet's trip around its star. The planet's light levels went up or down, as detected by Spitzer, depending on whether the planet's sunlit or dark side was pointed toward Earth. These data indicate that the temperature difference between the two hemispheres of the planet is about 1,400 degrees Celsius (2,550 degrees Fahrenheit). According to astronomers, this means that the side of the planet that faces the star is always as hot as lava, while the other side could potentially be as cold as ice. Specifically, the hot side of the planet ranges from about 1,400 to 1,650 degrees Celsius (2,550 to 3,000 degrees Fahrenheit), and the cold side from about

  13. Pathways Towards Habitable Moons

    CERN Document Server

    Kipping, David M; Campanella, Giammarco; Schneider, Jean; Tinetti, Giovanna

    2009-01-01

    The search for life outside of the Solar System should not be restricted to exclusively planetary bodies; large moons of extrasolar planets may also be common habitable environments throughout the Galaxy. Extrasolar moons, or exomoons, may be detected through transit timing effects induced onto the host planet as a result of mutual gravitational interaction. In particular, transit timing variations (TTV) and transit duration variations (TDV) are predicted to produce a unique exomoon signature, which is not only easily distinguished from other gravitational perturbations, but also provides both the period and mass of an exomoon. Using these timing effects, photometry greater or equal to that of the Kepler Mission is readily able to detect habitable-zone exomoons down to 0.2 Earth masses and could survey up to 25,000 stars for 1 Earth-mass satellites. We discuss future possibilities for spectral retrieval of such bodies and show that transmission spectroscopy with JWST should be able to detect molecular species...

  14. Shepherd Moons

    Science.gov (United States)

    2007-01-01

    [figure removed for brevity, see original site] Click on the image for movie of Shepherd Moons The New Horizons spacecraft took the best images of Jupiter's charcoal-black rings as it approached and then looked back at Jupiter in February 2007. This sequence of pictures from the Long Range Reconnaissance Imager (LORRI) shows the well-defined lanes of gravel- to boulder-sized material composing the bulk of the rings; labels point out how these narrow rings are confined in their orbits by small 'shepherding' moons (Metis and Adrastea).

  15. Kepler-20: A Sun-like Star with Three Sub-Neptune Exoplanets and Two Earth-size Candidates

    CERN Document Server

    Gautier, Thomas N; Rowe, Jason F; Marcy, Geoffrey W; Isaacson, Howard; Torres, Guillermo; Fressin, Francois; Rogers, Leslie A; Désert, Jean-Michel; Buchhave, Lars A; Latham, David W; Quinn, Samuel N; Ciardi, David R; Fabrycky, Daniel C; Ford, Eric B; Gilliland, Ronald L; Walkowicz, Lucianne M; Bryson, Stephen T; Cochran, William D; Endl, Michael; Fischer, Debra A; Howel, Steve B; Horch, Elliott P; Barclay, Thomas; Batalha, Natalie; Borucki, William J; Christiansen, Jessie L; Geary, John C; Henze, Christopher E; Holman, Matthew J; Ibrahim, Khadeejah; Jenkins, Jon M; Kinemuchi, Karen; Koch, David G; Lissauer, Jack J; Sanderfer, Dwight T; Sasselov, Dimitar D; Seager, Sara; Silverio, Kathryn; Smith, Jeffrey C; Still, Martin; Stumpe, Martin C; Tenenbaum, Peter; Van Cleve, Jeffrey

    2011-01-01

    We present the discovery of the Kepler-20 planetary system, which we initially identified through the detection of five distinct periodic transit signals in the Kepler light curve of the host star 2MASSJ19104752+4220194. We find a stellar effective temperature Teff=5455+-100K, a metallicity of [Fe/H]=0.01+-0.04, and a surface gravity of log(g)=4.4+-0.1. Combined with an estimate of the stellar density from the transit light curves we deduce a stellar mass of Mstar=0.912+-0.034 Msun and a stellar radius of Rstar=0.944^{+0.060}_{-0.095} Rsun. For three of the transit signals, our results strongly disfavor the possibility that these result from astrophysical false positives. We conclude that the planetary scenario is more likely than that of an astrophysical false positive by a factor of 2e5 (Kepler-20b), 1e5 (Kepler-20c), and 1.1e3 (Kepler-20d), sufficient to validate these objects as planetary companions. For Kepler-20c and Kepler-20d, the blend scenario is independently disfavored by the achromaticity of the ...

  16. Sun Allergy

    Science.gov (United States)

    ... if you have unusual, bothersome skin reactions after exposure to sunlight. For severe or persistent symptoms, you may need ... m. when the sun is brightest. Avoid sudden exposure to lots of sunlight. Many people have sun allergy symptoms when they ...

  17. IMPROVED V II log(gf) VALUES, HYPERFINE STRUCTURE CONSTANTS, AND ABUNDANCE DETERMINATIONS IN THE PHOTOSPHERES OF THE SUN AND METAL-POOR STAR HD 84937

    Energy Technology Data Exchange (ETDEWEB)

    Wood, M. P.; Lawler, J. E.; Den Hartog, E. A. [Department of Physics, University of Wisconsin, Madison, WI 53706 (United States); Sneden, C. [Department of Astronomy and McDonald Observatory, University of Texas, Austin, TX 78712 (United States); Cowan, J. J., E-mail: mpwood@wisc.edu, E-mail: jelawler@wisc.edu, E-mail: eadenhar@wisc.edu, E-mail: chris@verdi.as.utexas.edu, E-mail: cowan@nhn.ou.edu [Homer L. Dodge Department of Physics and Astronomy, University of Oklahoma, Norman, OK 73019 (United States)

    2014-10-01

    New experimental absolute atomic transition probabilities are reported for 203 lines of V II. Branching fractions are measured from spectra recorded using a Fourier transform spectrometer and an echelle spectrometer. The branching fractions are normalized with radiative lifetime measurements to determine the new transition probabilities. Generally good agreement is found between this work and previously reported V II transition probabilities. Two spectrometers, independent radiometric calibration methods, and independent data analysis routines enable a reduction in systematic uncertainties, in particular those due to optical depth errors. In addition, new hyperfine structure constants are measured for selected levels by least squares fitting line profiles in the FTS spectra. The new V II data are applied to high resolution visible and UV spectra of the Sun and metal-poor star HD 84937 to determine new, more accurate V abundances. Lines covering a range of wavelength and excitation potential are used to search for non-LTE effects. Very good agreement is found between our new solar photospheric V abundance, log ε(V) = 3.95 from 15 V II lines, and the solar-system meteoritic value. In HD 84937, we derive [V/H] = –2.08 from 68 lines, leading to a value of [V/Fe] = 0.24.

  18. Improved log(gf) Values for Lines of V I and V II, New Vanadium Abundances in the Sun and the Metal-Poor Star HD 84937

    Science.gov (United States)

    Lawler, James E.; Wood, Michael P.; Den Hartog, Elizabeth; Feigenson, Thomas; Sneden, Chris; Cowan, John J.

    2015-01-01

    New emission branching fraction measurements for 836 lines of the first spectrum of vanadium (V I) and 203 lines of V II are determined from hollow cathode lamp spectra recorded with the National Solar Observatory 1m Fourier transform spectrometer (FTS) and a high resolution echelle spectrometer. The branching fractions are combined with new radiative lifetimes from laser induced fluorescence measurements to determine accurate absolute atomic transition probabilities for 1039 lines of V I and V II. The FTS data are also used to extract new hyperfine structure A coefficients for both spectra. These new laboratory data are applied to determine the V abundance in the Sun and metal-poor star HD 84937, yielding log ɛ(V) = 3.96 (σ = 0.04) based on 93 V I lines and log ɛ(V) = 1.89 (σ = 0.07) based on nine V I lines respectively, and yielding log ɛ(V) = 3.95 (σ = 0.05) based on 15 V II lines and log ɛ(V) = 1.87 (σ = 0.07) based on 68 V II lines respectively1-3.1. Wood et al., ApJS 214:18 (2014), 2. Den Hartog et al. ApJS in press (2014), 3. Lawler et al. ApJS submitted (2014). This work is supported by NASA grant NNX10AN93G (JEL), NSF AST-1211055 (EDH & JEL), and NSF AST-1211585 (CS).

  19. MagAO Imaging of Long-period Objects (MILO). I. A Benchmark M Dwarf Companion Exciting a Massive Planet around the Sun-like Star HD 7449

    CERN Document Server

    Rodigas, Timothy J; Faherty, Jackie; Anglada-Escude, Guillem; Kaib, Nathan; Butler, R Paul; Shectman, Stephen; Weinberger, Alycia; Males, Jared R; Morzinski, Katie M; Close, Laird M; Hinz, Philip M; Crane, Jeffrey D; Thompson, Ian; Teske, Johanna; Diaz, Matias; Minniti, Dante; Lopez-Morales, Mercedes; Adams, Fred C; Boss, Alan P

    2015-01-01

    We present high-contrast Magellan adaptive optics (MagAO) images of HD 7449, a Sun-like star with one planet and a long-term radial velocity (RV) trend. We unambiguously detect the source of the long-term trend from 0.6-2.15 \\microns ~at a separation of \\about 0\\fasec 54. We use the object's colors and spectral energy distribution to show that it is most likely an M4-M5 dwarf (mass \\about 0.1-0.2 \\msun) at the same distance as the primary and is therefore likely bound. We also present new RVs measured with the Magellan/MIKE and PFS spectrometers and compile these with archival data from CORALIE and HARPS. We use a new Markov chain Monte Carlo procedure to constrain both the mass ($> 0.17$ \\msun ~at 99$\\%$ confidence) and semimajor axis (\\about 18 AU) of the M dwarf companion (HD 7449B). We also refine the parameters of the known massive planet (HD 7449Ab), finding that its minimum mass is $7.8^{+3.7}_{-1.35}$ \\mj, its semimajor axis is $2.33^{+0.01}_{-0.02}$ AU, and its eccentricity is $0.8^{+0.08}_{-0.06}$. ...

  20. Formative Assessment Probes: Where Are the Stars?

    Science.gov (United States)

    Keeley, Page

    2011-01-01

    Gazing at the night sky is a familiar experience for many elementary students. Depending on where children live, they can often look out a window and see the Moon and stars. Children may have seen the Moon and stars in television shows, movies, posters, or children's picture books. Regardless of whether they see the Moon and stars firsthand or…

  1. 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

  2. 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,…

  3. 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,…

  4. 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.

  5. Why Study the Sun?

    Indian Academy of Sciences (India)

    Arvind Bhatnagar

    2006-06-01

    In this presentation we briefly describe the Sun through large number of illustrations and pictures of the Sun taken from early times to the present day space missions. The importance of the study of the Sun is emphasized as it is the nearest star which presents unparallelled views of surface details and numerous phenomena. Our Sun offers a unique celestial laboratory where a large variety of phenomena take place, ranging in temporal domain from a few milliseconds to several decades, in spatial domain from a few hundred kilometers to thousands of kilometers, and in the temperature domain from a few thousand degrees to several million degrees. Its mass motion ranges from thousandths to thousands of kilometers per second. Such an object provides us with a unique laboratory to study the state of matter in the Universe. The existing solar ground-based and space missions have already revealed several mysteries of the outer environment of our Sun and much more is going to come in the near future from planned new sophisticated ground-based solar telescopes and Space missions. The new technique of helioseismology has unravelled many secrets of the solar interior and has put the Standard Solar Model (SSM) on firm footing. The long-standing problem of solar neutrinos has been recently sorted out, and even the ‘back side’ view of the Sun can be seen using the technique of holographic helioseismology.

  6. Aztec Suns

    Science.gov (United States)

    Petersen, Hugh

    2010-01-01

    The Aztec Sun Stone is a revered Mexican artifact. It is said to be perhaps the most famous symbol of Mexico, besides its flag. It primarily depicts the four great disasters that led to the migration of the Mexica people to modern-day Mexico City. The Aztec Sun Stone also contains pictographs depicting the way the Mexica measured time, and was…

  7. Aztec Suns

    Science.gov (United States)

    Petersen, Hugh

    2010-01-01

    The Aztec Sun Stone is a revered Mexican artifact. It is said to be perhaps the most famous symbol of Mexico, besides its flag. It primarily depicts the four great disasters that led to the migration of the Mexica people to modern-day Mexico City. The Aztec Sun Stone also contains pictographs depicting the way the Mexica measured time, and was…

  8. 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,...

  9. 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…

  10. Using Moon Phases to Measure Time

    Science.gov (United States)

    Sharp, Janet; Lutz, Tracie; LaLonde, Donna E.

    2015-01-01

    Cultures need to accurately record dates and times for various societal purposes, ranging from knowing when to plant crops to planning travel. In ancient times, the sun and moon were used as measurement devices because of the scientific understanding of the physical world at that time. Ancient timekeepers monitored celestial events and either used…

  11. The Mount Wilson Observatory S-index of the Sun

    Science.gov (United States)

    Egeland, Ricky; Soon, Willie; Baliunas, Sallie; Hall, Jeffrey C.; Pevtsov, Alexei A.; Bertello, Luca

    2017-01-01

    The most commonly used index of stellar magnetic activity is the instrumental flux scale of singly ionized calcium H & K line core emission, S, developed by the Mount Wilson Observatory (MWO) HK Project, or the derivative index {R}{HK}\\prime . Accurately placing the Sun on the S scale is important for comparing solar activity to that of the Sun-like stars. We present previously unpublished measurements of the reflected sunlight from the Moon using the second-generation MWO HK photometer during solar cycle 23 and determine cycle minimum {S}23,\\min =0.1634+/- 0.0008, amplitude {{Δ }}{S}23=0.0143+/- 0.0012, and mean =0.1701+/- 0.0005. By establishing a proxy relationship with the closely related National Solar Observatory Sacramento Peak calcium K emission index, itself well correlated with the Kodaikanal Observatory plage index, we extend the MWO S time series to cover cycles 15–24 and find on average =0.1621+/- 0.0008, =0.0145+/- 0.0012, =0.1694+/- 0.0005. Our measurements represent an improvement over previous estimates that relied on stellar measurements or solar proxies with non-overlapping time series. We find good agreement from these results with measurements by the Solar-Stellar Spectrograph at Lowell Observatory, an independently calibrated instrument, which gives us additional confidence that we have accurately placed the Sun on the S-index flux scale.

  12. 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.

  13. 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.

  14. Star-Paths, Stones and Horizon Astronomy

    Science.gov (United States)

    Brady, Bernadette

    2015-05-01

    Archaeoastronomers tend to approach ancient monuments focusing on the landscape and the horizon calendar events of sun and moon and, due to problems with precession, generally ignore the movement of the stars. However, locating the position of solar calendar points on the horizon can have other uses apart from calendar and/or cosmological purposes. This paper firstly suggests that the stars do not need to be ignored. By considering the evidence of the Phaenomena, a sky poem by Aratus of Soli, a third century BC Greek poet, and his use of second millennium BC star lore fragments, this paper argues that the stars were a part of the knowledge of horizon astronomy. Aratus' poem implied that the horizon astronomy of the late Neolithic and Bronze Age periods included knowledge of star-paths or 'linear constellations' that were defined by particular horizon calendar events and other azimuths. Knowledge of such star-paths would have enabled navigation and orientation, and by using permanent markers, constructed or natural, to define these paths, they were immune to precession as the stones could redefine a star-path for a future generation. Finally the paper presents other possible intentions behind the diverse orientation of passage tombs and some megalithic sites.

  15. Midnight sun

    Energy Technology Data Exchange (ETDEWEB)

    Brunger, A.P.; Lambert, S.B.; Gagnon, M.P.

    1990-09-01

    Midnight Sun, the University of Waterloo's solar-electric car, was designed and built by about 30 engineering, kinesiology and physics students for the GM Sunrayce USA held in July 1990. The car measures 2 m by 4.2 m, weighs 224 kg, can collect about 1000 W of solar electricity in full sun, and had a top speed of 79 km/h. The race took 11 days to cover the 1644 miles from the Epcot Center in Lake Buena Vista, Florida to the GM Technical Center in Warren, Michigan. Thirty-two cars, powered only by solar energy, competed in this race. Midnight Sun showed its potential during the race qualifying runs by completing the required qualifying course with the 12th fastest time of 52.83 seconds, and the 6th fastest trap speed of 63 km/h. During the Sunrayce, Midnight Sun came in second on day 1 of the race, tenth on day 6, and eighth on day 7, and was one of only 17 solar cars that were able to make it up the toughest hill in the race on day 8. The most serious problems encountered by the car were a weak rear suspension, power losses, and failure of bypass diodes in the photovoltaic array. Midnight Sun was in 17th place overall at the end of day 9. At about 11:00 am on day 10 in Ohio, the Waterloo car was moving at 60 km/h when it was bumped off the road by an out of control pickup truck. The solar car driver was not hurt. Despite the difficulties, the next day Midnight Sun was repaired and driven across the finish line at the ceremonial finish. After receiving time penalties for not completing the last day and a half of the race, Midnight Sun was awarded 24th place with an official cumulative time of 114 h 37 min 15 s. 4 figs., 4 tabs.

  16. 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…

  17. Observing the Moon

    Science.gov (United States)

    North, Gerald

    2014-03-01

    Preface; Acknowledgements; 1. 'Magnificent desolation'; 2. The moon through the looking glass; 3. Telescopes and drawing boards; 4. The Moon in camera; 5. Stacking up the Moon; 6. The physical Moon; 7. Lunarware; 8. 'A to Z' of selected lunar landscapes; 9. TLP or not TLP?; Appendix 1. Telescope collimation; Appendix 2. Field-testing a telescope's optics; Appendix 3. Polar alignment; Index.

  18. Sun, Earth and Sky

    Science.gov (United States)

    Lang, Kenneth R.

    1995-01-01

    The Sun is enveloped by a hot, tenuous million-degree corona that expands to create a continuous solar wind that sweeps past all the planets and fills the heliosphere. The solar wind is modulated by strong gusts that are initiated by powerful explosions on the Sun, including solar flares and coronal mass ejections. This dynamic, invisible outer atmosphere of the Sun is currently under observation with the soft X-ray telescope aboard the Yohkoh spacecraft, whose results are presented. We also show observations from the Ulysses spacecraft that is now passing over the solar pole, sampling the solar wind in this region for the first time. Two other spacecraft, Voyager 1 and 2, have recently detected the outer edge of the invisible heliosphere, roughly halfway to the nearest star. Magnetic solar activity, the total radiative output from the Sun, and the Earth's mean global surface temperature all vary with the 11-year sunspot cycle in which the total number of sunspots varies from a maximum to a minimum and back to a maximum again in about 11 years. The terrestrial magnetic field hollows out a protective magnetic cavity, called the magnetosphere, within the solar wind. This protection is incomplete, however, so the Sun feeds an unseen world of high-speed particles and magnetic fields that encircle the Earth in space. These particles endanger spacecraft and astronauts, and also produce terrestrial aurorae. An international flotilla of spacecraft is now sampling the weak points in this magnetic defense. Similar spacecraft have also discovered a new radiation belt, in addition to the familiar Van Allen belts, except fed by interstellar ions instead of electrons and protons from the Sun.

  19. The new sun-sky-lunar Cimel CE318-T multiband photometer - a comprehensive performance evaluation

    Science.gov (United States)

    Barreto, África; Cuevas, Emilio; Granados-Muñoz, María-José; Alados-Arboledas, Lucas; Romero, Pedro M.; Gröbner, Julian; Kouremeti, Natalia; Almansa, Antonio F.; Stone, Tom; Toledano, Carlos; Román, Roberto; Sorokin, Mikhail; Holben, Brent; Canini, Marius; Yela, Margarita

    2016-02-01

    assess the CE318-T performance as well as to confirm its estimated uncertainty. Daytime AOD evaluation, performed at Izaña 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 star-photometer-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 ( ≤ 0.013) and differences with AERONET daytime data (1 h after and before sunset and sunrise) in agreement with the estimated uNAOD 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.Precipitable 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.

  20. 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...

  1. 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...

  2. News and Views: Double whammy: seeing the Sun and Moon at Glastonbury; What in the world is your object, Hanny? Old Milky Way stars; A star being born; Black hole's big bubble

    Science.gov (United States)

    2010-08-01

    Dutch schoolteacher Hanny van Arkel made headlines when she discovered a new type of object, a greenish gas cloud, as part of the Galaxy Zoo project in which citizen scientists can search the Sloan Digital Sky Survey database.

  3. Reconstructing the star knowledge of Aboriginal Tasmanians

    Science.gov (United States)

    Gantevoort, Michelle; Hamacher, Duane W.; Lischick, Savannah

    2016-12-01

    The canopy of stars is a central presence in the daily and spiritual lives of Aboriginal Tasmanians. With the arrival of European colonists, Tasmanian astronomical knowledge and traditions were interrupted and dispersed. Fragments can be found scattered in the ethnographic and historical record throughout the nineteenth century. We draw from these ethnohistorical documents to analyse and reconstruct Aboriginal astronomical knowledge in Tasmania. This analysis demonstrates that stars, the Milky Way, constellations, dark nebula, the Sun, Moon, meteors and aurorae held cultural, spiritual and subsistence significance for the Aboriginal cultures of Tasmania. We move beyond a monolithic view of Aboriginal astronomical knowledge in Tasmania, commonly portrayed in previous research, to lay the groundwork for future ethnographic and archaeological fieldwork with Aboriginal elders and communities.

  4. Reconstructing the Star Knowledge of Aboriginal Tasmanians

    CERN Document Server

    Gantevoort, Michelle; Lischick, Savannah

    2016-01-01

    The canopy of stars is a central presence in the daily and spiritual lives of Aboriginal Tasmanians. With the arrival of European colonists, Tasmanian astronomical knowledge and traditions were interrupted and dispersed. Fragments can be found scattered in the ethnographic and historical record throughout the nineteenth century. We draw from ethnohistorical documents to analyse and reconstruct Aboriginal astronomical knowledge in Tasmania. This analysis demonstrates that stars, the Milky Way, constellations, dark nebula, the Sun, Moon, meteors, and aurorae held cultural, spiritual, and subsistence significance within the Aboriginal cultures of Tasmania. We move beyond a monolithic view of Aboriginal astronomical knowledge in Tasmania, commonly portrayed in previous research, to lay the groundwork for future ethnographic and archaeological fieldwork with Aboriginal elders and communities.

  5. Finding the lost siblings of the Sun

    Science.gov (United States)

    Liu, Cheng; Feltzing, Sofia; Ruchti, Gregory

    2014-01-01

    We have performed a spectral analysis on 18 stars solar sibling candidate. We found that only one one of the candidateshas solar metallicity and at the same time might have an age comparable to that of the Sun.

  6. 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.

  7. Detectability of extrasolar moons as gravitational microlenses

    CERN Document Server

    Liebig, Christine

    2009-01-01

    We evaluate gravitational lensing as a technique for the detection of extrasolar moons. Since 2004 gravitational microlensing has been successfully applied as a detection method for extrasolar planets. In principle, the method is sensitive to masses as low as an Earth mass or even a fraction of it. Hence it seems natural to investigate the microlensing effects of moons around extrasolar planets. We explore the simplest conceivable triple lens system, containing one star, one planet and one moon. From a microlensing point of view, this system can be modelled as a particular triple with hierarchical mass ratios very different from unity. Since the moon orbits the planet, the planet-moon separation will be small compared to the distance between planet and star. Such a configuration can lead to a complex interference of caustics. We present detectability and detection limits by comparing triple-lens light curves to best-fit binary light curves as caused by a double-lens system consisting of host star and planet -...

  8. Improved Laboratory Transition Probabilities for Ce II, Application to the Cerium Abundances of the Sun and Five r-process Rich, Metal-Poor Stars, and Rare Earth Lab Data

    CERN Document Server

    Lawler, J E; Cowan, J J; Ivans, I I; Hartog, E A Den

    2009-01-01

    Recent radiative lifetime measurements accurate to +/- 5% using laser-induced fluorescence (LIF) on 43 even-parity and 15 odd-parity levels of Ce II have been combined with new branching fractions measured using a Fourier transform spectrometer (FTS) to determine transition probabilities for 921 lines of Ce II. This improved laboratory data set has been used to determine a new solar photospheric Ce abundance, log epsilon = 1.61 +/- 0.01 (sigma = 0.06 from 45 lines), a value in excellent agreement with the recommended meteoritic abundance, log epsilon = 1.61 +/- 0.02. Revised Ce abundances have also been derived for the r-process-rich metal-poor giant stars BD+17 3248, CS 22892-052, CS 31082-001, HD 115444 and HD 221170. Between 26 and 40 lines were used for determining the Ce abundance in these five stars, yielding a small statistical uncertainty of 0.01 dex similar to the Solar result. The relative abundances in the metal-poor stars of Ce and Eu, a nearly pure r-process element in the Sun, matches r-process ...

  9. The moons of Saturn

    Science.gov (United States)

    Soderblom, L. A.; Johnson, T. V.

    1982-01-01

    Knowledge gained of the 17 Saturn moons with observations by the Voyager spacecraft are reviewed. Titan was found to have the only atmosphere, which is opaque and precludes geologic inferences. Synchronous rotation is experienced by the 14 inner moons, with a constant inner face turned toward the planet. Phoebe is too far away from the planet to lose its spin to planetary tidal forces, and has an orbit inclined 150 deg from the equatorial plane, while Iapetus is inclined 14.7 deg in its orbit. The abundance of ice on the moons is accepted as evidence of condensation formation of the moons at very low temperatures. Newly discovered moons of Saturn, including both the shepherd moons, which are suspected to maintain the rings in place, and the moons discovered by earth-based astronomy, are discussed. Finally, photographs of all the moons are examined for definitive details.

  10. Magnetic activity and hot Jupiters of young Suns: the weak-line T Tauri stars V819 Tau and V830 Tau

    CERN Document Server

    Donati, JF; Hussain, G; Moutou, C; Malo, L; Grankin, K; Vidotto, AA; Alencar, SHP; Gregory, SG; Jardine, MM; Herczeg, G; Morin, J; Fares, R; Ménard, F; Bouvier, J; Delfosse, X; Doyon, R; Takami, M; Figueira, P; Petit, P; Boisse, I

    2015-01-01

    We report results of a spectropolarimetric and photometric monitoring of the weak-line T Tauri stars (wTTSs) V819 Tau and V830 Tau within the MaTYSSE programme, involving the ESPaDOnS spectropolarimeter at the Canada-France-Hawaii Telescope. At ~3 Myr, both stars dissipated their discs recently and are interesting objects for probing star and planet formation. Profile distortions and Zeeman signatures are detected in the unpolarized and circularly-polarized lines, whose rotational modulation we modelled using tomographic imaging, yielding brightness and magnetic maps for both stars. We find that the large-scale magnetic fields of V819 Tau and V830 Tau are mostly poloidal and can be approximated at large radii by 350-400 G dipoles tilted at ~30 degrees to the rotation axis. They are significantly weaker than the field of GQ Lup, an accreting classical T Tauri star (cTTS) with similar mass and age which can be used to compare the magnetic properties of wTTSs and cTTSs. The reconstructed brightness maps of both ...

  11. Under a Harvest Moon

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    When it comes to expressing adoration for a loved one,doing it under the light of a full moon is guaranteed to score mega romantic points.In China,at Mid-Autumn Festival the moon is the guest of honor and along with a connection of hearts comes a nation’s insatiable desire for moon cakes. Second in importance only to the Chinese New Year, Mid-Autumn Festival,also known as Moon Festival,has

  12. Hysteresis Effect in the Activity Indices of the Atmospheres of the Sun and Solar-Type Stars During the Rising and Falling Phases of Cycles

    Science.gov (United States)

    Bruevich, E. A.; Yakunina, G. V.

    2016-09-01

    The hysteresis effect that shows up as a nonunique relationship among the emissions from the photosphere, chromosphere, and corona during the rising and falling phases of solar and stellar activity is analyzed. The following solar indices are analyzed and compared in different phases of the cycle: the radiative flux in the hydrogen Lyman alpha line FLα, radio emission at 10.7 cm F10.7, the sunspot number SSN, the radiative flux in the 530.0 nm green coronal line F530.3, the solar constant TSI, and the relative flux ratio c/w (ratio of the fluxes in the center and in the wings) for the 280 nm Mg II line. In stars with cycles, a hysteresis effect is observed between the CaII chromospheric S-activity index for stars in the Mount Wilson HK project and the photospheric flux Fph for these stars.

  13. The Mount Wilson Observatory S-index of the Sun

    CERN Document Server

    Egeland, Ricky; Baliunas, Sallie; Hall, Jeffrey C; Pevtsov, Alexei A; Bertello, Luca

    2016-01-01

    The most commonly used index of stellar magnetic activity is the instrumental flux scale of singly-ionized calcium H & K line core emission, S, developed by the Mount Wilson Observatory (MWO) HK Project, or the derivative index R'_HK. Accurately placing the Sun on the S scale is important for comparing solar activity to that of the Sun-like stars. We present previously unpublished measurements of the reflected sunlight from the Moon using the second-generation MWO HK photometer during solar cycle 23 and determine cycle minimum S_min,23 = 0.1634 +/- 0.0008, amplitude Delta S_23 = 0.0143 +/- 0.0015, and mean = 0.1701 +/- 0.0005. By establishing a proxy relationship with the closely related National Solar Observatory Sacramento Peak calcium K emission index, itself well-correlated with the Kodaikanal Observatory plage index, we extend the MWO S time series to cover cycles 15-24 and find on average = 0.1621 +/- 0.0008, = 0.0145 +/- 0.0012, = 0.1694 +/- 0.0005. Our measurements represent an improvement ove...

  14. The Moon in the 14th Century Frescoes in Padova

    Science.gov (United States)

    Bellinati, Claudio

    Padova, already in the 14th century a great cultural center of international reputation, struggled with the problems posed by the Moon with Pietro d'Abano, physician and astronomer. But it was with the great painters of that time, namely Giotto and Giusto de'Menabuoi, that its most intimate connections with the contemporary popular culture and theology were illustrated. Giotto depicts the Moon in the Giudizio Universale of the Scrovegni Chapel (1305). The Moon appears on the upper part of the painting, to the left of Christ the Judge, to crown together with the Sun, His presence. The Moon is a heavenly body similar to those appearing on Roman coins of emperors, to signify the Judge is an immortal creature. The color is pale, witeish, almost veiled. More important, the Moon has a face that by popular belief was that of Cain, condemned to amass `mucchi di rovi spinosi' for the fire of the damned (Dante Alighieri, Divina Commedia, Inferno XX, 126). Giusto de' Menabuoi on the other hand expounds, in the Crucifixion of the Duomo (1375 ca), a theological interpretation. The day of God's justice, following the death of the Savior, the Moon will burn and the Sun will pale (Isaiah, 24, 23). And indeed the Moon has a dark reddish colour. Therefore, while in Giotto the Moon is seen as in the popular beliefs, Giusto underlines the theological visions of his times with the words of the prophets.

  15. Perceptions about Moon Phases.

    Science.gov (United States)

    Rider, Steven

    2002-01-01

    Presents research on different techniques to determine the level of understanding among middle school students regarding the phases of the moon. Quotes student responses to provide some insight into students' level of understanding of general knowledge about the moon, moon phases, and modeling the phases. Presents implications for teachers. (KHR)

  16. A Note on Dynamics About the Coherent Sun–Earth–Moon Collinear Libration Points

    Science.gov (United States)

    Olikara, Zubin P.; Gómez, Gerard; Masdemont, Josep J.

    Orbits about the Sun-Earth libration points are perturbed by the Moon, and orbits about the Earth-Moon libration points are perturbed by the Sun. We study both situations in the framework of a single, coherent model, the Hill restricted four-body problem. This model is presented in a Sun-Earth rotating reference frame to complement its earlier Earth-Moon frame formulation. We provide an overview of the planar quasi-periodic orbits that originate from the L 1 and L 2 Lyapunov periodic orbits in Hill's problem and the circular restricted three-body problem. The role of resonances is also discussed.

  17. The Extreme Ultraviolet and X-Ray Sun in Time: High-Energy Evolutionary Tracks of a Solar-Like Star

    CERN Document Server

    Tu, Lin; Güdel, Manuel; Lammer, Helmut

    2015-01-01

    Aims. We aim to describe the pre-main sequence and main-sequence evolution of X-ray and extreme-ultaviolet radiation of a solar mass star based on its rotational evolution starting with a realistic range of initial rotation rates. Methods. We derive evolutionary tracks of X-ray radiation based on a rotational evolution model for solar mass stars and the rotation-activity relation. We compare these tracks to X-ray luminosity distributions of stars in clusters with different ages. Results. We find agreement between the evolutionary tracks derived from rotation and the X-ray luminosity distributions from observations. Depending on the initial rotation rate, a star might remain at the X-ray saturation level for very different time periods, approximately from 10 Myr to 300 Myr for slow and fast rotators, respectively. Conclusions. Rotational evolution with a spread of initial conditions leads to a particularly wide distribution of possible X-ray luminosities in the age range of 20 to 500 Myrs, before rotational co...

  18. The extreme ultraviolet and X-ray Sun in Time: High-energy evolutionary tracks of a solar-like star

    Science.gov (United States)

    Tu, Lin; Johnstone, Colin P.; Güdel, Manuel; Lammer, Helmut

    2015-05-01

    Aims: We aim to describe the pre-main-sequence and main-sequence evolution of X-ray and extreme-ultaviolet radiation of a solar-mass star based on its rotational evolution starting with a realistic range of initial rotation rates. Methods: We derive evolutionary tracks of X-ray radiation based on a rotational evolution model for solar-mass stars and the rotation-activity relation. We compare these tracks to X-ray luminosity distributions of stars in clusters with different ages. Results: We find agreement between the evolutionary tracks derived from rotation and the X-ray luminosity distributions from observations. Depending on the initial rotation rate, a star might remain at the X-ray saturation level for very different time periods, from ≈10 Myr to ≈300 Myr for slow and fast rotators, respectively. Conclusions: Rotational evolution with a spread of initial conditions leads to a particularly wide distribution of possible X-ray luminosities in the age range of 20-500 Myr, before rotational convergence and therefore X-ray luminosity convergence sets in. This age range is crucial for the evolution of young planetary atmospheres and may thus lead to very different planetary evolution histories.

  19. 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

  20. Modelling the magnetic activity & filtering radial velocity curves of young Suns: the weak-line T Tauri star LkCa 4

    CERN Document Server

    Donati, J -F; Hussain, G; Moutou, C; Grankin, K; Boisse, I; Morin, J; Gregory, S G; Vidotto, A A; Bouvier, J; Alencar, S H P; Delfosse, X; Doyon, R; Takami, M; Jardine, M M; Fares, R; Cameron, A C; Menard, F; Dougados, C; Herczeg, G

    2014-01-01

    We report results of a spectropolarimetric and photometric monitoring of the weak-line T Tauri star LkCa4 within the MaTYSSE programme, involving ESPaDOnS at the Canada-France-Hawaii Telescope. Despite an age of only 2Myr and a similarity with prototypical classical T Tauri stars, LkCa4 shows no evidence for accretion and probes an interesting transition stage for star and planet formation. Large profile distortions and Zeeman signatures are detected in the unpolarized and circularly-polarized lines of LkCa4 using Least-Squares Deconvolution (LSD), indicating the presence of brightness inhomogeneities and magnetic fields at the surface of LkCa4. Using tomographic imaging, we reconstruct brightness and magnetic maps of LkCa4 from sets of unpolarized and circularly-polarized LSD profiles. The large-scale field is strong and mainly axisymmetric, featuring a ~2kG poloidal component and a ~1kG toroidal component encircling the star at equatorial latitudes - the latter making LkCa4 markedly different from classical...

  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. Evolutionary tracks and isochrones for low- and intermediate-mass stars from 0.15 to 7 M$_sun$, and from Z=0.0004 to 0.03

    CERN Document Server

    Girardi, L; Bertelli, G; Chiosi, C; Girardi, Leo; Bressan, Alessandro; Bertelli, Gianpaolo; Chiosi, Cesare

    2000-01-01

    We present a large grid of stellar evolutionary tracks, which are suitable to modelling star clusters and galaxies by means of population synthesis. The tracks are presented for the initial chemical compositions [Z=0.0004, Y=0.23], [Z=0.001, Y=0.23], [Z=0.004, Y=0.24], [Z=0.008, Y=0.25], [Z=0.019, Y=0.273] (solar composition), and [Z=0.03, Y=0.30]. They are computed with updated opacities and equation of state, and a moderate amount of convective overshoot. The range of initial masses goes from 0.15 M_sun to 7 M_sun, and the evolutionary phases extend from the zero age main sequence (ZAMS) till either the thermally pulsing AGB regime or carbon ignition. We also present an additional set of models with solar composition, computed using the classical Schwarzschild's criterion for convective boundaries. From all these tracks, we derive the theoretical isochrones in the Johnson-Cousins UBVRIJHK broad-band photometric system.

  3. Neptune as a Mirror for the Sun

    Science.gov (United States)

    Kohler, Susanna

    2017-01-01

    How would the Kepler mission see a star like the Sun? We now know the answer to this question due to a creative approach: a new study has used the Kepler K2 mission to detect signals from the Sun reflected off of the surface of Neptune.Asteroseismology uses different oscillation modes of a star to probe its internal structure and properties. [Tosaka]Information in OscillationsKeplers most glamorous work is in discovering new planets around other stars. To successfully do this, however, the spacecraft is also quietly doing a lot of very useful work in the background, characterizing the many stars in our vicinity that planets might be found around.One of the ways Kepler gets information about these stars is from oscillations of the stars intensities. In asteroseismology, we look at oscillatory modes that are caused by convection-driven pressure changes on the inside of the star. All stars with near-surface convection oscillate like this including the Sun and by measuring the oscillations in intensity of these stars, we can make inferences about the stars properties.A Planetary MirrorWe do this by first understanding our Suns oscillations especially well (made easier by the fact that its nearby!). Then we use asteroseimic scaling relations determined empirically that relate characteristics like mass and radius of other stars to those of the Sun, based on the relation between the stars oscillation properties to the Suns.The trouble is, those oscillation properties are difficult to measure, and different instruments often measure different values. For this reason, wed like to measure the Suns oscillations with the same instrument we use to measure other stars oscillations: Kepler.Top panel: Kepler K2 49-day light curve of Neptune. Bottom panel: power density spectrum as a function of frequency (grey). Neptunes rotation frequencies and harmonics appear toward the left side (blue); the excess power due to the solar modes is visible toward the bottom right. The green curve

  4. Extrasolar Comets in our Solar System Captured During Close Encounters with Nearby Stars?

    Science.gov (United States)

    Rocca, M. C. L.; Acevedo, R. D.

    2014-09-01

    It is a fact that many nearby Sun like stars have their own cometary clouds. Close encounters with passing nearby stars may induce to the capture and exchange of cometary nuclei between the Sun and the coming star.

  5. 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

  6. Improved Laboratory Transition Probabilities for Er II and Applications to the Erbium Abundances of the Sun and Five r-Process Rich, Metal-Poor Stars

    CERN Document Server

    Lawler, J E; Cowan, J J; Wyart, J -F; Ivans, I I; Sobeck, J S; Stockett, M H; Hartog, E A Den

    2008-01-01

    Recent radiative lifetime measurements accurate to +/- 5% (Stockett et al. 2007, J. Phys. B 40, 4529) using laser-induced fluorescence (LIF) on 8 even-parity and 62 odd-parity levels of Er II have been combined with new branching fractions measured using a Fourier transform spectrometer (FTS) to determine transition probabilities for 418 lines of Er II. This work moves Er II onto the growing list of rare earth spectra with extensive and accurate modern transition probability measurements using LIF plus FTS data. This improved laboratory data set has been used to determine a new solar photospheric Er abundance, log epsilon = 0.96 +/- 0.03 (sigma = 0.06 from 8 lines), a value in excellent agreement with the recommended meteoric abundance, log epsilon = 0.95 +/- 0.03. Revised Er abundances have also been derived for the r-process-rich metal-poor giant stars CS 22892-052, BD+17 3248, HD 221170, HD 115444, and CS 31082-001. For these five stars the average Er/Eu abundance ratio, = 0.42, is in very good agreement ...

  7. 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

  8. The Impact of Stereo Display on Student Understanding of Phases of the Moon

    Science.gov (United States)

    Cid, Ximena C.; Lopez, Ramon E.

    2010-01-01

    Understanding lunar phases requires three-dimensional information about the relative positions of the Moon, Earth, and Sun, thus using a stereo display in instruction might improve student comprehension of lunar phases or other topics in basic astronomy. We conducted a laboratory (15 sections) on phases of the Moon as part of the introductory…

  9. Earth-Affecting Solar Causes Observatory (EASCO): A Potential International Living with a Star Mission from Sun-Earth L5

    Science.gov (United States)

    Gopalswamy, N.; Davila, J. M.; St Cyr, O. C.; Sittler, E. C.; Auchere, F.; Duvall, Jr. T. L.; Hoeksema, J. T.; Maksimovic, M.; MacDowall, R. J.; Szabo, A.; Collier, M. R.

    2011-01-01

    This paper describes the scientific rationale for an L5 mission and a partial list of key scientific instruments the mission should carry. The L5 vantage point provides an unprecedented view of the solar disturbances and their solar sources that can greatly advance the science behind space weather. A coronagraph and a heliospheric imager at L5 will be able to view CMEs broadsided, so space speed of the Earth-directed CMEs can be measured accurately and their radial structure discerned. In addition, an inner coronal imager and a magnetograph from L5 can give advance information on active regions and coronal holes that will soon rotate on to the solar disk. Radio remote sensing at low frequencies can provide information on shock-driving CMEs, the most dangerous of all CMEs. Coordinated helioseismic measurements from the Sun Earth line and L5 provide information on the physical conditions at the base of the convection zone, where solar magnetism originates. Finally, in situ measurements at L5 can provide information on the large-scale solar wind structures (corotating interaction regions (CIRs)) heading towards Earth that potentially result in adverse space weather.

  10. 太阳同步轨道星敏感器热设计典型工况确定%Typical work states analysis on thermal design of the sun-synchronous orbit star sensors

    Institute of Scientific and Technical Information of China (English)

    关奉伟

    2015-01-01

    以某太阳同步轨道卫星星敏感器为例,阐述了热环境分析、外热流计算、典型工况条件确定以及热试验模拟的全过程。首先,分析了星敏感器所处的内、外部热环境,确定了其温度水平的主要影响因素。其次,进行了星敏感器通光孔到达外热流的计算,确定了典型工况的工况条件。然后,制定了星敏感器热平衡试验外热流的模拟方案,利用闭环程控系统进行外热流加载。最后,依据星敏感器自身特点,提出了热试验外热流的加载策略。典型工况条件的确定合理可行。%The whole process of thermal environment analysis,space heat flux calculation,typical work states analysis and heat flux simulation for thermal test is expatiated for a given star sensors working on sun-synchronous orbit.Firstly,the inner and outer thermal environments of the star sensors were analyzed,and the main influential fac-tors on temperature level were determined.Secondly,heat fluxes that reach the given star sensors were calculated,and the typical work state conditions were obtained.Thirdly,the space heat flux simulation scheme of heat balance test was determined,and closed loop programmable system was applied to load heat flux.Finally,the space heat flux simulation method and tactic of thermal test is proposed according to the characteristics of the star sensors.It proves that the typi-cal work states are rational and feasible.

  11. The SOPHIE search for northern extrasolar planets. V. Follow-up of ELODIE candidates: Jupiter-analogs around Sun-like stars

    Science.gov (United States)

    Boisse, I.; Pepe, F.; Perrier, C.; Queloz, D.; Bonfils, X.; Bouchy, F.; Santos, N. C.; Arnold, L.; Beuzit, J.-L.; Díaz, R. F.; Delfosse, X.; Eggenberger, A.; Ehrenreich, D.; Forveille, T.; Hébrard, G.; Lagrange, A.-M.; Lovis, C.; Mayor, M.; Moutou, C.; Naef, D.; Santerne, A.; Ségransan, D.; Sivan, J.-P.; Udry, S.

    2012-09-01

    We present radial-velocity measurements obtained in one of a number of programs underway to search for extrasolar planets with the spectrograph SOPHIE at the 1.93-m telescope of the Haute-Provence Observatory. Targets were selected from catalogs observed with ELODIE, which had been mounted previously at the telescope, in order to detect long-period planets with an extended database close to 15 years. Two new Jupiter-analog candidates are reported to orbit the bright stars HD 150706 and HD 222155 in 16.1 yr and 10.9 yr at 6.7-1.4+4.0 AU and 5.1-0.7+0.6 AU, and to have minimum masses of 2.71-0.66+1.14 MJup and 1.90-0.53+0.67 MJup, respectively. Using the measurements from ELODIE and SOPHIE, we refine the parameters of the long-period planets HD 154345b and HD 89307b, and publish the first reliable orbit for HD 24040b. This last companion has a minimum mass of 4.01 ± 0.49 MJup orbiting its star in 10.0 yr at 4.92 ± 0.38 AU. Moreover, the data provide evidence of a third bound object in the HD 24040 system. With a surrounding dust debris disk, HD 150706 is an active G0 dwarf for which we partially corrected the effect of the stellar spot on the SOPHIE radial-velocities. In contrast, HD 222155 is an inactive G2V star. In the SOPHIE measurements, an instrumental effect could be characterized and partly corrected. On the basis of the previous findings of Lovis and collaborators and since no significant correlation between the radial-velocity variations and the activity index are found in the SOPHIE data, these variations are not expected to be only due to stellar magnetic cycles. Finally, we discuss the main properties of this new population of long-period Jupiter-mass planets, which for the moment consists of fewer than 20 candidates. These stars are preferential targets either for direct-imaging or astrometry follow-up surveys to constrain the system parameters and for higher-precision radial-velocity searches for lower mass planets, aiming to find a solar system twin

  12. Tower To The Moon

    Institute of Scientific and Technical Information of China (English)

    ShirleeP.Newman; 黄献党

    2002-01-01

    There was once a king who was different from other kings. Instead of sitting on a high throne(王位、宝座),this king liked to sit outside and lood at the moon. He would sit for hours, just looking at the moon and wondering what it would be like to go there.

  13. Accretion of the Moon from non-canonical discs.

    Science.gov (United States)

    Salmon, J; Canup, R M

    2014-09-13

    Impacts that leave the Earth-Moon system with a large excess in angular momentum have recently been advocated as a means of generating a protolunar disc with a composition that is nearly identical to that of the Earth's mantle. We here investigate the accretion of the Moon from discs generated by such 'non-canonical' impacts, which are typically more compact than discs produced by canonical impacts and have a higher fraction of their mass initially located inside the Roche limit. Our model predicts a similar overall accretional history for both canonical and non-canonical discs, with the Moon forming in three consecutive steps over hundreds of years. However, we find that, to yield a lunar-mass Moon, the more compact non-canonical discs must initially be more massive than implied by prior estimates, and only a few of the discs produced by impact simulations to date appear to meet this condition. Non-canonical impacts require that capture of the Moon into the evection resonance with the Sun reduced the Earth-Moon angular momentum by a factor of 2 or more. We find that the Moon's semi-major axis at the end of its accretion is approximately 7R⊕, which is comparable to the location of the evection resonance for a post-impact Earth with a 2.5 h rotation period in the absence of a disc. Thus, the dynamics of the Moon's assembly may directly affect its ability to be captured into the resonance.

  14. Transits of extrasolar moons around luminous giant planets

    CERN Document Server

    Heller, René

    2016-01-01

    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 ($\\gtrsim10$ 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 H$_2$O-rich moon around $\\beta$ Pic b would have a transit depth of $1.5\\times10^{-3}$, in reach of near-future technology.

  15. The Sun's New Exotic Neighbour

    Science.gov (United States)

    2006-03-01

    Using ESO's Very Large Telescope in Chile, an international team of researchers [1] discovered a brown dwarf belonging to the 24th closest stellar system to the Sun. Brown dwarfs are intermediate objects that are neither stars nor planets. This object is the third closest brown dwarf to the Earth yet discovered, and one of the coolest, having a temperature of about 750 degrees Celsius. It orbits a very small star at about 4.5 times the mean distance between the Earth and the Sun. Its mass is estimated to be somewhere between 9 and 65 times the mass of Jupiter. At a time when astronomers are peering into the most distant Universe, looking at objects as far as 13 billion light-years away, one may think that our close neighbourhood would be very well known. Not so. Astronomers still find new star-like objects in our immediate vicinity. Using ESO's VLT, they just discovered a brown dwarf companion to the red star SCR 1845-6357, the 36th closest star to the Sun. ESO PR Photo 11/06 ESO PR Photo 11a/06 New Brown Dwarf in the Solar Neighbourhood (Artist's Impression) "This newly found brown dwarf is a valuable object because its distance is well known, allowing us to determine with precision its intrinsic brightness", said team member Markus Kasper (ESO). "Moreover, from its orbital motion, we should be able in a few years to estimate its mass. These properties are vital for understanding the nature of brown dwarfs." To discover this brown dwarf, the team used the high-contrast adaptive optics NACO Simultaneous Differential Imager (SDI [2]) on ESO's Very Large Telescope, an instrument specifically developed to search for extrasolar planets. The SDI camera enhances the ability of the VLT and its adaptive optics system to detect faint companions that would normally be lost in the glare of the primary star. In particular, the SDI camera provides additional, often very useful spectral information which can be used to determine a rough temperature for the object without follow

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

    CERN Document Server

    Borucki, William J; Batalha, Natalie; Bryson, Stephen T; Caldwell, Douglas A; Christensen-Dalsgaard, Jørgen; Cochran, William D; DeVore, Edna; Gautier, Thomas N; Geary, John C; Gilliland, Ronald; Gould, Alan; Howell, Steve B; Jenkins, Jon M; Latham, David W; Lissauer, Jack J; Marcy, Geoffrey W; Rowe, Jason; Sasselov, Dimitar; Boss, Alan; Charbonneau, David; Ciardi, David; Torres, Guillermo; Fressin, Francois; Kaltenegger, Lisa; Doyle, Laurance; Dupree, Andrea K; Ford, Eric B; Fortney, Jonathan; Holman, Matthew J; Steffen, Jason A; Mullally, Fergal; Still, Martin; Tarter, Jill; Ballard, Sarah; Buchhave, Lars A; Carter, Josh; Christiansen, Jessie L; Demory, Brice-Olivier; Désert, Jean-Michel; Dressing, Courtney; Endl, Michael; Fabrycky, Daniel; Fischer, Debra; Haas, Michael R; Henze, Christopher; Horch, Elliott; Howard, Andrew W; Isaacson, Howard; Kjeldsen, Hans; Johnson, John Asher; Klaus, Todd; Kolodziejczak, Jeffery; Barclay, Thomas; Li, Jie; Meibom, Søren; Prsa, Andrej; Quinn, Samuel N; Quintana, Elisa V; Robertson, Paul; Sherry, William; Shporer, Avi; Tenenbaum, Peter; Thompson, Susan E; Twicken, Joseph D; Van Cleve, Jeffrey; Welsh, William F; Basu, Sarbani; Chaplin, Bill; Miglio, Andrea; Kawaler, Steve; Arentoft, Torben; Stello, Dennis; Metcalfe, Travis S; Verner, Graham; Karoff, Christoffer; Lundkvist, Mia; Lund, Mikkel; Handberg, Rasmus; Elsworth, Yvonne; Hekker, Saskia; Huber, Daniel; Bedding, Timothy R

    2011-01-01

    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 asteroseismic analysis of the Kepler photometry, leading to an estimated mass and radius of 0.970 +/- 0.060 MSun and 0.979 +/- 0.020 RSun. The depth of 492 +/- 10ppm for the three observed transits yields a radius of 2.38 +/- 0.13 REarth for the planet. The system passes a battery of tests for false positives, including reconnaissance spectroscopy, high-resolution imaging, and centroid motion. A full BLENDER analysis provides further validation of the planet interpretation by showing that contamination of the target by an eclipsing system would rarely mimic the observed shape of the transits. The final validation of the planet is provided by 16 radial velocities obtained with HIRES on Keck 1 over a one year span. Although t...

  17. The long-period librations of large synchronous icy moons

    Science.gov (United States)

    Yseboodt, Marie; Van Hoolst, Tim

    2014-11-01

    A moon in synchronous rotation has longitudinal librations because of its non-spherical mass distribution and its elliptical orbit around the planet. We study the long-period librations of the Galilean satellites and Titan and include deformation effects and the existence of a subsurface ocean. We take into account the fact that the orbit is not keplerian and has other periodicities than the main period of orbital motion around Jupiter or Saturn due to perturbations by the Sun, other planets and moons. An orbital theory is used to compute the orbital perturbations due to these other bodies. For Titan we also take into account the large atmospheric torque at the semi-annual period of Saturn around the Sun.We numerically evaluate the amplitude and phase of the long-period librations for many interior structure models of the icy moons constrained by the mass, radius and gravity field.

  18. A Mixture of Ancient and Modern Understanding Concerning the Distance and Motion of the Moon

    CERN Document Server

    Krisciunas, Kevin

    2013-01-01

    Ptolemy's model of the Moon's motion implied that its distance varies by nearly a factor of two, implying that its angular size should also vary by nearly a factor of two. We present an analysis of 100 naked eye observations of the Moon's angular size obtained over 1145 days, showing regular variations of at least 3 arc minutes. Thus, ancient astronomers could have shown that a key implication of Ptolemy's model was wrong. In modern times we attribute the variation of distance of the Moon to the combined effect of the ellipticity of the Moon's orbit and the perturbing effect of the Sun on the Earth-Moon system. We show graphically how this affects the ecliptic longitudes and radial distance of the Moon. The longitude and distance "anomalies" are correlated with the Moon's phase. This is illustrated without any complex equations or geometry.

  19. 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.

  20. Transit Model of Planets with Moon and Ring System

    CERN Document Server

    Tusnski, Luis Ricardo M; 10.1088/0004-637X/743/1/97

    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 planetar...

  1. The Moon Village Concept

    Science.gov (United States)

    Messina, Piero; Foing, Bernard H.; Hufenbach, Bernhard; Haignere, Claudie; Schrogl, Kai-Uwe

    2016-07-01

    The "Moon Village" concept Space exploration is anchored in the International Space Station and in the current and future automatic and planetary automatic and robotic missions that pave the way for future long-term exploration objectives. The Moon represents a prime choice for scientific, operational and programmatic reasons and could be the enterprise that federates all interested Nations. On these considerations ESA is currently elaborating the concept of a Moon Village as an ensemble where multiple users can carry out multiple activities. The Moon Village has the ambition to serve a number of objectives that have proven to be of interest (including astronomy, fundamental research, resources management, moon science, etc. ) to the space community and should be the catalyst of new alliances between public and private entities including non-space industries. Additionally the Moon Village should provide a strong inspirational and education tool for the younger generations . The Moon Village will rely both on automatic, robotic and human-tendered structures to achieve sustainable moon surface operations serving multiple purposes on an open-architecture basis. This Europe-inspired initiative should rally all communities (across scientific disciplines, nations, industries) and make it to the top of the political agendas as a the scientific and technological undertaking but also political and inspirational endeavour of the XXI century. The current reflections are of course based on the current activities and plans on board the ISS and the discussion held in international fora such as the ISECG. The paper will present the status of these reflections, also in view of the ESA Council at Ministerial Level 2016, and will give an overview of the on-going activities being carried out to enable the vision of a Moon Village.

  2. Introducing the Moon's Orbital Eccentricity

    Science.gov (United States)

    Oostra, Benjamin

    2014-11-01

    I present a novel way to introduce the lunar orbital eccentricity in introductory astronomy courses. The Moon is perhaps the clearest illustration of the general orbital elements such as inclination, ascending node, eccentricity, perigee, and so on. Furthermore, I like the students to discover astronomical phenomena for themselves, by means of a guided exercise, rather than just telling them the facts.1 The inclination and nodes may be found by direct observation, monitoring carefully the position of the Moon among the stars. Even the regression of the nodes may be discovered in this way2 To find the eccentricity from students' observations is also possible,3 but that requires considerable time and effort. if a whole class should discover it in a short time, here is a method more suitable for a one-day class or home assignment. The level I aim at is, more or less, advanced high school or first-year college students. I assume them to be acquainted with celestial coordinates and the lunar phases, and to be able to use algebra and trigonometry.

  3. Shoot the Moon

    Science.gov (United States)

    Dupont-Bloch, Nicolas

    2016-11-01

    1. Introducing lunar imaging; 2. Choosing your imaging equipment; 3. Adapting your image device to the instrument; 4. Tuning your telescope for lunar imaging; 5. Wide-field, lunar imaging; 6. High-resolution, lunar imaging; 7. Essential image processing; 8. Advanced image processing; 9. Making 3D lunar images; 10. Measuring and identifying lunar features; 11. Photogenic features of the Moon; 12. Naming, archiving, printing and sharing lunar images; Appendix: maps of the Moon, Lunar 100 and other targets; Web pages, books and freeware for the Moon; Figure data; Index.

  4. Origin of earth's moon

    Science.gov (United States)

    Wood, J. A.

    1977-01-01

    The major geochemical properties of the moon are briefly considered along with the significant facts of the moon's geologic history, and then the three current hypotheses regarding the moon's origin, namely, fission, capture, and binary accretion, are reviewed. The individual merits and improbabilities associated with each mechanism are taken into consideration. Special attention is given to the binary accretion model as the most promising one. In the variants of this model, of crucial importance is the nature of the more general hypothesis assumed for planetary formation from the solar nebula. The two main models differ considerably in the amount of chemical fractionation they allow to accompany planetary formation.

  5. Moons around Jupiter

    Science.gov (United States)

    2007-01-01

    The New Horizons Long Range Reconnaissance Imager (LORRI) took this photo of Jupiter at 20:42:01 UTC on January 9, 2007, when the spacecraft was 80 million kilometers (49.6 million miles) from the giant planet. The volcanic moon Io is to the left of the planet; the shadow of the icy moon Ganymede moves across Jupiter's northern hemisphere. Ganymede's average orbit distance from Jupiter is about 1 million kilometers (620,000 miles); Io's is 422,000 kilometers (262,000 miles). Both Io and Ganymede are larger than Earth's moon; Ganymede is larger than the planet Mercury.

  6. Alternative paths to Earth-Moon transfer

    Directory of Open Access Journals (Sweden)

    2006-01-01

    Full Text Available The planar, circular, restricted three-body problem predicts the existence of periodic orbits around the Lagrangian equilibrium point L1. Considering the Earth-lunar-probe system, some of these orbits pass very close to the surfaces of the Earth and the Moon. These characteristics make it possible for these orbits, in spite of their instability, to be used in transfer maneuvers between Earth and lunar parking orbits. The main goal of this paper is to explore this scenario, adopting a more complex and realistic dynamical system, the four-body problem Sun-Earth-Moon-probe. We defined and investigated a set of paths, derived from the orbits around L1, which are capable of achieving transfer between low-altitude Earth (LEO and lunar orbits, including high-inclination lunar orbits, at a low cost and with flight time between 13 and 15 days.

  7. The Appearance of the Sun and Moon Seen Through Clouds

    Science.gov (United States)

    1993-12-01

    relevant conferences, I received valuable insight on my research from David Lynch , William Livingston, and others whose names I do not recall. I must...angular width. A remark by David Lynch at the 1993 Optical Society of America Topical Meeting on Light and Color in the Open Air that he had never seen a

  8. The Global Strategy of "Sun and Moon in Daming Palace"

    Institute of Scientific and Technical Information of China (English)

    Sun Donghai

    2010-01-01

    @@ As the most splendid and magnificent architectural complex in Chang'an city,the world renowned capital of the Tang Empire,Daming Palace once served as the office and living place for 17 emperors of the Tang Dynasty.Daming Palace heritage is the national key cultural relics protection unit,and also an archaeological treasure house of palace architectures of the Tang Dynasty.

  9. 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...

  10. Santa and the moon

    CERN Document Server

    Barthel, Peter

    2011-01-01

    Happy end-of-the-year evening and night events provide good opportunities to explain the phases of the moon. The need for such moon phase education is once again demonstrated, through an investigation of illustrations on Santa Claus and Christmas gift wrap and in children's books, in two countries which have been important in shaping the image of Santa Claus and his predecessor Sinterklaas: The Netherlands and the USA. The moon on Halloween illustrations is also considered. The lack of knowledge concerning the physical origin of the moon phases, or lack of interest in understanding, is found to be widespread in The Netherlands but is also clearly present in the USA, and is quite possibly global. Definitely incomplete, but surely representative lists compiling both scientifically correct and scientifically incorrect gift wrap and children's books are also presented.

  11. 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

  12. Under a Harvest Moon

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    When it comes to expressing adoration for a loved one,doing it under the light of a full moon is guaranteed to score mega romantic points.In China,at MidAutumn Festival the moon is the guest of honor and along with a connection of hearts comes a nation's insatiable desire for moon cakes.Second in importance only to the Chinese New Year,Mid-Autumn Festival,also known as Moon Festival,has as its focus the reunion of families and loved ones.As an officially sanctioned one day holiday,it has therefore developed over time into a gathering of family members living in the same city - and for those split by distance,it's become a lunar connection.

  13. Geometry and Moon Phases.

    Science.gov (United States)

    Thompson, Kenneth W.; Harrell, Marvin E.

    1997-01-01

    Describes an activity, designed to comply with the National Science Education Standards, that integrates science and mathematics concepts. Mathematical modeling of the moon's phases is employed to show students the role of mathematics in describing scientific phenomena. (DKM)

  14. Map of the Moon

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    China releases data about the Moon collected its first lunar probe China has finished the full map of the Moon based on data obtained by its lunar probe Chang ’e 1,said Ouyang Ziyuan,chief scientist of China’s lunar exploration program and an academician at the Chinese Academy of Sciences (CAS),at a press conference about the scientific achievements made by Chang’e 1 on July 16,2010.

  15. 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.

  16. Three in one: The model of Sun–Earth–Moon

    Directory of Open Access Journals (Sweden)

    Ünal İbrahim

    2016-01-01

    Full Text Available The purpose of this study is to develop a Sun-Earth-Moon model which will be used in describing fundamental topics of astronomy, hardly understood correctly because of their three dimensional and complicated nature. Abstract and complex frame of science is the most significant obstacle against comprehension of scientific topics. Students have difficulties in explaining the meaning of the events that they cannot see, hear and touch, and they cannot relate the events and the information they have. So concepts must be supported with material for quality in science education. In this study, a model has been developed to make it easier to describe the real and the apparent motions of the Sun-Earth-Moon system and the results of these motions, a topic within the scope of Astronomy, which has been taught to senior undergraduate students of Science Education Programs, followed in the Faculty of Education in İnönü University. Our Sun-Earth-Moon model is a more complicated and detailed model than previous ones in terms of explaining single setting topics such as eclipses, seasons, night-day cycle and moon phases and in addition, having many features such as orbital and axial inclinations, axial rotation and orbital motion at the same time. As a result of a literature review, this study has showed that the previous models aren’t as comprehensive and well-equipped as our model in terms of the features in ours.

  17. Solar Eclipse Monitoring for Solar Energy Applications Using the Solar and Moon Position Algorithms

    Energy Technology Data Exchange (ETDEWEB)

    Reda, I.

    2010-03-01

    This report includes a procedure for implementing an algorithm (described by Jean Meeus) to calculate the moon's zenith angle with uncertainty of +/-0.001 degrees and azimuth angle with uncertainty of +/-0.003 degrees. The step-by-step format presented here simplifies the complicated steps Meeus describes to calculate the Moon's position, and focuses on the Moon instead of the planets and stars. It also introduces some changes to accommodate for solar radiation applications.

  18. 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.

  19. Moon (Form-Origin)

    Science.gov (United States)

    Tsiapas, Elias

    2016-04-01

    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

  20. 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

  1. 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

  2. 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

  3. 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…

  4. 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...

  5. 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...

  6. 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.

  7. 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.

  8. Creating an Isotopically Similar Earth and Moon from a Giant Impact with Correct Angular Momentum

    Science.gov (United States)

    Sumpter, William

    2017-01-01

    The giant-impact hypothesis is the dominant theory as to how the Earth-Moon system was formed, but angular momentum concerns have cast a shadow on its validity. Computer generated impacts have been successful in producing virtual Earth-Moon systems that possess many of the properties of the observed system, but when tasked with addressing the isotopic similarities between the Earth and Moon they result in systems with excessive angular momentum. Evection resonance between the Moon and the Sun has been put forth as a means of removing the excess angular momentum, but this reasoning was rejected by The Royal Society at a special session called to discuss the origin of the Moon. We show here how to use impactor spins to create an impact that preserves all the favorable aspects of previous simulations and produces an Earth-Moon system with the correct angular momentum. Evection resonance is not needed.

  9. Studying the Moon

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The moon,sister sphere to the Earth, has long held the attention of mankind as a source of mystery,inspiration and wonder.Its sway has been chronicled in myth,literature and song.In the final week of October,China embarked on its first attempt to better scientifically understand the moon and its relationship to the Earth by launching the lunar orbiter Chang’e-1.Though named after a deity that Chinese fairy tales say lived in the moon,this new venture to study our closest celestial neighbor is based largely on the reality of technology and scientific advancement.As the most recent phase in China’s decades old aerospace program,the launch showcases both the country’s place on the world stage and its technological and scientific advancements-not only for the benefit of its own people,but for all of mankind.

  10. 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…

  11. Personal, Seasonal Suns

    Science.gov (United States)

    Sutley, Jane

    2010-01-01

    This article presents an art project designed for upper-elementary students to (1) imagine visual differences in the sun's appearance during the four seasons; (2) develop ideas for visually translating their personal experiences regarding the seasons to their sun drawings; (3) create four distinctive seasonal suns using colors and imagery to…

  12. Moon influence on equatorial atmospheric angular momentum

    Science.gov (United States)

    Bizouard, Christian; Zotov, Leonid; Sidorenkov, Nikolay

    2014-05-01

    The variation of the equatorial atmospheric angular momentum function, coordinated with respect to a star-fixed system, is investigated in relation with the lunar tide. We isolate the rapid fluctuations, below 30 days, where Moon motion has a possible influence. First we notice that pressure term and wind term are almost proportional, by contrast to celestial seasonal band (S1). This would mean that, in this frequency band, the torque of the atmosphere on the solid Earth mostly results from the equatorial bulge. Spectrum reveals sharp lunar tidal peaks at 13.66 days (O1 diurnal tide in the terrestrial frame) and 13.63 days, reflecting the Moon influence on meridional circulation. We also observe powerful episodic fluctuations between 5 and 8 days (up to 10 mas), possibly resulting from non linear effect of the O1 tide, or tidal waves 2Q1 (6.86 days) and σ1 (7.095 days).

  13. 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

  14. 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.

  15. Meridional circulation in the Sun and stars

    CERN Document Server

    Kitchatinov, L L

    2016-01-01

    Mean-field hydrodynamics advanced to clear explanations for the origin and properties of the global meridional flow in stellar convection zones. Qualitative arguments and analysis of basic equations both show that the meridional circulation is driven by non-conservative centrifugal and buoyancy forces and results from a slight disbalance between these two drivers. The deviations from the thermal wind balance are relatively large near the boundaries of convection zones. Accordingly, the meridional flow attains its largest velocities in the boundary layers and decreases inside the convection zone. This picture, however, is neither supported nor dismissed by the conflicting results of recent helioseismic soundings or 3D numerical experiments. The relevant physics of the differential temperature and its possible relation to the solar oblateness are briefly discussed.

  16. Exoplanets Clue to Sun's Curious Chemistry

    Science.gov (United States)

    2009-11-01

    A ground-breaking census of 500 stars, 70 of which are known to host planets, has successfully linked the long-standing "lithium mystery" observed in the Sun to the presence of planetary systems. Using ESO's successful HARPS spectrograph, a team of astronomers has found that Sun-like stars that host planets have destroyed their lithium much more efficiently than "planet-free" stars. This finding does not only shed light on the lack of lithium in our star, but also provides astronomers with a very efficient way of finding stars with planetary systems. "For almost 10 years we have tried to find out what distinguishes stars with planetary systems from their barren cousins," says Garik Israelian, lead author of a paper appearing this week in the journal Nature. "We have now found that the amount of lithium in Sun-like stars depends on whether or not they have planets." Low levels of this chemical element have been noticed for decades in the Sun, as compared to other solar-like stars, and astronomers have been unable to explain the anomaly. The discovery of a trend among planet-bearing stars provides a natural explanation to this long-standing mystery. "The explanation of this 60 year-long puzzle is for us rather simple," adds Israelian. "The Sun lacks lithium because it has planets." This conclusion is based on the analysis of 500 stars, including 70 planet-hosting stars. Most of these stars were monitored for several years with ESO's High Accuracy Radial Velocity Planet Searcher. This spectrograph, better known as HARPS, is attached to ESO's 3.6-metre telescope and is the world's foremost exoplanet hunter. "This is the best possible sample available to date to understand what makes planet-bearing stars unique," says co-author Michel Mayor. The astronomers looked in particular at Sun-like stars, almost a quarter of the whole sample. They found that the majority of stars hosting planets possess less than 1% of the amount of lithium shown by most of the other stars

  17. Meteoroids Impact the Moon

    Science.gov (United States)

    Moser, D. E.

    2017-01-01

    Most meteoroids are broken up by Earth's atmosphere before they reach the ground. The Moon, however, has little-to-no atmosphere to prevent meteoroids from impacting the lunar surface. Upon impact they excavate a crater and generate a plume of debris. A flash of light at the moment of impact can also be seen. Meteoroids striking the Moon create an impact flash observable by telescopes here on Earth. NASA observers use telescopes at the Automated Lunar and Meteor Observatory (ALaMO) to routinely monitor the Moon for impact flashes each month when the lunar phase is right. Flashes recorded by two telescope simultaneously rule out false signals from cosmic rays and satellites. Over 400 impact flashes have been observed by NASA since 2005. This map shows the location of each flash. No observations are made near the poles or center line. On average, one impact is observed every two hours. The brightest and longest-lasting impact flash was observed in Mare Imbrium on March 17, 2013. The imaging satellite Lunar Reconnaissance Orbiter, in orbit around the Moon, discovered the fresh crater created by this impact. The crater is 60 across and was caused by a meteoroid 9 inches in diameter likely traveling at a speed of 57,000 mph!

  18. Over the Moon

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Chinese Premier Wen Jiabao (right) applauds after he unveiled China’s first photo of the moon surface,taken by its lunar probe Chang’e-1,in Beijing on November 26. The framed black-and-white photo,grouping 19 images,shows part of the moon’s highland that is mainly composed of plagioclase,a common

  19. 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…

  20. Approaching the Moon

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    China’s second unmanned lunar probe,Chang’e-2,completed its second braking on October 8.The satellite needs to brake three times before entering the designed 118-minute orbit around the Moon.The first braking,shown by virtual animation on a screen in the Beijing Aerospace Control Center in this picture,succeeded on October 6.

  1. Map of the Moon

    Institute of Scientific and Technical Information of China (English)

    TANG YUANKAI

    2010-01-01

    @@ China has finished the full map of the Moon based on data obtained by its lunar probe Chang'e l,said Ouyang Ziyuan,chief scientist of China's lunar exploration program and an academician at the Chinese Academy of Sciences(CAS),at a press conference about the scientific achievements made by Chang'e1 on July 16,2010.

  2. Santa and the Moon

    NARCIS (Netherlands)

    Barthel, P.

    2012-01-01

    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 appearanc

  3. Wenestor ja Moons

    Index Scriptorium Estoniae

    1999-01-01

    1995. a. tööd alustanud mööblifirma Wenestor (70 töötajat) ja selle tütarfirma Moons (15 töötajat) toodangust, millest eksporditakse 95%. Mehhiko stiili mööblist, klotsmööblist (disainer Kuldar Moor)

  4. 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

  5. Horseshoe orbits in the Earth-Moon system

    Science.gov (United States)

    Kreisman, B. B.

    2016-11-01

    Horseshoe orbits in the restricted three-body problem have been mostly considered in the Sun-Jupiter system and, in recent years, in the Sun-Earth system. Here, these orbits have been used to find asteroids that have orbits of this kind. We have built a planar family of horseshoe orbits in the Earth-Moon system and determined the points of planar and 1/1 vertical resonances on this family. We have presented examples of orbits generated by these spatial families.

  6. The Face of the Moon

    Institute of Scientific and Technical Information of China (English)

    张保

    2001-01-01

    Have you ever seen the man in the moon?If you look closelyat the moon on some nights, you can see the face of the man in themoon. Some people say that they can see an old man carryingsticks. Others see a girl reading a book. These pictures are madeby the mountains (山脉) and plains (平原) of the moon.

  7. 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...

  8. A Sub-Earth-Mass Moon Orbiting a Gas Giant Primary or a High Velocity Planetary System in the Galactic Bulge

    CERN Document Server

    Bennett, D P; Bond, I A; Bennett, C S; Suzuki, D; Beaulieu, J -P; Udalski, A; Donatowicz, J; Abe, F; Botzler, C S; Freeman, M; Fukunaga, D; Fukui, A; Itow, Y; Koshimoto, N; Ling, C H; Masuda, K; Matsubara, Y; Muraki, Y; Namba, S; Ohnishi, K; Rattenbury, N J; Saito, To; Sullivan, D J; Sumi, T; Sweatman, W L; Tristram, P J; Tsurumi, N; Wada, K; Yock, P C M; Albrow, M D; Bachelet, E; Brillant, S; Caldwell, J A R; Cassan, A; Cole, A A; Corrales, E; Coutures, C; Dieters, S; Prester, D Dominis; Fouque, P; Greenhill, J; Horne, K; Koo, J -R; Kubas, D; Marquette, J -B; Martin, R; Menzies, J W; Sahu, K C; Wambsganss, J; Williams, A; Choi, M Zub J Y; DePoy, D L; Dong, Subo; Gaudi, B S; Gould, A; Han, C; Henderson, C B; McGregor, D; Lee, C -U; Pogge, R W; Shin, I -G; Yee, J C; Szymaski, M K; Skowron, J; Poleski, R; Kozowski, S; Wyrzykowski, L; Kubiak, M; Pietrukowicz, P; Pietrzyski, G; Soszyski, I; Ulaczyk, K; Tsapras, Y; Street, R A; Dominik, M; Bramich, D M; Browne, P; Hundertmark, M; Kains, N; Snodgrass, C; Steele, I A; Dekany, I; Gonzalez, O A; Heyrovsky, D; Kandori, R; Kerins, E; Lucas, P W; Minniti, D; Nagayama, T; Rejkuba, M; Robin, A C; Saito, R

    2013-01-01

    We present the first microlensing candidate for a free-floating exoplanet-exomoon system, MOA-2011-BLG-262, with a primary lens mass of M_host ~ 4 Jupiter masses hosting a sub-Earth mass moon. The data are well fit by this exomoon model, but an alternate star+planet model fits the data almost as well. Nevertheless, these results indicate the potential of microlensing to detect exomoons, albeit ones that are different from the giant planet moons in our solar system. The argument for an exomoon hinges on the system being relatively close to the Sun. The data constrain the product M pi_rel, where M is the lens system mass and pi_rel is the lens-source relative parallax. If the lens system is nearby (large pi_rel), then M is small (a few Jupiter masses) and the companion is a sub-Earth-mass exomoon. The best-fit solution has a large lens-source relative proper motion, mu_rel = 19.6 +- 1.6 mas/yr, which would rule out a distant lens system unless the source star has an unusually high proper motion. However, data f...

  9. 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...

  10. Global Instability of the Exo-moon System Triggered by Photo-evaporation

    Science.gov (United States)

    Yang, Ming; Xie, Ji-Wei; Zhou, Ji-Lin; Liu, Hui-Gen; Zhang, Hui

    2016-12-01

    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.

  11. Identification of craters on Moon using Crater Density Parameter

    Science.gov (United States)

    Vandana, Vandana

    2016-07-01

    Lunar craters are the most noticeable features on the face of the moon. They take up 40.96% of the lunar surface and, their accumulated area is approximately three times as much as the lunar surface area. There are many myths about the moon. Some says moon is made of cheese. The moon and the sun chase each other across the sky etc. but scientifically the moon are closest and are only natural satellite of earth. The orbit plane of the moon is tilted by 5° and orbit period around the earth is 27-3 days. There are two eclipse i.e. lunar eclipse and solar eclipse which always comes in pair. Moon surface has 3 parts i.e. highland, Maria, and crater. For crater diagnostic crater density parameter is one of the means for measuring distance can be easily identity the density between two craters. Crater size frequency distribution (CSFD) is being computed for lunar surface using TMC and MiniSAR image data and hence, also the age for the selected test sites of mars is also determined. The GIS-based program uses the density and orientation of individual craters within LCCs (as vector points) to identify potential source craters through a series of cluster identification and ejection modeling analyses. JMars software is also recommended and operated only the time when connected with server but work can be done in Arc GIS with the help of Arc Objects and Model Builder. The study plays a vital role to determine the lunar surface based on crater (shape, size and density) and exploring affected craters on the basis of height, weight and velocity. Keywords: Moon; Crater; MiniSAR.

  12. The new moon illusion and the role of perspective in the perception of straight and parallel lines.

    Science.gov (United States)

    Rogers, Brian; Naumenko, Olga

    2015-01-01

    In the new moon illusion, the sun does not appear to be in a direction perpendicular to the boundary between the lit and dark sides of the moon, and aircraft jet trails appear to follow curved paths across the sky. In both cases, lines that are physically straight and parallel to the horizon appear to be curved. These observations prompted us to investigate the neglected question of how we are able to judge the straightness and parallelism of extended lines. To do this, we asked observers to judge the 2-D alignment of three artificial "stars" projected onto the dome of the Saint Petersburg Planetarium that varied in both their elevation and their separation in horizontal azimuth. The results showed that observers make substantial, systematic errors, biasing their judgments away from the veridical great-circle locations and toward equal-elevation settings. These findings further demonstrate that whenever information about the distance of extended lines or isolated points is insufficient, observers tend to assume equidistance, and as a consequence, their straightness judgments are biased toward the angular separation of straight and parallel lines.

  13. Dualband infrared imaging spectrometer: observations of the moon

    Science.gov (United States)

    LeVan, Paul D.; Beecken, Brian P.; Lindh, Cory

    2008-08-01

    We reported previously on full-disk observations of the sun through a layer of black polymer, used to protect the entrance aperture of a novel dualband spectrometer while transmitting discrete wavelength regions in the MWIR & LWIR1. More recently, the spectrometer was used to assess the accuracy of recovery of unknown blackbody temperatures2. Here, we briefly describe MWIR observations of the full Moon made in Jan 2008. As was the case for the solar observations, the Moon was allowed to drift across the spectrometer slit by Earth's rotation. A detailed sensor calibration performed prior to the observations accounts for sensor non-uniformities; the spectral images of the Moon therefore include atmospheric transmission features. Our plans are to repeat the observations at liquid helium temperatures, thereby allowing both MWIR & LWIR spectral coverage.

  14. The WR / OB Number Ratio Within 2.5-KPC from the Sun

    Science.gov (United States)

    Vanbeveren, D.

    Comparing the observed and theoretical HR diagram for massive stars, it is concluded that at least 34% of the stars within 2.5 kpc from the sun with initial ZAMS mass larger than 35 M_sun; have not yet been detected. It is argued that the number of core helium burning pop I WR stars within 2.5 kpc from the sun may be as low as 26. If the progenitors of WR stars have initial ZAMS masses larger than 35 M_sun;, it is then concluded that the observed number ratio (core helium burning pop I WR stars)/(WR progenitors) within 2.5 kpc from the sun ranges between 0.05 and 0.09.

  15. 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 ...

  16. Could Ultracool Dwarfs Have Sun-Like Activity?

    Science.gov (United States)

    Kohler, Susanna

    2016-11-01

    Solar-like stars exhibit magnetic cycles; our Sun, for instance, displays an 11-year period in its activity, manifesting as cyclic changes in radiation levels, the number of sunspots and flares, and ejection of solar material. Over the span of two activity cycles, the Suns magnetic field flips polarity and then returns to its original state.An artists illustration comparing the Sun to TRAPPIST-1, an ultracool dwarf star known to host several planets. [ESO]But what about the magnetic behavior of objects near the cooler end of the stellar main sequence do they exhibit similar activity cycles?Effects of a Convecting InteriorDwarf stars have made headlines in recent years due to their potential to harbor exoplanets. Because these cooler stars have lower flux levels compared to the Sun, their habitable zones lie much closer to the stars. The magnetic behavior of these stars is therefore important to understand: could ultracool dwarfs exhibit solar-like activity cycles that would affect planets with close orbits?The differences in internal structure between different mass stars. Ultracool dwarfs have fully convective interiors. [www.sun.org]Theres a major difference between ultracool dwarfs (stars of spectral type higher than M7 and brown dwarfs) and Sun-like stars: their internal structures. Sun-like stars have a convective envelope that surrounds a radiative core. The interiors of cool, low-mass objects, on the other hand, are fully convective.Based on theoretical studies of how magnetism is generated in stars, its thought that the fully convective interiors of ultracool dwarfs cant support large-scale magnetic field formation. This should prevent these stars from exhibiting activity cycles like the Sun. But recent radio observations of dwarf stars have led scientist Matthew Route (ITaP Research Computing, Purdue University) to question these models.A Reversing Field?During observations of the brown dwarf star J1047+21 in 20102011, radio flares were detected with

  17. 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 ...

  18. Ferry to the moon

    Science.gov (United States)

    Aston, Graeme

    1987-01-01

    Solar-electric propulsion for a fleet of lunar ferry vehicles may allow the creation of a permanent lunar base not long after the turn of the century with greater cost effectiveness than a fleet of chemically powered spacecraft. After delivery by the Space Shuttle to a 300-km earth orbit, the lunar ferry envisioned would travel in spiral trajectory to the moon under the power of 300-kW solar arrays and ten 30-kW Xe-ion engines; each of the solar arrays would be 12 x 61 m long. Each trip between the earth parking orbit and the moon would take about 1 year, so that a fleet of four ferries operating simultaneously could deliver 20 metric tons to a lunar base every 100 days.

  19. Moon Portrait Accomplished

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    After the release of its first picture of the moon surface cap- tured by Chang’e-l last November,China published a photo of the moon’s polar areas on January 31,the first-ever such picture taken by China."We have obtained pictures of good quality,"said spokes- person Pei Zhaoyu of the China National Space Administration. Chinese scientists adjusted the camera aboard the satellite

  20. Himalia, a Small Moon of Jupiter

    Science.gov (United States)

    2001-01-01

    NASA's Cassini spacecraft captured images of Himalia, the brightest of Jupiter's outer moons, on Dec. 19, 2000, from a distance of 4.4 million kilometers (2.7 million miles).This near-infrared image, with a resolution of about 27 kilometers (17 miles) per pixel, indicates that the side of Himalia facing the spacecraft is roughly 160 kilometers (100 miles) in the up-down direction. Himalia probably has a non-spherical shape. Scientists believe it is a body captured into orbit around Jupiter, most likely an irregularly shaped asteroid.In the main frame, an arrow indicates Himalia. North is up. The inset shows the little moon magnified by a factor of 10, plus a graphic indicating Himalia's size and the direction of lighting (with sunlight coming from the left). Cassini's pictures of Himalia were taken during a brief period when Cassini's attitude was stabilized by thrusters instead of by a steadier reaction-wheel system. No spacecraft or telescope had previously shown any of Jupiter's outer moons as more than a star-like single dot.Cassini is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the Cassini mission for NASA's Office of Space Science, Washington, D.C.

  1. Watching the Sun to Improve Exoplanet Detection

    Science.gov (United States)

    Kohler, Susanna

    2015-12-01

    Looking for stars that wobble is one of the key ways by which we detect exoplanets: the gravitational pull of planets cause tiny variations in stars radial velocities. But our ability to detect Earth twins is currently limited by our ability to distinguish between radial-velocity variations caused by exoplanets, and those caused by noise from the star itself. A team of scientists has recently proposed that the key to solving this problem may be to examine our own star.Precision Amid NoiseThe radial-velocity technique works well for detecting large planets on close orbits, but detecting an Earth twin requires being able to detect star motion on the order of 10 cm/s! This precision is hard to reach, because activity on the stellar surface i.e., sunspots, plages (bright spots), or granulation can also cause variations in the measured radial velocity for the star, obscuring the signature of a planet.Because the stars were examining arent resolved, we cant track the activity on their surfaces so how can we better understand the imprint that stellar activity has on radial-velocity measurements? A team of scientists has come up with a clever approach: examine the Sun as though it were a distant star.Wealth of InformationThe team, led by Xavier Dumusque (Branco-Weiss Fellow at the Harvard-Smithsonian Center for Astrophysics) and David F. Phillips (Harvard-Smithsonian Center for Astrophysics), has begun a project to observe the Sun with a ground-based solar telescope. The telescope observes the full disk of the Sun and feeds the data into the HARPS-N spectrograph in Spain, a spectrograph normally used for radial-velocity measurements of other stars in the hunt for exoplanets.But the team has access to other data about the Sun, too: information from satellites like the Solar Dynamics Observatory and SORCE about the solar activity and total irradiance during the time when the spectra were taken. Dumusque and collaborators have combined all of this information, during a week

  2. Direct and indirect capture of near-Earth asteroids in the Earth-Moon system

    Science.gov (United States)

    Tan, Minghu; McInnes, Colin; Ceriotti, Matteo

    2017-09-01

    Near-Earth asteroids have attracted attention for both scientific and commercial mission applications. Due to the fact that the Earth-Moon L1 and L2 points are candidates for gateway stations for lunar exploration, and an ideal location for space science, capturing asteroids and inserting them into periodic orbits around these points is of significant interest for the future. In this paper, we define a new type of lunar asteroid capture, termed direct capture. In this capture strategy, the candidate asteroid leaves its heliocentric orbit after an initial impulse, with its dynamics modeled using the Sun-Earth-Moon restricted four-body problem until its insertion, with a second impulse, onto the L2 stable manifold in the Earth-Moon circular restricted three-body problem. A Lambert arc in the Sun-asteroid two-body problem is used as an initial guess and a differential corrector used to generate the transfer trajectory from the asteroid's initial obit to the stable manifold associated with Earth-Moon L2 point. Results show that the direct asteroid capture strategy needs a shorter flight time compared to an indirect asteroid capture, which couples capture in the Sun-Earth circular restricted three-body problem and subsequent transfer to the Earth-Moon circular restricted three-body problem. Finally, the direct and indirect asteroid capture strategies are also applied to consider capture of asteroids at the triangular libration points in the Earth-Moon system.

  3. Stars a very short introduction

    CERN Document Server

    King, Andrew

    2012-01-01

    Stars: A Very Short Introduction looks at how stars live, producing all the chemical elements beyond helium, and how they die, leaving remnants such as black holes. Every atom of our bodies has been part of a star. Our very own star, the Sun, is crucial to the development and sustainability of life on Earth. Understanding stars is key to understanding the galaxies they inhabit, the existence of planets, and the history of our entire Universe. This VSI explores the science of stars, the mechanisms that allow them to form, the processes that allow them to shine, and the results of their death.

  4. Perry, Kelvin, and the age of the sun

    Science.gov (United States)

    Tipler, Frank J.

    2013-04-01

    Lord Kelvin argued that the Sun had to be between 20 and 100 million years old, based on the assumption that the Sun's energy source was gravitational contraction. As everyone now knows, the Sun's actual power source is the thermonuclear fusion of hydrogen into helium. But Kelvin's number is based on a physical assumption for which he could give no justification: the Sun's density is approximately constant. Had Kelvin assumed instead that the Sun had a small core near a black hole radius - an assumption allowed by the knowledge of physicists at the end of the nineteenth century - he would have obtained an age for the Sun as long as 10 trillion years, completely consistent with the long time scale required for evolution. Conversely, had Kelvin accepted the geologists' time scale, he would have been forced to acknowledge the existence of very dense objects, making it easier for twentieth century astronomers to accept the existence of black holes and neutron stars.

  5. Jupiter's Moons: Family Portrait

    Science.gov (United States)

    2007-01-01

    This montage shows the best views of Jupiter's four large and diverse 'Galilean' satellites as seen by the Long Range Reconnaissance Imager (LORRI) on the New Horizons spacecraft during its flyby of Jupiter in late February 2007. The four moons are, from left to right: Io, Europa, Ganymede and Callisto. The images have been scaled to represent the true relative sizes of the four moons and are arranged in their order from Jupiter. Io, 3,640 kilometers (2,260 miles) in diameter, was imaged at 03:50 Universal Time on February 28 from a range of 2.7 million kilometers (1.7 million miles). The original image scale was 13 kilometers per pixel, and the image is centered at Io coordinates 6 degrees south, 22 degrees west. Io is notable for its active volcanism, which New Horizons has studied extensively. Europa, 3,120 kilometers (1,938 miles) in diameter, was imaged at 01:28 Universal Time on February 28 from a range of 3 million kilometers (1.8 million miles). The original image scale was 15 kilometers per pixel, and the image is centered at Europa coordinates 6 degrees south, 347 degrees west. Europa's smooth, icy surface likely conceals an ocean of liquid water. New Horizons obtained data on Europa's surface composition and imaged subtle surface features, and analysis of these data may provide new information about the ocean and the icy shell that covers it. New Horizons spied Ganymede, 5,262 kilometers (3,268 miles) in diameter, at 10:01 Universal Time on February 27 from 3.5 million kilometers (2.2 million miles) away. The original scale was 17 kilometers per pixel, and the image is centered at Ganymede coordinates 6 degrees south, 38 degrees west. Ganymede, the largest moon in the solar system, has a dirty ice surface cut by fractures and peppered by impact craters. New Horizons' infrared observations may provide insight into the composition of the moon's surface and interior. Callisto, 4,820 kilometers (2,995 miles) in diameter, was imaged at 03:50 Universal Time on

  6. Accretion of the Moon from non-canonical disks

    CERN Document Server

    Salmon, Julien

    2014-01-01

    Impacts that leave the Earth-Moon system with a large excess in angular momentum have recently been advocated as a means of generating a protolunar disc with a composition that is nearly identical to that of the Earth's mantle. We here investigate the accretion of the Moon from discs generated by such "non-canonical" impacts, which are typically more compact than discs produced by canonical impacts and have a higher fraction of their mass initially located inside the Roche limit. Our model predicts a similar overall accretional history for both canonical and non-canonical discs, with the Moon forming in three consecutive steps over hundreds of years. However, we find that, to yield a lunar-mass Moon, the more compact non-canonical discs must initially be more massive than implied by prior estimates, and only a few of the discs produced by impact simulations to date appear to meet this condition. Non-canonical impacts require that capture of the Moon into the evection resonance with the Sun reduced the Earth-M...

  7. Micro moon versus macro moon: Brightness and size

    CERN Document Server

    Agrawal, Dulli Chandra

    2015-01-01

    The moon, moonlight, phases of the moon and its relatively simple recurring cycle has been of interest since time immemorial to the human beings, navigators, astronomers and astrologers. The fact that its orbit is elliptical as well its plane is inclined with the plane of rotation of the earth gives rise to new moon to full moon and solar and lunar eclipses. During the phase of the full moon, the luminous flux and its apparent size will depend on its distance from the earth. In case it is at farthest point known as lunar apogee causes smallest full moon or micro full moon and if it is closest to us termed as lunar perigee will result in macro full moon, also known as super moon, a term coined by astrologer Richard Nolle in 1979. The theoretical expressions for the lunar luminous fluxes on the earth representing the power of lunar light the earth intercepts in the direction normal to the incidence over an area of one square meter are derived for two extreme positions lunar apogee and lunar perigee. The express...

  8. 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

  9. 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.

  10. "Fly me to the moon"

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    @@ China's first lunar probe Chang'e-I, named after a mythical Chinese goddess who, according to legend, made her home on the moon, blasted off on 24 October from the Xichang Satellite Launch Center in the southwestern province of Sichuan. In addition to making the dream cherished by Chinese people to fly to the moon come true, it is the first step into China's ambitious threestage moon mission, marking a new milestone in the country's space exploration history.

  11. Impact origin of the Moon

    Energy Technology Data Exchange (ETDEWEB)

    Slattery, W.L.

    1998-12-31

    A few years after the Apollo flights to the Moon, it became clear that all of the existing theories on the origin of the Moon would not satisfy the growing body of constraints which appeared with the data gathered by the Apollo flights. About the same time, researchers began to realize that the inner (terrestrial) planets were not born quietly -- all had evidences of impacts on their surfaces. This fact reinforced the idea that the planets had formed by the accumulation of planetesimals. Since the Earth`s moon is unique among the terrestrial planets, a few researchers realized that perhaps the Moon originated in a singular event; an event that was quite probable, but not so probable that one would expect all the terrestrial planets to have a large moon. And thus was born the idea that a giant impact formed the Moon. Impacts would be common in the early solar system; perhaps a really large impact of two almost fully formed planets of disparate sizes would lead to material orbiting the proto-earth, a proto-moon. This idea remained to be tested. Using a relatively new, but robust, method of doing the hydrodynamics of the collision (Smoothed-Particle Hydrodynamics), the author and his colleagues (W. Benz, Univ. of Arizona, and A.G.W. Cameron, Harvard College Obs.) did a large number of collision simulations on a supercomputer. The author found two major scenarios which would result in the formation of the Moon. The first was direct formation; a moon-sized object is boosted into orbit by gravitational torques. The second is when the orbiting material forms a disk, which, with subsequent evolution can form the Moon. In either case the physical and chemical properties of the newly formed Moon would very neatly satisfy the physical and chemical constraints of the current Moon. Also, in both scenarios the surface of the Earth would be quite hot after the collision. This aspect remains to be explored.

  12. 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

  13. Does Vesta Have Moons?

    Science.gov (United States)

    McFadden, L. A.; Sykes, M.; Joy, S.; Tricarico, P.; O'Brien, D.; Li, J. Y.; Mutchler, M.; Memarsadeghi, N.; Safavi, H.; Gutierrez-Marques, P.; Nathues, A.; Sierks, H.; Schroder, S.; Polansky, C.; Jacobson, R.; Russell, C. T.; Raymond, C. A.; Rayman, M.; Weinstein-Weiss, S.; Palmer, E.

    2011-01-01

    Previous searches for moons around Vesta have found nothing to an upper limit of 22.5 magnitude, that corresponds to 44 +/- 4 m diameter assuming the same albedo as Vesta. The Dawn mission's approach phase has dedicated satellite search observations consisting of two mosaic sequences bracketing the first observations of a complete rotation of Vesta scheduled for early July, 2011. In addition, we use the approach optical navigation image sequences for initial satellite searches. We will report any findings from these observations, and upper limits of magnitude and size.

  14. The Moon and My Dream

    Institute of Scientific and Technical Information of China (English)

    曹萌

    2007-01-01

    The moon changes its shape and brightness each night all the year round. On the night of August 15 in the lunar calendar, the moon is said to be the most round and the most bright. As the round moon indicates "reunion" according to the Chinese culture, we usually celebrate the harvest by eating mooncakes and fruits and enjoy the full moon in the evening. Generally, all the family members would get together and have a good time on this occasion. I love this festival very much, not only because I can eat d...

  15. Sun-Earth Days

    Science.gov (United States)

    Thieman, J.; Ng, C.; Lewis, E.; Cline, T.

    2010-08-01

    Sun-Earth Day is a well-coordinated series of programs, resources and events under a unique yearly theme highlighting the fundamentals of heliophysics research and missions. A menu of activities, conducted throughout the year, inspire and educate participants. Sun-Earth Day itself can vary in date, but usually is identified by a celebration on or near the spring equinox. Through the Sun-Earth Day framework we have been able to offer a series of coordinated events that promote and highlight the Sun, its connection to Earth and the other planets. Sun-Earth Day events are hosted by educators, museums, amateur astronomers and scientists and occur at schools, community groups, parks, planetaria and science centers around the globe. Sun-Earth Day raises the awareness and knowledge of formal and informal education audiences concerning space weather and heliophysics. By building on the success of Sun-Earth Day yearly celebrations, we seek to affect people of all backgrounds and ages with the wonders of heliophysics science, discovery, and exploration in ways that are both tangible and meaningful to their lives.

  16. Global Instability of Exo-Moon System Triggered by Photo-Evaporation

    CERN Document Server

    Yang, Ming; Zhou, Ji-Lin; Liu, Hui-Gen; Zhang, Hui

    2016-01-01

    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 semi-major axes and eccentricities. When some moons approach their critical semi-major 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 fre...

  17. 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...

  18. Prospect for UV observations from the Moon

    Science.gov (United States)

    Safonova, Margarita; Mathew, Joice; Mohan, Rekhesh; Sreejith, A. G.; Murthy, Jayant; Brosch, Noah; Kappelmann, Norbert; Sharma, Arpit; Narayan, Rahul

    2014-10-01

    Space astronomy in the last 40 years has largely been done from spacecraft in low Earth orbit (LEO) for which the technology is proven and delivery mechanisms are readily available. However, new opportunities are arising with the surge in commercial aerospace missions. We describe here one such possibility: deploying a small instrument on the Moon. This can be accomplished by flying onboard the Indian entry to the Google Lunar X PRIZE competition, Team Indus mission, which is expected to deliver a nearly 30 kgs of payloads to the Moon, with a rover as its primary payload. We propose to mount a wide-field far-UV (130-180 nm) imaging telescope as a payload on the Team Indus lander. Our baseline operation is a fixed zenith pointing but with the option of a mechanism to allow observations of different attitudes. Pointing towards intermediate ecliptic latitude (50∘ or above) ensures that the Sun is at least 40∘ off the line of sight at all times. In this position, the telescope can cover higher galactic latitudes as well as parts of Galactic plane. The scientific objectives of such a prospective are delineated and discussed.

  19. Prospect for UV observations from the Moon

    CERN Document Server

    Safonova, Margarita; Mohan, Rekhesh; Sreejith, A G; Murthy, Jayant; Brosch, Noah; Kappelmann, Norbert; Sharma, Arpit; Narayan, Rahul

    2014-01-01

    Space astronomy in the last 40 years has largely been done from spacecraft in low Earth orbit (LEO) for which the technology is proven and delivery mechanisms are readily available. However, new opportunities are arising with the surge in commercial aerospace missions. We describe here one such possibility: deploying a small instrument on the Moon. This can be accomplished by flying onboard the Indian entry to the Google Lunar X PRIZE competition, Team Indus mission, which is expected to deliver a nearly 30 kgs of payloads to the Moon, with a rover as its primary payload. We propose to mount a wide-field far-UV (130--180 nm) imaging telescope as a payload on the Team Indus lander. Our baseline operation is a fixed zenith pointing but with the option of a mechanism to allow observations of different attitudes. Pointing towards intermediate ecliptic latitude (50 deg or above) ensures that the Sun is at least 40 deg off the line of sight at all times. In this position, the telescope can cover higher galactic lat...

  20. Properties of Microlensing Events by Wide-separation Planets with a Moon

    Science.gov (United States)

    Chung, Sun-Ju; Ryu, Yoon-Hyun

    2016-07-01

    We investigate the properties of microlensing events caused by planetary systems where planets with a moon are widely separated from their host stars. From this investigation, we find that the moon feature generally appears as a very short-duration perturbation on the smooth asymmetric light curve of the lensing event induced by the wide-separation planet; thus it can be easily discriminated from the planet feature responsible for the overall asymmetric light curve. For typical Galactic lensing events with an Einstein radius of ˜2 au, the asymmetry of the light curves due to bound planets can be noticed up to ˜20 au. We also find that the perturbations of wide planetary systems become dominated by the moon as the projected star-planet separation increases, and eventually the light curves of events produced by such systems appear as the single lensing light curve of the planet itself with a very short-duration perturbation induced by the moon, which is a representative light curve of the event induced by a star and a planet, except on the Einstein timescale of the planet. We also study the effect of a finite source star on the moon feature in wide planetary lensing events. From this study, we find that when the lunar caustic is sufficiently separated from the planetary caustic, the lower limit on the ratio of the size of the lunar caustic to the source radius causing a ≥5% lunar deviation depends mostly on the projected planet-moon separation regardless of the moon/star mass ratio, and it decreases as the planet-moon separation becomes smaller or larger than the planetary Einstein radius.

  1. 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...

  2. Capturing small asteroids into a Sun-Earth Lagrangian point

    Science.gov (United States)

    Lladó, Neus; Ren, Yuan; Masdemont, Josep J.; Gómez, Gerard

    2014-02-01

    In this paper we address the feasibility of capturing small Near-Earth Asteroids (NEAs) into the vicinity of the Sun-Earth L2 libration point using a continuous-thrust propulsion system assumed to be attached to the asteroid. The vicinity of this libration point is a gateway to the Earth-Moon neighborhood and using it for capture, or for transit, small NEAs could be interesting for mining or science purposes.

  3. 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.

  4. Moon4You : A first Dutch footprint on the moon

    NARCIS (Netherlands)

    Laan, E.

    2009-01-01

    Moon4You is an initiative led by the Dutch Organisation for Applied Scientific Research TNO, with partners from industry and universities in the Netherlands that aims to provide a combined Raman/LIBS instrument as scientific payload for lunar exploration missions, and specifically for Odyssey Moon's

  5. Moon4You : A first Dutch footprint on the moon

    NARCIS (Netherlands)

    Laan, E.

    2009-01-01

    Moon4You is an initiative led by the Dutch Organisation for Applied Scientific Research TNO, with partners from industry and universities in the Netherlands that aims to provide a combined Raman/LIBS instrument as scientific payload for lunar exploration missions, and specifically for Odyssey Moon's

  6. 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.

  7. Tidal friction in the Earth-Moon system and Laplace planes: Darwin redux

    Science.gov (United States)

    Rubincam, David Parry

    2016-03-01

    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 5.2°. 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.

  8. The Tethered Moon

    CERN Document Server

    Zahnle, Kevin J; Dobrovolskis, Anthony; Sleep, Norman H

    2015-01-01

    We address the thermal history of the Earth after the Moon-forming impact, taking tidal heating and thermal blanketing by the atmosphere into account. The atmosphere sets an upper bound of ~100 W/m^2 on how quickly the Earth can cool. The liquid magma ocean cools over 2-10 Myrs, with longer times corresponding to high angular-momentum events. Tidal heating is focused mostly in mantle materials that are just beginning to freeze. The atmosphere's control over cooling sets up a negative feedback between viscosity-dependent tidal heating and temperature-dependent viscosity of the magma ocean. While the feedback holds, evolution of the Moon's orbit is limited by the modest radiative cooling rate of Earth's atmosphere. Orbital evolution is orders of magnitude slower than in conventional constant Q models, which promotes capture by resonances. The evection resonance is encountered early, when the Earth is molten. Capture by the evection resonance appears certain but unlikely to generate much eccentricity because it ...

  9. Jupiter's Hot, Mushy Moon

    Science.gov (United States)

    Taylor, G. Jeffrey

    2003-01-01

    Jupiter's moon Io is the most volcanically active body in the Solar System. Observations by instruments on the Galileo spacecraft and on telescopes atop Mauna Kea in Hawai'i indicate that lava flows on Io are surprisingly hot, over 1200 oC and possibly as much as 1300 oC; a few areas might have lava flows as hot as 1500 oC. Such high temperatures imply that the lava flows are composed of rock that formed by a very large amount of melting of Io's mantle. This has led Laszlo Keszthelyi and Alfred S. McEwen of the University of Arizona and me to reawaken an old hypothesis that suggests that the interior of Io is a partially-molten mush of crystals and magma. The idea, which had fallen out of favor for a decade or two, explains high-temperature hot spots, mountains, calderas, and volcanic plains on Io. If correct, Io gives us an opportunity to study processes that operate in huge, global magma systems, which scientists believe were important during the early history of the Moon and Earth, and possibly other planetary bodies as well. Though far from proven, the idea that Io has a ocean of mushy magma beneath its crust can be tested with measurements by future spacecraft.

  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. Should Moon Cakes Be Taxed?

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    It is a custom in China that when the Mid-Autumn Festival draws near,a company or organization will offer its staff moon cakes,as non-cash benefits.It has recently been reported that these noncash benefits,such as moon cakes,should be taxed according to their value,which has spurred heated debate.

  12. Should Moon Cakes Be Taxed?

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    It is a custom in China that when the Mid-Autumn Festival draws near, a company or organization will offer its staff moon cakes, as non-cash benefits. It has recently been reported that these noncash benefits, such as moon cakes, should be taxed according to their value, which has spurred heated debate.

  13. 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

  14. THE UBV(RI){sub C} COLORS OF THE SUN

    Energy Technology Data Exchange (ETDEWEB)

    Ramirez, I. [McDonald Observatory and Department of Astronomy, University of Texas at Austin, 1 University Station, C1400 Austin, TX 78712-0259 (United States); Michel, R.; Schuster, W. J. [Observatorio Astronomico Nacional, Universidad Nacional Autonoma de Mexico, Apartado Postal 877, Ensenada, B.C., CP 22800 (Mexico); Sefako, R.; Van Wyk, F. [South African Astronomical Observatory, P.O. Box 9, Observatory 7935, Cape Town (South Africa); Tucci Maia, M. [UNIFEI, DFQ-Instituto de Ciencias Exatas, Universidade Federal de Itajuba, Itajuba MG (Brazil); Melendez, J. [Departamento de Astronomia do IAG/USP, Universidade de Sao Paulo, Rua do Matao 1226, Sao Paulo, 05508-900 SP (Brazil); Casagrande, L. [Max-Planck-Institut fuer Astrophysik, Karl-Schwarzschild-Str. 1, Postfach 1317, D-85741 Garching (Germany); Castilho, B. V. [Laboratorio Nacional de Astrofisica/MCT, Rua Estados Unidos 154, 37504-364 Itajuba, MG (Brazil)

    2012-06-10

    Photometric data in the UBV(RI){sub C} system have been acquired for 80 solar analog stars for which we have previously derived highly precise atmospheric parameters T{sub eff}, log g, and [Fe/H] using high-resolution, high signal-to-noise ratio spectra. UBV and (RI){sub C} data for 46 and 76 of these stars, respectively, are published for the first time. Combining our data with those from the literature, colors in the UBV(RI){sub C} system, with {approx_equal} 0.01 mag precision, are now available for 112 solar analogs. Multiple linear regression is used to derive the solar colors from these photometric data and the spectroscopically derived T{sub eff}, log g, and [Fe/H] values. To minimize the impact of systematic errors in the model-dependent atmospheric parameters, we use only the data for the 10 stars that most closely resemble our Sun, i.e., the solar twins, and derive the following solar colors: (B - V){sub Sun} = 0.653 {+-} 0.005, (U - B){sub Sun} = 0.166 {+-} 0.022, (V - R){sub Sun} = 0.352 {+-} 0.007, and (V - I){sub Sun} = 0.702 {+-} 0.010. These colors are consistent, within the 1{sigma} errors, with those derived using the entire sample of 112 solar analogs. We also derive the solar colors using the relation between spectral-line-depth ratios and observed stellar colors, i.e., with a completely model-independent approach, and without restricting the analysis to solar twins. We find (B - V){sub Sun} = 0.653 {+-} 0.003, (U - B){sub Sun} = 0.158 {+-} 0.009, (V - R){sub Sun} = 0.356 {+-} 0.003, and (V - I){sub Sun} = 0.701 {+-} 0.003, in excellent agreement with the model-dependent analysis.

  15. 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).

  16. Lithium Depletion in Fully Convective Pre-Main Sequence Stars

    CERN Document Server

    Bildsten, L; Matzner, C D; Ushomirsky, G; Bildsten, Lars; Brown, Edward F.; Matzner, Christopher D.; Ushomirsky, Greg

    1996-01-01

    We present an analytic calculation of the thermonuclear depletion of lithium in contracting, fully convective, pre-main sequence stars of mass M 0.08 M_sun) and for constraining the masses of lithium depleted stars.

  17. More than One Sun

    Science.gov (United States)

    Argyle, Bob; Argyle, R. W.

    On a clear, dark night several thousand stars can be seen at any one time. They form familiar patterns such as the Great Bear and Cygnets in the northern hemisphere and Scorpio and Crux in the south. The distances are so great that we see the constellation patterns essentially unchanged from those seen by the Ancient Egyptians for instance. This is partly due to the fact that some of the bright stars in constellations are in what are called moving groups—a loose association of stars moving through space together. More tightly bound are clusters of stars such as the Pleaders or Seven Sisters which appears in the northern sky in the late summer. Eventually the moving groups and clusters of stars will gradually disperse because the distance between the stars is such that the gravitational attraction between the members is relatively weak.

  18. Observations of the moon by the global ozone monitoring experiment: radiometric calibration and lunar albedo

    NARCIS (Netherlands)

    Dobber, M.R.; Goede, A.P.H.; Burrows, J.P.

    1998-01-01

    The Global Ozone Monitoring Experiment (GOME) is a new instrument, which was launched aboard the second European Remoting Sensing satellite ESA-ERS2 in 1995. For its long-term radiometric and spectral calibration the GOME observes the sun and less frequently the moon on a regular basis. These measur

  19. 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.

  20. 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.

  1. 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

  2. Storms and Moons

    Science.gov (United States)

    2007-01-01

    The New Horizons Long Range Reconnaissance Imager (LORRI) took this 2-millisecond exposure of Jupiter at 04:41:04 UTC on January 24, 2007. The spacecraft was 57 million kilometers (35.3 million miles) from Jupiter, closing in on the giant planet at 41,500 miles (66,790 kilometers) per hour. At right are the moons Io (bottom) and Ganymede; Ganymede's shadow creeps toward the top of Jupiter's northern hemisphere. Two of Jupiter's largest storms are visible; the Great Red Spot on the western (left) limb of the planet, trailing the Little Red Spot on the eastern limb, at slightly lower latitude. The Great Red Spot is a 300-year old storm more than twice the size of Earth. The Little Red Spot, which formed over the past decade from the merging of three smaller storms, is about half the size of its older and 'greater' counterpart.

  3. 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

  4. Moon shots for management.

    Science.gov (United States)

    Hamel, Gary

    2009-02-01

    In May 2008, a group of management scholars and senior executives worked to define an agenda for management during the next 100 years. The so-called renegade brigade, led by Gary Hamel, included academics, such as C.K. Prahalad, Peter Senge, and Jeffrey Pfeffer; new-age thinkers, like James Surowiecki; and progressive CEOs, such as Whole Foods' John Mackey, W.L. Gore's Terri Kelly, and IDEO's Tim Brown. What drew them together was a set of shared beliefs about the importance of management and a sense of urgency about reinventing it for a new era. The group's first task was to compile a roster of challenges that would focus the energies of management innovators around the world. Accordingly, in this article, Hamel (who has set up the Management Lab, a research organization devoted to management innovation) outlines 25 "moon shots"--ambitious goals that managers should strive to achieve and in the process create Management 2.0. Topping the list is the imperative of extending management's responsibilities beyond just creating shareholder value. To do so will require both reconstructing the field's philosophical foundations so that work serves a higher purpose and fully embedding the ideas of community and citizenship into organizations. A number of challenges focus on ameliorating the toxic effects of hierarchy. Others focus on better ways to unleash creativity and capitalize on employees' passions. Still others seek to transcend the limitations of traditional patterns of management thinking. Not all the moon shots are new, but many tackle issues that are endemic in large organizations. Their purpose is to inspire new solutions to long-simmering problems by making every company as genuinely human as the people who work there.

  5. Continuous measurements of the total ozone content in the full moon period

    Science.gov (United States)

    Ishov, Alexander G.

    1994-01-01

    Presented are the experimental data on the total ozone content obtained during continuous measurements (day-night-...-night-day) by Brewer 044 spectrophotometer near the Issyk Kul Lake (42.59N, 77.04W) at 1650 m above the sea level at full moon from 13 to 18 October 1989 under anomalously high transparent atmospheric conditions (the horizontal visibility range exceeded 50 km). At night the total O3 content decreased regularly to about 20 percent of the average daytime values. The minimum values at night were observed in 1-2 hours after the maximum solar dip below the horizon. In the daytime the measurements were carried out from direct Sun, at night - from the Moon. The values of the total ozone content for adjacent measurements from the Sun and from the Moon in the evening as well as in the morning are in good agreement.

  6. Earth-moon Trajectory Optimization Using Solar Electric Propulsion

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The optimization of the Earth-moon trajectory using solar electric propulsion is presented. A feasible method is proposed to optimize the transfer trajectory starting from a low Earth circular orbit (500 km altitude) to a low lunar circular orbit (200 km altitude). Due to the use of low-thrust solar electric propulsion, the entire transfer trajectory consists of hundreds or even thousands of orbital revolutions around the Earth and the moon. The Earth-orbit ascending (from low Earth orbit to high Earth orbit) and lunar descending (from high lunar orbit to low lunar orbit) trajectories in the presence of J2 perturbations and shadowing effect are computed by an analytic orbital averaging technique. A direct/indirect method is used to optimize the control steering for the trans-lunar trajectory segment, a segment fiom a high Earth orbit to a high lunar orbit, with a fixed thrust-coast-thrust engine sequence. For the trans-lunar trajectory segment, the equations of motion are expressed in the inertial coordinates about the Earth and the moon using a set of nonsingular equinoctial elements inclusive of the gravitational forces of the sun, the Earth, and the moon. By way of the analytic orbital averaging technique and the direct/indirect method, the Earth-moon transfer problem is converted to a parameter optimization problem, and the entire transfer trajectory is formulated and optimized in the form of a single nonlinear optimization problem with a small number of variables and constraints. Finally, an example of an Earth-moon transfer trajectory using solar electric propulsion is demonstrated.

  7. 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

  8. 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

  9. 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

  10. The undulating spiral motion of celestial bodies in solar system relative to a certain point on the earth (Ⅰ)---the derivation and simulation analysis of spiral motion equation of the sun and the moon relative to a certain point on the earth%太阳系天体相对地球某点的波动式螺线运动(Ⅰ)--太阳、月球相对地球某点螺线运动方程推导及模拟分析

    Institute of Scientific and Technical Information of China (English)

    李嘉; 李琳; 张勇军; 李钦豪

    2014-01-01

    motion around the earth transfered into the sun's cosine undulation around geocentric , which was used as standardize cosine curve.In order to derive the locus equation of undulating spiral motion about the sun relative to a certain point on terrestrial equator , and to complete computer simulation and analysis , the sun's motion around the earth was decomposed into undulation and “rotation”, and the coordinate axis was relatively decom-posed into double-undulation and undulation-spiral surface coordinate axis .At the same time, it was easy to obtain the locus equation of undulating spiral motion about the sun relative to a certain point on any lat -itude .It was possible to derive the locus equation of undulating spiral motion about any solar system body relative to any point on the earth and to complete computer simulation and analysis .The result indicated that the trajectory about the sun and the moon relative to any point on the earth was undulation spiral re-lated to its amplitude and angle .Besides its constant spread toward x axis, the property goes as:a) ac-cording to the analysis under double-undulation coordinate axis , the undulation of the sun and the moon on z axis was so faint that it can be regarded as plane undulation in classical mechanics; the spiral ap-pears periodical change and its projection on the three coordinate planes were all periodical wave func -tion;the entire spread appears thin film fluctuation;the direction of the moon's motion was complicated . b) according to the analysis under the undulation-spiral surface coordinate axis , x axis order of magni-tudes is parallel to the one of z axis, and the ratio of zaxis maximum to x axis was approximately 2/5;spi-ral undulation was a periodical spread around cosine fluctuation plane , which moved from starting point and along Archimedean spiral , and the rotation speed of spiral was related to the undulation period of the sun and the moon;the entire spread appears thin film undulating plane .c

  11. Space-radiation-induced Photon Luminescence of the Moon

    Science.gov (United States)

    Wilson, Thomas; Lee, Kerry

    2008-01-01

    We report on the results of a study of the photon luminescence of the Moon induced by Galactic Cosmic Rays (GCRs) and space radiation from the Sun, using the Monte Carlo program FLUKA. The model of the lunar surface is taken to be the chemical composition of soils found at various landing sites during the Apollo and Luna programs, averaged over all such sites to define a generic regolith for the present analysis. This then becomes the target that is bombarded by Galactic Cosmic Rays (GCRs) and Solar Energetic Particles (SEPs) above 1 keV in FLUKA to determine the photon fluence albedo produced by the Moon's surface when there is no sunlight and Earthshine. This is to be distinguished from the gamma-ray spectrum produced by the radioactive decay of radiogenic constituents lying in the surface and interior of the Moon. From the photon fluence we derive the spectrum which can be utilized to examine existing lunar spectral data and to design orbiting instrumentation for measuring various components of the space-radiation-induced photon luminescence present on the Moon.

  12. Neutral atmosphere near the icy surface of Jupiter's moon Ganymede

    Science.gov (United States)

    Shematovich, V. I.

    2016-07-01

    The paper discusses the formation and dynamics of the rarefied gas envelope near the icy surface of Jupiter's moon Ganymede. Being the most massive icy moon, Ganymede can form a rarefied exosphere with a relatively dense near-surface layer. The main parent component of the gas shell is water vapor, which enters the atmosphere due to thermal degassing, nonthermal radiolysis, and other active processes and phenomena on the moon's icy surface. A numerical kinetic simulation is performed to investigate, at the molecular level, the formation, chemical evolution, and dynamics of the mainly H2O- and O2-dominant rarefied gas envelopes. The ionization processes in these rarefied gas envelopes are due to exposure to ultraviolet radiation from the Sun and the magnetospheric plasma. The chemical diversity of the icy moon's gas envelope is attributed to the primary action of ultraviolet solar photons and plasma electrons on the rarefied gas in the H2O- or O2-dominant atmosphere. The model is used to calculate the formation and development of the chemical diversity in the relatively dense near-surface envelope of Ganymede, where an important contribution comes from collisions between parent molecules and the products of their photolysis and radiolysis.

  13. A Vanishing Star Revisited

    Science.gov (United States)

    1999-07-01

    unsual star in question is designated NN Serpentis , or just NN Ser . As the name indicates, it is located in the constellation of Serpens (The Serpent), about 12° north of the celestial equator. A double letter, here "NN", is used to denote variable stars [2]. It is a rather faint object of magnitude 17, about 25,000 times fainter than what can be perceived with the unaided eye. The distance is about 600 light-years (180 pc). In July 1988, Reinhold Häfner performed observations of NN Ser (at that time still known by its earlier name PG 1550+131 ) with the Danish 1.54-m telescope at La Silla. He was surprised, but also very pleased to discover that it underwent a very deep eclipse every 187 minutes. Within less than 2 minutes, the brightness dropped by a factor of more than 100 (5 magnitudes). During the next 9 minutes, the star completely disappeared from view - it was too faint to be observed with this telescope. It then again reappeared and the entire event was over after just 11 minutes. Why eclipses are so important for stellar studies An eclipse occurs when one of the stars in a binary stellar system moves in front of the other, as seen by the observer. The effect is similar to what happens during a solar eclipse when the Moon moves in front of the Sun. In both cases, the eclipse may be partial or total , depending on whether or not the eclipsed star (or the Sun) is completely hidden from view. The occurence of eclipses in stellar systems, as seen from the Earth, depends on the spatial orientation of the orbital plane and the sizes of the two stars. Two eclipses take place during one orbital revolution, but they may not both be observable. The physical properties of the two stars in a binary system (e.g., the sizes of the stars, the size and shape of the orbit, the distribution of the light on the surfaces of the stars, their temperatures etc.) can be determined from the measured "light-curve" of the system (a plot of brightness vrs. time). The stars are always

  14. Revised Anatomy of Stars

    CERN Document Server

    Dubin, M; Dubin, Maurice; Soberman, Robert K.

    1997-01-01

    Stars accrete near invisible hydrogen dominated agglomerates. This population, the `dark matter,' effects the nature of stars. Measurements show plasma streams impacting Earth, planets, Sun and stars. This mass-energy source contradicts nebula collapse model for stars. The visual derived model, to which later discoveries (e.g., fusion) were appended, is confounded and contradicted by new observations. Discovery of a quantity of beryllium 7 (53 day half-life) in the Earth's upper atmosphere, fusion produced, hence from the solar outer zone, proves core fusion wrong. Magnetically pinched plasmas from aggregates impact stars at hundreds of km/s, create impulsive conditions for nuclear explosions below the surface. Disks with planets aid cluster capture. Planets modulate the influx varying fusion, hence luminosity (e.g., solar cycle). This population, with no assumptions or ad hoc physics, explains mysterious phenomena, e.g., luminosity/wind variation, sunspots, high temperature corona, CMEs, etc. Standard explan...

  15. 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

  16. Magnetohydrodynamics of the sun

    CERN Document Server

    Priest, Eric

    2014-01-01

    Magnetohydrodynamics of the Sun is a completely new up-to-date rewrite from scratch of the 1982 book Solar Magnetohydrodynamics, taking account of enormous advances in understanding since that date. It describes the subtle and complex interaction between the Sun's plasma atmosphere and its magnetic field, which is responsible for many fascinating dynamic phenomena. Chapters cover the generation of the Sun's magnetic field by dynamo action, magnetoconvection and the nature of photospheric flux tubes such as sunspots, the heating of the outer atmosphere by waves or reconnection, the structure of prominences, the nature of eruptive instability and magnetic reconnection in solar flares and coronal mass ejections, and the acceleration of the solar wind by reconnection or wave-turbulence. It is essential reading for graduate students and researchers in solar physics and related fields of astronomy, plasma physics and fluid dynamics. Problem sets and other resources are available at www.cambridge.org/9780521854719.

  17. The Sun's Supergranulation

    CERN Document Server

    Rieutord, Michel

    2010-01-01

    The Sun's supergranulation refers to a physical pattern covering the surface of the quiet Sun with a typical horizontal scale of approximately 30000km. Its most noticeable observable signature is as a fluctuating velocity field whose components are mostly horizontal. Supergranulation was discovered more than fifty years ago, however explaining why and how it originates still represents one of the main challenges of modern solar physics. A lot of work has been devoted to the subject over the years, but observational constraints, conceptual difficulties and numerical limitations have all concurred to prevent a detailed understanding of the supergranulation phenomenon so far. With the advent of 21st century supercomputing resources and the availability of unprecedented high-resolution observations of the Sun, the solar community has now reached a stage at which key progress can be made on this question. A unifying strategy between observations and modeling is more than ever required for this to be possible. The ...

  18. 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

  19. Near-Sun asteroids

    Science.gov (United States)

    Emel'yanenko, V. V.

    2017-01-01

    As follows from dynamical studies, in the course of evolution, most near-Earth objects reach orbits with small perihelion distances. Changes of the asteroids in the vicinity of the Sun should play a key role in forming the physical properties, size distribution, and dynamical features of the near-Earth objects. Only seven of the discovered asteroids are currently moving along orbits with perihelion distances q orbits farther from the Sun. In this study, we found asteroids that have been recently orbiting with perihelion distances q orbits for hundreds to tens of thousands of years. To carry out astrophysical observations of such objects is a high priority.

  20. The SUN S TRAVELS

    Institute of Scientific and Technical Information of China (English)

    Robert; Louis; Stevenson

    2005-01-01

    The sun is not a-bed, when I At night upon my pillow lie; Stilt round the earth his Way he takes, And morning after morning makes. White here at home, in shining day, We round the sunny garden play, Each tittle Indian sleepy - head Is being kissed and put to bed. And When at eve I rise from tea, Day dawns beyond the Atlantic Sea; And all the children in the West Are getting up and being dressed.The SUN'S TRAVELS@Robert Louis Stevenson

  1. 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.

  2. A Swarm of Ancient Stars

    Science.gov (United States)

    1999-01-01

    This stellar swarm is M80 (NGC 6093), one of the densest of the 147 known globular star clusters in the Milky Way galaxy. Located about 28,000 light-years from Earth, M80 contains hundreds of thousands of stars, all held together by their mutual gravitational attraction. Globular clusters are particularly useful for studying stellar evolution, since all of the stars in the cluster have the same age (about 15 billion years), but cover a range of stellar masses. Every star visible in this image is either more highly evolved than, or in a few rare cases more massive than, our own Sun. Especially obvious are the bright red giants, which are stars similar to the Sun in mass that are nearing the ends of their lives.

  3. Moon Cakes, A Chinese Favorite

    Institute of Scientific and Technical Information of China (English)

    1996-01-01

    CHINA is a nation with many ethnic groups. Thus, there are many legends to explain the nation’s many festivals. The largest and most striking of these festivals are the Spring Festival and Midautumn Festival. Anywhere Chinese people go, they will remember and celebrate these two festivals. The Mid-autumn Festival falls on the fifteenth day of the 8th lunar month. In this festival, Chinese people eat moon cakes, a baked food, with a flour crust around a dense filling. Coming in a great variety of flavors and styles, the moon cake carries a great deal of symbolic significance. The moon cake is round like the moon. "Round" is pronounced "yuan" in Chinese. This character is full of good meanings. When used in reference to a

  4. Wreathes of Magnetism in Rapidly Rotating Suns

    CERN Document Server

    Brown, Benjamin P; Brun, Allan Sacha; Toomre, Juri

    2009-01-01

    When our Sun was young it rotated much more rapidly than now. Observations of young, rapidly rotating stars indicate that many possess substantial magnetic activity and strong axisymmetric magnetic fields. We conduct simulations of dynamo action in rapidly rotating suns with the 3-D MHD anelastic spherical harmonic (ASH) code to explore the complex coupling between rotation, convection and magnetism. Here we study dynamo action realized in the bulk of the convection zone for two systems, rotating at three and five times the current solar rate. We find that substantial organized global-scale magnetic fields are achieved by dynamo action in these systems. Striking wreathes of magnetism are built in the midst of the convection zone, coexisting with the turbulent convection. This is a great surprise, for many solar dynamo theories have suggested that a tachocline of penetration and shear at the base of the convection zone is a crucial ingredient for organized dynamo action, whereas these simulations do not includ...

  5. Maximising the sun

    CSIR Research Space (South Africa)

    Conradie, Dirk CU

    2010-08-01

    Full Text Available South Africa is blessed with some of the best quality solar radiation in the world. In the light of this many exciting opportunities exist to utilize the sun to its full potential in the design of energy efficient buildings. Passive solar buildings...

  6. 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.

  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. Go Sun Smart

    Science.gov (United States)

    Scott, Michael D.; Buller, David B.; Walkosz, Barbara J.; Andersen, Peter A.; Cutter, Gary R.; Dignan, Mark B.

    2008-01-01

    This is the story of Go Sun Smart, a worksite wellness program endorsed by the North American Ski Area Association and funded by the National Cancer Institute. Between 2000 and 2002 we designed and implemented a large-scale worksite intervention at over 300 ski resorts in North America with the objective of reducing ski area employees and guests…

  9. 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...

  10. 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…

  11. 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.

  12. Using the Moon as a Strange Quark Nugget Detector

    Science.gov (United States)

    Herrin, Eugene T.; Rosenbaum, Doris C.; Teplitz, Vigdor L.

    2007-11-01

    We review the romance and mystery of strange quark matter (SQM), including: its basics, our recent work on bounds on the abundance of ton-range strange quark nuggets (SQNs) from Earth seismology, potential SQN bounds from a possible seismic search on the Moon, and our recent bounds on SQNs in the 10 kilogram to ton range from the data of Apollo-implanted seismometers. Finally, we speculate a bit on using the sun or the solar system to detect passage of SQNs of much greater mass than the aforementioned.

  13. Using the Moon as a Strange Quark Nugget Detector

    Energy Technology Data Exchange (ETDEWEB)

    Herrin, Eugene T. [Geology Department, Southern Methodist University, Dallas, TX 75275 (United States); Rosenbaum, Doris C. [Physics Department, Southern Methodist University, Dallas, TX 75275 (United States); Teplitz, Vigdor L. [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States)

    2007-11-15

    We review the romance and mystery of strange quark matter (SQM), including: its basics, our recent work on bounds on the abundance of ton-range strange quark nuggets (SQNs) from Earth seismology, potential SQN bounds from a possible seismic search on the Moon, and our recent bounds on SQNs in the 10 kilogram to ton range from the data of Apollo-implanted seismometers. Finally, we speculate a bit on using the sun or the solar system to detect passage of SQNs of much greater mass than the aforementioned.

  14. Tracing the journey of the sun and the solar siblings through the Milky Way

    NARCIS (Netherlands)

    Martinez, Barbosa C.A.

    2016-01-01

    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

  15. 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

  16. 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.

  17. Keplerian frequency of uniformly rotating neutron stars and quark stars

    CERN Document Server

    Haensel, P; Bejger, M; Lattimer, J M

    2009-01-01

    We calculate Keplerian (mass shedding) configurations of rigidly rotating neutron stars and quark stars with crusts. We check the validity of empirical formula for Keplerian frequency, f_K, proposed by Lattimer & Prakash, f_K(M)=C (M/M_sun)^1/2 (R/10km)^-3/2, where M is the (gravitational) mass of Keplerian configuration, R is the (circumferential) radius of the non-rotating configuration of the same gravitational mass, and C = 1.04 kHz. Numerical calculations are performed using precise 2-D codes based on the multi-domain spectral methods. We use a representative set of equations of state (EOSs) of neutron stars and quark stars. We show that the empirical formula for f_K(M) holds within a few percent for neutron stars with realistic EOSs, provided 0.5 M_sun < M < 0.9 M_max,stat, where M_max,stat is the maximum allowable mass of non-rotating neutron stars for an EOS, and C=C_NS=1.08 kHz. Similar precision is obtained for quark stars with 0.5 M_sun < M < 0.9 M_max,stat. For maximal crust masses...

  18. The Inside of the Moon

    Science.gov (United States)

    Phillips, Roger J.

    2008-09-01

    Fundamental questions remain regarding the lunar interior, e.g.: Why did the Moon apparently cool so early? Why does the Moon have an asymmetric structure (nearside/farside)? What is the thickness of the lunar crust? How much of crustal variability is due to variable melting vs. impact redistribution? How big are impact basins and how deep did they excavate and thermally perturb the mantle? What was the temporal evolution of magmatism and brecciation? Did the mantle overturn subsequent to magma ocean solidification? How laterally heterogeneous is the lunar mantle? Does the Moon have a seismic discontinuity in the mantle? Does the Moon have a core? Does the Moon have a liquid outer core? Did the Moon have a core dynamo? Some of these questions will be at least partially answered in the next several years through new spacecraft investigations such as the GRAIL mission, which will map the lunar gravity field to unprecedented spatial resolution and accuracy. Furthermore, a long-lived, multi-station seismic network is also essential for understanding interior structure. Recent analyses of Apollo seismic data call into question the existence of the mantle discontinuity at 500-km depth, and the thickness of the lunar crust beneath the Apollo 12 and 14 landing sites now has multiple estimates. However, there is still a great deal that can be learned from existing lunar data sets. One productive approach would construct a set of self-consistent models that describe the coupled petrological-thermal evolution of the Moon. Such an investigation involves the high-level marriage of detailed petrological information from samples of the lunar crust and possibly mantle; of models that can predict accurately lunar solidi, liquidi, and equilibrium compositions; and of sophisticated thermal models that accurately incorporate the physics of melting and melt migration.

  19. Modeling the Orbital Sampling Effect of Extrasolar Moons

    CERN Document Server

    Heller, René; Jackson, Brian

    2016-01-01

    The orbital sampling effect (OSE) appears in phase-folded transit light curves of extrasolar planets with moons. Analytical OSE models have hitherto neglected stellar limb darkening and non-zero transit impact parameters and assumed that the moon is on a circular, co-planar orbit around the planet. Here, we present an analytical OSE model for eccentric moon orbits, which we implement in a numerical simulator with stellar limb darkening that allows for arbitrary transit impact parameters. We also describe and publicly release a fully numerical OSE simulator (PyOSE) that can model arbitrary inclinations of the transiting moon orbit. Both our analytical solution for the OSE and PyOSE can be used to search for exomoons in long-term stellar light curves such as those by Kepler and the upcoming PLATO mission. Our updated OSE model offers an independent method for the verification of possible future exomoon claims via transit timing variations and transit duration variations. Photometrically quiet K and M dwarf star...

  20. 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.

  1. 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)

  2. How hot is the sun

    Institute of Scientific and Technical Information of China (English)

    刘超

    2001-01-01

    Do you know how hot thesun is? There are no solidsor liquids on the sun. Why not? The temperature onoutside the sun is more than 10, 000℃, and that at the centre is about 20, 000, 000℃.The sun is so hot that all thesolids and all the liquids havebeen turned into gases.

  3. DENSITY DETERMINATIONS OF THE CORONAE OF COOL STARS USING A NEWLY ASSIGNED PAIR OF Fe xiv LINES IN THE SPECTRA OF α CANIS MINOR, α CENTAURI, AND THE SUN

    Energy Technology Data Exchange (ETDEWEB)

    Beiersdorfer, P.; Hell, N. [Physics Division, Lawrence Livermore National Laboratory, Livermore, CA 94550 (United States); Lepson, J. K. [Space Sciences Laboratory, University of California, Berkeley, CA 94720 (United States); Diaz, F.; Ishikawa, Y., E-mail: beiersdorfer@llnl.gov [Department of Chemistry and the Chemical Physics Program, University of Puerto Rico, San Juan, PR 00931 (United States)

    2015-12-10

    We have identified a previously unassigned pair of lines between 169 and 170 Å in the coronae of cool stars. We attribute these lines to Fe xiv and show that their intensity ratio is sensitive to the electron density. Using observations taken with the Low Energy Transmission Grating Spectrometer of the Chandra X-ray Observatory we infer a density of log(n{sub e}/cm{sup −3})  =  10.2 ± 0.7 and 10.3 ± 0.8 from the newly identified line pair in the coronae of Procyon and α Cen A, respectively.

  4. Notes on Archaeoastronomy in Portugal: From First Light to Dark Moon

    Science.gov (United States)

    Silva, Cândido Marciano da

    2015-05-01

    These notes review the concepts and analyses that were developed over the years, regarding the region of Central Alentejo, in Portugal, following the report in 1971 of the Almendres Cromlech discovery. Field work on menhirs and enclosures, initially targeted at the identification of standstill orientations, would show that some lines seemed to suggest possible equinoctial orientations. However, it appears that it was the orientation pattern of the dolmens that would prevail over equinoctial directions and led to the concepts of the Spring Full Moon and of the rising Sun and Moon crossovers presently under debate.

  5. Notes on Archaeoastronomy in Portugal: From First Light to Dark Moon

    Science.gov (United States)

    da Silva, Cândido Marciano

    2015-05-01

    These notes review the concepts and analyses that were developed over the years, regarding the region of Central Alentejo, in Portugal, following the report in 1971 of the Almendres Cromlech discovery. Field work on menhirs and enclosures, initially targeted at the identification of standstill orientations, would show that some lines seemed to suggest possible equinoctial orientations. However, it appears that it was the orientation pattern of the dolmens that would prevail over equinoctial directions and led to the concepts of the Spring Full Moon and of the rising Sun and Moon crossovers presently under debate.

  6. 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!

  7. 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.

  8. Shooting Star Experiment

    Science.gov (United States)

    1997-01-01

    The Shooting Star Experiment (SSE) is designed to develop and demonstrate the technology required to focus the sun's energy and use the energy for inexpensive space Propulsion Research. Pictured is an engineering model (Pathfinder III) of the Shooting Star Experiment (SSE). This model was used to test and characterize the motion and deformation of the structure caused by thermal effects. In this photograph, alignment targets are being placed on the engineering model so that a theodolite (alignment telescope) could be used to accurately measure the deformation and deflections of the engineering model under extreme conditions, such as the coldness of deep space and the hotness of the sun as well as vacuum. This thermal vacuum test was performed at the X-Ray Calibration Facility because of the size of the test article and the capabilities of the facility to simulate in-orbit conditions

  9. Resource Production on the Moon

    Science.gov (United States)

    Landis, Geoffrey A.

    2014-01-01

    A self-sustaining settlement on the moon, or on other airless bodies such as asteroids, will require the ability to refine desired raw materials from available resources, such as lunar or asteroidal regolith. This work will focus on the example case of pro-duction from lunar regolith. The same process sequences could be used at other locations. Stony asteroids typically have regolith similar to that of the moon, and refining of asteroidal material could use the same techniques, adapted for microgravity. Likewise, Martian rock and soil could also be processed by the techniques discussed here.

  10. General Relativity&Compact Stars

    Energy Technology Data Exchange (ETDEWEB)

    Glendenning, Norman K.

    2005-08-16

    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{sup 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.

  11. Analysis of medium-energy transfers to the Moon

    Science.gov (United States)

    Oshima, Kenta; Topputo, Francesco; Campagnola, Stefano; Yanao, Tomohiro

    2017-03-01

    This study analyzes a recently discovered class of exterior transfers to the Moon. These transfers terminate in retrograde ballistic capture orbits, i.e., orbits with negative Keplerian energy and angular momentum with respect to the Moon. Yet, their Jacobi constant is relatively low, for which no forbidden regions exist, and the trajectories do not appear to mimic the dynamics of the invariant manifolds of the Lagrange points. This paper shows that these orbits shadow instead lunar collision orbits. We investigate the dynamics of singular, lunar collision orbits in the Earth-Moon planar circular restricted three-body problem, and reveal their rich phase space structure in the medium-energy regime, where invariant manifolds of the Lagrange point orbits break up. We show that lunar retrograde ballistic capture trajectories lie inside the tube structure of collision orbits. We also develop a method to compute medium-energy transfers by patching together orbits inside the collision tube and those whose apogees are located in the appropriate quadrant in the Sun-Earth system. The method yields the novel family of transfers as well as those ending in direct capture orbits, under particular energetic and geometrical conditions.

  12. How Small are Small Stars Really?

    Science.gov (United States)

    2002-11-01

    VLT Interferometer Measures the Size of Proxima Centauri and Other Nearby Stars [1] Summary At a distance of only 4.2 light-years, Proxima Centauri is the nearest star to the Sun currently known [2]. It is visible as an 11-magnitude object in the southern constellation of Centaurus and is the faintest member of a triple system, together with Alpha Centauri , the brightest (double) star in this constellation. Proxima Centauri is a very-low-mass star, in fact barely massive enough to burn hydrogen to helium in its interior. It is about seven times smaller than the Sun, and the surface temperature is "only" about 3000 degrees, about half of that of our own star. Consequently, it is also much fainter - the intrinsic brightness is only 1/150th of that of our Sun. Low-mass stars are very interesting objects , also because the physical conditions in their interiors have much in common with those of giant planets, like Jupiter in our solar system. A determination of the sizes of the smallest stars has been impossible until now because of their general faintness and lack of adequate instrumentation. However, astronomers have long been keen to move forward in this direction, since such measurements would provide indirect, crucial information about the behaviour of matter under extreme conditions. When the first observations with the VLT Interferometer (VLTI), combining the light from two of the 8.2-m VLT Unit Telescopes (ANTU and MELIPAL), were made one year ago ( ESO PR 23/01 ), interferometric measurements were also obtained of Proxima Centauri . They formed part of the VLTI commissioning and the data were soon released to the ESO community, cf. the special website. Now, an international team of astronomers from Switzerland, France and ESO/Chile has successfully analysed these observations by means of newly developed, advanced software. For the first time ever, they obtained a highly accurate measurement of the size of such a small star . Three other small stars were also

  13. The Portrayal of the Medicean Moons in Early Astronomical Charts and Books

    Science.gov (United States)

    Mendillo, Michael

    2014-06-01

    Galileo’s talents in perspective and chiaroscuro drawing led to his images of the Moon being accepted as the portrayal of a truly natural physical place. The Moon was seen as a world—real but separate from Earth. In contrast to his resolved views of the Moon, Galileo saw the moons of Jupiter as only points of light, and thus in Sidereus Nuncius they appear as star-symbols. Within 50 years, in Cellarius’ Atlas Coelestis seu Harmonia Macrocosmica (1660), the Medicean moons continue to appear in multiple charts as star-shaped symbols—in most cases equidistant from Jupiter. They appear in the Cellarius charts as updates to the cosmological systems of Copernicus and Tycho Brahe, but not in the charts devoted to the Ptolemaic system. A quarter century later, Mallet did not include the moons of Jupiter in his Copernican chart in Description de l’Universe (1683). Around 1690, in Jaillot’s Four Systems of Cosmology, the Medicean moons appear as circular symbols in four distinct concentric orbits around Jupiter. Additional examples appear in a later edition of Mallet ((1690s), and in De Fer (1705), Dopplemayer (1720), and still later in Buy de Mornas (1761). As objects discussed in scientific book, symbolic representations of the Medicean moons appear in Marius (1614), Descartes (1644), Fontana (1646) and Hevelius (1647). A pictorial survey of antiquarian charts and books depicting the Medicean moons will be the focus of this presentation. As telescope sizes increased, the Galilean moons could be seen as extended objects, and thus the transition occurred from portraying the moons as points of light to disks with physically-meaningful details. Initially, these were done via drawings of glimpses of the disks of the four moons during moments of extremely good seeing (termed “lucky images” in the pre-adaptive optics period). This era of portraying surface characteristics of Io, Europa, Ganymede and Callisto by hand-drawn images from naked-eye observations ended

  14. Detecting extrasolar moons akin to solar system satellites with an orbital sampling effect

    Energy Technology Data Exchange (ETDEWEB)

    Heller, René, E-mail: rheller@physics.mcmaster.ca [Department of Physics and Astronomy, McMaster University (Canada)

    2014-05-20

    Despite years of high accuracy observations, none of the available theoretical techniques has yet allowed the confirmation of a moon beyond the solar system. Methods are currently limited to masses about an order of magnitude higher than the mass of any moon in the solar system. I here present a new method sensitive to exomoons similar to the known moons. Due to the projection of transiting exomoon orbits onto the celestial plane, satellites appear more often at larger separations from their planet. After about a dozen randomly sampled observations, a photometric orbital sampling effect (OSE) starts to appear in the phase-folded transit light curve, indicative of the moons' radii and planetary distances. Two additional outcomes of the OSE emerge in the planet's transit timing variations (TTV-OSE) and transit duration variations (TDV-OSE), both of which permit measurements of a moon's mass. The OSE is the first effect that permits characterization of multi-satellite systems. I derive and apply analytical OSE descriptions to simulated transit observations of the Kepler space telescope assuming white noise only. Moons as small as Ganymede may be detectable in the available data, with M stars being their most promising hosts. Exomoons with the ten-fold mass of Ganymede and a similar composition (about 0.86 Earth radii in radius) can most likely be found in the available Kepler data of K stars, including moons in the stellar habitable zone. A future survey with Kepler-class photometry, such as Plato 2.0, and a permanent monitoring of a single field of view over five years or more will very likely discover extrasolar moons via their OSEs.

  15. Moon-Struck: Artists Rediscover Nature And Observe

    Science.gov (United States)

    Pasachoff, Jay M.; Olson, Roberta J. M.

    We discuss rare early depictions of the Moon by artists who actually observed Earth's nearest neighbor rather than relying on stylized formulas. The earliest, from the 14th and 15th centuries, reveal that revolutionary advances in both pre-telescopic astronomy and naturalistic painting could go hand-in-hand. This link suggests that when painters observed the world, their definition of world could also include the heavens and the Moon. Many of the artists we discuss - e.g., Pietro Lorenzetti, Giotto, and Jan Van Eyck - actually studied the Moon, incorporating their studies into several works. We also consider the star map on the dome over the altar in the Old Sacristy of San Lorenzo, Florence (c. 1442), whose likely advisor was Toscanelli. In addition, we examine representations by artists who painted for Popes Julius II and Leo X - Raphael and Sebastiano del Piombo, both of whom were influenced by individuals at the papal court, such as the astronomer, painter, and cartographer Johann (Giovanni) Ruysch and Leonardo da Vinci. We also discuss Leonardo's pre-telescopic notes and lunar drawings as they impacted on art and science in Florence, where Galileo would study perspective and chiaroscuro. Galileo's representations of the Moon (engraved in his Sidereus Nuncius, 1610) are noted, together with those by Harriot and Galileo's friend, the painter Cigoli. During the 17th century, the Moon's features were telescopically mapped by astronomers with repercussions in art, e.g., paintings by Donati Creti and Raimondo Manzini as well as Adam Elsheimer. Ending with a consideration of the 19th-century artists/astronomers John Russell and John Brett and early lunar photography, we demonstrate that artistic and scientific visual acuity belonged to the burgeoning empiricism of the 14th, 15th, and 16th centuries that eventually yielded modern observational astronomy.

  16. A New Disintegrative Capture Theory for the Origin of the Moon

    CERN Document Server

    Noerdlinger, Peter D

    2012-01-01

    The object that resulted in the creation of the Moon started in the same orbital path as Earth around the Sun, but at Earth's L4. This proto-Moon (PM) was 4 times less massive than the usual Giant Impact (GI) object "Theia" and was captured into Earth orbit. It had a 32% Iron-Nickel-Sulfur core supporting a dynamo, which explains magnetized lunar rocks. Following capture, it was torn apart by tidal forces and its core of iron plastered itself, with some of its rock mantle, on the surface of Earth at a very flat angle (producing the "Late Veneer"). After tidal stripping, the remaining PM rock was driven away from Earth to about 3.8 times Earth's radius and formed into what is now the Moon. The GI theory has several troubles: The violent collision melts the entire Earth, contrary to geological evidence. The Moon itself also has to condense out of the vapor cloud generated in the collision, but there is evidence that the Moon was not condensed out of vapor. In the new theory, the Moon as we know it may be only 3...

  17. The Moon in Close Up

    Institute of Scientific and Technical Information of China (English)

    TANG YUANKAI

    2010-01-01

    @@ Anifty gold-colored vehicle equipped with two solar panel wings attracted the attention of many visitors to the Space Pavilion at the World Expo site in Shanghai.It was the model of the lunar rover for China's moon probe program.

  18. Full moon: uh-oh?

    National Research Council Canada - National Science Library

    Hollander, Dore

    2005-01-01

    ... of the moon, the researchers found no statistically significant differences in the number of births overall or of births to women who had had more than one pregnancy, in types of delivery or in complications. Nevertheless, with a nod to human nature, they expect that the superstition will endure and that some labor and delivery personnel "will continue to l...

  19. When the Moon Is Perfect

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    The Mid-Autumn Festival is a time for all Chinese people to enjoy the Moon while making family reunion september 22 will be the Mid-Autumn Festival, a traditional Chinese festival celebrated on the 15th day of the eighth month eachyear according to the lunar calendar.

  20. Harvest Moon At Lakeview Place

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The Mid-Autumn Festival is an important traditional Chinese festival. Although many families usually celebrate the festival at home in the traditional way, this year, thousands of families had their celebration at Lakeview Place enjoying the lake and full moon.

  1. Fly Me to the Moon

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    One of the most prominent talking points last month was the high-profile launch on October 24 of China’s first moon orbiter.Named Chang ’e-1,the satellite is expected to fulfill a number of scientific objectives,ranging from

  2. Geochemical Exploration of the Moon.

    Science.gov (United States)

    Adler, Isidore

    1984-01-01

    Provides information based on explorations of the Apollo program about the geochemistry of the moon and its importance in developing an understanding of formation/evolution of the solar system. Includes description and some results of orbital remote sensing, lunar x-ray experiments, gamma-ray experiments, alpha-particle experiments, and the Apollo…

  3. Backyard Astronomy: Observing Moon Phases.

    Science.gov (United States)

    Brandou, Bob

    1997-01-01

    Presents an activity involving the observation of moon phases that can provide a one-on-one learning experience and stimulate interaction between a child and an adult family member. This activity can also be initiated by teachers and outcomes can be integrated into the classroom science curriculum. (JRH)

  4. Review - The Sun Rises

    Directory of Open Access Journals (Sweden)

    Mark Bender

    2012-12-01

    Full Text Available Review of: Blackburn, Stuart H. 2010. The Sun Rises: A Shaman's Chant, Ritual Exchange and Fertility in the Apatani Valley. Leiden: Brill. xvii+401. Color and black and white photographs, maps. ISBN: 9789-0041-7578-5 (hardcover, 97USD. The Sun Rises is a model study contextualizing an oral narrative tradition in the social and ritual fabric of a remote community in northeast India. In many ways a companion volume to Himalayan Tribal Tales (Blackburn 2008, the text presents the first substantial translation of a key ritual text of the Apantani Valley dwellers in Arunachal Pradesh, located on the contested border between China (Tibet and India. The Apatani speak a Tibeto-Burman language, practice intensive rice agriculture in carefully terraced fields, and number about 35,000. Their clans populate several centuries-old villages. Until recently, they were separated from the lowlands of Assam and surrounded only by peoples practicing various forms of shifting agriculture. The valley dwellers have increasingly encountered modernization over the last few decades, including Indian and global popular culture, and Christianity. The heart of this book is a chant of nineteen segments.

  5. 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

  6. 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.

  7. Europa--Jupiter's Icy Ocean Moon

    Science.gov (United States)

    Lowes, L.

    1999-01-01

    Europa is a puzzle. The sixth largest moon in our solar system, Europa confounds and intrigues scientists. Few bodies in the solar system have attracted as much scientific attention as this moon of Jupiter because of its possible subsurface ocean of water. The more we learn about this icy moon, the more questions we have.

  8. Jupiter Icy Moons Orbiter (JIMO) Electrical Systems Testbed

    Science.gov (United States)

    Trapp, Scott J.

    2004-01-01

    The Jupiter Icy Moons Orbiter (JIMO) mission will send a spacecraft to explore three of Jupiter s moons (Callisto, Ganymede, and Europa), all of which show evidence of containing vast subterranean oceans beneath their icy surfaces. The evidence of these oceans was discovered by Galileo, and the moons are believed to have the three essential ingredients for life: water, energy, and the necessary chemical elements. Galileo has shown that melted water on Europa has been in contact with the surface of the moon in geologically recent times, and may still lie relatively close to the surface. This project will also introduce a revolutionary new form of electric propulsion powered by a nuclear fission reactor. This electric propulsion is called ion propulsion. It was used on a previous mission called Deep Space 1, proving that ion propulsion works for interplanetary travel. Since JIMO will be traveling farther from the sun, solar power will be difficult to supply the electric energy demanded by the mission. Therefore a nuclear reactor and a thermo-electric converter system will be necessary. Besides making the trip to three of Jupiter's moons - one after the other - a realistic possibility, this new form of power and propulsion opens up the rest of the outer solar system for future exploration. JIMO will fulfill its goals by exploring Europa first, with subsequent trips to the moons Callisto and Ganymede in order to provide comparisons key to understanding the evolution of all three. In order to ensure the stability and proper preparation of the electrical system on JIMO, the High Power AC Power Management and Distribution (PMAD) Test Bed is being developed. The testing on.this AC PMAD will consist of electrical performance verification of candidate power system components. Examples of these components are: high power AC switchgear, high power ACDC converters, AC power distribution units, DC power distribution units, etc. Throughout the course of the summer the over

  9. 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....... The weekly sunburn fraction correlated strongly with the number of ambient sun hours (r=0.73, p

  10. The Sun, Mercury, and Venus

    CERN Document Server

    Elkins-Tanton, Linda T

    2010-01-01

    The Messenger mission to Mercury opened a new window into the inner solar system. In 2008, this mission began a number of years of flybys, culminating in an orbital insertion around Mercury and producing unparalleled observations about this mysterious innermost planet. Mercury orbits so close to the Sun, from the point of view of Earth, that seeing it from the Earth against the Sun's glare is a great challenge. At the same time, the huge gravitational force of the Sun makes it a challenge to put a mission on Mercury without losing it into the Sun. Now, with heightened understanding of Mercury,

  11. 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

  12. The Rapidly Rotating Sun

    Science.gov (United States)

    Hanasoge, Shravan M.; Duvall, Thomas L., Jr.; Sreenivasan, Katepalli R.

    2012-01-01

    Convection in the solar interior is thought to comprise structures at a continuum of scales, from large to small. This conclusion emerges from phenomenological studies and numerical simulations though neither covers the proper range of dynamical parameters of solar convection. In the present work, imaging techniques of time-distance helioseismology applied to observational data reveal no long-range order in the convective motion. We conservatively bound the associated velocity magnitudes, as a function of depth and the spherical-harmonic degree l to be 20-100 times weaker than prevailing estimates within the wavenumber band l ux of a solar luminosity outwards? The Sun is seemingly a much faster rotator than previously thought, with advection dominated by Coriolis forces at scales l < 60.

  13. 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

  14. 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...

  15. Why the sun sucks - Architects versus the sun

    NARCIS (Netherlands)

    De Lange, N.; Niesten, J.; Taminiau, P.

    2014-01-01

    This "designers' manual" is made during the TIDO-course AR0531 Innovation and Sustainability This manual will show how not to design with the Sun. By showing examples how buildings have failed that have not taken the Sun and its effects in consideration, one should get a clearer picture of how you

  16. Why the sun sucks - Architects versus the sun

    NARCIS (Netherlands)

    De Lange, N.; Niesten, J.; Taminiau, P.

    2014-01-01

    This "designers' manual" is made during the TIDO-course AR0531 Innovation and Sustainability This manual will show how not to design with the Sun. By showing examples how buildings have failed that have not taken the Sun and its effects in consideration, one should get a clearer picture of how you

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

    Indian Academy of Sciences (India)

    V V Ivashkin

    2005-12-01

    The Moon-to-Earth low energy trajectories of `detour’type are found and studied within the frame of the Moon –Earth –Sun-particle system.These trajectories use a passive flight to the Earth from an initial elliptic selenocentric orbit with a high aposelenium.The Earth perturbation increases the particle selenocentric energy from a negative value first to zero and then to a positive one and therefore leads to a passive escape of the particle motion from the Moon attraction near the translunar libration point 2. 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 the particle approaching the Earth vicinity in about 100 days of the flight.A set of the Moon-to-Earth `detour’trajectories is de fined numerically.Characteristics of these trajectories are presented.The `detour’trajectories give essential economy of energy (about 150 m/s in Delta V)relative to the usual ones.

  18. Identification of moon craters and solar corona during total solar eclipse on 9th March 2016

    Science.gov (United States)

    Luthfiandari; Ekawanti, N.; Purwati, F. G.; Herdiwijaya, D.

    2016-11-01

    Total Solar Eclipse (TSE) is a rare natural event in which the positions of Sun, Moon, and Earth are perfectly aligned. In the past by using this phenomenon, many researches have been done to understand characteristic of the corona. In this paper we carried out the study of TSE which crossed over Indonesia from West to East on 9th March 2016. We observed TSE which occured in Palembang (2.9883° S 104.7513° E), Indonesia. The aim of this research is to understand the effect of moon craters on the appearance of solar corona and identification of solar active regions during TSE. This research was done using Canon SX170 IS camera with ND 5 sun-filter. Although the sky was cloudy during the totality of the phase, coronal video was still taken. Camera also took solar images of partial eclipse phase. Coronal images for every frame were then extracted from the video. Image processing of coronal images was done using RegiStax and PhotoScape freewares. To study solar corona, images from Virtual Moon Atlas, Hinode XRT, and SOHO-LASCO were compared with the result of oriented coronal image. Wider and many more moon craters were found having positive correlation with the brighter effect on solar corona as shown at westward coronal streamer. Those craters are represented by Bel'kovich crater, the biggest one. We also found that only the eastward coronal streamer was correlated with active region, sunspot number 12519, from behind solar limb.

  19. Access to Mars from Earth-Moon Libration Point Orbits:. [Manifold and Direct Options

    Science.gov (United States)

    Kakoi, Masaki; Howell, Kathleen C.; Folta, David

    2014-01-01

    This investigation is focused specifically on transfers from Earth-Moon L(sub 1)/L(sub 2) libration point orbits to Mars. Initially, the analysis is based in the circular restricted three-body problem to utilize the framework of the invariant manifolds. Various departure scenarios are compared, including arcs that leverage manifolds associated with the Sun-Earth L(sub 2) orbits as well as non-manifold trajectories. For the manifold options, ballistic transfers from Earth-Moon L(sub 2) libration point orbits to Sun-Earth L(sub 1)/L(sub 2) halo orbits are first computed. This autonomous procedure applies to both departure and arrival between the Earth-Moon and Sun-Earth systems. Departure times in the lunar cycle, amplitudes and types of libration point orbits, manifold selection, and the orientation/location of the surface of section all contribute to produce a variety of options. As the destination planet, the ephemeris position for Mars is employed throughout the analysis. The complete transfer is transitioned to the ephemeris model after the initial design phase. Results for multiple departure/arrival scenarios are compared.

  20. Star Shows It Has The Right Stuff

    Science.gov (United States)

    2004-01-01

    Astronomers have used an observation by NASA's Chandra X-ray Observatory to make the best case yet that a star can be engulfed by its companion star and survive. This discovery will help astronomers better understand how closely coupled stars, and perhaps even stars and planets, evolve when one of the stars expands enormously in its red giant phase. The binary star system known as V471 Tauri comprises a white dwarf star (the primary) in a close orbit -- one thirtieth of the distance between Mercury and the Sun -- with a normal Sun-like star (the secondary). Chandra's data showed that the hot upper atmosphere of the secondary star has a deficit of carbon atoms relative to nitrogen atoms. "This deficit of carbon atoms is the first clear observational evidence that the normal star was engulfed by its companion in the past," according to Jeremy Drake of the Smithsonian Astrophysical Observatory in Cambridge, MA, who coauthored an article on V471 in The Astrophysical Journal Letters with Marek Sarna of the N. Copernicus Astronomical Center in Poland. The white dwarf star was once a star several times as massive as the Sun. Nuclear fusion reactions in the core of such a star convert carbon into nitrogen over a period of about a billion years. When the fuel in the core of the star is exhausted, the core collapses, triggering more energetic nuclear reactions that cause the star to expand and transform into a red giant before eventually collapsing to become a white dwarf. The carbon-poor material in the core of the red giant is mixed with outer part of the star, so its atmosphere shows a deficit of carbon, as compared with Sun-like stars. The X-ray spectra of a red giant star (top panel) and a Sun-like star (bottom panel) show the large difference in the peaks due to carbon atoms in the two stars. Theoretical calculations indicate that a red giant in a binary system can completely envelop its companion star and dramatically affect its evolution. During this common envelope