Proceedings of Spie
Total Page:16
File Type:pdf, Size:1020Kb
Load more
Recommended publications
-
Naming the Extrasolar Planets
Naming the extrasolar planets W. Lyra Max Planck Institute for Astronomy, K¨onigstuhl 17, 69177, Heidelberg, Germany [email protected] Abstract and OGLE-TR-182 b, which does not help educators convey the message that these planets are quite similar to Jupiter. Extrasolar planets are not named and are referred to only In stark contrast, the sentence“planet Apollo is a gas giant by their assigned scientific designation. The reason given like Jupiter” is heavily - yet invisibly - coated with Coper- by the IAU to not name the planets is that it is consid- nicanism. ered impractical as planets are expected to be common. I One reason given by the IAU for not considering naming advance some reasons as to why this logic is flawed, and sug- the extrasolar planets is that it is a task deemed impractical. gest names for the 403 extrasolar planet candidates known One source is quoted as having said “if planets are found to as of Oct 2009. The names follow a scheme of association occur very frequently in the Universe, a system of individual with the constellation that the host star pertains to, and names for planets might well rapidly be found equally im- therefore are mostly drawn from Roman-Greek mythology. practicable as it is for stars, as planet discoveries progress.” Other mythologies may also be used given that a suitable 1. This leads to a second argument. It is indeed impractical association is established. to name all stars. But some stars are named nonetheless. In fact, all other classes of astronomical bodies are named. -
Cosmological Aspects of Planetary Habitability
Cosmological aspects of planetary habitability Yu. A. Shchekinov Department of Space Physics, SFU, Rostov on Don, Russia [email protected] M. Safonova, J. Murthy Indian Institute of Astrophysics, Bangalore, India [email protected], [email protected] ABSTRACT The habitable zone (HZ) is defined as the region around a star where a planet can support liquid water on its surface, which, together with an oxygen atmo- sphere, is presumed to be necessary (and sufficient) to develop and sustain life on the planet. Currently, about twenty potentially habitable planets are listed. The most intriguing question driving all these studies is whether planets within habitable zones host extraterrestrial life. It is implicitly assumed that a planet in the habitable zone bears biota. How- ever along with the two usual indicators of habitability, an oxygen atmosphere and liquid water on the surface, an additional one – the age — has to be taken into account when the question of the existence of life (or even a simple biota) on a planet is addressed. The importance of planetary age for the existence of life as we know it follows from the fact that the primary process, the photosynthesis, is endothermic with an activation energy higher than temperatures in habitable zones. Therefore on planets in habitable zones, due to variations in their albedo, orbits, diameters and other crucial parameters, the onset of photosynthesis may arXiv:1404.0641v1 [astro-ph.EP] 2 Apr 2014 take much longer time than the planetary age. Recently, several exoplanets orbiting Population II stars with ages of 12–13 Gyr were discovered. -
Geodynamics and Rate of Volcanism on Massive Earth-Like Planets
The Astrophysical Journal, 700:1732–1749, 2009 August 1 doi:10.1088/0004-637X/700/2/1732 C 2009. The American Astronomical Society. All rights reserved. Printed in the U.S.A. GEODYNAMICS AND RATE OF VOLCANISM ON MASSIVE EARTH-LIKE PLANETS E. S. Kite1,3, M. Manga1,3, and E. Gaidos2 1 Department of Earth and Planetary Science, University of California at Berkeley, Berkeley, CA 94720, USA; [email protected] 2 Department of Geology and Geophysics, University of Hawaii at Manoa, Honolulu, HI 96822, USA Received 2008 September 12; accepted 2009 May 29; published 2009 July 16 ABSTRACT We provide estimates of volcanism versus time for planets with Earth-like composition and masses 0.25–25 M⊕, as a step toward predicting atmospheric mass on extrasolar rocky planets. Volcanism requires melting of the silicate mantle. We use a thermal evolution model, calibrated against Earth, in combination with standard melting models, to explore the dependence of convection-driven decompression mantle melting on planet mass. We show that (1) volcanism is likely to proceed on massive planets with plate tectonics over the main-sequence lifetime of the parent star; (2) crustal thickness (and melting rate normalized to planet mass) is weakly dependent on planet mass; (3) stagnant lid planets live fast (they have higher rates of melting than their plate tectonic counterparts early in their thermal evolution), but die young (melting shuts down after a few Gyr); (4) plate tectonics may not operate on high-mass planets because of the production of buoyant crust which is difficult to subduct; and (5) melting is necessary but insufficient for efficient volcanic degassing—volatiles partition into the earliest, deepest melts, which may be denser than the residue and sink to the base of the mantle on young, massive planets. -
The Spitzer Search for the Transits of HARPS Low-Mass Planets II
A&A 601, A117 (2017) Astronomy DOI: 10.1051/0004-6361/201629270 & c ESO 2017 Astrophysics The Spitzer search for the transits of HARPS low-mass planets II. Null results for 19 planets? M. Gillon1, B.-O. Demory2; 3, C. Lovis4, D. Deming5, D. Ehrenreich4, G. Lo Curto6, M. Mayor4, F. Pepe4, D. Queloz3; 4, S. Seager7, D. Ségransan4, and S. Udry4 1 Space sciences, Technologies and Astrophysics Research (STAR) Institute, Université de Liège, Allée du 6 Août 17, Bat. B5C, 4000 Liège, Belgium e-mail: [email protected] 2 University of Bern, Center for Space and Habitability, Sidlerstrasse 5, 3012 Bern, Switzerland 3 Cavendish Laboratory, J. J. Thomson Avenue, Cambridge CB3 0HE, UK 4 Observatoire de Genève, Université de Genève, 51 Chemin des Maillettes, 1290 Sauverny, Switzerland 5 Department of Astronomy, University of Maryland, College Park, MD 20742-2421, USA 6 European Southern Observatory, Karl-Schwarzschild-Str. 2, 85478 Garching bei München, Germany 7 Department of Earth, Atmospheric and Planetary Sciences, Department of Physics, Massachusetts Institute of Technology, 77 Massachusetts Ave., Cambridge, MA 02139, USA Received 8 July 2016 / Accepted 15 December 2016 ABSTRACT Short-period super-Earths and Neptunes are now known to be very frequent around solar-type stars. Improving our understanding of these mysterious planets requires the detection of a significant sample of objects suitable for detailed characterization. Searching for the transits of the low-mass planets detected by Doppler surveys is a straightforward way to achieve this goal. Indeed, Doppler surveys target the most nearby main-sequence stars, they regularly detect close-in low-mass planets with significant transit probability, and their radial velocity data constrain strongly the ephemeris of possible transits. -
Mètodes De Detecció I Anàlisi D'exoplanetes
MÈTODES DE DETECCIÓ I ANÀLISI D’EXOPLANETES Rubén Soussé Villa 2n de Batxillerat Tutora: Dolors Romero IES XXV Olimpíada 13/1/2011 Mètodes de detecció i anàlisi d’exoplanetes . Índex - Introducció ............................................................................................. 5 [ Marc Teòric ] 1. L’Univers ............................................................................................... 6 1.1 Les estrelles .................................................................................. 6 1.1.1 Vida de les estrelles .............................................................. 7 1.1.2 Classes espectrals .................................................................9 1.1.3 Magnitud ........................................................................... 9 1.2 Sistemes planetaris: El Sistema Solar .............................................. 10 1.2.1 Formació ......................................................................... 11 1.2.2 Planetes .......................................................................... 13 2. Planetes extrasolars ............................................................................ 19 2.1 Denominació .............................................................................. 19 2.2 Història dels exoplanetes .............................................................. 20 2.3 Mètodes per detectar-los i saber-ne les característiques ..................... 26 2.3.1 Oscil·lació Doppler ........................................................... 27 2.3.2 Trànsits -
Determining the True Mass of Radial-Velocity Exoplanets with Gaia F
Determining the true mass of radial-velocity exoplanets with Gaia F. Kiefer, G. Hébrard, A. Lecavelier Des Etangs, E. Martioli, S. Dalal, A. Vidal-Madjar To cite this version: F. Kiefer, G. Hébrard, A. Lecavelier Des Etangs, E. Martioli, S. Dalal, et al.. Determining the true mass of radial-velocity exoplanets with Gaia: Nine planet candidates in the brown dwarf or stellar regime and 27 confirmed planets. Astronomy and Astrophysics - A&A, EDP Sciences, 2021, 645, pp.A7. 10.1051/0004-6361/202039168. hal-03085694 HAL Id: hal-03085694 https://hal.archives-ouvertes.fr/hal-03085694 Submitted on 21 Dec 2020 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. A&A 645, A7 (2021) Astronomy https://doi.org/10.1051/0004-6361/202039168 & © F. Kiefer et al. 2020 Astrophysics Determining the true mass of radial-velocity exoplanets with Gaia Nine planet candidates in the brown dwarf or stellar regime and 27 confirmed planets? F. Kiefer1,2, G. Hébrard1,3, A. Lecavelier des Etangs1, E. Martioli1,4, S. Dalal1, and A. Vidal-Madjar1 1 Institut d’Astrophysique de Paris, Sorbonne -
The Hd 40307 Planetary System: Super-Earths Or Mini-Neptunes?
The Astrophysical Journal, 695:1006–1011, 2009 April 20 doi:10.1088/0004-637X/695/2/1006 C 2009. The American Astronomical Society. All rights reserved. Printed in the U.S.A. THE HD 40307 PLANETARY SYSTEM: SUPER-EARTHS OR MINI-NEPTUNES? Rory Barnes1, Brian Jackson1, Sean N. Raymond2,4, Andrew A. West3, and Richard Greenberg1 1 Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ 85721, USA 2 Center for Astrophysics and Space Astronomy, University of Colorado, Boulder, CO 80309, USA 3 Astronomy Department, University of California, 601 Campbell Hall, Berkeley, CA 94720-3411, USA Received 2008 July 9; accepted 2009 January 15; published 2009 April 6 ABSTRACT Three planets with minimum masses less than 10 M⊕ orbit the star HD 40307, suggesting these planets may be rocky. However, with only radial velocity data, it is impossible to determine if these planets are rocky or gaseous. Here we exploit various dynamical features of the system in order to assess the physical properties of the planets. Observations allow for circular orbits, but a numerical integration shows that the eccentricities must be at least 10−4. Also, planets b and c are so close to the star that tidal effects are significant. If planet b has tidal parameters similar to the terrestrial planets in the solar system and a remnant eccentricity larger than 10−3, then, going back in time, the system would have been unstable within the lifetime of the star (which we estimate to be 6.1 ± 1.6 Gyr). Moreover, if the eccentricities are that large and the inner planet is rocky, then its tidal heating may be an order of magnitude greater than extremely volcanic Io, on a per unit surface area basis. -