DOCSLIB.ORG

Extrasolar Planets

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Extrasolar Planets Extrasolar Planets to appear in Encyclopedia of Time, Sage Publishing, in preparation, H.J. Birx (Ed.) The term extrasolar planets or exoplanets stands for planets outside our Solar System, i.e. not orbiting the Sun, but other stars. Planets in our Solar System are defined as objects with enough mass to be spherical and round by their own gravity and to be alone on their orbit around the Sun, i.e. to be the dominant object in a particular orbit, and not to be a moon or asteroid (see the entry Planet in this encyclopedia for the official definition, the historical debate, and a discussion of the planets of our Solar System). Most exoplanets are discovered by observing the stellar motion around the common center of mass of the star+planet system, i.e. by observing somehow the motion of the objects in orbit around each other, i.e. by measuring precisely the periodic variation of certain values, e.g. radial velocity or brightness, with time, e.g. the first extrasolar planets were found with the timing technique around a pulsating neutron star. The recent definition of Planets of our Solar System by the International Astronomical Union deals mainly with the question of the minimum mass for an object to qualify as planet and excludes Pluto. This matter was raised by the fact that more and more objects similar to Pluto were discovered by larger and larger telescopes. The questions of maximum mass and formation of planets were left out in this new definition, possibly partly because there is not yet a consensus in the international community. For a discussion of extrasolar planets, however, the maximum mass is very important, namely in order to classify an object as planet or nor - and to distinguish between planets and brown dwarfs. Both planets and brown dwarfs are sub-stellar objects in the sense that they are less massive than stars, so that they cannot fuse normal hydrogen (as stars do to produce energy and to shine for a long time). Brown dwarfs, while they cannot fuse normal hydrogen (atomic nucleus made up by just one proton), can burn deuterium, i.e. heavy hydrogen (a proton plus a neutron), so that they are self-luminous for a few millions of years until the original deuterium content is depleted. The upper mass limit of planets can be defined either through the lower mass limit for deuterium fusion, which is around 13 times the mass of Jupiter depending slightly on the chemical composition, or by the mass range of the so-called brown dwarf desert (see next paragraphs). We will next discuss the different exoplanet discovery techniques by chronological order of success and thereby also discuss the properties of objects found so far. Radial Velocity: Since a few thousand years, speculations exist as to whether other stars can have their own planets. Both Giordano Bruno and Nikolaus of Cues have answered this question positively a few hundred years ago. However, not until 1989, the first object was discovered which could really be an extrasolar planets and which is today still regarded as planet candidate. This first extrasolar planet candidate was discovered serendipitously by the so-called radial velocity technique: The velocity of the motion of an object directly towards us or away from us (in one dimension) is called radial velocity and can be measured by the so-called Doppler shift of spectral lines. Atoms in the atmosphere of stars can absorb light coming from the interior of the star, namely at a certain energy, frequency, or wavelength for each kind of atom or ion, producing absorption lines in the spectrum of the star. If the star moves away from us, such lines are red-shifted (blue-shifted when approaching us), i.e. at a wavelength different from the normal wavelength (larger for red-shifted). When a second object like a planet orbits around a star, actually both objects orbit around their common center of mass. Hence, also the star wobbles: It sometimes approaches us, sometimes flies away from us. This can be observed as periodically changing radial velocity. The period of the variation gives the orbital period and the amplitude of the change in radial velocity yields the mass of the companion. However, because the inclination between the orbital plane and our line of sight is normally not known, only a lower mass limit is known. Therefore, such low-mass companions detected by the radial velocity technique are to be seen as planet candidates, they could have a mass above the maximum mass for planets, namely then being brown dwarfs or even low-mass stars. The first such case was published in 1989 by Latham et al., namely a companion with minimum mass of 11 Jupiter masses around the star HD 114762. This planet is called HD 114762 b, always the first planet found around a star is called by the name of the star plus a small b behind the star name (small letter c for next planet, etc). This planet may very well have a true mass above 13 Jupiter masses, in which case it could be regarded as brown dwarf. The first object discovered around a sun-like normal star, which is almost certainly a planet, is called 51 Peg b and is a planet with about half the mass of Jupiter as minimum mass found by Mayor & Queloz around the star 51 Peg in 1995. The radial velocity can nowadays be measured with an accuracy of about one meter per second, so that planets with minimum mass of a few Earth masses can be detected by the wobble they produce on a low-mass star. One Jupiter orbit, i.e. 12 years after the important discovery of 51 Peg b, there are now about 250 planet candidates discovered. In some cases, several planet candidates are orbiting a single star, in some other cases, individual planet candidates are found in binary stars. Because the high precision of radial velocity technique is available since about the early 1990s, planets with more than 20 years of orbital period could not yet be discovered, one needs to observe at least one orbital period. Many planet candidates found so far orbit their stars with only few days, which is quite different from our Solar System, where the innermost planet Mercury needs several month to orbit the Sun. The high number of planet candidates with short orbital period, however, can be seen as observational bias, because such planets also introduce a larger wobble on their star due to Kepler´s and Newton´s laws of gravity. The mass range of all these planet candidates shows a strong peak at about one Jupiter mass and a strong dip at around 20 to 30 Jupiter masses, even though this method would be biased towards more massive companions, because they have a stronger effect on their central star. There are about 250 planet candidates all with masses below about 20 Jupiter masses, then almost no objects with minimum mass between about 20 and 70 Jupiter masses, i.e. only few brown dwarfs, and then again a large number of stellar companions (with minimum mass above 70 Jupiter masses). This paucity of brown dwarfs from the radial velocity technique is called brown dwarf desert and the dip in the mass spectrum is deepest at around 20 to 30 Jupiter masses. Either the lower mass range of the brown dwarf desert or the minimum mass for deuterium burning can be used as upper mass limit for planets, if one would define the upper mass limit for planets. Pulsar timing: At the end of the life time of a massive star, after most of the material is burned by fusion, the star collapses due to its own gravity, then forms a very dense and compact object made up mostly by neutrons, called neutron star, while the rest explodes due to a rebound as super nova. A neutron star typically has about 1.4 times the mass of our Sun, but a diameter of only 20 to 30 kilo meters. Such neutron stars rotate very fast, sometimes even about 100 times per second, sometimes once in few seconds. Most known neutron stars emit strong radio emission along their rotation axes (beams), which appear pulsed due to the fast rotation. We should keep in mind that so-called Puslars are not pulsating, but rotating fast. One can measure the rotation period as pulses with both high precision and high accuracy, such objects are called Pulsars. In the case of the Pulsar called PSR1257, Wolszczan & Frail discovered sinusoidal variations of the millisecond pulses in 1992 and interpreted these variations to be caused by low-mass objects in orbit around the neutron star, with a mass of only about the planet Earth. This discovery of Pulsar planets (by Pulsar timing) came as a big surprise, because planets were not expected around neutron stars; it is still dubious as to whether planets can survive the supernova explosion, or whether the objects found around PSR1257 are either remnants of the explosion or formed afterwards. Transit: In the case of planets or planet candidates discovered by the radial velocity technique, the inclination of the orbit of the planet around the star in not known. One way to determine this inclination would be a so-called transit, i.e. when the planet orbits around the star in our line-of-sight, so that the planet moves in front of the star once per orbit (and behind the star also once per orbit). When the planet is in front of the star (i.e.
Load more

Recommended publications
  • Astronomie in Theorie Und Praxis 8. Auflage in Zwei Bänden Erik Wischnewski
    Astronomie in Theorie und Praxis 8. Auflage in zwei Bänden Erik Wischnewski Inhaltsverzeichnis 1 Beobachtungen mit bloßem Auge 37 Motivation 37 Hilfsmittel 38 Drehbare Sternkarte Bücher und Atlanten Kataloge Planetariumssoftware Elektronischer Almanach Sternkarten 39 2 Atmosphäre der Erde 49 Aufbau 49 Atmosphärische Fenster 51 Warum der Himmel blau ist? 52 Extinktion 52 Extinktionsgleichung Photometrie Refraktion 55 Szintillationsrauschen 56 Angaben zur Beobachtung 57 Durchsicht Himmelshelligkeit Luftunruhe Beispiel einer Notiz Taupunkt 59 Solar-terrestrische Beziehungen 60 Klassifizierung der Flares Korrelation zur Fleckenrelativzahl Luftleuchten 62 Polarlichter 63 Nachtleuchtende Wolken 64 Haloerscheinungen 67 Formen Häufigkeit Beobachtung Photographie Grüner Strahl 69 Zodiakallicht 71 Dämmerung 72 Definition Purpurlicht Gegendämmerung Venusgürtel Erdschattenbogen 3 Optische Teleskope 75 Fernrohrtypen 76 Refraktoren Reflektoren Fokus Optische Fehler 82 Farbfehler Kugelgestaltsfehler Bildfeldwölbung Koma Astigmatismus Verzeichnung Bildverzerrungen Helligkeitsinhomogenität Objektive 86 Linsenobjektive Spiegelobjektive Vergütung Optische Qualitätsprüfung RC-Wert RGB-Chromasietest Okulare 97 Zusatzoptiken 100 Barlow-Linse Shapley-Linse Flattener Spezialokulare Spektroskopie Herschel-Prisma Fabry-Pérot-Interferometer Vergrößerung 103 Welche Vergrößerung ist die Beste? Blickfeld 105 Lichtstärke 106 Kontrast Dämmerungszahl Auflösungsvermögen 108 Strehl-Zahl Luftunruhe (Seeing) 112 Tubusseeing Kuppelseeing Gebäudeseeing Montierungen 113 Nachführfehler
    [Show full text]
  • The Slow Spin of the Young Sub-Stellar Companion GQ Lupi B and Its Orbital Configuration Henriette Schwarz1?, Christian Ginski1, Remco J
    Astronomy & Astrophysics manuscript no. AA-2016-28908-preprint c ESO 2016 July 4, 2016 The slow spin of the young sub-stellar companion GQ Lupi b and its orbital configuration Henriette Schwarz1?, Christian Ginski1, Remco J. de Kok1; 2, Ignas A. G. Snellen1, Matteo Brogi3; 5, and Jayne L. Birkby4; 6 1 Leiden Observatory, Leiden University, PO Box 9513, 2300 RA Leiden, The Netherlands 2 SRON Netherlands Institute for Space Research, Sorbonnelaan 2, 3584 CA Utrecht, The Netherlands 3 Center for Astrophysics and Space Astronomy, University of Colorado at Boulder, CO 80309 Boulder, USA 4 Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, MA 02138 Cambridge, USA 5 NASA Hubble Fellow 6 NASA Sagan Fellow ABSTRACT The spin of a planet or brown dwarf is related to the accretion process, and therefore studying spin can help promote our understand- ing of the formation of such objects. We present the projected rotational velocity of the young sub-stellar companion GQ Lupi b, along with its barycentric radial velocity. The directly imaged exoplanet or brown dwarf companion joins a small but growing en- semble of wide-orbit sub-stellar companions with a spin measurement. The GQ Lupi system was observed at high spectral resolution (R ∼100 000), and in the analysis we made use of both spectral and spatial filtering to separate the signal of the companion from that of the host star. We detect both CO (S/N=11.6) and H2O (S/N=7.7) in the atmosphere of GQ Lupi b by cross-correlating with model +0:9 −1 spectra, and we find it to be a slow rotator with a projected rotational velocity of 5:3−1:0 km s .
    [Show full text]
  • An Upper Limit on the Mass of the Circumplanetary Disk for DH Tau B
    Draft version August 28, 2021 Preprint typeset using LATEX style emulateapj v. 12/16/11 AN UPPER LIMIT ON THE MASS OF THE CIRCUM-PLANETARY DISK FOR DH TAU B* Schuyler G. Wolff1, Franc¸ois Menard´ 2, Claudio Caceres3, Charlene Lefevre` 4, Mickael Bonnefoy2,Hector´ Canovas´ 5,Sebastien´ Maret2, Christophe Pinte2, Matthias R. Schreiber6, and Gerrit van der Plas2 Draft version August 28, 2021 ABSTRACT DH Tau is a young (∼1 Myr) classical T Tauri star. It is one of the few young PMS stars known to be associated with a planetary mass companion, DH Tau b, orbiting at large separation and detected by direct imaging. DH Tau b is thought to be accreting based on copious Hα emission and exhibits variable Paschen Beta emission. NOEMA observations at 230 GHz allow us to place constraints on the disk dust mass for both DH Tau b and the primary in a regime where the disks will appear optically thin. We estimate a disk dust mass for the primary, DH Tau A of 17:2 ± 1:7 M⊕, which gives a disk- to-star mass ratio of 0.014 (assuming the usual Gas-to-Dust mass ratio of 100 in the disk). We find a conservative disk dust mass upper limit of 0.42M⊕ for DH Tau b, assuming that the disk temperature is dominated by irradiation from DH Tau b itself. Given the environment of the circumplanetary disk, variable illumination from the primary or the equilibrium temperature of the surrounding cloud would lead to even lower disk mass estimates. A MCFOST radiative transfer model including heating of the circumplanetary disk by DH Tau b and DH Tau A suggests that a mass averaged disk temperature of 22 K is more realistic, resulting in a dust disk mass upper limit of 0.09M⊕ for DH Tau b.
    [Show full text]
  • Constraints on the Spin Evolution of Young Planetary-Mass Companions Marta L
    Constraints on the Spin Evolution of Young Planetary-Mass Companions Marta L. Bryan1, Björn Benneke2, Heather A. Knutson2, Konstantin Batygin2, Brendan P. Bowler3 1Cahill Center for Astronomy and Astrophysics, California Institute of Technology, 1200 East California Boulevard, MC 249-17, Pasadena, CA 91125, USA. 2Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA 91125, USA. 3McDonald Observatory and Department of Astronomy, University of Texas at Austin, Austin, TX 78712, USA. Surveys of young star-forming regions have discovered a growing population of planetary- 1 mass (<13 MJup) companions around young stars . There is an ongoing debate as to whether these companions formed like planets (that is, from the circumstellar disk)2, or if they represent the low-mass tail of the star formation process3. In this study we utilize high-resolution spectroscopy to measure rotation rates of three young (2-300 Myr) planetary-mass companions and combine these measurements with published rotation rates for two additional companions4,5 to provide a look at the spin distribution of these objects. We compare this distribution to complementary rotation rate measurements for six brown dwarfs with masses <20 MJup, and show that these distributions are indistinguishable. This suggests that either that these two populations formed via the same mechanism, or that processes regulating rotation rates are independent of formation mechanism. We find that rotation rates for both populations are well below their break-up velocities and do not evolve significantly during the first few hundred million years after the end of accretion. This suggests that rotation rates are set during late stages of accretion, possibly by interactions with a circumplanetary disk.
    [Show full text]
  • Linking Asteroids and Meteorites Through Reflectance Spectroscopy
    Astronomy 100 Exploring the Universe Tuesday, Wednesday, Thursday Tom Burbine [email protected] Composition of the Planets Different bodies have different densities • Density = Mass/Volume • M = 4π2d3/GP2 V =4/3πR3 Life of a Star • A star-forming cloud is called a molecular cloud because low temperatures allow Hydrogen to form Hydrogen molecules (H2) • Temperatures like 10-50 K Region is approximately 50 light years across Condensing • Interstellar clouds tends to be lumpy • These lumps tend to condense into stars • That is why stars tend to be found in clusters Protostar • The dense cloud fragment gets hotter as it contracts • The cloud becomes denser and radiation cannot escape • The thermal pressure and gas temperature start to rise and rise • The dense cloud fragment becomes a protostar When does a protostar become a star • When the core temperatures reaches 10 million K, hydrogen fusion can start occurring Formation of Solar System • Solar Nebula Theory (18th century) – Solar System originated from a rotating, disk-shaped cloud of gas and dust • Modern theory is that the Solar System was born from an interstellar cloud (an enormous rotating cloud of gas and dust) Composition • ~71% is Hydrogen • ~27% is Helium • ~2% are other elements (Fe, Si, O) in the form of interstellar grains • Show animation • Dust grains collide and stick to form larger and larger bodies. • When the bodies reach sizes of approximately one kilometer, then they can attract each other directly through their mutual gravity, becoming protoplanets • Protoplanets
    [Show full text]
  • Gas and Dust from Hot, Rocky Exoplanets Delivery of Organic
    Adaptive optics for high-contrast imaging: The Holographic Modal Wavefront Sensor (HMWFS) Goal: Combining focal-plane Meetings feature presentations by PhD students, postdocs and professors wavefront sensing with apodising phase plate coronography to create who are carrying out research relating to planetary science. temporally stable high-contrast regions in the science PSF, suited to Next meeting: 29 MAY 2015 AT LEIDEN OBSERVATORY, LEIDEN UNIVERSITY direct imaging of exoplanets and Michael Wilby If you would like to join or would like more information, Fig: Focal-plane image of a 6 Zernike mode HMWFS, with a) flat their characterisation with next- Leiden Observatory wavefront and b) 1.5 radians defocus error (Z3). Modal content of the generation instrumentation. [email protected] input wavefront is measured directly by coupled pairs of WFS spots please email [email protected]. Aqueous alteration of polycyclic aromatic hydrocarbons Delivery of organic material and water Present in meteorites and asteroids to planets through asteroid impacts at NAC Is it possible through The goal is to define observables for observations aqueous alteration to alter or breakdown with JWST, METIS & SPICA. polycyclic aromatic hydrocarbons We will study the role of "exo-asteroids" in the delivery of water in asteroids/meteorites? and organics to exoplanets which is interesting because water and organics are relevant for astro-biology. Kateryna Frantseva Claudia-Corina Giese Fig: Scanning electron microscope SRON Groningen/Kapteyn Institute, Leiden
    [Show full text]
  • Astrometric and Photometric Monitoring of GQ Lupi and Its Sub-Stellar Companion
    A&A 484, 281–291 (2008) Astronomy DOI: 10.1051/0004-6361:20078493 & c ESO 2008 Astrophysics Astrometric and photometric monitoring of GQ Lupi and its sub-stellar companion R. Neuhäuser1,M.Mugrauer1,A.Seifahrt1,T.O.B.Schmidt1, and N. Vogt2,3 1 Astrophysikalisches Institut, Universität Jena, Schillergässchen 2-3, 07745 Jena, Germany e-mail: [email protected] 2 Departamento de Física y Astronomía, Universidad de Valparaíso, Avenida Gran Bretaña 1111, Valparaíso, Chile 3 Instituto de Astronomía, Universidad Catolica del Norte, Avda. Angamos 0610, Antofagasta, Chile Received 16 August 2007 / Accepted 4 December 2007 ABSTRACT Context. Neuhäuser et al. (2005, A&A, 435, L13) presented direct imaging evidence for a sub-stellar companion to the young T Tauri star GQ Lupi. Common proper motion was highly significant, but no orbital motion was detected. Faint luminosity, low gravity, and a late-M/early-L spectral type indicated that the companion is either a planet or a brown dwarf. Aims. We have monitored GQ Lupi and its companion in order to detect orbital and parallactic motion and variability in its brightness. We also search for closer and fainter companions. Methods. We have taken six more images with the VLT Adaptive Optics instrument NACO from May 2005 to Feb. 2007, always with the same calibration binary from Hipparcos for both astrometric and photometric calibration. By adding up all the images taken so far, we search for additional companions. Results. The position of GQ Lupi A and its companion compared to a nearby non-moving background object varies as expected for parallactic motion by about one pixel (2 · π with parallax π).
    [Show full text]
  • Orders of Magnitude (Length) - Wikipedia
    03/08/2018 Orders of magnitude (length) - Wikipedia Orders of magnitude (length) The following are examples of orders of magnitude for different lengths. Contents Overview Detailed list Subatomic Atomic to cellular Cellular to human scale Human to astronomical scale Astronomical less than 10 yoctometres 10 yoctometres 100 yoctometres 1 zeptometre 10 zeptometres 100 zeptometres 1 attometre 10 attometres 100 attometres 1 femtometre 10 femtometres 100 femtometres 1 picometre 10 picometres 100 picometres 1 nanometre 10 nanometres 100 nanometres 1 micrometre 10 micrometres 100 micrometres 1 millimetre 1 centimetre 1 decimetre Conversions Wavelengths Human-defined scales and structures Nature Astronomical 1 metre Conversions https://en.wikipedia.org/wiki/Orders_of_magnitude_(length) 1/44 03/08/2018 Orders of magnitude (length) - Wikipedia Human-defined scales and structures Sports Nature Astronomical 1 decametre Conversions Human-defined scales and structures Sports Nature Astronomical 1 hectometre Conversions Human-defined scales and structures Sports Nature Astronomical 1 kilometre Conversions Human-defined scales and structures Geographical Astronomical 10 kilometres Conversions Sports Human-defined scales and structures Geographical Astronomical 100 kilometres Conversions Human-defined scales and structures Geographical Astronomical 1 megametre Conversions Human-defined scales and structures Sports Geographical Astronomical 10 megametres Conversions Human-defined scales and structures Geographical Astronomical 100 megametres 1 gigametre
    [Show full text]
  • Exoplanet Atmosphere Measurements from Direct Imaging
    Exoplanet Atmosphere Measurements from Direct Imaging Beth A. Biller and Mickael¨ Bonnefoy Abstract In the last decade, about a dozen giant exoplanets have been directly im- aged in the IR as companions to young stars. With photometry and spectroscopy of these planets in hand from new extreme coronagraphic instruments such as SPHERE at VLT and GPI at Gemini, we are beginning to characterize and classify the at- mospheres of these objects. Initially, it was assumed that young planets would be similar to field brown dwarfs, more massive objects that nonetheless share sim- ilar effective temperatures and compositions. Surprisingly, young planets appear considerably redder than field brown dwarfs, likely a result of their low surface gravities and indicating much different atmospheric structures. Preliminarily, young free-floating planets appear to be as or more variable than field brown dwarfs, due to rotational modulation of inhomogeneous surface features. Eventually, such inho- mogeneity will allow the top of atmosphere structure of these objects to be mapped via Doppler imaging on extremely large telescopes. Direct imaging spectroscopy of giant exoplanets now is a prelude for the study of habitable zone planets. Even- tual direct imaging spectroscopy of a large sample of habitable zone planets with future telescopes such as LUVOIR will be necessary to identify multiple biosigna- tures and establish habitability for Earth-mass exoplanets in the habitable zones of nearby stars. Introduction Since 1995, more than 3000 exoplanets have been discovered, mostly via indirect means, ushering in a completely new field of astronomy. In the last decade, about a dozen planets have been directly imaged, including archetypical systems such as arXiv:1807.05136v1 [astro-ph.EP] 13 Jul 2018 Beth A.
    [Show full text]
  • Noao Annual Report Fy07
    AURA/NOAO ANNUAL REPORT FY 2007 Submitted to the National Science Foundation September 30, 2007 Revised as Final and Submitted January 30, 2008 Emission nebula NGC6334 (Cat’s Paw Nebula): star-forming region in the constellation Scorpius. This 2007 image was taken using the Mosaic-2 imager on the Blanco 4-meter telescope at Cerro Tololo Inter- American Observatory. Intervening dust in the plane of the Milky Way galaxy reddens the colors of the nebula. Image credit: T.A. Rector/University of Alaska Anchorage, T. Abbott and NOAO/AURA/NSF NATIONAL OPTICAL ASTRONOMY OBSERVATORY NOAO ANNUAL REPORT FY 2007 Submitted to the National Science Foundation September 30, 2007 Revised as Final and Submitted January 30, 2008 TABLE OF CONTENTS EXECUTIVE SUMMARY ............................................................................................................................. 1 1 SCIENTIFIC ACTIVITIES AND FINDINGS ..................................................................................... 2 1.1 NOAO Gemini Science Center .............................................................................. 2 GNIRS Infrared Spectroscopy and the Origins of the Peculiar Hydrogen-Deficient Stars...................... 2 Supermassive Black Hole Growth and Chemical Enrichment in the Early Universe.............................. 4 1.2 Cerro Tololo Inter-American Observatory (CTIO)................................................ 5 The Nearest Stars.......................................................................................................................................
    [Show full text]
  • A Absorptivity, 642, 682 Abundance(S), 339, 388, 389, 408
    Index A momentum, 354, 383–385, 443–445, 475, Absorptivity, 642, 682 479, 510, 589, 607, 681, 701, 778 Abundance(s), 339, 388, 389, 408, 410, 484, resolution, 686 485, 491, 509, 541, 560, 561, 616, velocity/velocities, 349, 350, 354, 570, 605 619, 621, 648, 654, 658–661, 665, Apollonius of Myndus, 598 667, 668, 670, 673, 676, 780 Aquinas, T., 598 Acetonitrile (CH3CN), 561, 619 Archaeomagnetic data, 423 Acetylene (C2H2), 559, 560, 562 Ariel (satellite, Uranus I), 523, 527, 532, Adams, J.C., 492, 493, 582 533, 564 Adams-Williamson equation, 494 albedo, 564 Adiabatic Aristotle, 598, 599 convection, 344, 345 Artemis, 648 lapse rate, 348, 368, 369, 375, 385 Asteroid(s) (general) pressure-density relation, 344 albedo(s), 683, 686–688, 696, 700 processes, 345 densities, 639, 689–690 Adoration of Magi, 610, 612 dimension(s), 686–690 Adrastea (satellite, Jupiter XV), 524, 529, 572 double, 689 Airy, G.B., 492 inner solar system plot, 678, 681, 690 Albedo masses, 686–690 bolometric, 338, 477, 636, 642, 687, 780 nomenclature, 648–649, 677–681 bond, 477, 516, 627, 747, 772, 780 orbital properties geometric (visual), 477, 564, 581 families, 681–685 Alfve´n waves, 460 Kirkwood gaps, 582, 678, 695, 697 Aluminum isotopes, 694 outer solar system plot, 588–590, 603 Alvarez, L., 668 radii, 688 Amalthea (satellite, Jupiter V), 355, 529, rotations, 688, 700 537, 572 thermal emissions, 697 Ambipolar diffusion, 402, 703 Asteroid mill, 639, 676, 769 American Meteor Society, 637, 638 Asteroids (individual) Amidogen radical (NH2), (2101) Adonis, 683 Ammonia (NH3), 348, 391, 480, 481, 483, (1221) Amor, 681, 690 485, 512, 558, 560, 619, 625, (3554) Amun, 683 627, 756 (1943) Anteros, 681 Ammonium hydrosulfide (NH4SH), 481, 483 (2061) Anza, 681 Anaxagoras of Clazomenae, 598 (1862) Apollo, 683, 684, 698 Angular (197) Ariete, 689 diameter(s), 493, 686 (2062) Aten, 683 E.F.
    [Show full text]
  • Extrasolar Planets
    Extrasolar Planets Dieter Schmitt Lecture Max Planck Institute for Introduction to Solar System Research Solar System Physics KatlenburgLindau Uni Göttingen, 8 June 2009 Outline • Historical Overview • Detection Methods • Planet Statistics • Formation of Planets • Physical Properties • Habitability Historical overview • 1989: planet / brown dwarf orbiting HD 114762 (Latham et al.) • 1992: two planets orbiting pulsar PSR B1257+12 (Wolszczan & Frail) • 1995: first planet around a solarlike star 51 Peg b (Mayor & Queloz) • 1999: first multiple planetary system with three planets Ups And (Edgar et al.) • 2000: first planet by transit method HD 209458 b (Charbonneau et al.) • 2001: atmosphere of HD 209458 b (Charbonneau et al.) • 2002: astrometry applied to Gliese 876 (Benedict et al.) • 2005: first planet by direct imaging GQ Lupi b (Neuhäuser et al.) • 2006: Earthlike planet by gravitational microlensing (Beaulieu et al.) • 2007: Gliese 581d, small exoplanet near habitability zone (Selsis et al.) • 2009: Gliese 581e, smallest exoplanet with 1.9 Earth masses (Mayor et al.) • As of 7 June 2009: 349 exoplanets in 296 systems (25 systems with 2 planets, 9 with 3, 2 with 4 and 1 with 5) www.exoplanet.eu Our Solar System 1047 MJ 0.39 AU 0.00314 MJ 1 MJ 0.30 MJ 0.046 MJ 0.054 MJ 1 AU 5.2 AU 9.6 AU 19 AU 30 AU 1 yr 11.9 yr 29.5 yr 84 yr 165 yr Definition Planet IAU 2006: • in orbit around the Sun / star • nearly spherical shape / sufficient mass for hydrostatic equilib. • cleared neighbourhood around its orbit Pluto: dwarf planet, as Ceres Brown
    [Show full text]