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Extrasolar Planets (extrasolar + planet)
Selected AbstractsBooks and Multimedia ReviewsMETEORITICS & PLANETARY SCIENCE, Issue 3 2001Article first published online: 4 FEB 2010 Book reviewed in this article: Catalogue of Meteorites, Fifth Edition (Revised and Enlarged) by Monica M. Grady Extrasolar Planets: The Search for New Worlds by Stuart Clark The Moon: Resources, Future Development and Colonization by David Schrunk, Burton Sharpe, Bonnie Cooper and Madhu Thangavelu Rare Earth: Why Complex Life is Uncommon in the Universe by Peter D. Ward and Donald E. Brownlee [source] A method for the direct determination of the surface gravities of transiting extrasolar planetsMONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY: LETTERS (ELECTRONIC), Issue 1 2007John Southworth ABSTRACT We show that the surface gravity of a transiting extrasolar planet can be calculated from only the spectroscopic orbit of its parent star and the analysis of its transit light curve. This does not require additional constraints, such as are often inferred from theoretical stellar models or model atmospheres. The surface gravity of the planet can therefore be measured precisely and from only directly observable quantities. We outline the method and apply it to the case of the first known transiting extrasolar planet, HD 209458b. We find a surface gravity of gp= 9.28 ± 0.15 m s,2, which is an order of magnitude more precise than the best available measurements of its mass, radius and density. This confirms that the planet has a much lower surface gravity than that predicted by published theoretical models of gas giant planets. We apply our method to all 14 known transiting extrasolar planets and find a significant correlation between surface gravity and orbital period, which is related to the known correlation between mass and period. This correlation may be the underlying effect as surface gravity is a fundamental parameter in the evaporation of planetary atmospheres. [source] STARE operations experience and its data quality controlASTRONOMISCHE NACHRICHTEN, Issue 6-8 2004R. Alonso Abstract The STARE instrument was the first to detect the transits of an extrasolar planet in 1999. To date it has performed one of the longest running searches for transits, being in nearly continous operations since July 2001 at Teide Observatory, Tenerife. We describe the instrumental setup and the scheme that is used for data acquisition, handling and analysis. To this end, we first review the conditions under which we obtained data suggestive of transits, and we then follow a chain of verification and follow-up measures, progressing from fairly simple ones of low cost and effort towards more involved ones, which may be needed to positively verify the existence of a true planetary transit. (© 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Core instability models of giant planet accretion and the planetary desertMONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, Issue 1 2008Y. Miguel ABSTRACT With the aim of studying the final mass distribution of extrasolar planets, we have developed a simple model based on the core instability model, which allows us to form a large population of planets and make them evolve in circumstellar discs with various initial conditions. We investigate the consequences that different prescriptions for the solid and gas accretion rates would have on this distribution and found that it is strongly dependent on the adopted model for the gas accretion. [source] Parent stars of extrasolar planets , VIII.MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, Issue 3 2007Chemical abundances for 18 elements in 31 stars ABSTRACT We present the results of detailed spectroscopic abundance analyses for 18 elements in 31 nearby stars with planets (SWPs). The resulting abundances are combined with other similar studies of nearby SWPs and compared to a sample of nearby stars without detected planets. We find some evidence for abundance differences between these two samples for Al, Si and Ti. Some of our results are in conflict with a recent study of SWPs in the SPOCS data base. We encourage continued study of the abundance patterns of SWPs to resolve these discrepancies. [source] A stability catalogue of the habitable zones in extrasolar planetary systemsMONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, Issue 4 2007Zs. Sándor ABSTRACT In the near future, space missions will be launched (e.g. COROT, KEPLER) to detect Earth-like extrasolar planets. The orbital elements of these (still hypothetic) planets will contain some uncertainties that can only be eliminated by careful dynamical investigations of the hosting planetary systems. The proportion of extrasolar planetary systems with one known giant planet is high (,90 per cent). Therefore, as a first step we have investigated the possible existence of terrestrial planets in these systems. In this paper, the development of a stability catalogue of the habitable zones of exoplanetary systems is reported. This catalogue is formed by a series of stability maps, which can help to establish where Earth-like planets could exist in extrasolar planetary systems having one giant planet. After a description of the dynamical model and the numerical methods, details of the stability maps are discussed. An application of the stability catalogue to 15 known exoplanetary systems is also shown, and a characterization of the stability properties of their habitable zones is given. [source] Stable satellites around extrasolar giant planetsMONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, Issue 3 2006R. C. Domingos ABSTRACT In this work, we study the stability of hypothetical satellites of extrasolar planets. Through numerical simulations of the restricted elliptic three-body problem we found the borders of the stable regions around the secondary body. From the empirical results, we derived analytical expressions of the critical semimajor axis beyond which the satellites would not remain stable. The expressions are given as a function of the eccentricities of the planet, eP, and of the satellite, esat. In the case of prograde satellites, the critical semimajor axis, in the units of Hill's radius, is given by aE, 0.4895 (1.0000 , 1.0305eP, 0.2738esat). In the case of retrograde satellites, it is given by aE, 0.9309 (1.0000 , 1.0764eP, 0.9812esat). We also computed the satellite stability region (aE) for a set of extrasolar planets. The results indicate that extrasolar planets in the habitable zone could harbour the Earth-like satellites. [source] Reversing type II migration: resonance trapping of a lighter giant protoplanetMONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, Issue 4 2001F. Masset We present a mechanism related to the migration of giant protoplanets embedded in a protoplanetary disc whereby a giant protoplanet is caught up, before having migrated all the way to the central star, by a lighter outer giant protoplanet. This outer protoplanet may get captured into the 2:3 resonance with the more massive one, in which case the gaps that the two planets open in the disc overlap. Two effects arise, namely a squared mass-weighted torque imbalance and an increased mass flow through the overlapping gaps from the outer disc to the inner disc, which both play in favour of an outwards migration. Indeed, under the conditions presented here, which describe the evolution of a pair of protoplanets respectively Jupiter- and Saturn-sized, the migration is reversed, while the semimajor axis ratio of the planets is constant and the eccentricities are confined to small values by the disc material. The long-term behaviour of the system is briefly discussed, and could account for the high eccentricities observed for the extrasolar planets with semimajor axis [source] A method for the direct determination of the surface gravities of transiting extrasolar planetsMONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY: LETTERS (ELECTRONIC), Issue 1 2007John Southworth ABSTRACT We show that the surface gravity of a transiting extrasolar planet can be calculated from only the spectroscopic orbit of its parent star and the analysis of its transit light curve. This does not require additional constraints, such as are often inferred from theoretical stellar models or model atmospheres. The surface gravity of the planet can therefore be measured precisely and from only directly observable quantities. We outline the method and apply it to the case of the first known transiting extrasolar planet, HD 209458b. We find a surface gravity of gp= 9.28 ± 0.15 m s,2, which is an order of magnitude more precise than the best available measurements of its mass, radius and density. This confirms that the planet has a much lower surface gravity than that predicted by published theoretical models of gas giant planets. We apply our method to all 14 known transiting extrasolar planets and find a significant correlation between surface gravity and orbital period, which is related to the known correlation between mass and period. This correlation may be the underlying effect as surface gravity is a fundamental parameter in the evaporation of planetary atmospheres. [source] Pulsations and planets: The asteroseismology-extrasolar-planet connectionASTRONOMISCHE NACHRICHTEN, Issue 5 2010S. Schuh Abstract The disciplines of asteroseismology and extrasolar planet science overlap methodically in the branch of high-precision photometric time series observations. Light curves are, amongst others, useful to measure intrinsic stellar variability due to oscillations, as well as to discover and characterize those extrasolar planets that transit in front of their host stars, periodically causing shallow dips in the observed brightness. Both fields ultimately derive fundamental parameters of stellar and planetary objects, allowing to study for example the physics of various classes of pulsating stars, or the variety of planetary systems, in the overall context of stellar and planetary system formation and evolution. Both methods typically also require extensive spectroscopic follow-up to fully explore the dynamic characteristics of the processes under investigation. In particularly interesting cases, a combination of observed pulsations and signatures of a planet allows to characterize a system's components to a very high degree of completeness by combining complementary information. The planning of the relevant space missions has consequently converged with respect to science cases, where at the outset there was primarily a coincidence in instrumentation and techniques. Whether space- or ground-based, a specific type of stellar pulsations can themselves be used in an innovative way to search for extrasolar planets. Results from this additional method at the interface of stellar pulsation studies and exoplanet hunts in a beyond-mainstream area are presented (© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] VLT-CRIRES: "Good Vibrations" Rotational-vibrational molecular spectroscopy in astronomyASTRONOMISCHE NACHRICHTEN, Issue 5 2010H.U. Käufl Abstract Near-Infrared high spectral and spatial resolution spectroscopy offers new and innovative observing opportunities for astronomy. The "traditional" benefits of IR-astronomy , strongly reduced extinction and availability of adaptive optics , more than offset for many applications the compared to CCD-based astronomy strongly reduced sensitivity. Especially in high resolution spectroscopy interferences by telluric lines can be minimized. Moreover for abundance studies many important atomic lines can be accessed in the NIR. A novel spectral feature available for quantitative spectroscopy are the molecular rotational-vibrational transitions which allow for fundamentally new studies of condensed objects and atmospheres. This is also an important complement to radio-astronomy, especially with ALMA, where molecules are generally only observed in the vibrational ground state. Rot-vib transitions also allow high precision abundance measurements , including isotopic ratios , fundamental to understand the thermo-nuclear processes in stars beyond the main sequence. Quantitative modeling of atmospheres has progressed such that the unambiguous interpretation of IR-spectra is now well established. In combination with adaptive optics spectro-astrometry is even more powerful and with VLT-CRIRES a spatial resolution of better than one milli-arcsecond has been demonstrated. Some highlights and recent results will be presented: our solar system, extrasolar planets, star- and planet formation, stellar evolution and the formation of galactic bulges (© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Are extrasolar oceans common throughout the Galaxy?ASTRONOMISCHE NACHRICHTEN, Issue 8 2007D. Ehrenreich Abstract Light and cold extrasolar planets such as OGLE 2005-BLG-390Lb, a 5.5 Earth masses planet detected via microlensing, could be frequent in the Galaxy according to some preliminary results from microlensing experiments. These planets can be frozen rocky- or ocean-planet, situated beyond the snow line and, therefore, beyond the habitable zone of their system. They can nonetheless host a layer of liquid water, heated by radiogenic energy, underneath an ice shell surface for billions of years, before freezing completely. These results suggest that oceans under ice, like those suspected to be present on icy moons in the Solar system, could be a common feature of cold low-mass extrasolar planets. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Unsolved problems in observational astronomy.ASTRONOMISCHE NACHRICHTEN, Issue 6-8 2004Abstract We present the highlights of current observational programs in stellar optical spectroscopy carried out with 8-10 m class telescopes as well as with smaller telescopes. Topics discussed include: 1. light elements abundances and their cosmological implications; 2. search for Population III stars and spectroscopy of extremely metal deficient stars; 3. abundances of different stellar populations in the Galaxy; 4. spectroscopy of resolved stars in Local Group galaxies; 5. Li and Be abundances and internal mixing in stars; 6. spectroscopy of very-low mass stars and brown dwarfs; 7. radial velocity search of extrasolar planets; 8. stellar oscillations and asteroseismology; 9. stellar magnetic activity and Doppler imaging of stellar surface features. We also highlight the role that dedicated 1-2 m automatic telescopes with spectroscopic capabilities can play in several fields of stellar optical spectroscopy. (© 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Searching for extrasolar planets with the 1.3 m Robotically Controlled Telescope on Kitt PeakASTRONOMISCHE NACHRICHTEN, Issue 6-8 2004C.H. McGruder III No abstract is available for this article. [source] Looking inside stars and looking for planetsASTRONOMY & GEOPHYSICS, Issue 6 2002Alan Penny Asteroseismology and extrasolar planets are the main science goals of the Eddington mission, now approved by ESA for a 2007 launch. Alan Penny presents a summary of the January 2002 RAS meeting that discussed the sciences of this wide-field high-precision photometric space telescope. Since the date of this meeting, ESA has decided to implement the mission in the framework of a 2007,08 launch. [source] | ||||||||||