Comparative Planetary Atmospheres: Models of TrES-1 and HD 209458b

TL;DR: For hydrogen-helium-rich planets, the authors in this article couple planetary evolution to stellar irradiation over a wide range of orbital separations (0.02-10 AU) through a nongray radiative-convective equilibrium atmosphere model.

TL;DR: In this paper, the authors highlight the potential importance of gaseous TiO and VO opacity on the highly irradiated close-in giant planets and calculate model atmospheres for these planets, including pressure-temperature profiles, spectra, and characteristic radiative time constants.

Abstract: To aid in the physical interpretation of planetary radii constrained through observations of transiting planets, or eventually direct detections, we compute model radii of pure hydrogen-helium, water, rock, and iron planets, along with various mixtures. Masses ranging from 0.01 Earth masses to 10 Jupiter masses at orbital distances of 0.02-10 AU are considered. For hydrogen-helium rich planets, our models are the first to couple planetary evolution to stellar irradiation over a wide range of orbital separations (0.02-10 AU) through a nongray radiative-convective equilibrium atmosphere model. Stellar irradiation retards the contraction of giant planets, but its effect is not a simple function of the irradiation level: a planet at 1 AU contracts as slowly as a planet at 0.1 AU. We confirm the assertion of Guillot that very old giant planets under modest stellar irradiation (like that received by Jupiter and Saturn) develop isothermal atmospheric radiative zones once the planet's intrinsic flux drops to a small fraction of the incident flux. For hydrogen-helium planets, we consider cores up to 90% of the total planet mass, comparable to those of Uranus and Neptune. If "hot Neptunes" have maintained their original masses and are not remnants of more massive planets, radii of ~0.30-0.45 RJ are expected. Water planets are ~40%-50% larger than rocky planets, independent of mass. Finally, we provide tables of planetary radii at various ages and compositions, and for ice-rock-iron planets we fit our results to analytic functions, which will allow for quick composition estimates, given masses and radii, or mass estimates, given only planetary radii. These results will assist in the interpretation of observations for both the current transiting planet surveys as well as upcoming space missions, including COROT and Kepler.

TL;DR: For hydrogen-helium-rich planets, a non-gray radiative-convective equilibrium atmosphere model was proposed in this article to couple planetary evolution to stellar irradiation over a wide range of orbital separations.

TL;DR: The presence of a Jupiter-mass companion to the star 51 Pegasi is inferred from observations of periodic variations in the star's radial velocity as discussed by the authors, which would be well inside the orbit of Mercury in our Solar System.

TL;DR: In this article, the authors present a series of nongray calculations of the atmospheres, spectra, colors, and evolution of extrasolar giant planets (EGPs) and brown dwarfs for effective temperatures below 1300 K.

TL;DR: In this paper, high-precision spectrophotometric observations of four planetary transits of HD 209458, in the region of the sodium resonance doublet at 589.3 nm, were reported.

TL;DR: High-precision, high-cadence photometric measurements of the star HD 209458 are reported, which is known from radial velocity measurements to have a planetary-mass companion in a close orbit and the detailed shape of the transit curve due to both the limb darkening of thestar and the finite size of the planet is clearly evident.