Atmosphere and spectral models of the kepler-field planets HAT-P-7b and TrES-2

David S. Spiegel, Adam S. Burrows

Research output: Contribution to journalArticle

37 Scopus citations

Abstract

We develop atmosphere models of two of the three Kepler-field planets that were known prior to the start of the Kepler mission (HAT-P-7b and TrES-2). We find that published Kepler and Spitzer data for HAT-P-7b appear to require an extremely hot upper atmosphere on the dayside, with a strong thermal inversion and little day-night redistribution. The Spitzer data for TrES-2 suggest a mild thermal inversion with moderate day-night redistribution. We examine the effect of nonequilibrium chemistry on TrES-2 model atmospheres and find that methane levels must be adjusted by extreme amounts in order to cause even mild changes in atmospheric structure and emergent spectra. Our best-fit models to the Spitzer data for TrES-2 lead us to predict a low secondary eclipse planet-star flux ratio (∼2 × 10-5) in the Kepler bandpass, which is consistent with what very recent observations have found. Finally, we consider how the Kepler-band optical flux from a hot exoplanet depends on the strength of a possible extra optical absorber in the upper atmosphere.We find that the optical flux is not monotonic in optical opacity, and the non-monotonicity is greater for brighter, hotter stars.

Original languageEnglish (US)
Pages (from-to)871-879
Number of pages9
JournalAstrophysical Journal
Volume722
Issue number1
DOIs
StatePublished - Oct 10 2010

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science

Keywords

  • Planetary systems
  • Radiative transfer
  • Stars: individual (HAT-P-7, TrES-2)

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