Abstract
We estimate flux ratios of the extrasolar planet XO-1b to its host star XO-1 at 3.6, 4.5, 5.8, and 8.0 μm with IRAC on the Spitzer Space Telescope to be 0.00086 ±0.00007,0.00122 ±0.00009, 0.00261 ±0.00031, and 0.00210 ± 0.00029, respectively. The fluxes are inconsistent with a canonical cloudless model for the thermal emission from a planet and suggest an atmosphere with a thermal inversion layer and a possible stratospheric absorber. A newly emerging correlation between the presence of a thermal inversion layer in the planetary atmosphere and stellar insolation of the planet, as by Burrows and colleagues, is refined. The substellar point flux from the parent star at XO-1b of ∼0.49 × 109 erg cm-2 s_1 sets a new lower limit for the occurrence of a thermal inversion in a planetary atmosphere.
Original language | English (US) |
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Pages (from-to) | 1427-1432 |
Number of pages | 6 |
Journal | Astrophysical Journal |
Volume | 684 |
Issue number | 2 |
DOIs | |
State | Published - Sep 10 2008 |
All Science Journal Classification (ASJC) codes
- Astronomy and Astrophysics
- Space and Planetary Science
Keywords
- Binaries: eclipsing
- Infrared: stars
- Planetary systems
- Stars: individual (XO-1)