Thermal emission of exoplanet XO-1b

Pavel Machalek, Peter R. McCullough, Christopher J. Burke, Jeff A. Valenti, Adam Burrows, Joseph L. Hora

Research output: Contribution to journalArticlepeer-review

73 Scopus citations


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 languageEnglish (US)
Pages (from-to)1427-1432
Number of pages6
JournalAstrophysical Journal
Issue number2
StatePublished - Sep 10 2008

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science


  • Binaries: eclipsing
  • Infrared: stars
  • Planetary systems
  • Stars: individual (XO-1)


Dive into the research topics of 'Thermal emission of exoplanet XO-1b'. Together they form a unique fingerprint.

Cite this