Warm Spitzer Photometry of XO-4b, HAT-P-6b and HAT-P-8b

Understand

We have analyzed Warm Spitzer/IRAC observations of the secondary eclipses of three planets, XO-4b, HAT-P-6b and HAT-P-8b.

• We measure secondary eclipse amplitudes at 3.6{\mu}m and 4.5{\mu}m for each target.
• XO-4b exhibits a stronger eclipse depth at 4.5{\mu}m than at 3.6{\mu}m, which is consistent with the presence of a temperature inversion.
• HAT-P-8b shows a stronger eclipse amplitude at 3.6{\mu}m, and is best-described by models without a temperature inversion.