Dynamic atmosphere of the eccentric and massive planet XO-3b
Abstract
We propose to observe the extended duration (63.0 hours) phase light curves spanning the transit and secondary eclipse of the exoplanet XO-3b, which has a period of 3.19 days, in the 3.6 and 4.5 micron IRAC bands to study the presence of a thermal inversion in its stratosphere and determine the phase variability of the planetary emission temperature. Full phase 3.6 and 4.5 micron photometry will allow us to constrain the longitudinal variation of the XO-3b emission, determine the day-night side heat circulation as well as constrain the presence of any hot-spots on the surface. XO-3b is an unique planet with a high mass Mp D 12.5 MJup, which is close to the deuterium burning limit and so far has the highest observed surface gravity, g D 209 m.s^-2 amongst the known transiting planets. Its orbit has eccentricity e D 0.287, which causes stellar irradiance to vary three-fold over the entire orbit. Unique to XO-3b, the planet revolves around the star on an almost polar orbit with a 70 +/- 15 deg inclination angle relative to the stellar equatorial plane . Of the 11 transiting planets with measured Rossitter-McLaughlin effect, XO-3b is the only one with a nearly polar orbit, thus XO-3b represents a new orbital mode of transiting Hot Jupiters, which in principle would allow us to constrain the latitudinal distribution of the thermal emission from the planet, in addition to the longitudinal thermal distribution. This proposal is a follow-up to the approved Cycle-5 Cold Spitzer DDT program OX3B 'Thermal Inversion in the atmosphere of XO-3b', which investigates the secondary eclipse of XO-3b in all 4 IRAC channels.
- Publication:
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Spitzer Proposal
- Pub Date:
- April 2009
- Bibcode:
- 2009sptz.prop60058M