# WASP-8: Eccentric Hot Jupiter

## WASP-8: Eccentric Hot Jupiter

WASP-8b: Characterization of a Cool and Eccentric Exoplanet with Spitzer
http://arxiv.org/abs/1303.5468

WASP-8b has 2.18 times Jupiter's mass and is on an eccentric ($e=0.31$) 8.16-day orbit. With a time-averaged equilibrium temperature of 948 K, it is one of the least-irradiated hot Jupiters observed with the Spitzer Space Telescope. We have analyzed six photometric light curves of WASP-8b during secondary eclipse observed in the 3.6, 4.5, and 8.0 {\microns} Infrared Array Camera bands. The eclipse depths are $0.113\pm 0.018$%, $0.069\pm 0.007$%, and $0.093\pm 0.023$%, respectively, giving respective brightness temperatures of 1552, 1131, and 938 K. We characterized the atmospheric thermal profile and composition of the planet using a line-by-line radiative transfer code and a Markov-chain Monte Carlo sampler. The data indicated no thermal inversion, independently of any assumption about chemical composition. We noted an anomalously high 3.6-{\microns} brightness temperature (1552 K); by modeling the eccentricity-caused thermal variation, we found that this temperature is plausible for radiative time scales less than $\sim 10^{2}$ hours. However, as no model spectra fit all three data points well, the temperature discrepancy remains as an open question.

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Sirius_Alpha

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## Re: WASP-8: Eccentric Hot Jupiter

why is this not in the SuperWASP results thread?

Shellface
Neptune-Mass

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## Re: WASP-8: Eccentric Hot Jupiter

Shellface wrote:why is this not in the SuperWASP results thread?
Well, you could argue that it's more Spitzer results than SuperWASP results. Besides, as these superWASP planets get better characterised over the years, instead of clogging up the SuperWASP thread, one may as well devote a system-specific thread to it.

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Sirius_Alpha

Number of posts : 3416
Location : Earth
Registration date : 2008-04-06