Water in HD 209458b's atmosphere from 3.6 - 8 microns IRAC photometric observations in primary transit - Astrophysics > Earth and Planetary AstrophysicsReport as inadecuate




Water in HD 209458b's atmosphere from 3.6 - 8 microns IRAC photometric observations in primary transit - Astrophysics > Earth and Planetary Astrophysics - Download this document for free, or read online. Document in PDF available to download.

Abstract: The hot Jupiter HD 209458b was observed during primary transit at 3.6, 4.5,5.8 and 8.0 microns using the Infrared Array Camera IRAC on the Spitzer SpaceTelescope. We detail here the procedures we adopted to correct for thesystematic trends present in the IRAC data. The light curves were fittedincluding limb darkening effects and fitted using Markov Chain Monte Carlo andprayer-bead Monte Carlo techniques, finding almost identical results. The finaldepth measurements obtained by a combined Markov Chain Monte Carlo fit are at3.6 microns, 1.469 +- 0.013 % and 1.448 +- 0.013 %; at 4.5 microns, 1.478 +-0.017 % ; at 5.8 microns, 1.549 +- 0.015 % and at 8.0 microns 1.535 +- 0.011 %.Our results clearly indicate the presence of water in the planetary atmosphere.Our broad band photometric measurements with IRAC prevent us from determiningthe additional presence of other other molecules such as CO, CO2 and methanefor which spectroscopy is needed. While water vapour with a mixing ratio of10^-4-10^-3 combined with thermal profiles retrieved from the day-side mayprovide a very good fit to our observations, this data set alone is unable toresolve completely the degeneracy between water abundance and atmosphericthermal profile.



Author: J.P. Beaulieu, D.M. Kipping, V. Batista, G. Tinetti, I. Ribas, S. Carey, J. A. Noriega-Crespo, C. A. Griffith, G. Campanella, S.

Source: https://arxiv.org/



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