Characterization of the hot Neptune GJ 436 b with Spitzer and ground-based observations
English
Demory, B*-O[Observatoire de Genève, Université de Genève, 1290 Sauverny, Switzerland ; Observatoire François-Xavier Bagnoud - ` OFXB, 3961 Saint-Luc, Switzerland]
Gillon, Michaël[Université de Liège - ULg > Département d'astrophys., géophysique et océanographie (AGO) > Astrophysique et traitement de l'image >]
Barman, T.[Lowell Observatory, 1400 West Mars Hill Road, Flagstaff, AZ 86001, USA]
Bonfils, X.[Observatório Astronómico de Lisboa, Tapada da Ajuda, 1349-018 Lisboa, Portugal]
Mayor, M.[Observatoire de Genève, Université de Genève, 1290 Sauverny, Switzerland]
Mazeh, T.[School of Physics and Astronomy, Raymond and Beverly Sackler Faculty of Exact Sciences, Tel Aviv University, Tel Aviv, Israel]
Queloz, D.[Observatoire de Genève, Université de Genève, 1290 Sauverny, Switzerland]
Udry, S.[Observatoire de Genève, Université de Genève, 1290 Sauverny, Switzerland]
Bouchy, F.[Institut d'Astrophysique de Paris, UMR7095 CNRS, Université Pierre & Marie Curie, 98bis Bd. Arago, 75014 Paris, France]
Delfosse, X.[Laboratoire d'Astrophysique de Grenoble, Observatoire de Grenoble, UMR5571 de l'Université J.Fourier et du CNRS, BP 53, 38041 Grenoble, France]
Forveille, T.[Laboratoire d'Astrophysique de Grenoble, Observatoire de Grenoble, UMR5571 de l'Université J.Fourier et du CNRS, BP 53, 38041 Grenoble, France]
Pepe, F.[Observatoire de Genève, Université de Genève, 1290 Sauverny, Switzerland]
Perrier, C.[Laboratoire d'Astrophysique de Grenoble, Observatoire de Grenoble, UMR5571 de l'Université J.Fourier et du CNRS, BP 53, 38041 Grenoble, France]
[en] techniques: photometric ; techniques: spectroscopic ; eclipses ; stars: individual: GJ 436 ; planetary systems ; infrared: general
[en] We present Spitzer Space Telescope infrared photometry of a secondary eclipse of the hot Neptune GJ 436 b. The observations were obtained using the 8-mum band of the InfraRed Array Camera (IRAC). The data spanning the predicted time of secondary eclipse show a clear flux decrement with the expected shape and duration. The observed eclipse depth of 0.58 mmag allows us to estimate a blackbody brightness temperature of T[SUB]p[/SUB] = 717 ± 35 K at 8 mum. We compare this infrared flux measurement to a model of the planetary thermal emission, and show that this model reproduces properly the observed flux decrement. The timing of the secondary eclipse confirms the non-zero orbital eccentricity of the planet, while also increasing its precision (e = 0.14 ± 0.01). Additional new spectroscopic and photometric observations allow us to estimate the rotational period of the star and to assess the potential presence of another planet. Our final secondary eclipse, photometric and Ca II H+K index time series are available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/475/1125
[Université de Liège - ULg > Département d'astrophys., géophysique et océanographie (AGO) > Astrophysique et traitement de l'image >]
