Статья

WASP-71b: a bloated hot Jupiter in a 2.9-day, prograde orbit around an evolved F8 star

A. M. S. SmithAstrophysics Group, Lennard-Jones LaboratoriesKeele University, Keele, Staffordshire ST5 5BG, UKD. R. AndersonAstrophysics Group, Lennard-Jones LaboratoriesKeele University, Keele, Staffordshire ST5 5BG, UKF. BouchyInstitut d’Astrophysique de Paris, UMR 7095 CNRS, Université Pierre & Marie Curie, 98bis boulevard Arago, 75014 Paris, FranceA. Collier CameronSUPA, School of Physics and Astronomy, University of St. Andrews, North Haugh, St. Andrews, Fife, KY16 9SS, UKA. P. DoyleAstrophysics Group, Lennard-Jones LaboratoriesKeele University, Keele, Staffordshire ST5 5BG, UKA. FumelInstitut d’Astrophysique et de Géophysique, Université de Liège, Allée du 6 Août 17, Sart Tilman, Liège 1, BelgiumM. GillonInstitut d’Astrophysique et de Géophysique, Université de Liège, Allée du 6 Août 17, Sart Tilman, Liège 1, BelgiumG. HébrardInstitut d’Astrophysique de Paris, UMR 7095 CNRS, Université Pierre & Marie Curie, 98bis boulevard Arago, 75014 Paris, FranceC. HellierAstrophysics Group, Lennard-Jones LaboratoriesKeele University, Keele, Staffordshire ST5 5BG, UKE. JehinInstitut d’Astrophysique et de Géophysique, Université de Liège, Allée du 6 Août 17, Sart Tilman, Liège 1, BelgiumM. LendlObservatoire de Genève, Université de Genève, 51 chemin des Maillettes, 1290 Sauverny, SwitzerlandP. F. L. MaxtedAstrophysics Group, Lennard-Jones LaboratoriesKeele University, Keele, Staffordshire ST5 5BG, UKC. MoutouAix Marseille Université, CNRS, LAM (Laboratoire d’Astrophysique de Marseille) UMR 7326, 13388 Marseille, FranceF. PepeObservatoire de Genève, Université de Genève, 51 chemin des Maillettes, 1290 Sauverny, SwitzerlandD. PollaccoDepartment of Physics, University of Warwick, Coventry CV4 7AL, UKD. QuelozObservatoire de Genève, Université de Genève, 51 chemin des Maillettes, 1290 Sauverny, SwitzerlandA. SanterneLaboratoire d’Astrophysique de MarseilleD. SegransanObservatoire de Genève, Université de Genève, 51 chemin des Maillettes, 1290 Sauverny, SwitzerlandB. SmalleyAstrophysics Group, Lennard-Jones LaboratoriesKeele University, Keele, Staffordshire ST5 5BG, UKJ. SouthworthAstrophysics Group, Lennard-Jones LaboratoriesKeele University, Keele, Staffordshire ST5 5BG, UKA. H. M. J. TriaudObservatoire de Genève, Université de Genève, 51 chemin des Maillettes, 1290 Sauverny, SwitzerlandS. UdryObservatoire de Genève, Université de Genève, 51 chemin des Maillettes, 1290 Sauverny, SwitzerlandR. G. WestDepartment of Physics & Astronomy, University of Leicester, Leicester, LE1 7RH, UK

2013en

ABI

Аннотация

We report the discovery by the WASP transit survey of a highly-irradiated, massive (2.242 ± 0.080 MJup) planet which transits a bright (V = 10.6), evolved F8 star every 2.9 days. The planet, WASP-71b, is larger than Jupiter (1.46 ± 0.13 RJup), but less dense (0.71 ± 0.16 ρJup). We also report spectroscopic observations made during transit with the CORALIE spectrograph, which allow us to make a highly-significant detection of the Rossiter-McLaughlin effect. We determine the sky-projected angle between the stellar-spin and planetary-orbit axes to be λ = 20.1 ± 9.7 degrees, i.e. the system is “aligned”, according to the widely-used alignment criteria that systems are regarded as misaligned only when λ is measured to be greater than 10 degrees with 3-σ confidence. WASP-71, with an effective temperature of 6059 ± 98 K, therefore fits the previously observed pattern that only stars hotter than 6250 K are host to planets in misaligned orbits. We emphasise, however, that λ is merely the sky-projected obliquity angle; we are unable to determine whether the stellar-spin and planetary-orbit axes are misaligned along the line-of-sight. With a mass of 1.56 ± 0.07 M⊙, WASP-71 was previously hotter than 6250 K, and therefore might have been significantly misaligned in the past. If so, the planetary orbit has been realigned, presumably through tidal interactions with the cooling star’s growing convective zone.

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Идентификаторы

DOI: 10.1051/0004-6361/201220727

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