Lendl, M, Triaud, AHMJ, Anderson, DR, Cameron, AC, Delrez, L, Doyle, AP, Gillon, M, Hellier, C, Jehin, E, Maxted, PFL, Neveu-VanMalle, M, Pepe, F, Pollacco, D, Queloz, D, Segransan, D, Smalley, B, Smith, AMS, Udry, S, Van Grootel, V and West, RG (2014) WASP-117b: a 10-day-period Saturn in an eccentric and misaligned orbit. ASTRONOMY & ASTROPHYSICS, 568. ISSN 0004-6361

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We report the discovery of WASP-117b, the first planet with a period beyond 10 days found by the WASP survey. The planet has a mass of Mp = 0.2755 ± 0.0089 MJ, a radius of and is in an eccentric (e = 0.302 ± 0.023), 10.02165 ± 0.00055 d orbit around a main-sequence F9 star. The host star’s brightness (V = 10.15 mag) makes WASP-117 a good target for follow-up observations, and with a periastron planetary equilibrium temperature of K and a low planetary mean density () it is one of the best targets for transmission spectroscopy among planets with periods around 10 days. From a measurement of the Rossiter-McLaughlin effect, we infer a projected angle between the planetary orbit and stellar spin axes of β = −44 ± 11 deg, and we further derive an orbital obliquity of deg. Owing to the large orbital separation, tidal forces causing orbital circularization and realignment of the planetary orbit with the stellar plane are weak, having had little impact on the planetary orbit over the system lifetime. WASP-117b joins a small sample of transiting giant planets with well characterized orbits at periods above ~8 days.

Item Type: Article
Uncontrolled Keywords: planetary systems, techniques: photometric, techniques: radial velocities
Subjects: Q Science > QB Astronomy
Divisions: Faculty of Natural Sciences > School of Physical and Geographical Sciences
Related URLs:
Depositing User: Symplectic
Date Deposited: 17 Dec 2015 09:31
Last Modified: 20 May 2019 08:17
URI: https://eprints.keele.ac.uk/id/eprint/1304

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