An orbital period of 0.94days for the hot-Jupiter planet WASP-18b
English
Hellier, Coel[Astrophysics Group, Keele University, Staffordshire, ST5 5BG, UK]
Anderson, D. R.[Astrophysics Group, Keele University, Staffordshire, ST5 5BG, UK]
Cameron, A Collier[School of Physics and Astronomy, University of St Andrews, North Haugh, Fife, KY16 9SS, UK]
Gillon, Michaël[Université de Liège - ULiège > Département d'astrophys., géophysique et océanographie (AGO) > Astrophysique et traitement de l'image >]
Hebb, L.[School of Physics and Astronomy, University of St Andrews, North Haugh, Fife, KY16 9SS, UK]
Maxted, P. F. L.[Astrophysics Group, Keele University, Staffordshire, ST5 5BG, UK]
Queloz, D.[Observatoire de Genève, Université de Genève, 51 ch. des Maillettes, 1290 Sauverny, Switzerland]
Smalley, B.[Astrophysics Group, Keele University, Staffordshire, ST5 5BG, UK]
Triaud, A H M J[Observatoire de Genève, Université de Genève, 51 ch. des Maillettes, 1290 Sauverny, Switzerland]
West, R. G.[Department of Physics and Astronomy, University of Leicester, Leicester, LE1 7RH, UK]
Wilson, D. M.[Astrophysics Group, Keele University, Staffordshire, ST5 5BG, UK]
Bentley, S. J.[Astrophysics Group, Keele University, Staffordshire, ST5 5BG, UK]
Enoch, B.[School of Physics and Astronomy, University of St Andrews, North Haugh, Fife, KY16 9SS, UK]
Horne, K.[School of Physics and Astronomy, University of St Andrews, North Haugh, Fife, KY16 9SS, UK]
Irwin, J.[Department of Astronomy, Harvard University, 60 Garden Street, MS 10, Cambridge, Massachusetts 02138, USA]
Lister, T. A.[Las Cumbres Observatory, 6740 Cortona Dr. Suite 102, Santa Barbara, California 93117, USA]
Mayor, M.[Observatoire de Genève, Université de Genève, 51 ch. des Maillettes, 1290 Sauverny, Switzerland]
Parley, N.[School of Physics and Astronomy, University of St Andrews, North Haugh, Fife, KY16 9SS, UK]
Pepe, F.[Observatoire de Genève, Université de Genève, 51 ch. des Maillettes, 1290 Sauverny, Switzerland]
Pollacco, D. L.[Astrophysics Research Centre, School of Mathematics and Physics, Queen's University, University Road, Belfast, BT7 1NN, UK]
Segransan, D.[Observatoire de Genève, Université de Genève, 51 ch. des Maillettes, 1290 Sauverny, Switzerland]
Udry, S.[Observatoire de Genève, Université de Genève, 51 ch. des Maillettes, 1290 Sauverny, Switzerland]
Wheatley, P. J.[Department of Physics, University of Warwick, Coventry, CV4 7AL, UK]
[en] The `hot Jupiters' that abound in lists of known extrasolar planets are thought to have formed far from their host stars, but migrate inwards through interactions with the proto-planetary disk from which they were born, or by an alternative mechanism such as planet-planet scattering. The hot Jupiters closest to their parent stars, at orbital distances of only ~0.02 astronomical units, have strong tidal interactions, and systems such as OGLE-TR-56 have been suggested as tests of tidal dissipation theory. Here we report the discovery of planet WASP-18b with an orbital period of 0.94days and a mass of ten Jupiter masses (10M[SUB]Jup[/SUB]), resulting in a tidal interaction an order of magnitude stronger than that of planet OGLE-TR-56b. Under the assumption that the tidal-dissipation parameter Q of the host star is of the order of 10[SUP]6[/SUP], as measured for Solar System bodies and binary stars and as often applied to extrasolar planets, WASP-18b will be spiralling inwards on a timescale less than a thousandth that of the lifetime of its host star. Therefore either WASP-18 is in a rare, exceptionally short-lived state, or the tidal dissipation in this system (and possibly other hot-Jupiter systems) must be much weaker than in the Solar System.
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