[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.
Disciplines :
Aérospatiale, astronomie & astrophysique
Auteur, co-auteur :
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
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