1. Astrophysics Group, Keele University, Staffordshire, ST5 5BG, UK
2. School of Physics and Astronomy, University of St Andrews, North Haugh, Fife, KY16 9SS, UK
3. Observatoire de Genève, Université de Genève, 51 ch. des Maillettes, 1290 Sauverny, Switzerland
4. Institut d'Astrophysique et de Géophysique, Université de Liège, 17 Allée du 6 Août, Batiment B5C, Liège 1, Belgium
5. Department of Physics and Astronomy, University of Leicester, Leicester, LE1 7RH, UK
6. Department of Astronomy, Harvard University, 60 Garden Street, MS 10, Cambridge, Massachusetts 02138, USA
7. Las Cumbres Observatory, 6740 Cortona Dr. Suite 102, Santa Barbara, California 93117, USA
8. Astrophysics Research Centre, School of Mathematics and Physics, Queen's University, University Road, Belfast, BT7 1NN, UK
9. Department of Physics, University of Warwick, Coventry, CV4 7AL, UK

Correspondence to: Coel Hellier¹ Correspondence and requests for materials should be addressed to C.H. (Email: ch@astro.keele.ac.uk).

Abstract

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^{1, 2}, or by an alternative mechanism such as planet–planet scattering³. The hot Jupiters closest to their parent stars, at orbital distances of only 0.02 astronomical units, have strong tidal interactions^{4, 5}, and systems such as OGLE-TR-56 have been suggested as tests of tidal dissipation theory^{6, 7}. Here we report the discovery of planet WASP-18b with an orbital period of 0.94 days and a mass of ten Jupiter masses (10 M_Jup), 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 10⁶, 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.

1. Astrophysics Group, Keele University, Staffordshire, ST5 5BG, UK
2. School of Physics and Astronomy, University of St Andrews, North Haugh, Fife, KY16 9SS, UK
3. Observatoire de Genève, Université de Genève, 51 ch. des Maillettes, 1290 Sauverny, Switzerland
4. Institut d'Astrophysique et de Géophysique, Université de Liège, 17 Allée du 6 Août, Batiment B5C, Liège 1, Belgium
5. Department of Physics and Astronomy, University of Leicester, Leicester, LE1 7RH, UK
6. Department of Astronomy, Harvard University, 60 Garden Street, MS 10, Cambridge, Massachusetts 02138, USA
7. Las Cumbres Observatory, 6740 Cortona Dr. Suite 102, Santa Barbara, California 93117, USA
8. Astrophysics Research Centre, School of Mathematics and Physics, Queen's University, University Road, Belfast, BT7 1NN, UK
9. Department of Physics, University of Warwick, Coventry, CV4 7AL, UK

Correspondence to: Coel Hellier¹ Correspondence and requests for materials should be addressed to C.H. (Email: ch@astro.keele.ac.uk).

MORE ARTICLES LIKE THIS

These links to content published by NPG are automatically generated.