[en] We report the discovery of WASP-6b, an inflated sub-Jupiter mass planet transiting every 3.3610060[SUP]+ 0.0000022 [/SUP][SUB]- 0.0000035 [/SUB] days a mildly metal-poor solar-type star of magnitude V = 11.9. A combined analysis of the WASP photometry, high-precision followup transit photometry and radial velocities yield a planetary mass M[SUB]p[/SUB] = 0.503[SUP]+0.019[/SUP][SUB]-0.038[/SUB] M[SUB]J[/SUB] and radius R[SUB]p[/SUB] = 1.224[SUP]+0.051[/SUP][SUB]-0.052[/SUB] R_J, resulting in a density rho[SUB]p[/SUB] = 0.27 ± 0.05 rho_J. The mass and radius for the host star are M_ast = 0.88[SUP]+0.05[/SUP][SUB]-0.08[/SUB] M_o and R_ast = 0.870[SUP]+0.025[/SUP][SUB]-0.036[/SUB] R_o. The non-zero orbital eccentricity e = 0.054^+0.018[SUB]-0.015[/SUB] that we measure suggests that the planet underwent a massive tidal heating 1 Gyr ago that could have contributed to its inflated radius. High-precision radial velocities obtained during a transit allow us to measure a sky-projected angle between the stellar spin and orbital axis beta = 11[SUP]+14[/SUP][SUB]-18[/SUB] deg. In addition to similar published measurements, this result favors a dominant migration mechanism based on tidal interactions with a protoplanetary disk. Based on data collected with the HARPS spectrograph at ESO La Silla Observatory in the programs 082.C-0040(E) and 082.C-0608. The photometric time-series and radial velocities (Tables 4, 5) used in this work are only available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/501/785
Disciplines :
Space science, astronomy & astrophysics
Author, co-author :
Gillon, Michaël ; Université de Liège - ULiège > Département d'astrophys., géophysique et océanographie (AGO) > Astrophysique et traitement de l'image
Anderson, D. R.; Astrophysics Group, Keele University, Staffordshire, ST5 5BG, UK
Triaud, A H M J; Observatoire de Genève, Université de Genève, 51 Chemin des Maillettes, 1290 Sauverny, Switzerland
Hellier, C.; Astrophysics Group, Keele University, Staffordshire, ST5 5BG, UK
Maxted, P. F. L.; Astrophysics Group, Keele University, Staffordshire, ST5 5BG, UK
Pollaco, D.; Astrophysics Research Centre, School of Mathematics & Physics, Queen's University, University Road, Belfast, BT7 1NN, UK
Queloz, D.; Observatoire de Genève, Université de Genève, 51 Chemin des Maillettes, 1290 Sauverny, Switzerland
Smalley, B.; Astrophysics Group, Keele University, Staffordshire, ST5 5BG, UK
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
Collier Cameron, A.; School of Physics and Astronomy, University of St. Andrews, North Haugh, Fife, KY16 9SS, UK
Enoch, B.; School of Physics and Astronomy, University of St. Andrews, North Haugh, Fife, KY16 9SS, UK
Hebb, L.; 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
Joshi, Y. C.; Astrophysics Research Centre, School of Mathematics & Physics, Queen's University, University Road, Belfast, BT7 1NN, UK
Lister, T. A.; Las Cumbres Observatory, 6740 Cortona Dr. Suite 102, Santa Barbara, CA 93117, USA
Mayor, M.; Observatoire de Genève, Université de Genève, 51 Chemin des Maillettes, 1290 Sauverny, Switzerland
Pepe, F.; Observatoire de Genève, Université de Genève, 51 Chemin des Maillettes, 1290 Sauverny, Switzerland
Parley, N.; Department of Physics and Astronomy, University of Leicester, Leicester, LE1 7RH, UK
Segransan, D.; Observatoire de Genève, Université de Genève, 51 Chemin des Maillettes, 1290 Sauverny, Switzerland
Udry, S.; Observatoire de Genève, Université de Genève, 51 Chemin des Maillettes, 1290 Sauverny, Switzerland
Wheatley, P. J.; Department of Physics, University of Warwick, Coventry, CV4 7AL, UK
