methods: data analysis; techniques: photometric; techniques: radial velocities; planetary systems
Résumé :
[en] We have detected low-amplitude radial-velocity variations in two stars, USNO-B1.0 1219-0005465 (GSC 02265-00107 = WASP-1) and USNO-B1.0 0964-0543604 (GSC 00522-01199 = WASP-2). Both stars were identified as being likely host stars of transiting exoplanets in the 2004 SuperWASP wide-field transit survey. Using the newly commissioned radial-velocity spectrograph SOPHIE at the Observatoire de Haute-Provence, we found that both objects exhibit reflex orbital radial-velocity variations with amplitudes characteristic of planetary-mass companions and in-phase with the photometric orbits. Line-bisector studies rule out faint blended binaries as the cause of either the radial-velocity variations or the transits. We perform preliminary spectral analyses of the host stars, which together with their radial-velocity variations and fits to the transit light curves yield estimates of the planetary masses and radii. WASP-1b and WASP-2b have orbital periods of 2.52 and 2.15 d, respectively. Given mass estimates for their F7V and K1V primaries, we derive planet masses 0.80-0.98 and 0.81-0.95 times that of Jupiter, respectively. WASP-1b appears to have an inflated radius of at least 1.33 R[SUB]Jup[/SUB], whereas WASP-2b has a radius in the range 0.65-1.26 R[SUB]Jup[/SUB].
Disciplines :
Aérospatiale, astronomie & astrophysique
Auteur, co-auteur :
Cameron, A Collier; School of Physics and Astronomy, University of St Andrews, North Haugh, St Andrews, Fife KY16 9SS
Bouchy, F.; Institut d'Astrophysique de Paris, CNRS (UMR 7095) - Université Pierre & Marie Curie, 98bis bvd. Arago, 75014 Paris, France ; Observatoire de Haute-Provence, 04870 St Michel l'Observatoire, France
Hébrard, G.; Institut d'Astrophysique de Paris, CNRS (UMR 7095) - Université Pierre & Marie Curie, 98bis bvd. Arago, 75014 Paris, France
Maxted, P.; Astrophysics Group, Keele University, Staffordshire ST5 5BG
Pollacco, D.; ARC, Main Physics Building, School of Mathematics & Physics, Queen's University, University Road, Belfast BT7 1NN
Pont, F.; Observatoire de Genève, Université de Genève, 51 Ch. des Maillettes, 1290 Sauverny, Switzerland
Skillen, I.; Isaac Newton Group of Telescopes, Apartado de Correos 321, E-38700 Santa Cruz de la Palma, Tenerife, Spain
Smalley, B.; Astrophysics Group, Keele University, Staffordshire ST5 5BG
Street, R. A.; ARC, Main Physics Building, School of Mathematics & Physics, Queen's University, University Road, Belfast BT7 1NN
West, R. G.; Department of Physics and Astronomy, University of Leicester, Leicester LE1 7RH
Wilson, D. M.; Astrophysics Group, Keele University, Staffordshire ST5 5BG
Aigrain, S.; Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA
Christian, D. J.; ARC, Main Physics Building, School of Mathematics & Physics, Queen's University, University Road, Belfast BT7 1NN
Clarkson, W. I.; Department of Physics and Astronomy, The Open University, Milton Keynes MK7 6AA ; STScI, 3700 San Martin Drive, Baltimore, MD 21218, USA
Enoch, B.; Department of Physics and Astronomy, The Open University, Milton Keynes MK7 6AA
Evans, A.; Astrophysics Group, Keele University, Staffordshire ST5 5BG
Fitzsimmons, A.; ARC, Main Physics Building, School of Mathematics & Physics, Queen's University, University Road, Belfast BT7 1NN
Fleenor, M.; Volunteer Observatory, 10305 Mantooth Lane Knoxville, TN 37932, USA
Gillon, Michaël ; Université de Liège - ULiège > Département d'astrophys., géophysique et océanographie (AGO) > Astrophysique et traitement de l'image
Haswell, C. A.; Department of Physics and Astronomy, The Open University, Milton Keynes MK7 6AA
Hebb, L.; School of Physics and Astronomy, University of St Andrews, North Haugh, St Andrews, Fife KY16 9SS
Hellier, C.; Astrophysics Group, Keele University, Staffordshire ST5 5BG
Hodgkin, S. T.; Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA
Horne, K.; School of Physics and Astronomy, University of St Andrews, North Haugh, St Andrews, Fife KY16 9SS
Irwin, J.; Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA
Kane, S. R.; Department of Astronomy, University of Florida, 211 Bryant Space Science Center, Gainesville, FL 32611-2055, USA
Keenan, F. P.; ARC, Main Physics Building, School of Mathematics & Physics, Queen's University, University Road, Belfast BT7 1NN
Loeillet, B.; Laboratoire d'Astrophysique de Marseille, BP 8, 13376 Marseille Cedex 12, France
Lister, T. A.; School of Physics and Astronomy, University of St Andrews, North Haugh, St Andrews, Fife KY16 9SS ; Astrophysics Group, Keele University, Staffordshire ST5 5BG
Mayor, M.; Observatoire de Genève, Université de Genève, 51 Ch. des Maillettes, 1290 Sauverny, Switzerland
Moutou, C.; Laboratoire d'Astrophysique de Marseille, BP 8, 13376 Marseille Cedex 12, France
Norton, A. J.; Department of Physics and Astronomy, The Open University, Milton Keynes MK7 6AA
Osborne, J.; Department of Physics and Astronomy, University of Leicester, Leicester LE1 7RH
Parley, N.; Department of Physics and Astronomy, The Open University, Milton Keynes MK7 6AA
Queloz, D.; Observatoire de Genève, Université de Genève, 51 Ch. des Maillettes, 1290 Sauverny, Switzerland
Ryans, R.; ARC, Main Physics Building, School of Mathematics & Physics, Queen's University, University Road, Belfast BT7 1NN
Triaud, A H M J; School of Physics and Astronomy, University of St Andrews, North Haugh, St Andrews, Fife KY16 9SS
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
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