| Institution: | School of Physics and Astronomy, University of St Andrews, North Haugh, St Andrews, Fife KY16 9SS;Institut d'Astrophysique de Paris, CNRS (UMR 7095) –UniversitéPierre &Marie Curie, 98bis bvd. Arago, 75014 Paris, France;Observatoire de Haute-Provence, 04870 St Michel l'Observatoire, France;Astrophysics Group, Keele University, Staffordshire ST5 5BG;ARC, Main Physics Building, School of Mathematics &Physics, Queen's University, University Road, Belfast BT7 1NN;Observatoire de Genève, Universitéde Genève, 51 Ch. des Maillettes, 1290 Sauverny, Switzerland;Isaac Newton Group of Telescopes, Apartado de Correos 321, E-38700 Santa Cruz de la Palma, Tenerife, Spain;Department of Physics and Astronomy, University of Leicester, Leicester LE1 7RH;Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA;Department of Physics and Astronomy, The Open University, Milton Keynes MK7 6AA;STScI, 3700 San Martin Drive, Baltimore, MD 21218, USA;Volunteer Observatory, 10305 Mantooth Lane Knoxville, TN 37932, USA;Institut d'Astrophysique et de Géophysique, Universitéde Liège, Allée du 6 Août 17, 4000 Liège, Belgium;Department of Astronomy, University of Florida, 211 Bryant Space Science Center, Gainesville, FL 32611-2055, USA;Laboratoire d'Astrophysique de Marseille, BP 8, 13376 Marseille Cedex 12, France;Department of Physics, University of Warwick, Coventry CV4 7AL |
| Abstract: | 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 Jup, whereas WASP-2b has a radius in the range 0.65–1.26 R Jup. |
