WASP-1b and WASP-2b: two new transiting exoplanets detected with SuperWASP and SOPHIE

A. Collier Cameron, F. Bouchy, G. Hébrard, P. Maxted, D. Pollacco, F. Pont, I. Skillen, B. Smalley, R.~A. Street, R.~G. West, D.~M. Wilson, S. Aigrain, D.~J. Christian, W.~I. Clarkson, B. Enoch, A. Evans, A. Fitzsimmons, M. Fleenor, M. Gillon, C.~A. HaswellL. Hebb, C. Hellier, S.~T. Hodgkin, K. Horne, J. Irwin, S.~R. Kane, F.~P. Keenan, B. Loeillet, T.~A. Lister, M. Mayor, C. Moutou, A.~J. Norton, J. Osborne, N. Parley, D. Queloz, R. Ryans, A.~H.~M.~J. Triaud, S. Udry, P.~J. Wheatley

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162 Citations (Scopus)


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$_Jup$.
Original languageEnglish
Pages (from-to)951-957
Number of pages7
JournalRoyal Astronomical Society. Monthly Notices
Publication statusPublished - 1 Mar 2007


  • methods: data analysis, techniques: photometric, techniques: radial velocities, planetary systems


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