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

Andrew Collier Cameron, F Bouchy, G Hebrard, 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, Keith Douglas 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
JournalMonthly Notices of the Royal Astronomical Society
Issue number3
Publication statusPublished - 1 Mar 2007


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


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