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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    157 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 RJup, whereas WASP-2b has a radius in the range 0.65-1.26 RJup.

    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
    • Planetary systems
    • Techniques: photometric
    • Techniques: radial velocities

    ASJC Scopus subject areas

    • Astronomy and Astrophysics
    • Space and Planetary Science

    Cite this

    Cameron, A. C., Bouchy, F., Hébrard, G., Maxted, P., Pollacco, D., Pont, F., Skillen, I., Smalley, B., Street, R. A., West, R. G., Wilson, D. M., Aigrain, S., Christian, D. J., Clarkson, W. I., Enoch, B., Evans, A., Fitzsimmons, A., Fleenor, M., Gillon, M., ... Wheatley, P. J. (2007). WASP-1b and WASP-2b: Two new transiting exoplanets detected with SuperWASP and SOPHIE. Monthly Notices of the Royal Astronomical Society, 375(3), 951-957. https://doi.org/10.1111/j.1365-2966.2006.11350.x