A fast hybrid algorithm for exoplanetary transit searches

A. Collier Cameron, D. Pollacco, R. A. Street, T. A. Lister, R. G. West, D. M. Wilson, F. Pont, D. J. Christian, W. I. Clarkson, B. Enoch, A. Evans, A. Fitzsimmons, C. A. Haswell, C. Hellier, S. T. Hodgkin, K. Horne, J. Irwin, S. R. Kane, F. P. Keenan, A. J. NortonN. R. Parley, J. Osborne, R. Ryans, I. Skillen, P. J. Wheatley

    Research output: Contribution to journalArticle

    144 Citations (Scopus)

    Abstract

    We present a fast and efficient hybrid algorithm for selecting exoplanetary candidates from wide-field transit surveys. Our method is based on the widely used SysRem and Box Least-Squares (BLS) algorithms. Patterns of systematic error that are common to all stars on the frame are mapped and eliminated using the SysRem algorithm. The remaining systematic errors caused by spatially localized flat-fielding and other errors are quantified using a boxcarsmoothing method. We show that the dimensions of the search-parameter space can be reduced greatly by carrying out an initial BLS search on a coarse grid of reduced dimensions, followed by Newton-Raphson refinement of the transit parameters in the vicinity of the most significant solutions. We illustrate the method's operation by applying it to data from one field of the SuperWASP survey, comprising 2300 observations of 7840 stars brighter than V = 13.0. We identify 11 likely transit candidates. We reject stars that exhibit significant ellipsoidal variations caused indicative of a stellar-mass companion. We use colours and proper motions from the Two Micron All Sky Survey and USNO-B1.0 surveys to estimate the stellar parameters and the companion radius. We find that two stars showing unambiguous transit signals pass all these tests, and so qualify for detailed high-resolution spectroscopic follow-up.

    Original languageEnglish
    Pages (from-to)799-810
    Number of pages12
    JournalMonthly Notices of the Royal Astronomical Society
    Volume373
    Issue number2
    DOIs
    Publication statusPublished - 1 Dec 2006

      Fingerprint

    Keywords

    • Methods: data analysis
    • Stars: planetary systems
    • Techniques: photometric

    ASJC Scopus subject areas

    • Astronomy and Astrophysics
    • Space and Planetary Science

    Cite this

    Collier Cameron, A., Pollacco, D., Street, R. A., Lister, T. A., West, R. G., Wilson, D. M., Pont, F., Christian, D. J., Clarkson, W. I., Enoch, B., Evans, A., Fitzsimmons, A., Haswell, C. A., Hellier, C., Hodgkin, S. T., Horne, K., Irwin, J., Kane, S. R., Keenan, F. P., ... Wheatley, P. J. (2006). A fast hybrid algorithm for exoplanetary transit searches. Monthly Notices of the Royal Astronomical Society, 373(2), 799-810. https://doi.org/10.1111/j.1365-2966.2006.11074.x