2007/10/18 by David T. F. Weldrake, David T F Weldrake, Penny D Sackett +4
Physics and Astronomy · #Astro and Planetary Science #Astronomy #Astronomy and Astrophysical Research #Astrophysics #Exoplanet #Globular cluster #Hot Jupiter #Orbital period #Photometry (optics) #Physics #Planet #RADIUS #Stars #Stellar, planetary, and galactic studies #Transit (satellite) #astro-ph
paper · pdf · doi:10.1086/524917
22 pages, 8 figures, accepted for publication in ApJ
arxiv created 2007/10/18 · openalex publication_date 2008/02/15 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
We present the results of a deep, wide-field search for transiting hot Jupiter (HJ) planets in the globular cluster ω Centauri. As a result of a 25 night observing run with the ANU 40 inch (1 m) telescope at Siding Spring Observatory, a total of 109,726 stellar time series composed of 787 independent data points were produced with differential photometry in a 52' × 52' (0.75 deg 2 ) field centered on the cluster core, but extending well beyond. Taking into account the size of transit signals as a function of stellar radius, 45,406 stars have suitable photometric accuracy (≤0.045 mag to V = 19.5) to search for transits. Of this sample, 31,000 stars are expected to be main-sequence cluster members. All stars, both cluster and foreground, were subjected to a rigorous search for transit signatures; none were found. Extensive Monte Carlo simulations based on our actual data set allow us to determine the sensitivity of our survey to planets with radii ~1.5 R Jup and thus place statistical upper limits on their occurrence frequency F . Smaller planets are undetectable in our data. At 95% confidence, the frequency of very hot Jupiters (VHJs) with periods P satisfying 1 day < P < 3 days can be no more than F VHJ < 1/1040 in ω Cen. For HJs and VHJs distributed uniformly over the orbital period range 1 day < P < 5 days, F VHJ+HJ < 1/600. Our limits on large, short-period planets are comparable to those recently reported for other Galactic fields, despite being derived with less telescope time.