HAT-P-1b: A Large-Radius, Low-Density Exoplanet Transiting One Member of a Stellar Binary

February 2007 • 2007ApJ...656..552B

Authors • Bakos, G. Á. • Noyes, R. W. • Kovács, G. • Latham, D. W. • Sasselov, D. D. • Torres, G. • Fischer, D. A. • Stefanik, R. P. • Sato, B. • Johnson, J. A. • Pál, A. • Marcy, G. W. • Butler, R. P. • Esquerdo, G. A. • Stanek, K. Z. • Lázár, J. • Papp, I. • Sári, P. • Sipőcz, B.

Abstract • Using small automated telescopes in Arizona and Hawaii, the HATNet project has detected an object transiting one member of the double star system ADS 16402. This system is a pair of G0 main-sequence stars with age about 3 Gyr at a distance of ~139 pc and projected separation of ~1550 AU. The transit signal has a period of 4.46529 days and depth of 0.015 mag. From follow-up photometry and spectroscopy, we find that the object is a ``hot Jupiter'' planet with mass about 0.53M_J and radius ~1.36R_J traveling in an orbit with semimajor axis 0.055 AU and inclination about 85.9°, thus transiting the star at impact parameter 0.74 of the stellar radius. Based on a data set spanning 3 yr, ephemerides for the transit center are T_C=2453984.397+N_tr×4.46529. The planet, designated HAT-P-1b, appears to be at least as large in radius, and smaller in mean density, than any previously known planet.

Based in part on data collected at the Subaru Telescope, which is operated by the National Astronomical Observatory of Japan.

Based in part on observations obtained at the W. M. Keck Observatory, which is operated by the University of California and the California Institute of Technology. Keck time has been granted by NASA.

Links

View on ADS

IPAC Authors
(alphabetical)

Brigitta Sipőcz

Applications Developer