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

2006/09/15 by G. A. Bakos, G. Á. Bakos, R. W. Noyes +29 · 10 citations
Physics and Astronomy · #Astro and Planetary Science #Astronomy #Astronomy and Astrophysical Research #Astrophysics #Ephemeris #Exoplanet #Hot Jupiter #Photometry (optics) #Physics #Planet #Planetary system #RADIUS #Satellite #Stars #Stellar, planetary, and galactic studies #Transit (satellite) #astro-ph

paper · pdf · doi:10.1086/509874

published as Astrophys.J.656:552-559,2007 · 8 pages, accepted for publication in ApJ, see also http://www.hatnet.hu (www.hatnet.hu)

arxiv created 2006/09/15 · openalex publication_date 2007/02/03 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05

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 0.53 M J and radius ~1.36 R 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.

Citations

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• The Frequency of Large‐Radius Hot and Very Hot Jupiters in ω Centauri
• The Dynamics-Based Approach to Studying Terrestrial Exoplanets
• The Transit Light Curve Project. III. Tres Transits of TrES‐1
• HAT-P-9b: A LOW-DENSITY PLANET TRANSITING A MODERATELY FAINT F STAR
• Predicting the Yields of Photometric Surveys for Transiting Extrasolar Planets
• HD 75289Ab revisited
• WASP-17b: AN ULTRA-LOW DENSITY PLANET IN A PROBABLE RETROGRADE ORBIT
• Homogeneous studies of transiting extrasolar planets – I. Light-curve analyses