HATS-17b: A Transiting Compact Warm Jupiter in a 16.3 Day Circular Orbit

Abstract

We report the discovery of HATS-17b, the first transiting warm Jupiter of the HATSouth network. HATS-17b transits its bright (V = 12.4) G-type (M =1.131 0.030  M, R = - + 1.091 0.046 0.070 R) metal-rich ([Fe/ H] = +0.3 dex) host star in a circular orbit with a period of P =16.2546 days. HATS-17b has a very compact radius of 0.777 0.056  RJ given its Jupiter-like mass of 1.338 0.065  MJ. Up to 50% of the mass of HATS-17b may be composed of heavy elements in order to explain its high density with current models of planetary structure. HATS-17b is the longest period transiting planet discovered to date by a ground-based photometric survey, and is one of the brightest transiting warm Jupiter systems known. The brightness of HATS-17 will allow detailed followup observations to characterize the orbital geometry of the system and the atmosphere of the planet.