HATS-59b,c: A Transiting Hot Jupiter and a Cold Massive Giant Planet around a Sun-like Star

We report the first discovery of a multi-planetary system by the HATSouth network, HATS-59b,c, a planetary system with an inner transiting hot Jupiter and an outer cold massive giant planet, which was detected via radial velocity. The inner transiting planet, HATS-59b, is on an eccentric orbit with e=0.129+/- 0.049, orbiting a V=13.951+/- 0.030 mag solar-like star ({M}_\star = 1.038+/- 0.039 {M}_⊙ and {R}_\star =1.036+/- 0.067 {R}_⊙ ) with a period of 5.416081+/- 0.000016 days. The outer companion, HATS-59c is on a circular orbit with m\sin i=12.70 +/- 0.87 {M}_{{J}} and a period of 1422 ± 14 days. The inner planet has a mass of 0.806+/- 0.069 {M}_{{J}} and a radius of 1.126+/- 0.077 {R}_{{J}}, yielding a density of 0.70+/- 0.16 {{g}} {cm}}^-3. Unlike most planetary systems that include only a single hot Jupiter, HATS-59b,c includes, in addition to the transiting hot Jupiter, a massive outer companion. The architecture of this system is valuable for understanding planet migration.

The HATSouth network is operated by a collaboration consisting of Princeton University (PU), the Max Planck Institute für Astronomie (MPIA), the Australian National University (ANU), and the Pontificia Universidad Católica de Chile (PUC). The station at Las Campanas Observatory (LCO) of the Carnegie Institute is operated by PU in conjunction with PUC, the station at the High Energy Spectroscopic Survey (H.E.S.S.) site is operated in conjunction with MPIA, and the station at Siding Spring Observatory (SSO) is operated jointly with ANU. This paper includes data gathered with 6.5 m Magellan Telescopes located as Las Campanas Observatory, Chile, and the MPG 2.2 m, the NTT, and the Euler 1.2 m telescopes at the ESO Observatory in La Silla. This paper uses observations obtained with facilities of the Las Cumbres Observatory Global Telescope. Based in part on observations made with the 3.9 m Anglo-Australian Telescope and the ANU 2.3 m Telescope both at SSO. Based in part on observations made with the facilities of the Las Cumbres Observatory Global Telescope, the Perth Exoplanet Survey Telescope, and the Nordic Optical Telescope.