HATS-54b-HATS-58Ab: five new transiting hot Jupiters including one with a possible temperate companion

Status Report From: e-Print archive
Posted: Wednesday, December 19, 2018

Néstor Espinoza, Joel D. Hartman, Gaspar Á. Bakos, Thomas Henning, Daniel Bayliss, Joao Bento, Waqas Bhatti, Rafael Brahm, Zoltan Csubry, Vincent Suc, Andrés Jordán, Luigi Mancini, T. G. Tan, Kaloyan Penev, Markus Rabus, Paula Sarkis, Miguel de Val-Borro, Stephen Durkan, Josef Lazar, Istvan Papp, Pal Sari

(Submitted on 18 Dec 2018)

We report the discovery by the HATSouth project of 5 new transiting hot Jupiters (HATS-54b through HATS-58Ab). HATS-54b, HATS-55b and HATS-58Ab are prototypical short period (P=2.54.2 days, Rp1.11.2 RJ) hot-Jupiters that span effective temperatures from 1350 K to 1750 K, putting them in the proposed region of maximum radius inflation efficiency. The HATS-58 system is composed of two stars, HATS-58A and HATS-58B, which are detected thanks to Gaia DR2 data and which we account for in the joint modelling of the available data --- with this, we are led to conclude that the hot jupiter orbits the brighter HATS-58A star. HATS-57b is a short-period (2.35-day) massive (3.15 MJ) 1.14 RJ, dense (2.65±0.21 g cm3) hot-Jupiter, orbiting a very active star (2% peak-to-peak flux variability). Finally, HATS-56b is a short period (4.32-day) highly inflated hot-Jupiter (1.7 RJ, 0.6 MJ), which is an excellent target for future atmospheric follow-up, especially considering the relatively bright nature (V=11.6) of its F dwarf host star. This latter exoplanet has another very interesting feature: the radial velocities show a significant quadratic trend. If we interpret this quadratic trend as arising from the pull of an additional planet in the system, we obtain a period of Pc=815+253143 days for the possible planet HATS-56c, and a minimum mass of Mcsinic=5.11±0.94 MJ. The candidate planet HATS-56c would have a zero-albedo equilibrium temperature of Teq=332±50 K, and thus would be orbiting close to the habitable zone of HATS-56. Further radial-velocity follow-up, especially over the next two years, is needed to confirm the nature of HATS-56c.

Comments: Submitted to AAS Journals

Subjects: Earth and Planetary Astrophysics (astro-ph.EP)

Cite as: arXiv:1812.07668 [astro-ph.EP] (or arXiv:1812.07668v1 [astro-ph.EP] for this version)

Submission history

From: Néstor Espinoza 

[v1] Tue, 18 Dec 2018 22:21:57 UTC (3,767 KB)

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