HATS-25b through HATS-30b: A Half-dozen New Inflated Transiting Hot Jupiters from the HATSouth Survey

Abstract

We report six new inflated hot Jupiters (HATS-25b through HATS-30b) discovered using the HATSouth global network of automated telescopes. The planets orbit stars with V magnitudes in the range of ∼12–14 and have masses in the largely populated 0.5 0.7 M M J J – region of parameter space but span a wide variety of radii, from 1.17RJ to 1.75RJ . HATS-25b, HATS-28b, HATS-29b, and HATS-30b are typical inflated hot Jupiters (Rp J = 1.17 1.26 – R ) orbiting G–type stars in short period (P = 3.2-4.6 days) orbits. However, HATS-26b (Rp J = 1.75R , P = 3.3024 days) and HATS-27b (Rp J = 1.50R , P = 4.6370 days) stand out as highly inflated planets orbiting slightly evolved F stars just after and in the turn–off points, respectively, which are among the least dense hot Jupiters, with densities of 0.153 - g cm 3 and 0.180 - g cm 3, respectively. All the presented exoplanets but HATS-27b are good targets for future atmospheric characterization studies, while HATS-27b is a prime target for Rossiter—McLaughlin monitoring in order to determine its spin–orbit alignment given the brightness (V = 12.8) and stellar rotational velocity (v i sin 9.3 » km s−1 ) of the host star. These discoveries significantly increase the number of inflated hot Jupiters known, contributing to our understanding of the mechanism(s) responsible for hot Jupiter inflation.