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 $0.5{M}_{J}\mbox{--}0.7{M}_{J}$ region of parameter space but span a wide variety of radii, from $1.17{R}_{J}$ to $1.75{R}_{J}$. HATS-25b, HATS-28b, HATS-29b, and HATS-30b are typical inflated hot Jupiters (${R}_{p}=1.17\mbox{--}1.26{R}_{J}$) orbiting G–type stars in short period (P = 3.2-4.6 days) orbits. However, HATS-26b (${R}_{p}=1.75{R}_{J}$, $P=3.3024$ days) and HATS-27b (${R}_{p}=1.50{R}_{J}$, $P=4.6370$ 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 ${\rm{g}}\,{\mathrm{cm}}^{-3}$ and 0.180 ${\rm{g}}\,{\mathrm{cm}}^{-3}$, 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 ($v\sin i\approx 9.3$ 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.