Hats-11B and Hats-12B: Two Transiting Hot Jupiters Orbiting Subsolar Metallicity Stars Selected for the K2 Campaign 7

Abstract

We report the discovery of two transiting extrasolar planets from the HATSouth survey. HATS-11, a V = 14.1 G0-star shows a periodic $12.9$ mmag dip in its light curve every 3.6192 days and a radial velocity variation consistent with a Keplerian orbit. HATS-11 has a mass of $1.000\pm 0.060$ ${M}_{\odot }$, a radius of $1.444\pm 0.057$ ${R}_{\odot }$ and an effective temperature of $6060\pm 150$ K, while its companion is a $0.85\pm 0.12$ ${M}_{{\rm{J}}}$, $1.510\pm 0.078$ ${R}_{{\rm{J}}}$ planet in a circular orbit. HATS-12 shows a periodic 5.1 mmag flux decrease every 3.1428 days and Keplerian RV variations around a V = 12.8 F-star. HATS-12 has a mass of $1.489\pm 0.071$ ${M}_{\odot }$, a radius of $2.21\pm 0.21$ ${R}_{\odot }$, and an effective temperature of $6408\pm 75$ K. For HATS-12b, our measurements indicate that this is a $2.38\pm 0.11$ ${M}_{{\rm{J}}}$, $1.35\pm 0.17$ ${R}_{{\rm{J}}}$ planet in a circular orbit. Both host stars show subsolar metallicities of $-0.390\pm 0.060$ dex and $-0.100\pm 0.040$ dex, respectively, and are (slightly) evolved stars. In fact, HATS-11 is among the most metal-poor and, HATS-12, with a $\mathrm{log}{g}_{\star }$ of $3.923\pm 0.065$, is among the most evolved stars hosting a hot-Jupiter planet. Importantly, HATS-11 and HATS-12 have been observed in long cadence by Kepler as part of K2 campaign 7 (EPIC216414930 and EPIC218131080 respectively).