Six newly-discovered hot Jupiters transiting F/G stars: WASP-87b, WASP-108b, WASP-109b, WASP-110b, WASP-111b & WASP-112b

Abstract

We present the discoveries of six transiting hot Jupiters: WASP-87b, WASP-108b, WASP-109b, WASP-110b, WASP-111b and WASP-112b. The planets have masses of 0.51--2.2 $M_{\mathrm{Jup}}$ and radii of 1.19--1.44 $R_{\mathrm{Jup}}$ and are in orbits of 1.68--3.78 d around stars with masses 0.81--1.50 $M_{\odot }$. WASP-111b is in a prograde, near-aligned ($\hat{I}»=-5\pm 16^{\circ }$), near-circular ($e<0.10$ at 2 $\ddot{I}ƒ$) orbit around a mid-F star. As tidal alignment around such a hot star is thought to be inefficient, this suggests that either the planet migrated inwards through the protoplanetary disc or that scattering processes happened to leave it in a near-aligned orbit. WASP-111 appears to have transitioned from an active to a quiescent state between the 2012 and 2013 seasons, which makes the system a candidate for studying the effects of variable activity on a hot-Jupiter atmosphere. We find evidence that the mid-F star WASP-87 is a visual binary with a mid-G star. Two host stars are metal poor: WASP-112 has [Fe/H] = $-0.64\pm 0.15$ and WASP-87 has [Fe/H] = $-0.41\pm 0.10$. The low density of WASP-112 (0.81 $M_{\odot }$, $0.80\pm 0.04$ $\ddot{I}{}_{\odot }$) cannot be matched by standard models for any reasonable value of the age of the star, suggesting it to be affected by the "radius anomaly".

14 pages, 12 figures, 6 tables, submitted to MNRAS. UPDATE: Fixed typos in declination and vsini of WASP-112