http://arxiv.org/abs/1702.05078
By analysing the K2 short-cadence photometry we detect starspot occultation events in the lightcurve of WASP-107, the host star of a warm-Saturn exoplanet. WASP-107 also shows a rotational modulation with a period of 17.5 +/- 1.4 d. The starspot occultation events do not seem to recur, which suggests a misaligned orbit unless the starspots’ lifetimes are shorter than the star’s rotational period. We also find stellar variability resembling gamma Doradus pulsations in the lightcurve of WASP-118, which hosts an inflated hot Jupiter. The variability is multi-periodic with a variable semi-amplitude of about 200 ppm. In addition to these findings we use the K2 data to refine the parameters of both systems, and report non-detections of transit-timing variations, secondary eclipses and any additional transiting planets. We used the upper limits on the secondary-eclipse depths to estimate upper limits on the planetary geometric albedos of 0.7 for WASP-107b and 0.2 for WASP-118b.
T. Mocnik, C. Hellier, D. Anderson, et. al.
Fri, 17 Feb 17
19/43
Comments: 8 pages, 8 figures, 2 tables