An Analysis of Transiting Hot Jupiters Observed with K2: WASP-55b and WASP-75b

TL;DR

This paper analyzes K2 data of two hot Jupiters, WASP-55b and WASP-75b, revealing stellar variability, refining system parameters, and searching for additional signals using high-precision lightcurves.

Contribution

It provides a detailed analysis of K2 observations of these exoplanets, including stellar variability detection and improved system parameter estimation.

Findings

Detected stellar variability in WASP-75b with an estimated rotation period of 11.2 days.

Calculated a possible stellar inclination angle of 41 degrees.

Refined the system parameters through combined K2 and previous data analysis.

Abstract

We present our analysis of the K2 short-cadence data of two previously known hot Jupiter exoplanets: WASP-55b and WASP-75b. The high precision of the K2 lightcurves enabled us to search for transit timing and duration variations, rotational modulation, starspots, phase-curve variations and additional transiting planets. We identified stellar variability in the WASP-75 lightcurve which may be an indication of rotational modulation, with an estimated period of $11.2\pm1.5$ days. We combined this with the spectroscopically measured $v\sin(i_*)$ to calculate a possible line of sight projected inclination angle of $i_*=41\pm16^{\circ}$. We also perform a global analysis of K2 and previously published data to refine the system parameters.