Properties of extrasolar planets and their host stars - a case study of HAT-P-7

TL;DR

This study uses Kepler data to improve the characterization of the exoplanet HAT-P-7 and its host star through combined asteroseismic and transit analysis, refining planetary and stellar parameters.

Contribution

It provides a more accurate asteroseismic analysis of HAT-P-7 and revises planetary parameters, including temperature estimates, based on extensive Kepler data.

Findings

Confirmed ellipsoidal variations with revised magnitude

Revised occultation depth and planetary temperature

More precise stellar and planetary parameters

Abstract

Data from the Kepler satellite (Q0-Q11) are used to study HAT-P-7. The satellite's data are extremely valuable for asteroseismic studies of stars and for observing planetary transits; in this work we do both. An asteroseismic study of the host star improves the accuracy of the stellar parameters derived by Christensen-Dalsgaard et al. (2010), who followed largely the same procedure but based the analysis on only one month of Kepler data. The stellar information is combined with transit observations, phase variations and occultations to derive planetary parameters. In particular, we confirm the presence of ellipsoidal variations as discovered by Welsh et al. (2010), but revise their magnitude, and we revise the occultation depth (Borucki et al. 2009), which leads to different planetary temperature estimates. All other stellar and planetary parameters are now more accurately determined.