PHOTOMETRICALLY DERIVED MASSES AND RADII OF THE PLANET AND STAR IN THE TrES-2 SYSTEM

Abstract

We measure the mass and radius of the star and planet in the TrES-2 system\nusing 2.7 years of observations by the Kepler spacecraft. The light curve shows\nevidence for ellipsoidal variations and Doppler beaming on a period consistent\nwith the orbital period of the planet with amplitudes of 2.79+0.44-0.62 and\n3.44+0.32-0.37 parts per million (ppm) respectively, and a difference between\nthe day and night side planetary flux of 3.41+0.55-0.82 ppm. We present an\nasteroseismic analysis of solar-like oscillations on TrES-2A which we use to\ncalculate the stellar mass of 0.94+/-0.05 MSun and radius of 0.95+/-0.02 RSun.\nUsing these stellar parameters, a transit model fit and the phase curve\nvariations, we determine the planetary radius of 1.162+0.020-0.024 RJup and\nderive a mass for TrES-2b from the photometry of 1.44+/-0.21 MJup. The ratio of\nthe ellipsoidal variation to the Doppler beaming amplitudes agrees to better\nthan 2{\\sigma} with theoretical predications, while our measured planet mass\nand radius agree within 2-{\\sigma} of previously published values based on\nspectroscopic radial velocity measurements. We measure a geometric albedo of\n0.0136+0.0022-0.0033 and an occultation (secondary eclipse) depth of\n6.5+1.7-1.8 ppm which we combined with the day/night planetary flux ratio to\nmodel the atmosphere of TReS-2b. We find an atmosphere model that contains a\ntemperature inversion is strongly preferred. We hypothesize that the Kepler\nbandpass probes a significantly greater atmospheric depth on the night side\nrelative to the day side.\n