Institute of Astronomy

Characterizing the Hot Kepler Objects of Interest

SpeakerTalk DateTalk Series
Leslie Rogers29 July 2014Across HR 2014 Talks


Thousands of exoplanets have been discovered to date; most orbit stars that are similar to our Sun (FGK dwarfs) or cooler (M dwarfs). Detecting planets orbiting hotter stars (A dwarfs) is a challenge because hot stars have rotationally-broadened spectral features and large radii. Accumulating a statistical sample of well-characterized planets orbiting A stars is important to constrain trends in planet occurrence and orbital properties as a function of stellar mass. Throughout its four years of operation, the Kepler mission monitored a few thousand hot stars (T_eff>7000K) with sufficient photometric precision to detect the transits of Jupiter-size planets. We characterize the main sequence A stars with transiting planet candidates detected by Kepler. We identify likely A stars in the Kepler Input Catalog (KIC) by their stellar effective temperatures, derived from KIC grizJHK photometry using the empirical relations from Boyajian et al. (2013). To verify the classification of a subset of these stars, we measure their spectra using Palomar DBSP and collect high-resolution images with Keck NIRC2. We determine the physical parameters of the transiting planetsÂ’ orbits by fitting the Kepler transit light curves with Markov Chain Monte Carlo methods. By constraining the semi-major axis and eccentricity distributions of planets orbiting A stars, we gain insights into the formation and tidal evolution of planets in a relatively uncharted region of the H-R diagram.