Doppler Tomographic Observations of Exoplanet Transits

Rapidly-rotating stars are not amenable to radial velocity confirmation of transiting planet candidates due to their broad stellar lines. An alternative approach is Doppler tomography, an extension of the Rossiter-McLaughlin technique to rapidly-rotating stars where the distortion of the stellar line shape during a transit is spectrally resolved. We have instituted a program of observations at McDonald Observatory to confirm and characterize transiting planet candidates discovered by the Kepler mission. In addition, we are observing selected previously known transiting planets. These observations also provide information on the spin-orbit misalignment of the star-planet system, an important statistical probe of planetary migration mechanisms. We present first results from these observations.