Photometric Light Curves and Polarization of Close‐in Extrasolar Giant Planets

Abstract

The close-in extrasolar giant planets (CEGPs), AU from their parent stars, may have a large (0.05 component of optically re—ected light. We present theoretical optical photometric light curves and polar- ization curves for the CEGP systems from re—ected planetary light. DiUerent particle sizes of three con- densates are considered. In the most re—ective case, the variability is B100 kmag, which will be easily detectable by the upcoming satellite missions Microvariability and Oscillations of Stars (MOST ), COROT , and Measuring Oscillations in Nearby Stars (MONS), and possibly from the ground in the near future. The least re—ective case is caused by small, highly absorbing grains such as solid Fe, with variation of much less than 1 kmag. Polarization for all cases is lower than current detectability limits. We also discuss the temperature-pressure pro—les and resulting emergent spectra of the CEGP atmospheres. We discuss the observational results of q Boo b by Cameron et al. and Charbonneau et al. in context of our model results. The predictionsthe shape and magnitude of the light curves and polarization curves¨ are highly dependent on the sizes and types of condensates present in the planetary atmosphere. Subject headings: planetary systemsradiative transferstars: atmospheres