A THEORY OF EXTRASOLAR GIANT PLANETS

We present a broad suite of models of extrasolar giant planets (EGPs), ranging in mass from 0.3 to 15 Jupiter masses. The models predict lum inosity (both reflected and emitted) as a function of age, mass, deute rium abundance, and distance from parent stars of various spectral typ es. We also explore the effects of helium mass fraction, rotation rate , and the presence of a rock-ice core. The models incorporate the most accurate available equation of state for the interior, including a ne w theory for the enhancement of deuterium fusion by electron screening , which is potentially important in these low-mass objects, The result s of our calculations reveal enormous sensitivity of EGPs to the prese nce of the parent star, particularly for G and earlier spectral types. They also show a strong sensitivity of the flux contrast in the mid-i nfrared, between parent star and EGP, to the mass and age of the EGPs. We interpret our results in terms of search strategies for ground- an d space-based observatories in place or anticipated in the near future .