Amaya MORO-MARTIN : Princeton University

Infrared Excesses Around Stars Harboring Radial Velocity Planets. Results from the Spitzer Legacy Survey FEPS

Finally, by adding these nine stars to the sample of 26 stars in Beichman et al. (2006) we explore the correlation of the frequency of dust emission with the presence of known planets.Based on observations performed with the Spitzer Space Telescope as part of the Legacy Science Program ``Formation and Evolution of Planetary Systems'' (FEPS), we have searched for debris disks toward 9 stars (with stellar ages ranging from 2 to 10 Gyr) known from radial velocity (RV) studies to have one or more massive planets. At MIPS 70 micron, only a few of the sources are found to have believable excesses emission above the stellar photosphere. From MIPS 24 micron and IRS low resolution spectra (7.6 -- 38 micron) it is found that none of the stars show infrared excesses for wavelengths less than 33 micron, which places upper limits to the maximum dust temperature. The infrared excesses are therefore thought to arise from the dust generated through planetesimal collisions within planetesimal belts like the Kuiper Belt. For stars with IR excesses, models of their spectral energy distribution (SEDs) are used to estimate the minimum inner edge of the dust disk R_in (or equivalently the maximum dust temperature), the mass of the emitting cold dust, and an upper limit to the amount of warm dust interior to R_in. In the regime where dust dynamics is controlled by dust collisions and not Poyinting-Robertson drag, the lack of observed warm dust indicates a depletion of dust-producing planetesimals inside R_in. We discuss how this depletion may be dynamically related to the gravitational perturbations by the known massive planet(s). Finally, by adding these nine stars to the sample of 26 stars in Beichman et al. (2006) we explore the correlation of the frequency of dust emission with the presence of known planets.