The Faint Hot Component of Debris Disks Revealed by Infrared Interferometry

Very few main-sequence stars exhibit warm dust in their 5-10AU close environment, where terrestrial planets are expected to have formed. Near-infrared interferometry is a powerful means, combining high dynamic range and high spatial resolution, to directly detect faint emission from hot grains in exozodiacal clouds. We will review the results of our search for 2 micron excesses around Vega-like stars, including the nearby Sun-like stars Tau Ceti and Epsilon Eridani, with the FLUOR interferometric instrument and the CHARA Array of telescopes. Our recent detections, combined with Spitzer observations around 10 micron, put strong constrains on the properties and distribution of hot grains in these inner planetary systems. We will present the conclusions of our preliminary modeling for the detected hot grains as well as their implication for the selection of targets for future planet finding missions like DARWIN or TPF.