A search for disks around exoplanet host stars

Abstract

We have assembled a database which comprises optical and infrared (IR) photometry of Exoplanet Host stars (EHs), and constructed the spectral energy distributions (SEDs) of these stars. We use several quantities to explore the existence of excess IR emission with respect to the photospheric level. In particular, the criteria proposed by Mannings & Barlow (1998) identify IR excess in 19-23% of the class V EH sources (i.e., in 6-7 out of 31). Several searches for Vega-like systems have yielded a similar fraction of objects with IR excess emission among main sequence stars. This excess emission is likely due to the presence of dust in circumstellar disks. We compare the optical polarization properties of the EHs, Vega-like candidate objects and pre-main sequence stars. While the median polarizations of the EHs and Vega-like candidate objects are very similar, both groups have significant lower median optical polarization values than T Tauri and Herbig AeBe stars.