A Survey for Habitable Zone Debris Disks with Nulling Interferometry: Complimentary Observations to Spitzer
First Author:
Wilson Liu
Email: wliu AT as.arizona.edu
University of Arizona
Steward Observatory-CAAO
933 N Cherry Ave, RM:N413
Tucson, AZ 85721-0065 USA
Abstract
The complex nature of debris disks necessitates the use of complementary observations at different wavelengths and spatial scales in order to form a complete understanding. We have observed six nearby main sequence stars (alpha CrB, alpha Lyr, beta Leo, gamma Ser, epsilon Eri, and zeta Lep) with the MMT Observatory using nulling interferometry in the N-band. Using this technique, we are sensitive to debris in the "habitable zones" of these systems, which are located at closer separations from the star (a few AU) than longer wavelength observations of cold debris by Spitzer (tens to hundreds of AU). Although no positive detection of habitable zone material was made with our observations, we can place firm upper limits for dust density in these systems, in the range of several hundred zodis. In several systems (e.g., Vega, beta Leo, epsilon Eri) this contrasts with a high density of dust in the outer systems detected by Spitzer. We discuss physical processes which could lead to the dust distribution observed in these systems.
