THE STRUCTURE OF THE {beta} LEONIS DEBRIS DISK

We combine nulling interferometry at 10 {mu}m using the MMT and Keck Telescopes with spectroscopy, imaging, and photometry from 3 to 100 {mu}m using Spitzer to study the debris disk around {beta} Leo over a broad range of spatial scales, corresponding to radii of 0.1 to {approx}100 AU. We have also measured the close binary star o Leo with both Keck and MMT interferometers to verify our procedures with these instruments. The {beta} Leo debris system has a complex structure: (1) relatively little material within 1 AU; (2) an inner component with a color temperature of {approx}600 K, fitted by a dusty ring from about 2-3 AU; and (3) a second component with a color temperature of {approx}120 K fitted by a broad dusty emission zone extending from about {approx}5 AU to {approx}55 AU. Unlike many other A-type stars with debris disks, {beta} Leo lacks a dominant outer belt near 100 AU.