Recent Results on the Circumbinary Transition Disk in KH 15D
First Author:
William Herbst
Email: wherbst AT wesleyan.edu
Astronomy Department
11 Foss Hill Drive
Middletown, CT 06459 USA
Abstract
Continued photometric monitoring of the binary weak T Tauri system KH 15D has allowed us to refine our model and understanding of this precessing transition disk and its central stars. By the end of the last observing season (i.e. April, 2008), neither binary component was fully visible at any time. The edge of the obscuring disk is sharp on the length scale of a fraction of a stellar radius and its location is predictable from cycle to cycle to about 1 stellar (1.3 solar) radius. There is no evidence in the optical data for small (~0.1 micron) grains in the disk and various arguments suggest that the solids are now typically of sand (0.5-2 mm) size or larger. We suggest that what is unique about the KH 15D system is its geometry and orientation and that what it reveals about the physical nature of a WTTS (transition) disk may have widespread applicability.
