Title:

Sub-AU structure of Circumstellar Material around Young Stellar Objects

Abstract:

Young stellar objects are often associated with excess infrared
emission which, presumably, originates from circumstellar material.
High angular resolution observations of this emission are essential 
to understanding its geometry, nature, and origin, and the resolution
requirements dictate the use of interferometry to attack this problem. 
The Infrared-Optical Telescope Array is a long baseline optical-ir
interferometer which is capable of measurements of the brightness
distribution of sources at the scale of a few milli-arcseconds, 
corresponding to scales of 1AU or less in the nearest systems.  In this
presentation, we will discuss: (1) contributions that IOTA has already 
made to the study of circumstellar matter around YSOs; (2) technical
aspects of long baseline OIR interferometry and IOTA's role in its
development; and (3) prospects for future work with the recently upgraded
IOTA instrument.