Cool Stars 14 - Submitted Abstract # 197
This version created on 05 October 2006

Directly measuring the physical properties of the dust evaporation
front in YSOs


John Monnier, University of Michigan
R. Millan-Gabet, Michelson Science Center
J.-P. Berger, Observatoire de Grenoble
A. Tannirkulam, University of Michigan
T. Harries, University of Exeter
T. ten Brummelaar, Georgia State University
W. Traub, Jet Propulsion Laboratory

Infrared interferometers directly probe YSO disk structures on scales
< 1 AU, and we report the latest high-resolution observations of disks
using the IOTA and CHARA Interferometers.  First closure phase results
from IOTA on YSO disks favor disks models with "curved" inner rims,
ruling out simple models of "vertical" inner walls of dust at the dust
sublimation radius.  Dust growth/settling into the midplane provides a
natural way to curve the dust evaporation front and we present the
first self-consistent calculation of the inner rim structure for this
case, confirming dramatic rim curvature for realistic z-dependent dust
properties.  Lastly, we present first YSO observations from CHARA with
<1 milliarcsec resolution, finding puzzling results for the Herbig Ae
star MWC 275 possibly signaling problems with the "inner rim"
paradigm.

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