Paper: astro-ph/0607387
Date: Mon, 17 Jul 2006 15:38:52 GMT (960kb)

Title: Disks around young stars with VLTI/MIDI

Authors: Roy van Boekel, Peter Abraham, Serge Correia, Alex de Koter, Carsten
Dominik, Anne Dutrey, Thomas Henning, Agnes Kospal, Regis Lachaume, Christoph
Leinert, Hendrik Linz, Michiel Min, Laszlo Mosoni, Thomas Preibisch, Sascha
Quanz, Thorsten Ratzka, Alexander Schegerer, Rens Waters, Sebastian Wolf, and
Hans Zinnecker

Comments: 19 pages, 12 figures, invited talk at SPIE conference "Astronomical
telescopes and instrumentation", Orlando, may 2006
\\
We report on observations of circumstellar disks around young stars that have
been obtained with the MIDI instrument, which is mounted on the VLT
Interferometer and operates in the 10 micrometer atmospheric window. The
maximum spatial resolution of 5 milli-arcsec corresponds to sub-AU scales at
the distance to nearby star formation regions. Thus, we can study the disks on
the spatial scales at which important processes occur, such as accretion, dust
processing, and planet formation. The main results obtained so far can be
summarized as follows: 1. The measured interferometric visibilities are in good
qualitative agreement with those predicted by models of circumstellar disks. In
particular, a predicted correlation between the strength of the far-infrared
excess and the spatial structure of the disk is confirmed by direct
measurements; 2. In several objects strong evidence for deviations from
circular symmetry is present, indicating that an inclined disk is indeed the
dominant component seen in the mid-infrared; 3. The dust properties are not
uniform over the disk, but are instead a strong function of distance to the
central star. The dust in the innermost disk regions is observed to be more
``processed'' than the dust further out, both in Herbig Ae star disks and in
those around T-Tauri stars.

\\ ( http://arXiv.org/abs/astro-ph/0607387 , 960kb)