From: LARRY KLAES (ljk4_at_msn.com)
Date: Tue Sep 20 2005 - 20:13:39 UTC
Paper: astro-ph/0509555
Date: Mon, 19 Sep 2005 17:16:37 GMT (570kb)
Title: Large dust particles in disks around T Tauri stars
Authors: J. Rodmann, Th. Henning, C. J. Chandler, L. G. Mundy and D. J.
Wilner
Categories: astro-ph
Comments: 11 pages, 4 figures
\\
We present 7-mm continuum observations of 14 low-mass pre-main-sequence
stars
in the Taurus-Auriga star-forming region obtained with the Very Large Array
with ~1.5" resolution and ~0.3 mJy rms sensitivity. For 10 objects, the
circumstellar emission has been spatially resolved. The large outer disk
radii
derived suggest that the emission at this wavelength is mostly optically
thin.
The millimetre spectral energy distributions are characterised by spectral
indices alpha = 2.3 to 3.2. After accounting for contribution from free-free
emission and corrections for optical depth, we determine dust opacity
indices
beta in the range 0.5 to 1.6, which suggest that millimetre-sized dust
aggregates are present in the circumstellar disks. Four of the sources with
beta > 1 may be consistent with submicron-sized dust as found in the
interstellar medium. Our findings indicate that dust grain growth to
millimetre-sized particles is completed within less than 1 Myr for the
majority
of circumstellar disks.
\\ ( http://arXiv.org/abs/astro-ph/0509555 , 570kb)
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