From: LARRY KLAES (ljk4_at_msn.com)
Date: Fri Jun 10 2005 - 08:29:25 PDT
Paper: astro-ph/0506187
Date: Wed, 8 Jun 2005 22:53:56 GMT (259kb)
Title: Circumstellar Dust Disks in Taurus-Auriga: The Submillimeter
Perspective
Authors: Sean M. Andrews & Jonathan P. Williams (University of Hawaii
Institute
for Astronomy)
Comments: accepted by ApJ
\\
We present a sensitive, multiwavelength submillimeter continuum survey of
153
young stellar objects in the Taurus-Auriga star formation region. The
submillimeter detection rate is 61% to a completeness limit of ~10 mJy
(3-sigma) at 850 microns. The inferred circumstellar disk masses are
log-normally distributed with a mean mass of ~0.005 solar masses and a large
dispersion (0.5 dex). Roughly one third of the submillimeter sources have
disk
masses larger than the minimal nebula from which the solar system formed.
The
median disk to star mass ratio is 0.5%. The empirical behavior of the
submillimeter continuum is best described as F_nu ~ nu^(2.0 +/- 0.5) between
350 microns and 1.3 mm, which we argue is due to the combined effects of the
fraction of optically thick emission and a flatter frequency behavior of the
opacity compared to the ISM. This latter effect could be due to a
substantial
population of large dust grains, which presumably would have grown through
collisional agglomeration. In this sample, the only stellar property that is
correlated with the outer disk is the presence of a companion. We find
evidence
for significant decreases in submillimeter flux densities, disk masses, and
submillimeter continuum slopes along the canonical infrared spectral energy
distribution evolution sequence for young stellar objects. The fraction of
objects detected in the submillimeter is essentially identical to the
fraction
with excess near-infrared emission, suggesting that dust in the inner and
outer
disk are removed nearly simultaneously.
\\ ( http://arXiv.org/abs/astro-ph/0506187 , 259kb)
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