SETI public: An 850 micron survey for dust around solar mass stars

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Paper: astro-ph/0508165
Date: Fri, 5 Aug 2005 19:39:25 GMT (73kb)

Title: An 850 micron survey for dust around solar mass stars

Authors: Joan Najita (NOAO) and Jonathan P. Williams (IfA Honolulu)

Comments: 31 pages, 5 figures. Accepted for publication in the ApJ
\\
We present the results of an 850 micron JCMT/SCUBA survey for dust around 13
nearby solar mass stars. The dust mass sensitivity ranged from 0.005 to 0.16
Earth masses. Three sources were detected in the survey, one of which (HD
107146) has been previously reported. One of the other two submillimeter
sources, HD 104860, was not detected by IRAS and is surrounded by a cold,
massive dust disk with a dust temperature and mass of Tdust = 33 K and Mdust
=
0.16 Mearth. The third source, HD 8907, was detected by IRAS and ISO at
60-87
microns, and has a dust temperature and mass Tdust = 48 K and Mdust = 0.036
Mearth. We find that the deduced masses and radii of the dust disks in our
sample are roughly consistent with models for the collisional evolution of
planetesimal disks with embedded planets. We also searched for residual gas
in
two of the three systems with detected submillimeter excesses and place
limits
on the mass of gas residing in these systems.
When the properties measured for the detected excess sources are combined
with the larger population of submillimeter excess sources from the
literature,
we find strong evidence that the mass in small grains declines significantly
on
a ~200 Myr timescale, approximately inversely with age. However, we also
find
that the characteristic dust radii of the population, obtained from the dust
temperature of the excess and assuming blackbody grains, is uncorrelated
with
age. This is in contrast to self-stirred collisional models for debris disk
evolution which predict a trend of radius increasing with age, t ~ R^3. The
lack of agreement suggests that processes beyond self-stirring, such as
giant
planet formation, play a role in the evolutionary histories of planetesimal
disks.

\\ ( http://arXiv.org/abs/astro-ph/0508165 , 73kb)

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Paper: astro-ph/0504628
replaced with revised version Fri, 5 Aug 2005 11:43:46 GMT (622kb)

Title: Gravoturbulent formation of planetesimals

Authors: Anders Johansen, Hubert Klahr, Thomas Henning (MPIA, Heidelberg)

Comments: Substantial changes in response to referee report. 35 pages, 12
figures. People who are interested in the original work are strongly
encouraged to read this revised manuscript

\\ ( http://arXiv.org/abs/astro-ph/0504628 , 622kb)

• Previous message: LARRY KLAES: "SETI public: Earth's surface transformed by massive asteroids"

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