http://xxx.uni-augsburg.de/abs/astro-ph/0112402
Astrophysics, abstract
astro-ph/0112402
From: Iain Neill Reid <inr@hep.upenn.edu>
Date: Mon, 17 Dec 2001 18:28:09 GMT (215kb)
On the Nature of Stars with Planets
Authors: I. Neill Reid
Comments: 46 pages, 13 figures; accepted for PASP
We consider the metallicities and kinematics of nearby stars known
to have planetary-mass companions in the general context of the
overall properties of the local Galactic Disk. We have used
Stromgren photometry to determine abundances for both the
extrasolar-planet host stars and for a volume-limited sample of
486 F, G and K stars selected from the Hipparcos catalogue. The
latter data show that the Sun lies near the modal abundance of the
disk, with over 45% of local stars having super-solar
metallicities. Twenty of the latter stars (4.1%) are known to have
planetary-mass companions. Using that ratio to scale data for the
complete sample of planetary host stars, we find that the fraction
of stars with extrasolar planets rises sharply with increasing
abundance, confirming previous results. However, the frequency
remains at the 3-4% level for stars within 0.15 dex of solar
abundance, and falls to ~1% only for stars with abundances less
than half solar. Given the present observational constraints, both
in velocity precision and in the available time baseline, these
numbers represent a lower limit to the frequency of extrasolar
planetary systems. A comparison between the kinematics of the
planetary host stars and a representative sample of disk stars
suggests that the former have an average age which is ~60% of the
latter.
Paper: Source (215kb), PostScript, or Other formats
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Amara Graps, PhD | Max-Planck-Institut fuer Kernphysik
Heidelberg Cosmic Dust Group | Saupfercheckweg 1
+49-6221-516-543 | 69117 Heidelberg, GERMANY
Amara.Graps@mpi-hd.mpg.de * http://www.mpi-hd.mpg.de/dustgroup/~graps
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"We came whirling out of Nothingness scattering stars like dust." --Rumi
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