Cool Stars 14 - Submitted Abstract # 91
This version created on 05 October 2006

Planets around K Giant Stars


A.P. Hatzes, Thueringer Landessterwarte Tautenburg
M. Doellinger, European Southern Observatory
W.D. Cochran, McDonald Observatory
L. Pasquini, European Southern Observatory
D.E. Mkrtichian,  ARCSEC, Sejong University
E. Guenther, Thueringer Landessterwarte Tautenburg
M. Hartmann, Thueringer Landessterwarte Tautenburg
M. Esposito, Thueringer Landessterwarte Tautenburg

Over a decade ago low amplitude, long period radial velocity
variations were discovered in several K giant stars.  At the time it
was not clear whether these variations were due to rotational
modulation or sub-stellar companions.  Since then it has been
established that giant stars can indeed host giant extrasolar planets.
For several of these giant stars the radial velocity variations have
persisted for 15-25 years.  To date giant planets have been found
orbiting about 10  giant stars.  The estimated masses of the host
stars rang from 1.2 - 3.5 M_sun.  The planets of these giant stars are
characterized by large masses (2-14 M_Jupiter) and relatively low
metallicities for the host star.  The latter is counter to the
planet-metallicity connection found for main sequence solar-type
stars.  Planets around giant stars may provide important clues as to
the dependence of planet formation on stellar mass since the
progenitors of many giant stars are main sequence A--F stars, stars
ill-suited for precise radial velocity measurements.  Another
interesting aspect of these K giant stars is that many show stellar
oscillations which opens the possibility of asteroseismic studies of
planet hosting giant stars.

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