Paper: astro-ph/0509490
Date: Fri, 16 Sep 2005 09:27:32 GMT (151kb)

Title: Cluster Origin of Triple Star HD 188753 and its Planet

Authors: Eric Pfahl (KITP/Ucsb)
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The recent discovery by M. Konacki of a ``hot Jupiter'' in the hierarchical
triple star system HD 188753 challenges established theories of giant-planet
formation. If the orbital geometry of the triple has not changed since the
birth of the planet, then a disk around the planetary host star would probably
have been too compact and too hot for a Jovian planet to form by the
core-accretion model or gravitational collapse. This paradox is resolved if the
star was initially either single or had a much more distant companion. It is
suggested here that a close multi-star dynamical encounter transformed this
initial state into the observed triple, an idea that follows naturally if HD
188753 formed in a moderately dense stellar system--perhaps an open
cluster--that has since dissolved. Three distinct types of encounters are
investigated. The most robust scenario involves an initially single planetary
host star that changes places with the outlying member of a pre-existing
hierarchical triple.

\\ ( http://arXiv.org/abs/astro-ph/0509490 , 151kb)