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 ms.tex ApJ, Nov 2010, in press
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%http://arxiv.org/abs/1011.0360

\documentclass[apj,iop]{emulateapj}

\begin{document}
\title{Binaries migrating in a gaseous disk: Where are the Galactic  
center binaries?}

\author{C. Baruteau, J. Cuadra and D.N.C. Lin}


\begin{abstract}
The massive stars in the Galactic center inner arcsecond share
analogous properties with the so-called Hot Jupiters. Most of these
young stars have highly eccentric orbits, and were probably not
formed in-situ. It has been proposed that these stars acquired their
current orbits from the tidal disruption of compact massive binaries
scattered toward the proximity of the central supermassive black
hole. Assuming a binary star formed in a thin gaseous disk beyond
$0.1$ pc from the central object, we investigate the relevance of
disk--satellite interactions to harden the binding energy of the
binary, and to drive its inward migration.  A massive, equal-mass
binary star is found to become more tightly wound as it migrates
inwards toward the central black hole. The migration timescale is
very similar to that of a single-star satellite of the same
mass. The binary's hardening is caused by the formation of spiral
tails lagging the stars inside the binary's Hill radius. We show
that the hardening timescale is mostly determined by the mass of gas
inside the binary's Hill radius, and that it is much shorter than
the migration timescale. We discuss some implications of the
binary's hardening process. When the more massive (primary)
components of close binaries eject most their mass through supernova
explosion, their secondary stars may attain a range of
eccentricities and inclinations.  Such processes may provide an
alternative unified scenario for the origin of the kinematic
properties of the central cluster and S-stars in the Galactic center
as well as the high velocity stars in the Galactic halo.
\end{abstract}