Paper: astro-ph/0510748
Date: Wed, 26 Oct 2005 18:39:33 GMT (165kb)

Title: Dynamical Interactions of Planetary Systems in Dense Stellar
Environments

Authors: John M. Fregeau, Sourav Chatterjee, Frederic A. Rasio (Northwestern
University)

Comments: 14 pages, 14 figures, submitted to ApJ
\\
We study dynamical interactions of star--planet binaries with other single
stars. We derive analytical cross sections for all possible outcomes, and
confirm them with numerical scattering experiments. We find that a wide mass
ratio in the binary introduces a region in parameter space that is inaccessible
to comparable-mass systems, in which the nature of the dynamical interaction is
fundamentally different from what has traditionally been considered in the
literature on binary scattering. We study the properties of the planetary
systems that result from the scattering interactions for all regions of
parameter space, paying particular attention to the location of the
"hard--soft" boundary. The structure of the parameter space turns out to be
significantly richer than a simple statement of the location of the
"hard--soft" boundary would imply. We consider the implications of our
findings, calculating characteristic lifetimes for planetary systems in dense
stellar environments, and applying the results to previous analytical studies,
as well as past and future observations. Recognizing that the system PSR
B1620-26 in the globular cluster M4 lies in the "new" region of parameter
space, we perform a detailed analysis quantifying the likelihood of different
scenarios in forming the system we see today.

\\ ( http://arXiv.org/abs/astro-ph/0510748 , 165kb)