Paper: astro-ph/0509754
Date: Mon, 26 Sep 2005 14:06:07 GMT (16kb)

Title: Constraints on the formation mechanism of the planetary mass companion
of 2MASS 1207334-393254

Authors: G. Lodato (1), E. Delgado-Donate (2) and C. J. Clarke (1) ((1)
Institute of Astronomy, Cambridge, UK (2) Stockholm Observatory, AlbaNova
University Centre, Sweden)

Categories: astro-ph

Comments: 5 pages, MNRAS in press
\\
In this paper we discuss the nature and the possible formation scenarios of
the companion of the brown dwarf 2MASS 1207334-393254. We initially discuss the
basic physical properties of this object and conclude that, although from its
absolute mass ($5M_{\rm Jup}$), it is a planetary object, in terms of its mass
ratio $q$ and of its separation $a$ with respect to the primary brown dwarf, it
is consistent with the statistical properties of binaries with higher primary
mass. We then explore the possible formation mechanism for this object. We show
that the standard planet formation mechanism of core accretion is far too slow
to form this object within 10 Myr, the observed age of the system. On the other
hand, the alternative mechanism of gravitational instability (proposed both in
the context of planet and of binary formation) may, in principle, work and form
a system with the observed properties.

\\ ( http://arXiv.org/abs/astro-ph/0509754 , 16kb)