Cool Stars 14 - Submitted Abstract # 186
This version created on 05 October 2006

A Spectroscopic Binary Survey of Young M Stars in Ophiuchus


Lisa Prato, Lowell Observatory

The frequency and mass ratio distribution of the closest, low-mass
binaries bear directly on models of star, brown dwarf, and planet
formation.  Furthermore, spectroscopic observations provide mass
ratios independent of many of the assumptions needed to convert visual
binary magnitude differences into mass ratios.  I present the results
of a survey of a uniform sample of several dozen T Tauri M stars in
the Ophiuchus molecular cloud.  Each star was observed at 3-4 epochs
over 3 years with the 10  meter Keck II telescope.  At least 4 of the
objects are newly discovered spectroscopic binaries, one of which is
located in a sub-arcsecond, hierarchical quadruple system.  Three
other sub-arcsecond visual binaries were also serendipitously
identified.  The spectroscopic multiplicity of the sample is
comparable to that of earlier type, pre-main-sequence objects.
Therefore, there is no dearth of young, low-mass spectroscopic binary
stars, at least in the Ophiuchus region, although selection effects
certainly constrain the range of secondary masses accessible to
surveys with limited radial velocity precision.  This work yields mass
functions and/or mass ratios for at least 4 new short period systems.
Followup observations may reveal additional eccentric, long-period,
and substellar companions.

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