New Very Low Mass Binaries in the Taurus Star-Forming Region release_cdf6oevu4fgpvfjbcd45txtvxu

by Q.M. Konopacky, A.M. Ghez, E.L. Rice, G. Duchene

Released as a article .

2007  

Abstract

We surveyed thirteen very low mass (VLM; M < 0.2 M_sun) objects in the Taurus star-forming region using near-infrared diffraction-limited imaging techniques on the W.M. Keck I 10 m telescope. Of these thirteen, five were found to be binary, with separations ranging from 0.04" to 0.6" and flux ratios from 1.4 to 3.7. In all cases, the companions are likely to be physically associated with the primaries (probability > 4-sigma). Using the theoretical models of Baraffe et al. (1998), we find that all five new companions, as well as one of the primaries, are likely brown dwarfs. The discovery of these systems therefore increases the total number of known, young VLM binaries by ~50%. These new systems, along with other young VLM binaries from the literature, have properties that differ significantly from older field VLM binaries in that the young systems have wider separations and lower mass ratios, supporting the idea that VLM binaries undergo significant dynamical evolution ~5 - 10 Myr after their formation. The range of separations of these binaries, four of which are over 30 AU, argues against the ejection scenario of brown dwarf formation. While several of the young, VLM binaries discovered in this study have lower binding energies than the previously suggested minimum for VLM binaries, the apparent minimum is still significantly higher than that found among higher mass binaries. We suggest that this discrepancy may be due to the small mass of a VLM binary relative to the average perturbing star, leading to more substantial changes in their binding energy over time.
In text/plain format

Archived Files and Locations

application/pdf  139.6 kB
file_5duloppoqbfljbwxaryzd3xq3m
archive.org (archive)
Read Archived PDF
Preserved and Accessible
Type  article
Stage   submitted
Date   2007-03-21
Version   v1
Language   en ?
Work Entity
access all versions, variants, and formats of this works (eg, pre-prints)
Catalog Record
Revision: 9ef4fc19-341d-41d7-8cca-b605d4ff1a84
API URL: JSON