PI: Peter Allen, Franklin and Marshall College, email@example.com
Address: Physics Department, PO Box 3003, Lancaster, PA 17604, USA
Title: Wide Ultracool Companions to Spectroscopic Binaries: Second Epoch Observations
Abstract: The wide low-mass star and brown dwarf companion rate of spectroscopic binaries is predicted by certain star formation simulations to be considerably higher than that of single stars (>10% versus 1-2%). We have been testing this hypothesis in a robust, statistically significant manner by measuring the wide brown dwarf binary rate of a large, volume-limited sample of 120 known spectroscopic binaries within 30 pc of the Sun. Measurements have been made through a common proper motion search with 2MASS serving as the initial first epoch and previous KPNO/CTIO 4m observations as the initial second epoch. We have fully analyzed 77 previously observed fields from two previous proposals (07A/B-0225), which found or confirmed 4 new M dwarf companions. Given previously known companions, this yields a companion rate of 19.5^+5.2_-3.7%, which confirms the simulation findings. The observations proposed here will serve primarily as a second epoch of deep imaging directly matching our previous deep imaging in 2007 - 2009. Additionally, there are several fields in our sample that still require first epoch deep imaging. This work has already identified previously unknown nearby cool dwarfs. This second epoch of deep imaging data, has the potential to discover nearby, very cold brown dwarfs into the Y dwarf regime, to which our first epoch common proper motion search via 2MASS was not sensitive. The observations proposed here will unlock the full potential of our earlier KPNO/CTIO data.
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