Cool Stars 14 - Submitted Abstract # 346
This version created on 05 October 2006

21 New Very Low Mass Close Binaries Resolved in the Visible


Nicholas Law, Caltech
Simon Hodgkin, IoA Cambridge
Craig Mackay, IoA Cambridge

We present the discovery of 21 new Very Low Mass binaries.  The
systems were found using Lucky Imaging, a new technique for easy
diffraction-limited imaging from the ground in the visible on 2.5m
telescopes.  Targets were selected from the field on the basis of high
proper motion and red colour.  The primaries are M5 and later, the
target magnitudes are significantly fainter than previous surveys, and
the detected binary separations range from 0.13 arcsec to 1.5 arcsec.
One new companion is probably substellar.  The survey is sensitive to
delta-I=5 at 1 arcsec, and delta-I=3 at 0.25 arcsec, although most new
binaries had roughly equal magnitude.  The 110  star survey was
completed in only 16 hours on-sky.  

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