NIRI SV observation 13

Many searches for low mass stars and brown dwarfs orbiting nearby stars have been completed recently or are currently underway. These include radial velocity studies for close companions at separations under a few AU, infrared speckle searches for companions 2-10 AU apart, deep infrared imaging of M dwarfs, and white dwarfs covering regions from tens of AU to a few hundred AU. These surveys are beginning to define the low mass stellar population around nearby stars but there has been no complete survey encompassing the bulk of the phase space surrounding nearby stars. With the advent of 8 m class telescopes like Gemini, combined with state of the art near infrared arrays and advanced coronagraphic techniques, it is possible to probe far deeper and closer to primaries in search of sub-stellar companions. Combining this type of survey with past surveys that have reached comparable levels of sensitivity but have not been able to reach very close toprimaries effectively "fills in the gap" left in past surveys for substellar companions.

Note this type of observation is still in an exploratory phase in astronomy in general, being "conceived" substantially only after the watershed discovery that GL 229B has strong methane absorption in the near-infrared. This set of observations therefore acts as a test of concepts that may feed into Gemini's near-infrared coronagraph. It feeds directly into core questions about star formation efficiency below the hydrogen-burn break in the H-R diagram, a key facet in Gemini's overall science mission.