16735

Characterizing the population of the coldest known free-floating substellar members of the solar neighborhood is now possible comma giving us the opportunity to gain key insights into the efficiency of star formation at the lowest masses as well as the chemistry of high-pressure comma low temperature atmospheres akin to cold comma extrasolar giant planets. As individuals comma each of these objects represents a unique probe into the complex chemistry present in the coldest photospheres produced in the Universe. We propose to obtain critical near-infrared F125W photometry of 12 newly discovered high proper motion comma cold brown dwarfs in the solar neighborhood. The purpose of these observations is threefolddoublePoint 1) to constrain each target.s physical properties comma 2) produce preliminary distance estimates comma and 3) to provide the photometry and astrometry necessary to prepare for future spectroscopic observations. These observations will provide the vital reconnaissance needed for spectroscopic follow-up observations with HST or JWST.