Name/Affiliation: Kimberly M. Aller (IfA/Hawaii)
Searching for the Elusive Substellar Members of Young Moving Groups with Pan-STARRS
Young moving groups (YMGs) are coeval, comoving groups of young (10—100 Myrs) stars that have migrated from their birthsites after formation. They provide a fundamental evolutionary link between ongoing star formation in molecular clouds (~1 Myr) and old field stars (>1 Gyr). While surveys such as Hipparcos, the Digitized Sky Survey, have been used to make significant progress in the past ~15 years in identifying the stellar members of YMGs, these surveys were insensitive to the lowest mass, optically faint, members. We have combined Pan-STARRS-1 (PS1) proper motions with optical—NIR photometry from PS1 and 2MASS for the first dedicated, homogeneous search for these elusive substellar YMG members (~0.01—0.08 Msun). PS1 is uniquely suited for such a systematic search because of its large-area sky coverage (30,000 sq degs), precise astrometry, and far-red sensitivity. We have identified candidate young brown dwarf members using a combination of color selection, spectral energy distribution fitting and proper motion analysis. Near-IR spectroscopic followup shows that our combined photometric+astrometric methods are ~5—10x more efficient than past efforts to identify young ultracool dwarfs in the solar neighborhood. Such substellar members of YMGs are valuable benchmarks to empirically define brown dwarf evolution with age and to study the lowest mass end of the initial mass function. Our new, young brown dwarfs will also be valuable targets for future surveys of brown dwarf binarity and young exoplanet characterization.