Program: GN-2017B-Q-75

Metal-poor stars are local relics of the high-redshift Universe. The acquisition of high signal-to-noise spectra for faint metal-poor stars requires a major telescope time commitment though, making the construction of large samples of metal-poor star abundances prohibitively expensive. The HK and HES Surveys have been exhausted of their bright metal-poor star candidates, while saturation in SDSS imaging precludes its use for the identification of bright metal-poor stars. Schlaufman & Casey (2014) used the lack of molecular absorption at 4.6 microns to efficiently identify bright metal-poor stars, and our now-completed survey to V < 12.5 is the most successful search for bright metal-poor stars ever conducted. We propose to extend the survey to V < 13 and request time to observe all 517 candidate metal-poor stars observable in 2017B. We expect to identify more than 180 stars with [Fe/H] < -2.0. The bright metal-poor stars identified from this survey will likely have precise parallaxes and proper motions available in Gaia Data Release 2 scheduled for April 2018. The proposed observations combined with our discoveries from past semesters should yield more than 600 bright stars with [Fe/H] < -2 and Gaia parallaxes and proper motions. Our survey is the first ever phase-space unbiased search for metal-poor stars, and the synthesis of abundances and kinematics available for the first time in our sample has the potential to break the degeneracies between different models for the origin of the most metal-poor stars.