YMGs. I. Young binaries & lithium-rich stars

We have carried out an all-sky search for late-type (~K7-M5) stars within 100pc selected primarily on the basis of activity indicators from the Galaxy Evolution Explorer and ROSAT. Approximately 2000 active and potentially young stars are identified, of which we have followed up over 600 with low-resolution optical spectroscopy and over 1000 with diffraction-limited imaging using Robo-AO at the Palomar 1.5m telescope.

Strong lithium is present in 58 stars, implying ages spanning ~10-200Myr. Most of these lithium-rich stars are new or previously known members of young moving groups including TWA, {beta}Pic, Tuc-Hor, Carina, Columba, Argus, ABDor, Upper Centaurus Lupus, and Lower Centaurus Crux; the rest appear to be young low-mass stars without connections to established kinematic groups. Over 200 close binaries are identified down to 0.2"-the vast majority of which are new-and will be valuable for dynamical mass measurements of young stars with continued orbit monitoring in the future.