Program: GN-2021A-Q-324

We propose obtaining GRACES spectroscopy for 107 members of the newly identified candidate tidal tails (Gagné et al. 2020) that may contain the long-missing low-mass members of the nearby 400-Myr-old Ursa Major association (UMA). These tidal structures may extend to distances up to 300 parsec from the Sun. We focus on the nearby targets accessible this semester to measure lithium absorption for 73 F- to K-type stars in the tidal tails, which will give us an estimate of the population’s age and verify coevality with UMA. We will combine this with heliocentric radial velocity measurements of 45 stars in the tidal tails, using the same observing mode, to also confirm that their kinematics are consistent with those of UMA. This proposal will test whether the newly uncovered structures are indeed associated to UMA, and will potentially provide dozens of new age-calibrated stars in the immediate neighborhood of the Sun (< 70 pc).