The Membership of Upgren One

Upgren One is a group of seven F stars which has been proposed as the remnant of a nearby old open cluster. We have monitored the radial velocities of these stars with the CfA digital speedometers. Two of the stars have velocities which are clearly inconsistent with physical association with the other five stars. Those five include a long-period binary and an unusual triple system. The velocity dispersion of the five stars is too large to be bound under reasonable assumptions about the total mass.