A Star in the M31 Giant Stream: the Highest Negative Stellar Velocity
  Known
  We report on a single star, B030D, observed as part of a large survey of
objects in M31, which has the unusual radial velocity of -780 km/s. Based on
details of its spectrum, we find that the star is an F supergiant, with a
circumstellar shell. The evolutionary status of the star could be one of a
post-mainsequence close binary, a symbiotic nova, or less likely, a post-AGB
star, which additional observations could help sort out. Membership of the star
in the Andromeda Giant Stream can explain its highly negative velocity.
