Red Runaways II: Low mass Hills stars in SDSS Stripe 82
  Stars ejected from the Galactic centre can be used to place important
constraints on the Milky Way potential. Since existing hypervelocity stars are
too distant to accurately determine orbits, we have conducted a search for
nearby candidates using full three-dimensional velocities. Since the efficacy
of such studies are often hampered by deficiencies in proper motion catalogs,
we have chosen to utilize the reliable, high-precision SDSS Stripe 82 proper
motion catalog. Although we do not find any candidates which have velocities in
excess of the escape speed, we identify 226 stars on orbits that are consistent
with Galactic centre ejection. This number is significantly larger than what we
would expect for halo stars on radial orbits and cannot be explained by disk or
bulge contamination. If we restrict ourselves to metal-rich stars, we find 29
candidates with [Fe/H] > -0.8 dex and 10 with [Fe/H] > -0.6 dex. Their
metallicities are more consistent with what we expect for bulge ejecta, and so
we believe these candidates are especially deserving of further study. We have
supplemented this sample using our own radial velocities, developing an
algorithm to use proper motions for optimizing candidate selection. This
technique provides considerable improvement on the blind spectroscopic sample
of SDSS, being able to identify candidates with an efficiency around 20 times
better than a blind search.
