Hunting the Parent of the Orphan Stream: Identifying Stream Members from
  Low-Resolution Spectroscopy
  We present candidate K-giant members in the Orphan Stream which have been
identified from low-resolution data taken with the AAOmega spectrograph on the
Anglo-Australian Telescope. From modest S/N spectra and independent cuts in
photometry, kinematics, gravity and metallicity we yield self-consistent,
highly probable stream members. We find a revised stream distance of 22.5 +/-
2.0 kpc near the celestial equator, and our kinematic signature peaks at Vgsr =
82.1 +/- 1.4 km/s. The observed velocity dispersion of our most probable
members is consistent with arising from the velocity uncertainties alone. This
indicates that at least along this line-of-sight, the Orphan Stream is
kinematically cold. Our data indicates an overall stream metallicity of [Fe/H]
= -1.63 +/- 0.19 dex which is more metal-rich than previously found and
unbiased by spectral type. Furthermore, the significant metallicity dispersion
displayed by our most probable members (0.56 dex) suggests that the
unidentified Orphan Stream parent is a dSph satellite. We highlight likely
members for high-resolution spectroscopic follow-up.
