Spectroscopic Validation of Low-Metallicity Stars from RAVE
  We present results from a medium-resolution (R ~ 2, 000) spectroscopic
follow-up campaign of 1,694 bright (V < 13.5), very metal-poor star candidates
from the RAdial Velocity Experiment (RAVE). Initial selection of the
low-metallicity targets was based on the stellar parameters published in RAVE
Data Releases 4 and 5. Follow-up was accomplished with the Gemini-N and
Gemini-S, the ESO/NTT, the KPNO/Mayall, and the SOAR telescopes. The wavelength
coverage for most of the observed spectra allows for the determination of
carbon and {\alpha}-element abundances, which are crucial for con- sidering the
nature and frequency of the carbon-enhanced metal-poor (CEMP) stars in this
sample. We find that 88% of the observed stars have [Fe/H] <= -1.0, 61% have
[Fe/H] <= -2.0, and 3% have [Fe/H] <= -3.0 (with four stars at [Fe/H] <= -3.5).
There are 306 CEMP star candidates in this sample, and we identify 169 CEMP
Group I, 131 CEMP Group II, and 6 CEMP Group III stars from the A(C) vs. [Fe/H]
diagram. Inspection of the [alpha/C] abundance ratios reveals that five of the
CEMP Group II stars can be classified as "mono-enriched second-generation"
stars. Gaia DR1 matches were found for 734 stars, and we show that transverse
velocities can be used as a confirmatory selection criteria for low-metallicity
candidates. Selected stars from our validated list are being followed-up with
high-resolution spectroscopy, to reveal their full chemical abundance patterns
for further studies.
