Spectroscopic Validation of Low-metallicity Stars from RAVE
- Department of Physics, University of Notre Dame, Notre Dame, IN 46556 (United States)
- Instituto de Estudos Sócio-Ambientais, Planetário, Universidade Federal de Goiás, Goiânia, GO 74055-140 (Brazil)
- Instituto de Astrofísica, Pontificia Universidad Católica de Chile, Santiago (Chile)
- Cerro Tololo Inter-American Observatory, Casilla 603, La Serena (Chile)
- Space Telescope Science Institute, Baltimore, MD 21218 (United States)
- Instituto de Astronomia, Geofísica e Ciências Atmosféricas, Universidade de São Paulo, SP 05508-900 (Brazil)
- Laboratoire Lagrange, Université Côte d’Azur, Observatoire de la Côte d’Azur, CNRS, F-06304 Nice cedex 4 (France)
- Department of Astronomy and Space Science, Chungnam National University, Daejeon 34134 (Korea, Republic of)
- Leibniz Institut für Astrophysik Potsdam (AIP), An der Sterwarte 16, D-14482 Potsdam (Germany)
- Joint Institute for Nuclear Astrophysics, Center for the Evolution of the Elements, 1 Cyclotron Laboratory, National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, MI 48824-1321 (United States)
We present results from a medium-resolution (R ∼ 2000) spectroscopic follow-up campaign of 1694 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 α-element abundances, which are crucial for considering 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) versus [Fe/H] diagram. Inspection of the [α/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.
- OSTI ID:
- 22897488
- Journal Information:
- Astronomical Journal (New York, N.Y. Online), Vol. 155, Issue 6; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 1538-3881
- Country of Publication:
- United States
- Language:
- English
Similar Records
SEARCHES FOR METAL-POOR STARS FROM THE HAMBURG/ESO SURVEY USING THE CH G BAND
METAL-POOR STARS OBSERVED WITH THE MAGELLAN TELESCOPE. I. CONSTRAINTS ON PROGENITOR MASS AND METALLICITY OF AGB STARS UNDERGOING s-PROCESS NUCLEOSYNTHESIS