RAVE J203843.2–002333: The First Highly R-process-enhanced Star Identified in the RAVE Survey

Journal Article · Thu Jul 20 04:00:00 EDT 2017 · Astrophysical Journal

DOI:https://doi.org/10.3847/1538-4357/AA78EF· OSTI ID:22876013

Placco, Vinicius M.; Holmbeck, Erika M.; Beers, Timothy C.; Surman, Rebecca A. ^[1]; Frebel, Anna; Ji, Alexander P.; Ezzeddine, Rana ^[2]; Points, Sean D. ^[3]; Kaleida, Catherine C. ^[4]; Hansen, Terese T. ^[5]; Sakari, Charli M. ^[6]

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1. Department of Physics, University of Notre Dame, Notre Dame, IN 46556 (United States)
2. JINA Center for the Evolution of the Elements (United States)
3. Cerro Tololo Inter-American Observatory, Casilla 603, La Serena (Chile)
4. Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States)
5. Observatories of the Carnegie Institution of Washington, 813 Santa Barbara Street, Pasadena, CA 91101 (United States)
6. Department of Astronomy, University of Washington, Seattle, WA 98195-1580 (United States)

We report the discovery of RAVE J203843.2−002333, a bright (V = 12.73), very metal-poor ([Fe/H] = −2.91), r-process-enhanced ([Eu/Fe] = +1.64 and [Ba/Eu] = −0.81) star selected from the RAVE survey. This star was identified as a metal-poor candidate based on its medium-resolution (R ∼ 1600) spectrum obtained with the KPNO/Mayall Telescope, and followed up with high-resolution (R ∼ 66,000) spectroscopy with the Magellan/Clay Telescope, allowing for the determination of elemental abundances for 24 neutron-capture elements, including thorium and uranium. RAVE J2038−0023 is only the fourth metal-poor star with a clearly measured U abundance. The derived chemical abundance pattern exhibits good agreement with those of other known highly r-process-enhanced stars, and evidence suggests that it is not an actinide-boost star. Age estimates were calculated using U/X abundance ratios, yielding a mean age of 13.0 ± 1.1 Gyr.

• OSTI ID: 22876013
• Journal Information: Astrophysical Journal, Journal Name: Astrophysical Journal Journal Issue: 1 Vol. 844; ISSN ASJOAB; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
ELEMENT ABUNDANCE
GALAXIES
NEUTRON REACTIONS
R PROCESS
SPECTRA
STARS
TELESCOPES
THORIUM
URANIUM