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

Vinicius M Placco, Erika M. Holmbeck, Anna Frebel, Timothy C Beers, Rebecca A. Surman, Alexander P. Ji, Rana Ezzeddine, Sean D. Points, Catherine C. Kaleida, Terese T. Hansen, Charli M. Sakari, Andrew R. Casey

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Abstract

We report the discovery of RAVE J203843.2-002333, a bright (V = 12.73), very metal-poor ( = -2.91), r-process-enhanced ( = +1.64 and = -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.

Original languageEnglish
Article number18
Number of pages13
JournalThe Astrophysical Journal
Volume844
Issue number1
DOIs
Publication statusPublished - 20 Jul 2017

Keywords

  • galaxy: halo
  • stars: abundances
  • stars: atmospheres
  • stars: individual (RAVE J203843.2-002333)
  • stars: Population II
  • techniques: imaging spectroscopy

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