2010/10/03 by Wako Aoki, Timothy C. Beers, Timothy C. Beer +3
Chemistry · Physics and Astronomy · #Astronomy #Astrophysical Phenomena and Observations #Astrophysics #Chemistry #Gamma-ray bursts and supernovae #Main sequence #Materials science #Metal #Metallicity #Metallurgy #Nucleosynthesis #Physics #Sequence (biology) #Sky #Spectroscopy #Star (game theory) #Stars #Stellar, planetary, and galactic studies #astro-ph.SR #r-process
paper · pdf · doi:10.1088/2041-8205/723/2/l201
16 pages, 3 figures, 2 tables, ApJL in press
arxiv created 2010/10/03 · openalex publication_date 2010/10/18 · arxiv updated 2015/05/20 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
We report the discovery of a cool metal-poor, main-sequence star exhibiting large excesses of r -process elements. This star is one of the two newly discovered cool subdwarfs (effective temperatures of 5000 K) with extremely low metallicity ([Fe/H] < −3) identified from follow-up high-resolution spectroscopy of metal-poor candidates from the Sloan Digital Sky Survey. SDSS J2357−0052 has [Fe/H] = −3.4 and [Eu/Fe] = +1.9, and exhibits a scaled solar r -process abundance pattern of heavy neutron-capture elements. This is the first example of an extremely metal-poor, main-sequence star showing large excesses of r -process elements; all previous examples of the large r -process-enhancement phenomena have been associated with metal-poor giants. The metallicity of this object is the lowest, and the excess of Eu ([Eu/Fe]) is the highest, among the r -process-enhanced stars found so far. We consider possible scenarios to account for the detection of such a star and discuss techniques to enable searches for similar stars in the future.