TY - JOUR
T1 - Extreme enhancements of r-process elements in the cool metal-poor main-sequence star SDSS J2357-0052
AU - Aoki, Wako
AU - Beers, Timothy C.
AU - Honda, Satoshi
AU - Carollo, Daniela
PY - 2010/11/10
Y1 - 2010/11/10
N2 - 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.
AB - 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.
KW - Nuclear reactions, nucleosynthesis, abundances
KW - Stars: abundances
KW - Stars: Population II
UR - http://www.scopus.com/inward/record.url?scp=78649299784&partnerID=8YFLogxK
U2 - 10.1088/2041-8205/723/2/L201
DO - 10.1088/2041-8205/723/2/L201
M3 - Article
AN - SCOPUS:78649299784
SN - 2041-8205
VL - 723
JO - Astrophysical Journal Letters
JF - Astrophysical Journal Letters
IS - 2 PART 2
ER -