2018ApJ...859..114B -
Astrophys. J., 859, 114-114 (2018/June-1)
Chemical composition of two bright, extremely metal-poor stars from the SDSS MARVELS pre-survey.
BANDYOPADHYAY A., SIVARANI T., SUSMITHA A., BEERS T.C., GIRIDHAR S., SURYA A. and MASSERON T.
Abstract (from CDS):
SDSS J082625.70+612515.10 (V = 11.4; [Fe/H] = -3.1) and SDSS J134144.60+474128.90 (V = 12.4; [Fe/H] = -3.2) were observed with the SDSS 2.5m telescope as part of the SDSS MARVELS spectroscopic pre-survey and identified as extremely metal-poor (EMP; [Fe/H] < -3.0) stars during the high-resolution follow-up using the Hanle Echelle Spectrograph (HESP) on the 2.0-m Himalayan Chandra Telescope. In this paper, the first science results using HESP, we present a detailed analysis of their chemical abundances. Both stars exhibit under-abundances in their neutron capture elements, while one of them (SDSS J134144.60+474128.90) is clearly enhanced in carbon. Lithium was also detected in this star at a level of about A(Li) = 1.95. The spectra were obtained over a span of 6-24 months, and indicate that both stars could be members of binary systems. We compare the elemental abundances derived for these two stars along with other carbon-enhanced metal-poor (CEMP) and EMP stars, in order to understand the nature of their parent supernovae. We find that CEMP-no stars and EMP-dwarfs show a very similar trend in their lithium abundances at various metallicities. We also find indications of CEMP-no stars having larger abundances of Cr and Co at given metallicities compared to EMP stars.
Abstract Copyright:
© 2018. The American Astronomical Society. All rights reserved.
Journal keyword(s):
stars: abundances - stars: carbon - stars: chemically peculiar - stars: early-type - stars: neutron - stars: Population III
Simbad objects:
4
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