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Title: Chemical Composition of Two Bright, Extremely Metal-poor Stars from the SDSS MARVELS Pre-survey
Authors: Bandyopadhyay, A
Sivarani, T
Susmitha, A
Beers, T. C
Giridhar, S
Arun Surya
Masseron, T
Keywords: Stars: abundances;Stars: carbon;Stars: chemically peculiar;Stars: early-type;Stars: neutron;Stars: Population III
Issue Date: 1-Jun-2018
Publisher: IOP Publishing
Citation: The Astrophysical Journal, Vol. 859, No. 2, 114
Abstract: 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.
Description: Restricted Access
ISSN: 0004-637X
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Appears in Collections:IIAP Publications

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