Observational constraints on first-star nucleosynthesis. II. Spectroscopy of an ultra metal-poor CEMP-no star

Journal Article · Sat Dec 10 04:00:00 EST 2016 · Astrophysical Journal

DOI:https://doi.org/10.3847/0004-637X/833/1/21· OSTI ID:22868377

Placco, Vinicius M.; Beers, Timothy C.; Yoon, Jinmi ^[1]; Frebel, Anna; Chiti, Anirudh ^[2]; Heger, Alexander; Chan, Conrad ^[3]; Casey, Andrew R. ^[4]; Christlieb, Norbert ^[5]

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1. Department of Physics, University of Notre Dame, Notre Dame, IN 46556 (United States)
2. JINA Center for the Evolution of the Elements, East Lansing, MI 48824 (United States)
3. Monash Centre for Astrophysics, School of Physics and Astronomy, 19 Rainforest Walk, Monash University, Vic 3800 (Australia)
4. Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA (United Kingdom)
5. Zentrum für Astronomie der Universität Heidelberg, Landessternwarte, Königstuhl 12, D-69117, Heidelberg (Germany)

We report on the first high-resolution spectroscopic analysis of HE 0020–1741, a bright (V = 12.9), ultra metal-poor ([Fe/H] = −4.1), carbon-enhanced ([C/Fe] = +1.7) star selected from the Hamburg/ESO Survey. This star exhibits low abundances of neutron-capture elements ([Ba/Fe] = −1.1) and an absolute carbon abundance A(C) = 6.1; based on either criterion, HE 0020–1741 is subclassified as a carbon-enhanced metal-poor star without enhancements in neutron-capture elements (CEMP-no). We show that the light-element abundance pattern of HE 0020–1741 is consistent with predicted yields from a massive (M = 21.5 M{sub ⊙}), primordial-composition, supernova (SN) progenitor. We also compare the abundance patterns of other ultra metal-poor stars from the literature with available measures of C, N, Na, Mg, and Fe abundances with an extensive grid of SN models (covering the mass range 10--100 M{sub ⊙}), in order to probe the nature of their likely stellar progenitors. Our results suggest that at least two classes of progenitors are required at [Fe/H] < −4.0, as the abundance patterns for more than half of the sample studied in this work (7 out of 12 stars) cannot be easily reproduced by the predicted yields.

• OSTI ID: 22868377
• Journal Information: Astrophysical Journal, Journal Name: Astrophysical Journal Journal Issue: 1 Vol. 833; ISSN ASJOAB; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
CAPTURE
CARBON
COMPARATIVE EVALUATIONS
ELEMENT ABUNDANCE
GALAXIES
MASS
NEUTRON REACTIONS
NUCLEOSYNTHESIS
RESOLUTION
SPECTROSCOPY
STARS
STELLAR ATMOSPHERES