Subdwarf studies. IV - Abundance ratios in extremely metal-deficient stars

Journal Article · Mon Jul 01 04:00:00 EDT 1991 · Astronomical Journal; (United States)

DOI:https://doi.org/10.1086/115878· OSTI ID:5261996

Ryan, S G; Norris, J E; Bessell, M S ^[1]

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1. Mount Stromlo and Siding Spring Observatories, Canberra (Australia)

High-resolution spectra of 19 metal-deficient proper motion stars were examined for basic trends in the abundances for iron and other elements. Results indicate that there is a mild support for the claim by Tomkin et al. (1986) and Carbon et al. (1987) of an upturn in the C/Fe ratio at Fe/H of -2.0, which might reflect an overproduction of carbon in the supernovae of 200-solar-mass, zero-initial-metallicity stars. The abundance ratios of Mg, Si, Ca, Ti, Cr, Sc, and Mn relative to Fe are found to extend the uniform trends previously reported for stars with Fe/H ratio between -2.5 and -1.0, down to at least Fe/H of -3.5. The Ni element is not as overabundant as was reported by Luck and Bond (1983, 1985), and Al element is overabundant with respect to both Fe and Mg. It was found that halo dwarfs have an Mn/Fe underabundance of -0/33 dex, and that the spread in relative abundances of Sr in the most metal-deficient stars is greater than 1 decade. 135 refs.

• OSTI ID: 5261996
• Journal Information: Astronomical Journal; (United States), Journal Name: Astronomical Journal; (United States) Vol. 102; ISSN 0004-6256; ISSN ANJOA
• Country of Publication: United States
• Language: English

Related Subjects

640102* -- Astrophysics & Cosmology-- Stars & Quasi-Stellar
Radio & X-Ray Sources
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ABUNDANCE
ALKALINE EARTH METALS
ALUMINIUM
CALCIUM
CARBON
CHEMICAL COMPOSITION
CHEMISTRY
CHROMIUM
COSMOCHEMISTRY
DWARF STARS
ELEMENT ABUNDANCE
ELEMENTS
ERUPTIVE VARIABLE STARS
HYDROGEN
IRON
LINE WIDTHS
MAGNESIUM
METALS
NICKEL
NONMETALS
SCANDIUM
SEMIMETALS
SILICON
SPECTROPHOTOMETRY
STARS
SUPERNOVAE
TITANIUM
TRANSITION ELEMENTS
VARIABLE STARS