A search for lithium-rich giant stars

Journal Article · Sun Oct 01 04:00:00 EDT 1989 · Astrophysical Journal, Supplement Series; (USA)

DOI:https://doi.org/10.1086/191375· OSTI ID:7017910

Brown, J A; Sneden, C; Lambert, D L; Dutchover, E Jr ^[1]

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1. Texas Univ. Observatory, Austin (USA)

Lithium abundances or upper limits have been determined for 644 bright G-K giant stars selected from the DDO photometric catalog. Two of these giants possess surface lithium abundances approaching the cosmic value of the interstellar medium and young main-sequence stars, and eight more giants have Li contents far in excess of standard predictions. At least some of these Li-rich giants are shown to be evolved to the stage of having convectively mixed envelopes, either from the direct evidence of low surface carbon isotope ratios, or from the indirect evidence of their H-R diagram positions. Suggestions are given for the unique conditions that might have allowed these stars to produce or accrete new lithium for their surface layers, or simply to preserve from destruction their initial lithium contents. The lithium abundance of the remaining stars demonstrates that giants only very rarely meet the expectations of standard first dredge-up theories; the average extra Li destruction required is about 1.5 dex. The evolutionary states of these giants and their average masses are discussed briefly, and the Li distribution of the giants is compared to predictions of Galactic chemical evolution. 110 refs.

• OSTI ID: 7017910
• Journal Information: Astrophysical Journal, Supplement Series; (USA), Journal Name: Astrophysical Journal, Supplement Series; (USA) Vol. 71; ISSN APJSA; ISSN 0067-0049
• 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
ALKALI METALS
CHEMICAL COMPOSITION
COMPARATIVE EVALUATIONS
DIAGRAMS
ELEMENTS
GIANT STARS
HERTZSPRUNG-RUSSELL DIAGRAM
INTERSTELLAR SPACE
LITHIUM
MAIN SEQUENCE STARS
MASS
METALS
SPACE
STAR EVOLUTION
STARS