High-resolution CCD spectra of stars in globular clusters. IV. Carbon isotope ratios in red giants

Journal Article · Wed Nov 01 04:00:00 EST 1989 · Astronomical Journal; (USA)

DOI:https://doi.org/10.1086/115248· OSTI ID:7144220

Brown, J A; Wallerstein, G ^[1]

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1. Washington Univ., Seattle (USA)

Carbon isotope ratios for stars in four globular clusters are derived by means of spectrum synthesis analysis of CN features in high-resolution spectra around 8000 A. In the strong-CN stars in the clusters M4, M22, Omega Cen, and 47 Tuc, the isotope ratios are generally quite low, approaching the equilibrium value in the CN cycle, namely 3-8; this includes a barium star and an S star in Omega Cen and a CH star in M22. (C-13)N is not detected in weak-CN stars, but the limits on the (C-12)/(C-13) ratios in these stars are not significant. Ratios as low as 3-8 are not predicted by standard evolution models of low-mass metal-poor stars. 37 refs.

• OSTI ID: 7144220
• Journal Information: Astronomical Journal; (USA), Journal Name: Astronomical Journal; (USA) Vol. 98; 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
CARBON ISOTOPES
CHARGE-COUPLED DEVICES
GIANT STARS
ISOTOPE RATIO
ISOTOPES
MASS
MATHEMATICAL MODELS
RED GIANT STARS
RESOLUTION
SEMICONDUCTOR DEVICES
STAR CLUSTERS
STAR EVOLUTION
STAR MODELS
STARS