Variations in C-12/C-13 as an explanation for the 3883 A CN-bimodality among 47 Tucanae subgiants

Journal Article · Thu Jun 01 04:00:00 EDT 1989 · Astrophysical Journal; (USA)

DOI:https://doi.org/10.1086/167537· OSTI ID:5711262

Briley, M M; Bell, R A; Smith, G H; Hesser, J E ^[1]

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1. Maryland Univ., College Park (USA)

Spectroscopic observations of subgiants in the metal-rich globular cluster 47 Tucanae are used to measure the strengths of the CN bands located at 3883 A and 4215 A. A bimodal distribution is clearly seen in the 3883 A CN band strengths, but not in the 4215 A bands. Synthetic spectrum calculations are used to probe the effect on both CN bands of varying the C-12/C-13 ratio. The sensitivity of the 3883 A CN feature to C-13 relative abundance is found to be considerably higher than that of the 4215 A band for the stars observed. Thus, spectroscopic indices derived from these features are observable probes of atmospheric C-13/C-12 enhancements. It is suggested that the bimodality observed in the 3883 A CN band may be due largely to a difference in the C-12/C-13 ratios of the two groups. 21 refs.

• OSTI ID: 5711262
• Journal Information: Astrophysical Journal; (USA), Journal Name: Astrophysical Journal; (USA) Vol. 341; ISSN ASJOA; ISSN 0004-637X
• 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
CARBON 12
CARBON 13
CARBON ISOTOPES
CHEMICAL COMPOSITION
CYANOGEN
EVEN-EVEN NUCLEI
EVEN-ODD NUCLEI
GIANT STARS
ISOTOPES
LIGHT NUCLEI
NUCLEI
SPECTROSCOPY
STABLE ISOTOPES
STAR CLUSTERS
STARS