Determination of the ratios of /sup 12/C//sup 13/C and C/O in the carbon stars V460 Cygni and TX Piscium

Journal Article · Mon Mar 01 04:00:00 EST 1982 · Astrophys. J.; (United States)

DOI:https://doi.org/10.1086/159721· OSTI ID:5202880

Johnson, H R; O'Brien, G T; Climenhaga, J L

Values of the ratio of carbon to oxygen (C/O) and the /sup 12/C//sup 13/C isotopic ratio have been determined for two N-type carbon stars: V460 Cygni and TX Piscium. The values have been determined by comparing synthetic spectra based on recently constructed model atmospheres for luminous carbon stars with high-resolution photographic spectra of V460 Cyg and TX Psc in the wavelength range from 7950 to 8065 A. The observed and synthetic spectra match most closely for values of C/O = 1.02 and /sup 12/C//sup 13/C = 24 (V460 Cyg) and 27 (TX Psc), while outer limits appear to be 1.00< or =C/O< or =1.05 and 15< or =/sup 12/C//sup 13/C< or =40 for both stars. The isotope ratio for V460 Cyg agrees well with the value obtained by Dominy et al., while that for TX Pcs agrees with recent determinations by Kilston and by Olson and Richer. However, the values derived for both stars are much larger than those obtained by Climenhaga et al. and much smaller than that obtained for V460 Cyg by Fujita and Tsuji. We discuss possible explanations for this discrepancy as well as the effect on our results of uncertainties in effective temperature, microturbulence, and surface gravity.

• Research Organization: Astronomy Department, Indiana University
• OSTI ID: 5202880
• Journal Information: Astrophys. J.; (United States), Journal Name: Astrophys. J.; (United States) Vol. 254:1; ISSN ASJOA
• Country of Publication: United States
• Language: English

Related Subjects

640102* -- Astrophysics &amp; Cosmology-- Stars &amp; Quasi-Stellar
Radio &amp; X-Ray Sources
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ABUNDANCE
ATMOSPHERES
CARBON
CARBON 12
CARBON 13
CARBON ISOTOPES
CARBON STARS
CHEMICAL COMPOSITION
CYANOGEN
ELEMENTS
EVEN-EVEN NUCLEI
EVEN-ODD NUCLEI
ISOTOPE RATIO
ISOTOPES
LIGHT NUCLEI
MAIN SEQUENCE STARS
MATHEMATICAL MODELS
NONMETALS
NUCLEI
OXYGEN
STABLE ISOTOPES
STAR MODELS
STARS
STELLAR ATMOSPHERES