Carbon and nitrogen abundances in giant stars of the metal-poor globular cluster M92

Abstract

view Abstract Citations (225) References Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Carbon and nitrogen abundances in giant stars of the metal-poor globular cluster M 92. Carbon, D. F. ; Langer, G. E. ; Butler, D. ; Kraft, R. P. ; Suntzeff, N. B. ; Kemper, E. ; Trefzger, C. F. ; Romanishin, W. Abstract The 169 low resolution image tube scanner spectra obtained at the Lick Observatory for 71 stars in the field of M92, covering the 3100-5200 A spectral interval, are matched with synthetically generated spectra to find the C and N abundances for a subset of 45 bright member giants. It is found that (1) stars side by side in the color-magnitude diagram show N and C abundance variations by factors of 10 and three, respectively, (2) the segregation of stars into small groups by effective temperature and log g shows no inversely proportional relationship between N and C abundance, and (3) the mean C abundance is 10 times smaller on the AGB than on the SGB. The C and N abundances of M92 therefore disagree with the predictions of classical evolutionary theory. Four different scenarios which have been suggested to account for the observations cited are discussed. In addition, primordial CNO abundances observed in, or deduced for, metal-poor field and cluster stars are compared with those deduced for M92, and then discussed in connection with the global galactic nucleosynthesis and cluster self-contamination process scenarios. Publication: The Astrophysical Journal Supplement Series Pub Date: June 1982 DOI: 10.1086/190796 Bibcode: 1982ApJS...49..207C Keywords: Abundance; Giant Stars; Globular Clusters; Late Stars; Stellar Evolution; Stellar Spectra; Asymptotic Giant Branch Stars; Atomic Spectra; Carbon; Color-Magnitude Diagram; Hyperfine Structure; Image Dissector Tubes; Molecular Spectra; Nitrogen; Nuclear Fusion; Solar Spectra; Stellar Atmospheres; Stellar Models; Stellar Temperature; Ubv Spectra; Astrophysics full text sources ADS | data products SIMBAD (76)