Carbon and nitrogen abundances in giant stars of the metal-poor globular cluster M15

Abstract

view Abstract Citations (122) References (34) 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 M15. Trefzger, D. V. ; Langer, G. E. ; Carbon, D. F. ; Suntzeff, N. B. ; Kraft, R. P. Abstract The authors derive carbon and nitrogen abundances for 33 giant-star members of the globular cluster M15, thus extending their earlier work in M92 to another cluster of comparably low metallicity ([M/H] ⪉ -2). They describe a technique for obtaining C and N abundances which is based on spectrophotometric indices that measure the strengths of NH, CN, and CH bands in low-resolution scanner spectra. The spectrophotometric indices are calibrated using scanner spectra of M92 giant stars in which estimates of C and N abundances had previously been obtained by the method of spectrum synthesis. The complex behavior of C and N abundances in M15 giants cannot be adequately described by models based on classical evolutionary theory. The scenarios already advanced to explain these abundance patterns in the case of M92 are discussed briefly in connection with M15. Publication: The Astrophysical Journal Pub Date: March 1983 DOI: 10.1086/160765 Bibcode: 1983ApJ...266..144T Keywords: Abundance; Giant Stars; Globular Clusters; Stellar Evolution; Stellar Spectrophotometry; Carbon Stars; Interstellar Extinction; Late Stars; Metallicity; Nitrogen; Stellar Spectra; Astrophysics full text sources ADS | data products SIMBAD (28)