Carbon and nitrogen abundances in red giant stars in the globular cluster 47 Tucanae

Abstract

view Abstract Citations (67) References (37) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Carbon and nitrogen abundances in red giant stars in the globular cluster 47 Tucanae. Dickens, R. J. ; Bell, R. A. ; Gustafsson, B. Abstract The effects of changes in temperature, gravity, overall metal abundance, and carbon and nitrogen abundances have been investigated for model stellar spectra and colors representing globular-cluster giants of moderate metal deficiency. The results are presented in the form of spectral atlases and theoretical color-color diagrams. Using these results, approximate abundances of carbon and nitrogen have been derived for some red giant stars in 47 Tuc, from intermediate- and low-dispersion spectra and from intermediate- and narrow-band photometry. In all the normal giants studied, nitrogen is overabundant by up to about a factor of 5 (the precise value depends on the adopted carbon abundance), with different enhancements for different giants. The observational material is not sufficient to distinguish between a normal carbon abundance and a slight carbon depletion for the giant-branch stars, but carbon appears to be somewhat depleted in stars on the asymptotic giant branch. A most probable value of M/H = -0.8 for the overall cluster metal abundance is suggested from analysis of Stromgren photometry of red horizontal-branch stars. Publication: The Astrophysical Journal Pub Date: September 1979 DOI: 10.1086/157303 Bibcode: 1979ApJ...232..428D Keywords: Abundance; Carbon; Globular Clusters; Nitrogen; Red Giant Stars; Asymptotic Giant Branch Stars; Color-Color Diagram; Graphs (Charts); Metals; Stellar Spectra; Wavelengths; Astrophysics; Atlases:Stellar Spectra; C-M Diagrams:Globular Clusters; Carbon:Red Giants; Colors:Red Giants; Globular Clusters:Red Giants; Nitrogen:Red Giants; Red Giants:Spectra full text sources ADS | data products SIMBAD (23)