Abundances in globular cluster red giants. IV. M22 and omega Centauri

Journal Article · Sat Aug 01 04:00:00 EDT 1981 · Astrophys. J.; (United States)

DOI:https://doi.org/10.1086/159097· OSTI ID:5974300

Cohen, J G

A detailed abundance analysis has been performed for three members of M22 and five of ..omega.. Cen. The three giants in M22 are chemically identical with (Fe/H) = -1.78 dex except for a range of Na and, less certainly, Ba larger than the observational and modeling errors. The ..omega.. Cengiants show a range of abundance for all elements, with the light elements and the rare earths (plus Ba) enhanced by a larger factor than the Fe peak nuclei in the more metal-rich ..omega.. Cen stars. The two most metal-rich ..omega.. Cen stars have vastly different Na/Mg and Al/Mg ratios and Sc abundances. Explosive nucleosynthesis fails to predict the Na/Mg observed ratios at large Al/Mg values. The deduced neutron excesses are etaroughly-equal10/sup -2/ and 5 x 10/sup -4/; the former is the largest known for any star. These high values of eta require massive (M> or =12 M/sub sun/) supernova progenitors and may also produce via the s-process the strong enhancement of Ba and the rare earths seen in the metal-rich ..omega.. Cen giants. It is suggested that such massive supernovae were much rarer in the less dense halo field, leading to the observed differences in abundance patterns of globular cluster giants versus halo field dwarfs.

• Research Organization: Palomar Observatory, California Institute of Technology; and Kitt Peak National Observatory
• OSTI ID: 5974300
• Journal Information: Astrophys. J.; (United States), Journal Name: Astrophys. J.; (United States) Vol. 247:3; ISSN ASJOA
• 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
ALKALI METALS
ALKALINE EARTH METALS
ALUMINIUM
ATMOSPHERES
CHEMICAL COMPOSITION
ELEMENTS
ERUPTIVE VARIABLE STARS
GIANT STARS
MAGNESIUM
MATHEMATICAL MODELS
METALS
NUCLEOSYNTHESIS
PHOTOMETRY
RED GIANT STARS
SODIUM
STAR CLUSTERS
STAR MODELS
STARS
STELLAR ATMOSPHERES
SUPERNOVAE
VARIABLE STARS