Abundances in the red giants of M13 and M22

Journal Article · Fri Feb 01 04:00:00 EST 1991 · Astrophysical Journal; (USA)

DOI:https://doi.org/10.1086/169648· OSTI ID:6002602

Lehnert, M D; Bell, R A; Cohen, J G ^[1]

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1. Maryland Univ., College Park (USA) Palomar Observatory, Pasadena, CA (USA)

Abundances of Ca, Na, and Fe are derived for 10 red giant branch stars in the globular clusters M13 and M22, by means of model atmosphere analyses of high-dispersion spectra. It was found that M13 and M22 represent two different types of globular clusters. M13 is similar to M92 and many other globular clusters in that it displays variations in CH and CN band strengths, while showing no variation in either Ca or Fe abundance. The Na abundance was found to vary and its variation correlates with CN band strengths. This suggests that the source of the observed CN band strength variation is the same as that of the Na variation. M22, on the other hand, is similar to Omega Cen, in that it displays variations in Ca, Na, and Fe abundances, and these variations correlate with variations in CH and CN band strengths. These correlations suggest that the cause of the variations in M22 is largely primordial, and that mixing may only make a relatively small contribution to the C and N variations observed. 61 refs.

• OSTI ID: 6002602
• Journal Information: Astrophysical Journal; (USA), Journal Name: Astrophysical Journal; (USA) Vol. 367; ISSN ASJOA; ISSN 0004-637X
• 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
ATMOSPHERES
CALCIUM
CHEMICAL COMPOSITION
CYANOGEN
ELEMENT ABUNDANCE
ELEMENTS
GIANT STARS
IRON
MATHEMATICAL MODELS
METALS
MIXING
RED GIANT STARS
SODIUM
STAR CLUSTERS
STAR MODELS
STARS
STELLAR ATMOSPHERES
TRANSITION ELEMENTS
VARIATIONS