Titre du document

## Red Giants in old Open Clusters

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Nom du Corpus

#### AstroConcepts

Auteur(s)
• R. D. Cannon
Résumé

A detailed comparison is made between the predictions of stellar evolution calculations and the observations of red giants in old open clusters. Colour–magnitude diagrams are presented for several such clusters, in which relative proper motions have been used to eliminate non-members. The published observations of other old clusters are summarized. A prominent feature of all these clusters is a ‘ clump ’ of red giants, centred near ${M}_{\nu }\,=\,+\,1,\,B-V\,=\,+\,1\cdot0$, which is tentatively identified with the horizontal branch found in globular clusters. Comparison with various theoretical calculations, mostly by I. Iben and J. Faulkner, supports this identification and indicates that the stars have a helium-burning core surrounded by a hydrogen-burning shell. The near constancy of the absolute magnitude of the clump is then interpreted as observational evidence for the occurrence of electron degeneracy in the cores of low mass red giants. The use of the clump for crude determinations of cluster distances and reddening, and as evidence of the internal composition of the stars, is advocated. Finally, it is suggested that a large number of field red giants may be in the helium-burning phase of evolution, some of which may be used to investigate mass loss and internal mixing in evolving stars.

Langue(s) du document
Indéterminé
Année de publication
1970
Revue

#### Monthly Notices of the Royal Astronomical Society

Éditeur
OUP
Type de publication
journal
Type de document
research-article
Présence de XML structuré
Non
Version de PDF
1.4
Score de qualité du texte
4.413
Nom du concept
• Blue stragglers
Catégories Science-Metrix
• 1 - natural sciences ; 2 - physics & astronomy ; 3 - astronomy & astrophysics
Catégories Scopus
• 1 - Physical Sciences ; 2 - Earth and Planetary Sciences ; 3 - Space and Planetary Science
• 1 - Physical Sciences ; 2 - Physics and Astronomy ; 3 - Astronomy and Astrophysics
Catégories WoS
• 1 - science ; 2 - astronomy & astrophysics
Identifiant ISTEX
0DE072E13E64CEC232939C8F7F9B594C5323B51F