Isochrones for H-burning globular cluster stars. II - The metallicity range Fe/H = minus 2. 3 to minus 0. 5

Journal Article · Sat Jun 01 04:00:00 EDT 1991 · Astrophysical Journal, Supplement Series; (United States)

DOI:https://doi.org/10.1086/191576· OSTI ID:5226255

Straniero, O; Chieffi, A ^[1]

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1. Scuola Normale Superiore, Pisa (Italy) CNR, Istituto di Astrofisica Spaziale, Frascati (Italy)

A set of theoretical isochrones ranging between 10 and 20 Gyr and between Z = {minus}40,000 and Z = {minus}6000 is presented. All the isochrones fully extend from the lower main sequence up to the He flash. Presented isochrones turn out to be similar in shape to those described in literature but systematically redder by few hundredths of a magnitude. The set differs profoundly from the Revised Yale Isochrones. A fit to a selected group of Galactic globular clusters including M92, M68, M30, NGC 6752, M10, M3, M5, NGC 362, 47 Tucanae, and Palomar 12 is also presented. It is found that eight of the eleven clusters show an age spread not exceeding 3 Gyr. The most metal-rich clusters NGC 362, 47 Tuc, and Palomar 12 turn out to be significantly younger by approximately 5 Gyr compared with the others. The metallicities inferred for these clusters fairly agree with the Zinn and West metallicity scale. The absolute visual magnitude of the horizontal branches of the clusters is determined as a function of the metallicity. 59 refs.

• OSTI ID: 5226255
• Journal Information: Astrophysical Journal, Supplement Series; (United States), Journal Name: Astrophysical Journal, Supplement Series; (United States) Vol. 76; ISSN APJSA; ISSN 0067-0049
• 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
AGE ESTIMATION
BRIGHTNESS
CHEMICAL COMPOSITION
COMPARATIVE EVALUATIONS
EVALUATION
GALAXIES
HELIUM BURNING
HYDROGEN BURNING
MILKY WAY
OPTICAL PROPERTIES
PHYSICAL PROPERTIES
STAR BURNING
STAR CLUSTERS
STAR EVOLUTION
TABLES