Metal abundance range in the Draco dwarf galaxy

Journal Article · Wed Nov 01 04:00:00 EST 1978 · Astrophys. J.; (United States)

DOI:https://doi.org/10.1086/156544· OSTI ID:6311177

Zinn, R

The multichannel scanner of the Hale telescope was used to measure the spectral flux distributions of 23 red giants in the Draco system over the range lambda lambda 3240 to 7620. The memberships of these stars in Draco were checked by use of the spectral scans, and for 17 of them the observations are of sufficient quality that estimates of metal abundance can be made. The scans of the Draco stars resemble in every way the scans of red giants in globular clusters. Large differences are seen among the scans of the Draco stars, which are due to a range in Fe/H. The distribution over metal abundance was found from the abundance estimates; its half-width corresponds to an abundance range of a factor of 2.7. The mean metal abundance (Fe/H) = -1.86 +- 0.09, which is larger than the abundance of M92. This result does not support the previous claims that Draco is more metal poor than the most metal-deficient globular clusters. The implications of these results for the interpetations of Draco's color--magnitude diagram and variable star population are discussed. The chemical evolution of Draco was modeled with simple models that assume mass loss and prompt initial enrichment. These models provide adequate fits to the observed abundance distribution, and suggest that the proto-Draco was initially approx. 100 times more massive than Draco is today. 10 figures, 2 tables.

• Research Organization: Hale Observatories, Pasadena, CA
• OSTI ID: 6311177
• Journal Information: Astrophys. J.; (United States), Journal Name: Astrophys. J.; (United States) Vol. 225:3; ISSN ASJOA
• Country of Publication: United States
• Language: English

Related Subjects

640102* -- Astrophysics & Cosmology-- Stars & Quasi-Stellar
Radio & X-Ray Sources
640105 -- Astrophysics & Cosmology-- Galaxies
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
CHEMICAL COMPOSITION
ELEMENTS
GALACTIC EVOLUTION
GALAXIES
GIANT STARS
MASS
MATHEMATICAL MODELS
METALS
PHOTOMETRY
RED GIANT STARS
SPECTRA
SPECTROPHOTOMETRY
STARS
VARIABLE STARS
VISIBLE SPECTRA