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White dwarf stars and the age of the Galactic diskThe history of the Galaxy is written in its oldest stars, the white dwarf (WD) stars. Significant limits can be placed on both the Galactic age and star formation history. A wide range of input WD model sequences is used to derive the current limits to the age estimates suggested by fitting to the observed falloff in the WD luminosity function. The results suggest that the star formation rate over the history of the Galaxy has been relatively constant, and that the disk age lies in the range 6-12 billion years, depending upon the assumed structure of WD stars, and in particular on the core composition and surface helium layer mass. Using plausible mixed C/O core input models, the estimates for the disk age range from 8-10.5 Gyr, i.e.,sustantially younger than most age estimates for the halo globular clusters. After speculating on the significance of the results, expected observational and theoretical refinements which will further enhance the reliability of the method are discussed.
Document ID
19900056154
Document Type
Reprint (Version printed in journal)
Authors
Wood, M. A. (Texas, University Austin, United States)
Date Acquired
August 14, 2013
Publication Date
June 1, 1990
Publication Information
Publication: Royal Astronomical Society of Canada, Journal
Volume: 84
ISSN: 0035-872X
Subject Category
ASTROPHYSICS
Funding Number(s)
CONTRACT_GRANT: NGT-50210
Distribution Limits
Public
Copyright
Other