AAS 197, January 2001
Session 44. Observations and Analysis of Stellar Atmospheres
Display, Tuesday, January 9, 2001, 9:30am-7:00pm, Exhibit Hall

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[44.18] Neutron-Capture Element Distributions in Metal-Poor Stars: Examination of a New Star with New Atomic Data

C. Sneden (U. Texas), J. J. Cowan (U. Oklahoma), T. C. Beers (Michigan State U.), S. Burles (U. Chicago), G. M. Fuller (U. California San Diego), I. I. Ivans (U. Texas), J. E. Lawler (U. Wisconsin)

In a recent large-sample abundance survey of about 50 halo giant stars in the metallicity regime [Fe/H] ~ -1.0 to -3.0, Burris et al. (2000, ApJ, in press) found that BD+17 3248 ([Fe/H] ~ -2.0) has the largest overabundance of europium ([Eu/Fe] ~ +1.0) and other very heavy elements. This star merits a detailed abundance scrutiny, and we present here a full new model atmosphere, equivalent width and spectrum synthesis analysis of this star. Our abundance analysis makes use of new laboratory transition probability data for three critical neutron-capture species (La II, Tb II and Dy II) to provide a more accurate confrontation of the abundance distribution with neutron-capture element predictions. An age estimate of the neutron-capture material in this star from Th II transitions will be presented, and the derived age is consistent with other radioactive thorium age results for Galactic halo stars. This work has been supported by grants from the National Science Foundation to several of the authors.


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