Abundances in the Uranium-rich Star CS 31082-001

The recent discovery by Cayrel et al. of U in CS 31082-001 along with Os andIr at greatly enhanced abundances but with [Fe/H]=-2.9 strongly reinforces theargument that there are at least two kinds of SNII sources for r-nuclei. Onesource is the high-frequency H events responsible for heavy r-nuclei (A>135)but not Fe. The H-yields calculated from data on other ultra-metal-poor starsand the sun provide a template for quantitatively predicting the abundances ofall other r-elements. In CS 31082-001 these should show a significantdeficiency at A<135 relative to the solar r-pattern. It is proposed that CS31082-001 should have had a companion that exploded as an SNII H event. If thebinary survived the explosion, this star should now have a compact companion,most likely a stellar-mass black hole. Comparison of abundance data withpredicted values and a search for a compact companion should provide astringent test of the proposed r-process model. The U-Th age determined byCayrel et al. for CS 31082-001 is, to within substantial uncertainties, inaccord with the r-process age determined from solar system data. The time gapbetween Big Bang and onset of normal star formation only allows r-processchronometers to provide a lower limit on the age of the universe.Comment: 5 pages, 1 figur