R-process pattern in the Very-Metal-Poor Halo Star CS31082-001

Abstract

The very-metal-poor halo star CS31082-001 was discovered to be very strongly r-process-enhanced during the course of a VLT+UVES high-resolution follow-up of metal-poor stars identified in the HK survey of Beers and colleagues. Both the strong n-capture element enhancement and the low carbon and nitrogen content of the star (reducing the CN molecular band contamination) led to the first $^{238}$U abundance measurement in a stellar spectrum (Cayrel et al. 2001), and the opportunity to use both radioactive species $^{238}$U and $^{232}$Th for dating the progenitor to this star. However, age computations all rely on the hypothesis that the r-process pattern is solar, as this was indeed observed in the other famous r-process-enhanced very metal poor stars CS22892-052 (Sneden et al. 1996, 2000) and in HD115444 (Westin et al. 2000). Here, we investigate whether this hypothesis is verified also for CS31082-001, using a preliminary analysis of over 20 abundances of n-capture elements in the range Z=38 to Z=92.