Speaker
Description
The nuclear mechanism responsible for roughly half of the heavy-elements (Z>30) abundances in our Solar system---the rapid neutron capture (r) process---was long thought to produce a "universal" abundance pattern. However, recent studies have challenged r-process universality by identifying significant variations between the elemental abundances patterns of metal-poor ([Fe/H]<-1.0), r-process-enhanced stars. In particular, r-process-rich ([Eu/Fe]>+0.3) stars show a signature that may possibly only be explained by fission. In this work, we construct a method of decomposing stellar abundance patterns into a basis set of patterns from which each star can be constructed as a linear combination, akin to a principal component decomposition. We use this method to uncover the underlying signature that is present in the r-process-rich stars in order to derive an empirical record of fission in the r-process. This talk will present the "pure" fission pattern is that is recovered from these metal-poor stars.
Support for this work was provided by NASA through the NASA Hubble Fellowship grant HST-HF2-51481.001 awarded by the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., for NASA, under contract NAS5-26555. This work performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.
