RUI: Expanding the Atomic Database for Nebular and Stellar Neutron-Capture Element Abundance Determinations

点击翻译按钮获取中文摘要

The slow-neutron-capture-process or s-process, which occurs in stars near the ends of their evolutionary lifetimes, is a major contributor to the chemical evolution of our Universe, producing roughly half of all isotopes of elements heavier than iron. The abundances and distribution of these neutron-capture elements in nebulae and stars within our galaxy are not well determined mainly due to a lack of atomic data. This project will combine theoretical, laboratory, and observational astrophysics to study the s-process in two such heavy elements; bromine (Br) and rubidium (Rb), in order to determine the process and rate by which these elements are synthesized within evolved stars.The project will investigate the details of asymptotic giant branch (AGB) nucleosynthesis through the study of Br and Rb, which have been recently been detected in planetary nebulae (PNe), HII regions and the interstellar medium of other galaxies. The project will compute photoionization cross-sections for the neutral state and first six ions of both Br and Rb. The calculated cross sections will then be verified through experiments on the Advanced Light Source (ALS) at the Lawrence Berkeley National Laboratory. The new atomic data will be incorporated into the Cloudy photoionization code where it will be used to derived corrections for the abundances of unobserved ions of Br and Rb in astrophysical nebulae. The Cloudy abundances, in turn, will be applied to high-resolution PNe spectra that were previously observed by the PI.This Research in Undergraduate Institutions (RUI) project offers numerous and wide-ranging opportunities to train new scientists with a strong emphasis on recruiting students from underrepresented groups into STEM fields. This will be the first RUI award at the PI?s institution and should help to build the infrastructure necessary to facilitate further faculty-student research collaboration. The project will communicate its results to the public through public open houses held at the observatory on the campus of the PI's home institution and through public demonstration nights organized through the PI?s department. The PI gives lectures at local K-12 schools and will incorporated the results of the research into those presentations.