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

慢中子捕获过程或 s 过程发生在恒星接近其演化寿命末期的过程中，是宇宙化学演化的主要贡献者，产生了大约一半的比铁重的元素同位素。 由于缺乏原子数据，我们银河系内的星云和恒星中这些中子捕获元素的丰度和分布尚未得到很好的确定。 该项目将结合理论、实验室和观测天体物理学来研究两种这样的重元素的 s 过程；溴（Br）和铷（Rb），以确定这些元素在演化恒星内合成的过程和速率。该项目将通过研究最近在行星状星云（PNe）、HII区域和其他星系的星际介质中检测到的Br和Rb来研究渐近巨分支（AGB）核合成的细节。 该项目将计算 Br 和 Rb 的中性态和前六个离子的光电离截面。 然后，计算出的横截面将通过劳伦斯伯克利国家实验室的先进光源（ALS）实验进行验证。 新的原子数据将被纳入多云光电离代码中，用于对天体物理星云中未观测到的 Br 和 Rb 离子的丰度进行修正。 反过来，多云丰度将应用于 PI 之前观察到的高分辨率 PNe 光谱。本科院校研究 (RUI) 项目提供了大量广泛的机会来培训新科学家，重点是从代表性不足的群体中招募学生进入 STEM 领域。 这将是 PI 所在机构的第一个 RUI 奖项，应有助于建立必要的基础设施，以促进进一步的师生研究合作。 该项目将通过在 PI 所属机构校园内的天文台举行的公共开放日以及通过 PI 部门组织的公共演示之夜向公众传达其结果。 PI 在当地 K-12 学校举办讲座，并将研究结果纳入这些演讲中。

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.