Stellar Chemistry: Abundances and Condensation

该研究项目是对太阳系内元素丰度和性质的全面理论研究。 研究人员将更新和完善所谓的“太阳丰度”，这是确定太空中气体和尘埃性质的基本参考。 这项研究的结果将使天文学家能够准确地解释各种恒星环境的观测结果，并了解化学如何影响恒星和行星的形成。该项目将培养一名研究生，并为本科生提供研究机会。 该项目的结果预计将被纳入教科书，它们将广泛适用于天体物理学以外的物理科学。这项工作旨在为解释恒星环境中气体和尘埃的丰度和化学成分提供一个基本框架。 研究人员将对所有陨石及其成分的元素和同位素组成进行详细评估，以评估和模拟太阳光球和罕见的“CI陨石”之间丰度的明显差异。 然后，他们将使用气体和冷凝化学的热化学模型来解决太阳和其他G型恒星之间耐火元素的明显丰度变化。 预计该项目将大大更新从陨石和太阳数据得出的太阳系元素和同位素丰度参考集。 它还将补充大气和恒星周围的恒星壳的光谱研究，以及从陨石中分离出的前太阳颗粒的分析。该奖项反映了NSF的法定使命，并被认为值得通过使用基金会的知识价值和更广泛的影响审查标准进行评估来支持。

This research project is a comprehensive theoretical investigation of the abundances and properties of elements within the Solar System. The investigators will update and refine so-called “solar abundances,” which are a fundamental reference for determining the properties of gas and dust in space. Results from the study will allow astronomers to accurately interpret observations of a variety of stellar environments and understand how chemistry influences the formation of stars and planets. This project will train a graduate student and provide research opportunities for undergraduate students. Results from the project are expected to be integrated into textbooks, and they will be broadly applicable to physical sciences besides astrophysics. This work seeks to provide a fundamental framework for interpreting abundances and chemical compositions of gas and dust in stellar environments. The researchers will undertake a detailed assessment of elemental and isotopic compositions of all chondritic meteorites and their components to evaluate and model apparent differences in abundance between the solar photosphere and rare “CI chondrites.” They will then use thermochemical models of gas and condensation chemistry to address the apparent abundance variations of refractory elements between the Sun and other G-type stars. The project is expected to result in a significant update to the Solar System elemental and isotopic abundance reference set derived from meteoritic and solar data. It will also complement spectroscopic studies of the atmospheres and circumstellar shells of evolved stars, as well as the analysis of presolar grains isolated from meteorites.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.