RII Track 4: Heavy Element Isotopic Characterization of Stardust

该项目将在实验室中研究微观星尘颗粒，以找到宇宙中元素起源这一最基本问题的答案，并了解构成我们太阳系的材料的性质。这项研究的结果有望带来一种潜在的变革性理解，即超新星和一些鲜为人知的奇异恒星是如何产生重元素的，这些恒星为我们的太阳系提供了启动材料。该奖学金项目将使PI能够与劳伦斯·利弗莫尔国家实验室发展长期合作，使她能够建立一个在高度跨学科领域出类拔萃的富有成效和声誉的宇宙化学实验室，并为路易斯安那大学拉斐特大学新的地球和能源科学多学科博士项目做出贡献。一个成功的项目将使她能够在她所在的大学获得最先进的分析设备，从而增加PI与路易斯安那州和世界各地跨学科科学家的合作。这笔赠款还将用于指导和培训一名未被充分代表的博士生掌握尖端分析技术，这些技术可用于纯研究和/或许多工业应用；从而有助于增加STEM领域多样性的迫切努力。星尘颗粒是真正的微观到亚微观恒星碎片，它们凝聚在垂死恒星的冷却喷射物中，早于我们太阳系的形成。该项目的主要目标是通过研究星尘颗粒中的这些特征，来探测通过核合成在恒星中形成重核的S、r、p和i过程。这一理解不仅将为这些恒星的核合成模型提供更严格的约束，也将为热力学和动力学演化模型提供更严格的约束，这些模型旨在构建这些星尘颗粒凝聚的化学和物理星际环境的清晰图景。在这项奖学金的帮助下，国际和平研究所将获得更多使用劳伦斯利弗莫尔国家实验室(LLNL)新的最先进的中性分子激光电离(LION)共振电离质谱仪(RIMS)设施的机会，并与负责科学家合作。Lion允许PI和她的研究生系统地测量来自超新星的单个微米大小的石墨质星尘颗粒和具有i过程特征的颗粒中重微量元素的同位素组成。RIMS是一种测量重同位素的强大技术，因为它选择性地电离感兴趣的元素并消除同量异压干扰。这位PI和她的研究生将在这一年里花时间在国内机构准备太阳系前的石墨化样品，然后前往LLNL获得对颗粒的测量。为了根据它们的恒星来源来描述这些颗粒的特征，获得的数据将通过与理论天体物理学家的合作与天体物理核合成模型进行比较。这一奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

This project will study microscopic stardust grains in the laboratory to find answers to the most fundamental question of the origin of elements in the Universe and to understand the properties of the materials that formed our solar system. The results from this study promise to bring about a potentially transformative understanding of how heavy elements are created in supernovae and some lesser-known exotic stars that contributed starter materials to our solar system. The fellowship project will allow the PI to develop a long-term collaboration with Lawrence Livermore National Laboratory that will enable her to establish a productive and reputable cosmochemistry laboratory that excels in a highly interdisciplinary field and contribute to the new Earth and Energy Sciences multidisciplinary PhD program at the University of Louisiana Lafayette. A successful project will enable her to obtain state-of-the-art analytical equipment at her university; thus, increasing the PI’s collaborations with interdisciplinary scientists across the state of Louisiana and the world. This grant will also be used to mentor and train an underrepresented PhD student in cutting edge analytical techniques that can be used in pure research and/or numerous industrial applications; thus, contributing to the imperative effort of increasing diversity in STEM fields.Stardust grains are bona fide microscopic to sub-microscopic pieces of stars that condensed in the cooling ejecta of dying stars and pre-date the formation of our solar system. The main goal of this project is to probe s-, r-, p-, and i-processes that make heavy nuclei in stars, via nucleosynthesis, by studying these signatures in stardust grains. This understanding will not only provide tighter constraints on the nucleosynthesis models of these stars but also to the thermodynamic and kinetic evolution models that aim to construct a clear picture of the chemical and physical circumstellar environments in which these stardust grains condensed. With the aid of this fellowship, the PI will gain extended access to the new, state-of-the-art, Laser Ionization of Neutrals (LION) resonant ionization mass spectrometry (RIMS) facility at Lawrence Livermore National Laboratory (LLNL) and collaborate with the scientist-in-charge. LION allows the PI and her graduate student to systematically measure isotopic compositions of heavy trace elements in individual micron-sized graphitic stardust grains from supernovae and grains with i-process signatures. RIMS is a powerful technique to measure heavy isotopes as it selectively ionizes elements of interest and eliminates isobaric interferences. The PI and her graduate student will spend time during the year preparing the presolar graphitic samples at the home institution and then travel to LLNL to acquire measurements on grains. In order to characterize the grains according to their stellar sources, the data obtained will be compared to astrophysical nucleosynthesis models through collaborations with theoretical astrophysicists.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.