Collaborative Research: Empirical Constraints on the s- and r-processes from Precision Nebular Abundances

合作研究：精确星云丰度对 s 和 r 过程的经验约束

• 批准号: 2307117
• 负责人: Harriet Dinerstein
• 金额: $ 11.27万
• 依托单位: University of Texas at Austin
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-08-01 至 2026-07-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2307117&HistoricalAwards=false
• 关键词: Collaborative; Research; Empirical; Constraints; processes

The origin of elements heavier than the iron-peak elements is an important question in modern astrophysics. The goal of this research project is to better define the relative contributions of the slow (s-) and rapid (r-) neutron(n)-capture processes, which occur respectively in dying Sun-like stars and in mergers of neutron stars, to the cosmic abundances of the trans-iron elements. To achieve that goal, the investigators will measure infrared and optical spectra of the ions of six n-capture elements (Se, Br, Rb, Te, Xe, and Kr) in a diverse sample of planetary nebulae (PNe) in the Milky Way and the Magellanic Clouds. Their analyses will reveal accurate abundances that reflect the amount of each element produced in the star before it became a planetary nebula. Results from the project will advance astronomers’ understanding of nucleosynthesis and galactic chemical evolution. This project will provide authentic research experiences to undergraduate students and support a vibrant program of science outreach to high school students.Using multiple ions of each element, the investigators will derive elemental abundances with far higher precision relative to previous determinations. The robust abundance determinations will yield reliable s-process elemental enrichment factors in Asymptotic Giant Branch (AGB) stars, which are the progenitors of PNe and major s-process sites in stellar populations. Quantifying the s-process contributions in PNe spanning a wide range in progenitor mass and metallicity will allow the investigators to place stringent empirical constraints on the range of r-process contributions to these elements and their candidate sites. It will also allow them to distinguish between different sets of evolutionary and nucleosynthetic models for AGB stars.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.

比铁峰元素重的元素的起源是现代天体物理学中的一个重要问题，该研究项目的目标是更好地定义慢中子 (s-) 和快中子 (n)- 的相对贡献。为了实现这一目标，研究人员将测量六种离子的红外光谱和光谱，这些过程分别发生在垂死的类太阳恒星和中子星的合并中。他们的分析将揭示反映每种元素含量的准确丰度。该项目的结果将促进天文学家对核合成和星系化学演化的理解，并为本科生提供真实的研究经验和支持。一个针对高中生的充满活力的科学推广计划。使用每种元素的多个离子，研究人员将获得相对于之前的测定精度更高的元素丰度，稳健的丰度测定将在渐近巨分支中产生可靠的 s 过程元素富集因子。 (AGB) 恒星，它们是 PNe 的前身和恒星族群中的主要 s 过程位点，量化 PNe 中 s 过程在前身质量和金属丰度范围内的贡献将有助于研究人员。对这些元素及其候选位点的 r 过程贡献范围施加严格的经验限制，这也将使他们能够区分 AGB 恒星的不同组进化和核合成模型。该奖项反映了 NSF 的法定使命，并被视为。值得通过使用基金会的智力优点和更广泛的影响审查标准进行评估来支持。