Accurate Stellar Opacities To Solve Astrophysical Problems

精确的恒星不透明度解决天体物理问题

• 批准号: 1409207
• 负责人: Anil Pradhan
• 金额: $ 44.01万
• 依托单位: Ohio State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-09-01 至 2020-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1409207&HistoricalAwards=false
• 关键词: Accurate; Stellar; Opacities; Solve; Astrophysical

In order to carry out any detailed study of nature on large scales, we often require a precise understanding of the microscopic processes that govern our universe. One of these, called opacity, measures the precise way that electromagnetic radiation (light, in all of its forms) interacts with atoms, molecules, and free-floating subatomic particles. Recent results from studies of the Sun's interior indicate that previous calculations of the relative abundance of the elements are off by an uncomfortable amount. The PI and his collaborators are world leaders in the field of laboratory astrophysics. They will improve the accuracy of opacity calculations guided by results from computer models of stellar interiors, by recent experimental physics results, and by including effects that were previously omitted. While it is primarily theoretical, this work has a very broad range of practical applications in and beyond astrophysics. These include nuclear fusion and medical physics. The PI is active in several programs promoting collaborative US-India efforts in STEM education. This project will involve specialized training of a postdoctoral fellow in this multi-disciplinary research.The PI will lead an effort to properly account for bound-free autoionization resonances and calculate mean opacities for a variety of compositions using improved atomic data and a new high-precision version of the Opacity Project codes. Recent helioseismology results, results from the Z-pinch inertial fusion device at Sandia National Laboratory, and re-examination of current opacities all suggest that true opacities are significantly higher than current models. This work could lead to the solution of the "solar abundance problem", and it is all but guaranteed to lead to improvements in fundamental atomic physics, the equation of state appropriate for stellar interiors that incorporates opacities of elements produced in r-process nucleosynthesis, and improved Rosseland and Planck mean opacities. It is a continuation and extension of prior successful work by the PI and his collaborators, guided by recent measurements and by improvements in computational techniques. Results will be made available to the physics, chemistry, and astrophysics communities via electronic databases.

为了在大尺度上对自然进行任何详细的研究，我们通常需要精确地了解支配我们宇宙的微观过程。 其中之一，称为不透明度，测量电磁辐射（所有形式的光）与原子，分子和自由浮动的亚原子粒子相互作用的精确方式。 最近对太阳内部的研究结果表明，以前对元素相对丰度的计算偏离了一个令人不安的数量。 PI和他的合作者是实验室天体物理学领域的世界领导者。 它们将提高恒星内部计算机模型结果、最近的实验物理结果以及包括以前忽略的影响所指导的不透明度计算的准确性。 虽然它主要是理论性的，但这项工作在天体物理学内外都有非常广泛的实际应用。 其中包括核聚变和医学物理学。 PI积极参与多个项目，促进美印在STEM教育方面的合作。 该项目将对一名博士后进行多学科研究的专门培训。PI将领导一项工作，利用改进的原子数据和新的高精度版本的不透明度项目代码，正确解释束缚-自由自电离共振，并计算各种成分的平均不透明度。 最近的日震学结果，桑迪亚国家实验室的Z箍缩惯性聚变装置的结果，以及对当前不透明度的重新检查都表明，真正的不透明度明显高于当前的模型。 这项工作可能会导致解决“太阳丰度问题”，这是所有，但保证导致改进基本原子物理学，状态方程适合恒星内部，纳入r-过程核合成中产生的元素的不透明度，并改善Rosseland和普朗克平均不透明度。 它是PI及其合作者先前成功工作的延续和扩展，由最近的测量和计算技术的改进指导。 研究结果将通过电子数据库提供给物理、化学和天体物理学界。