Transition probabilities of trans-iron elements

反式铁元素的转变概率

• 批准号: 386405709
• 负责人: Dr. Thomas Rauch
• 金额: --
• 依托单位: Abteilungen Astronomie und Hochenergieastrophysik
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2017
• 资助国家: 德国
• 起止时间: 2016-12-31 至 2023-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/386405709?language=en
• 关键词: Transition; probabilities; trans; iron; elements

For the quantitative spectral analysis of hot, compact stars, model atmospheres that consider deviations from the local thermodynamical equilibrium (LTE) are mandatory. In contrast to LTE where the occupations numbers of atomic levels are calculated via Saha and Boltzmann equations, in the so-called non-LTE, they have to be calculated in detail. A pre-requisite therefor is accurate data for all radiative and collisional transitions. This includes line transitions, i.e. radiative bound-bound transitions between the atomic levels. Precise oscillator strengths are necessary for all line transitions in the model atom that represents an element in the model-atmosphere calculation. The data quality is crucial for the precision of abundance determinations.The recent discovery of elements that are heavier that iron in a white dwarf allowed for the first time to determine the abundance of so-called trans-iron elements in evolved stars. This was only possible after the calculation of oscillator strengths. We propose in this project to extend the calculation of oscillator strengths to a large part of the trans-iron elements (copper to barium) and to calculate homogeneous data for the ionization stages III to VII, i.e. 2+ to 6+.The newly calculated oscillator strengths allow for the first time the abundance analysis of these elements in stars in the final phase of their evolution. This enables us to establish boundary conditions for the s-process nucleosynthesis, i.e. the creation of trans-iron elements by neutron captures.

对于热致密恒星的定量光谱分析，考虑偏离局部热力学平衡（LTE）的模型大气是强制性的。与通过Saha和Boltzmann方程计算原子能级的占据数的LTE相反，在所谓的非LTE中，它们必须详细计算。一个先决条件是所有辐射和碰撞跃迁的准确数据。这包括线跃迁，即原子能级之间的辐射束缚-束缚跃迁。精确的振子强度对于代表模型大气计算中的元素的模型原子中的所有谱线跃迁是必要的。数据质量对丰度测定的精确性至关重要。最近在一颗白色矮星中发现了比铁更重的元素，这使得人们首次能够确定演化恒星中所谓的反式铁元素的丰度。这只有在计算振子强度之后才有可能。我们建议在这个项目中的振子强度的计算扩展到大部分的反式铁元素（铜钡），并计算均匀的数据的电离阶段III至VII，即2+至6+。新计算的振子强度允许第一次的丰度分析，这些元素在恒星的最后阶段，他们的演变。这使我们能够建立边界条件的s-过程核合成，即创造反式铁元素的中子捕获。