A Re-examination of Stellar Opacities and Implications for Solar Models

AST-0907763 Pradhan该奖项由2009年美国复苏和再投资法案（公法111-5）资助。恒星不透明度是恒星模型中的基本量。 近年来出现了一种令人费解的太阳丰度异常，一方面是光谱和最复杂的大气模型得出的轻元素丰度，另一方面是与极其精确的日震观测相一致的内部模型。 增加10-20%的不透明度也许可以调和目前不同的模型，本项目的主要目的是调查模型的准确性，并测试这一建议，重点是对不透明度进行详细的定量重新评估。 这项工作需要更精确和更广泛的原子计算，包括相对论效应、“化学图像”中改进的状态方程、单色和平均不透明度的高分辨率计算以及辐射加速。 新的不透明度代码将与电子数据服务器连接，以便有效地分发。不透明度和辐射加速度的计算是原子物理学、等离子体物理学和天体物理学中的一项共生练习。 虽然这些结果在许多恒星研究中通常是有用的，但影响将更广泛。 大规模高精度的原子数据在星云、活动星系核、超新星和其他天体的光谱分析中非常有用，在核聚变等离子体诊断、激光-原子相互作用和基于同步加速器光源的光电离研究中也非常有用。 更一般地说，原子物理学中的这些先进方法涵盖了从大气研究到能源技术的重要科学。

AST-0907763PradhanThis award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).Stellar opacity is the fundamental quantity in stellar models. In recent years an inexplicable solar abundances anomaly has emerged, between light element abundances derived spectroscopically and from the most sophisticated atmospheres models, on the one hand, and interior models consistent with extremely accurate helioseismological observations, on the other hand. An increase in opacity of 10-20% could perhaps reconcile the currently divergent models, and the primary aim of this project is to investigate the accuracy of the models and test this suggestion, focusing on a detailed quantitative re-assessment of opacities. The work entails more accurate and extensive atomic calculations, including relativistic effects, an improved equation of state in the "chemical picture", and high-resolution computation of monochromatic and mean opacities, and radiative accelerations. The new opacities codes will be interfaced with an electronic data server for efficient distribution.The calculation of opacities and radiative accelerations is a symbiotic exercise in atomic physics, plasma physics, and astrophysics. Although the results will be generally useful in many stellar studies, the impact will be much wider. Large-scale high-accuracy atomic data are useful in spectral analysis of nebulae, active galactic nuclei, supernovae, and other astronomical objects, and also very helpful in nuclear fusion plasma diagnostics, laser-atom interactions, and photoionization studies on synchrotron based light sources. Even more generally, these advanced methods in atomic physics cover important science from atmospheric research to energy technology.