发表机构
University of Warwick; University of Auckland（华威大学; 奥克兰大学）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
针对BPASS最新单星模型重新校准并扩展了主序星解析演化公式，覆盖大质量恒星及[α/Fe]变化，显著提高寿命、半径和光度拟合精度。
AI 中文摘要
解析公式是近似计算给定质量和化学组成恒星演化的有效方法，在文献中被广泛用于计算恒星种群合成所需的大规模演化模型网格。此类公式依赖于对详细恒星演化模型的校准，而现有版本基于的网格相比现代模拟而言稀疏且有限。通过针对在双星种群与光谱合成（BPASS）框架内计算的最新一代单星演化模型进行校准，我们修订并扩展了已有公式，以涵盖大质量（M≳50 M☉）恒星的演化以及以[α/Fe]变化形式体现的化学丰度变化。我们引入了额外项，以更好地近似主序星寿命，以及主序开始和结束时的光度与半径。这些修订后的公式描述了主序年龄、零龄主序和终龄主序的半径与光度，除终龄主序半径外，所有量的平均误差均小于10%或0.05 dex，而终龄主序半径的均方根误差为20%和0.1 dex。对于[α/Fe]增丰的恒星种群，我们建议在公式中使用匹配铁丰度的金属量，这与铁是影响主序星演化的主要不透明度来源的预期一致。
英文摘要
Analytic formulae are an efficient way to approximate the evolution of a star of a given mass and chemical composition, and are widely used in the literature to compute large grids of evolutionary models for stellar population synthesis. Such formulae rely on calibration to detailed stellar evolution models, and existing versions are based on a sparse, limited grid in comparison to modern simulations. By calibrating against the latest generation of single-star evolution models calculated within the Binary Population and Spectral Synthesis (\bpass) framework, we revise and extend pre-existing equations to include the evolution of massive ($M\gtrsim50\,$\msun) stars and changes in chemical abundances in the form of variations in \afe. We introduce additional terms which allow for a better approximation of the main-sequence lifetimes, and the luminosities and radii at the beginning and end of the main sequence. These revised equations describe the main-sequence age, zero-age and terminal-age radius and luminosity with mean errors of less than 10 per cent or 0.05 dex, for all except the terminal age radius, which shows RMS errors of 20 per cent and 0.1 dex. For \afe\ enriched stellar populations, we advise using a matched-iron value for metallicity in the equations, consistent with the expectation that iron is the dominant opacity source affecting the evolution of main-sequence stars.
CommentsAccepted for publication in MNRAS. 18 pages, 13 figures, 1 table, plus appendices (12 pages, 7 tables 12 figures) Python functions to evaluate the equations are available at https://warwick.ac.uk/fac/sci/physics/research/astro/people/conorbyrne/byrne26_equations.py and a Fortran version is available at https://warwick.ac.uk/fac/sci/physics/research/astro/people/conorbyrne/byrne26_equations.f90
