论文标题
单个元素对恒星进化等线的敏感性
Individual element sensitivity for stellar evolutionary isochrones
论文作者
论文摘要
使用具有变化丰度比率的恒星演化计算来衡量各个阶段中对温度，亮度和寿命的影响。包括各个元素C，N，O，Mg，Si和Fe。与综合光模型相关的大多数效果都包含在温度变量中，而不是时间表或光度。我们得出了一个配方，用于包括适用于现有等线网格的丰度敏感温度效应。最终增强的等质线被纳入复合恒星种群模型中，并将其与斯隆数字天空调查的星系数据进行了比较。严重的氧气变性很明显，[o/r]中的每0.1 dex 2-3 gyr，其中r代表诸如fe之类的重元素。在早期型星系速度分散范围内，所有丰度比的跨度降低了，但年龄范围会增加，从系统地增加。允许Fe-peak元素自由变化加强这种年龄跨度的增长。总体而言，这些结果使年龄质量相关性升高，称为缩小尺寸，但降低了丰度梯度的陡度。反过来，这两种观察结果都意味着在典型椭圆星系的历史中，无气体合并的贡献更为强大。
Stellar evolution calculations with variable abundance ratios were used to gauge the effects on temperatures, luminosities, and lifetimes in various phases. Individual elements C, N, O, Mg, Si, and Fe were included. Most of the effect relevant to integrated light models is contained in the temperature variable, as opposed to the timescale or luminosity. We derive a recipe for including abundance-sensitive temperature effects that is applicable to existing isochrone grids. The resultant enhanced isochrones are incorporated into composite stellar population models and compared with galaxy data from the Sloan Digital Sky Survey. A severe oxygen-age degeneracy is apparent, 2 - 3 Gyr per 0.1 dex in [O/R], where R represents a heavy element such as Fe. Over the range of early-type galaxy velocity dispersion, the spans of all abundance ratios are reduced but the age range increases, systematically older. Allowing Fe-peak elements the freedom to vary accentuates this increase of age span. Overall, these results sharpen the age-mass correlation known as downsizing but decrease the steepness of abundance ratio gradients. Both of these observations, in turn, imply a more robust contribution from gas free mergers in the histories of typical elliptical galaxies.
