Interstellar Abundance Standards Revisited
Interstellar Abundance Standards Revisited
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DOI：
10.1086/321715
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发表时间：
2001-06
期刊：
影响因子：
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通讯作者：
U. Sofia;D. Meyer
中科院分区：
文献类型：
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作者：
U. Sofia;D. Meyer
我们评估通常用于表示星际介质总（气体加尘埃）组成的恒星丰度。将已发表的 B 型恒星、年轻的晚期型（F 和 G）型恒星以及太阳的丰度与星际介质的模拟尘埃相和测量的气相成分进行了比较。这项研究使用了尘埃颗粒中含量最多的五种元素（C、O、Mg、Si 和 Fe）以及宇宙中含量丰富的元素 N 的丰度。我们发现 B 星的金属丰度太低，无法被视为星际介质的有效表示。最近的观测也拒绝了通常引用的太阳成分三分之二的星际标准。然而，不能排除年轻（≤2 Gyr）F 和 G 盘恒星以及太阳作为总星际成分的可靠代表。如果它们的丰度是星际介质的有效代表，那么相对于尘埃模型所需的碳含量明显不足，即碳危机，就会大大缓解。
We evaluate the stellar abundances often used to represent the total (gas plus dust) composition of the interstellar medium. Published abundances for B stars, young later type (F and G) stars, and the Sun are compared to the modeled dust-phase and measured gas-phase compositions of the interstellar medium. This study uses abundances for the five most populous elements in dust grains—C, O, Mg, Si, and Fe—and the cosmically abundant element, N. We find that B stars have metal abundances that are too low to be considered valid representations of the interstellar medium. The commonly invoked interstellar standard that is two-thirds of the solar composition is also rejected by recent observations. Young (≤2 Gyr) F and G disk stars and the Sun, however, cannot be ruled out as reliable proxies for the total interstellar composition. If their abundances are valid representations of the interstellar medium, then the apparent underabundance of carbon with respect to that required by dust models, i.e., the carbon crisis, is substantially eased.