Chemical Abundances in the Secondary Star in the Black Hole Binary A0620–00
Chemical Abundances in the Secondary Star in the Black Hole Binary A0620–00
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黑洞双星 A0620–00 中副星的化学丰度
DOI：
10.1086/421102
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发表时间：
2004
期刊：
影响因子：
--
通讯作者：
G. Meynet
中科院分区：
文献类型：
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作者：
J. G. González Hernández;R. Rebolo;G. Israelian;J. Casares;A. Maeder;G. Meynet
利用黑洞双星A0620-00中二级星星的高分辨率光谱，我们以一致的方式推导出了恒星参数和吸积盘引起的面纱。我们已经使用了χ2最小化程序来探索800，000 LTE合成光谱的网格，该网格是针对恒星和面纱参数的合理范围计算的。采用找到的最佳模型参数，我们测定了大气中Fe、Ca、Ti、Ni和Al的丰度，得到该星星的Fe丰度为[Fe/H] = 0.14 ± 0.20。除了钙，我们发现其他元素适度过剩相比，在太阳附近的恒星类似的铁含量。考虑到小的轨道分离，质量转移率，和对流区的第二颗星星的质量，与超新星爆炸模型中的元素产量的比较表明，可能的爆炸事件的质量削减相媲美的紧凑对象的当前质量。我们还分析了Li丰度，对于这种光谱类型和相对低质量的星星来说，Li丰度异常高。
Using a high-resolution spectrum of the secondary star in the black hole binary A0620-00, we have derived the stellar parameters and veiling caused by the accretion disk in a consistent way. We have used a χ2 minimization procedure to explore a grid of 800,000 LTE synthetic spectra computed for a plausible range of both stellar and veiling parameters. Adopting the best model parameters found, we have determined atmospheric abundances of Fe, Ca, Ti, Ni, and Al. The Fe abundance of the star is [Fe/H] = 0.14 ± 0.20. Except for Ca, we found the other elements moderately overabundant as compared with stars in the solar neighborhood of similar iron content. Taking into account the small orbital separation, the mass transfer rate, and the mass of the convection zone of the secondary star, a comparison with element yields in supernova explosion models suggests a possible explosive event with a mass cut comparable to the current mass of the compact object. We have also analyzed the Li abundance, which is unusually high for a star of this spectral type and relatively low mass.