标题： 双黑洞双星系统天蝎座新星1994（GRO J1655-40）：改进的化学分析 显示英文标题

标题： The Black Hole Binary Nova Scorpii 1994 (GRO J1655-40): An improved chemical analysis

摘要： 次级恒星的化学分析为研究致密天体（黑洞或中子星）的形成过程提供了机会。在发现室女座新星1994年次级恒星的HIRES/Keck光谱中存在过量的$\alpha$元素之后，我们获得了UVES/VLT高分辨率光谱，目的是对这个次级恒星进行详细的丰度分析。使用$\chi2$最小化程序和合成光谱网格，我们利用新的UVES光谱和HIRES光谱推导出O、Mg、Al、Ca、Ti、Fe和Ni的恒星参数和大气丰度。Al、Ca、Ti、Fe和Ni的丰度似乎与太阳值一致，而Na，尤其是O、Mg、Si和S则明显高于这些元素的银河系趋势。与球对称和非球对称超新星爆炸模型比较可能为模型参数（如质量切割和爆炸能量）提供严格的约束，特别是从Si、S、Ca、Ti、Fe和Ni的相对丰度来看。最有可能的是，这个系统中的黑洞形成于一个30-35\Msun 的前体恒星的超新星爆炸，质量切割范围在2-3.5\Msun 。然而，这些模型产生的Al和Na丰度比观测值高出近十倍。 显示英文摘要

摘要： The chemical analysis of secondary stars of low mass X-ray binaries provides an opportunity to study the formation processes of compact objects, either black holes or neutron stars. Following the discovery of overabundances of $\alpha$-elements in the HIRES/Keck spectrum of the secondary star of Nova Scorpii 1994 (Israelian et al. 1999), we obtained UVES/VLT high-resolution spectroscopy with the aim of performing a detailed abundance analysis of this secondary star. Using a $\chi2$-minimization procedure and a grid of synthetic spectra, we derive the stellar parameters and atmospheric abundances of O, Mg, Al, Ca, Ti, Fe and Ni, using a new UVES spectrum and the HIRES spectrum.The abundances of Al, Ca, Ti, Fe and Ni seem to be consistent with solar values, whereas Na, and especially O, Mg, Si and S are significantly enhanced in comparison with Galactic trends of these elements. A comparison with spherically and non-spherically symmetric supernova explosion models may provide stringent constraints to the model parameters as mass-cut and the explosion energy, in particular from the relative abundances of Si, S, Ca, Ti, Fe and Ni. Most probably the black hole in this system formed in a hypernova explosion of a 30--35 \Msun progenitor star with a mass-cut in the range 2--3.5 \Msun. However, these models produce abundances of Al and Na almost ten times higher than the observed values.