arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 1809.04061astro-ph.SR
收藏

V478 Cyg，AH Cep，V453 Cyg和V578 Mon四颗主序星中大质量恒星的物理性质和CNO丰度

Physical properties and CNO abundances for high-mass stars in four main-sequence detached eclipsing binaries: V478 Cyg, AH Cep, V453 Cyg and V578 Mon

K. Pavlovski, J. Southworth, E. Tamajo

备注：
Accepted for publication in MNRAS
阅读 PDF
arXiv 页面 ↗HTML 原文 ↗

摘要：

探索大质量恒星理论演化模型的前提是高精度地确定恒星的物理性质。我们这样做的三个二元系统包含的组件质量超过10 Msun：V478 Cyg，AH Cep和V453 Cyg。新的高分辨率和高信噪比的阶梯光栅光谱被获得，并使用光谱解缠进行分析，产生了改进的轨道要素和组成星的单独光谱。结合对档案光变曲线的重新分析，恒星质量和半径的测量精度分别为1.5-2.5%和1.0- 1.9%。详细的光谱分析，然后得出大气参数和丰度的C，N，O，Mg和Si。还测定了V578 Mon的丰度。这些结果允许详细比较恒星演化模型的预测。在我们的样本中，没有一颗恒星的动力学质量符合它在演化轨道上的位置，这使得质量差异（或者说过光度）在理论建模中成为一个悬而未决的问题。此外，CNO丰度聚集在初始值附近，平均值log（N/C）= -0.56 +/- 0.06和log（N/O）= -1.01 +/- 0.06。没有趋势的CNO丰度的单OB星被发现在这里分析的八个大质量的恒星，以及在一个扩展的样本，包括文献的结果。这打开了一个重要的问题，在阻尼内部混合的恒星居住在双星系统的潮汐方面的作用。

英文摘要：

A prerequisite for probing theortical evolutionary models for high-mass stars is the determination of stellar physical properties with a high accuracy. We do this for three binary systems containing components with masses above 10 Msun: V478 Cyg, AH Cep and V453 Cyg. New high-resolution and high-S/N echelle spectra were secured and analysed using spectral disentangling, yielding improved orbital elements and the individual spectra for the component stars. In conjuction with a re-analysis of archival light curves, the stellar masses and radii were measured to accuracies of 1.5-2.5% and 1.0-1.9%, respectively. Detailed spectroscopic analysis then yielded atmospheric parameters and abundances for C, N, O, Mg and Si. Abundances were also deter- mined for V578 Mon. These results allowed a detailed comparison to the predictions of stellar evolutionary models. No star in our sample fits its position on the evolutionary track for its dynamical mass, leaving mass discrepancy (or alternatively overluminosity) an open problem in theoretical modelling. Moreover, the CNO abundances cluster around the initial values with mean values log(N/C) = -0.56 +/- 0.06 and log(N/O) = -1.01 +/- 0.06. No trend in the CNO abundances for single OB stars are found for the eight high-mass stars analysed here, as well in an extended sample including literature results. This opens an important question on the role of binarity in terms of tides on damping internal mixing in stars residing in binary systems.

机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。

↑