标题： 室女α：线轮廓变化与轨道元素 显示英文标题

标题： Alpha Virginis: line-profile variations and orbital elements

摘要： 简明版：室女座α（天蝎座）是一个双星系统，由于其接近性和亮度，可以详细研究经历时变潮汐相互作用的恒星的内部结构和演化。 先前的研究得出结论，室女座主星的内部结构可能比单星理论模型预测的更加中心凝聚，这表明这些相互作用可能导致目前结构和演化计算中忽略的影响。 确认这一结果的关键参数是轨道偏心率 $e$、近日点周期 $U$和主星半径 R_1 的值。 我们分析了线轮廓变异性对轨道元素及其 R_1 推导的影响。 我们使用2000年、2008年和2013年获得的高信噪比观测数据，通过拟合视向速度曲线来推导轨道元素。 我们使用从头开始的潮汐相互作用模型生成合成线轮廓。 结果： 线轮廓的变化可以用潮汐流来解释，其在旋转双星参考系中的大尺度结构相对固定。 对视向速度曲线的拟合得到 $e$=0.108$\pm$0.014。 然而，理论上基于线轮廓的类似视向速度曲线表明，线的畸变导致 $e$的拟合值依赖于近地点幅角；即，观测时刻。 因此，实际的 $e$值可能高达 0.125。 我们发现$U$= 117.9$\pm$1.8，这与先前的测定结果一致。使用由 Palate 等人（2013）得出的值$R_1=6.8 R_\odot$，观测到的内部结构常数$k_{2,obs}$的值与理论相符。我们证实了次级星谱线轮廓存在变化。 显示英文摘要

摘要： Abridged: Alpha Virginis is a binary system whose proximity and brightness allow detailed investigations of the internal structure and evolution of stars undergoing time-variable tidal interactions. Previous studies have led to the conclusion that the internal structure of Spica's primary star may be more centrally condensed than predicted by theoretical models of single stars, raising the possibility that the interactions could lead to effects that are currently neglected in structure and evolution calculations. The key parameters in confirming this result are the values of the orbital eccentricity $e$, the apsidal period $U$, and the primary star's radius, R_1. We analyze the impact that line profile variability has on the derivation of its orbital elements and R_1. We use high SNR observations obtained in 2000, 2008, and 2013 to derive the orbital elements from fits to the radial velocity curves. We produce synthetic line profiles using an ab initio tidal interaction model. Results: The variations in the line profiles can be understood in terms of the tidal flows, whose large-scale structure is relatively fixed in the rotating binary system reference frame. Fits to the radial velocity curves yield $e$=0.108$\pm$0.014. However, the analogous RV curves from theoretical line profiles indicate that the distortion in the lines causes the fitted value of $e$ to depend on the argument of periastron; i.e., on the epoch of observation. As a result, the actual value of $e$ may be as high as 0.125. We find that $U$=117.9$\pm$1.8, which is in agreement with previous determinations. Using the value $R_1=6.8 R_\odot$ derived by Palate et al. (2013) the value of the observational internal structure constant $k_{2,obs}$ is consistent with theory. We confirm the presence of variability in the line profiles of the secondary star.