AW UMa的时间序列光谱学。518 nm Mg I三重态区的展宽函数分析
Time sequence spectroscopy of AW UMa. The 518 nm Mg I triplet region analyzed with Broadening Functions
摘要：
AW UMa的高分辨率光谱观测，获得了连续三个晚上的中位数时间分辨率为2.1分钟，已被分析使用的展宽函数方法的频谱窗口多普勒图像的系统揭示了存在的激烈的质量运动的二元系统内，他们的存在提出了问题的接触二元模型的固体旋转假设。AW UMa看起来是一个非常紧密的半分离双星，质量从质量较大的部分转移到质量较小的部分。主星是一颗快速旋转的恒星，V sin i = 181.4+ 2.5 km s^-1，它被不均匀性所覆盖：非常缓慢地漂移的斑点和密集的涟漪网络更紧密地参与了它的旋转。主星的谱线显示出一个额外的增宽成分（称为“基座”），它要么起源于比恒星其他部分快约50 km/s的赤道区，要么起源于外部盘状结构。二次分量似乎比接触模型预测的要小。次级周围的径向速度场主要由从初级组件转移（并可能部分返回）的物质的吸积所控制。二进制的参数是：A sin i = 2.73 +/- 0.11 R_odot和M_1 sin^3 i = 1.29 +/- 0.15 M_odot，M_2 sin^3 i = 0.128 +/- 0.016 M_odot。质量比q_rmsp = M_2/M_1 = 0.099 +/- 0.003，虽然仍然是光谱元素中最不确定的，但与以前基于接触模型的众多相互一致的光度学研究有很大不同。应该研究为什么测光和光谱给出如此非常不一致的结果，以及AW UMa是否是一个不寻常的对象，或者只有非常高质量的光谱才能揭示W UMa型双星的真实性质。
英文摘要：
High resolution spectroscopic observations of AW UMa, obtained on three consecutive nights with the median time resolution of 2.1 minutes, have been analyzed using the Broadening Functions method in the spectral window Doppler images of the system reveal the presence of vigorous mass motions within the binary system; their presence puts into question the solid-body rotation assumption of the contact binary model. AW UMa appears to be a very tight, semi-detached binary; the mass transfer takes place from the more massive to the less massive component. The primary, a fast-rotating star with V sin i = 181.4+\-2.5 km s^-1, is covered by inhomogeneities: very slowly drifting spots and a dense network of ripples more closely participating in its rotation. The spectral lines of the primary show an additional broadening component (called the "pedestal") which originates either in the equatorial regions which rotate faster than the rest of the star by about 50 km s^-1 or in an external disk-like structure. The secondary component appears to be smaller than predicted by the contact model. The radial velocity field around the secondary is dominated by accretion of matter transferred from (and possibly partly returned to) the primary component. The parameters of the binary are: A sin i = 2.73 +/- 0.11 R_odot and M_1 sin^3 i = 1.29 +/- 0.15 M_odot, M_2 sin^3 i = 0.128 +/- 0.016 M_odot. The mass ratio q_rm sp = M_2/M_1 = 0.099 +/- 0.003, while still the most uncertain among the spectroscopic elements, is substantially different from the previous numerous and mutually consistent photometric investigations which were based on the contact model. It should be studied why photometry and spectroscopy give so very discrepant results and whether AW UMa is an unusual object or that only very high-quality spectroscopy can reveal the true nature of W UMa-type binaries.
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