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arXiv 0903.1206astro-ph.SR
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双星非同步自转引起的潮汐流

Tidal Flows from Asynchronous Rotation in Binaries

Gloria Koenigsberger, Edmundo Moreno, David Harrington

摘要:

双星的非同步旋转产生了非径向振荡,这是已知的轨道时间尺度上可观测到的变化。表面速度场的水平扰动称为"潮汐流"。在本文中,我们说明了潮汐流扰动的方式,从均匀旋转的表面速度场,使用一层恒星模型的计算。我们证明了这个简化模型的有效性,它预测的光球吸收线轮廓和观测数据的二进制系统室女座α之间的惊人的相似性。速度摄动被用来计算机械能耗散率,点E,由于剪切流的情况下,一个大规模的(50 + 28 Mo)的二元系统具有中等偏心(e = 0.3)的轨道。近星相点E的最大值出现在面对伴星的半球上。然而,在其他轨道阶段,最大点E可能会向两极迁移。假设点E在大质量双星系统的质量损失特征中起作用,这表明特殊的双星,如HD 5980和船底座η星可能具有高度非球对称的质量损失分布,此外,它是随时间变化的。

英文摘要:

Asynchronous rotation in binary stars produces non-radial oscillations that are known to cause observable variability on orbital timescales. The horizontal perturbations of the surface velocity fields are referred to as "tidal flows". In this paper we illustrate the manner in which tidal flows perturb the surface velocity field from that of uniform rotation, using a one-layer stellar model for the calculations. We justify the validity of this simplified model by the striking similarity between the photospheric absorption line-profiles it predicts and observational data of the binary system alpha Virginis. The velocity perturbations are used to compute the mechanical energy dissipation rates, dot-E, due to the shearing flows for the case of a massive (50+28 Mo) binary system having a moderately eccentric (e=0.3) orbit. The largest value of dot-E around periastron phases is found on the hemisphere facing the companion. However, at other orbital phases the maximum dot-E may migrate towards the poles. Assuming that dot-E plays a role in the mass-loss characteristics of massive binary systems, this suggests that peculiar binaries such as HD 5980 and eta Carinae may have a highly non-spherically symmetric mass-loss distribution which, in addition, is time-variable.

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。

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