MASS TRANSFER IN BINARY STARS USING SMOOTHED PARTICLE HYDRODYNAMICS. II. ECCENTRIC BINARIES
MASS TRANSFER IN BINARY STARS USING SMOOTHED PARTICLE HYDRODYNAMICS. II. ECCENTRIC BINARIES
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使用平滑粒子流体动力学进行双星中的质量传递。
DOI：
10.1088/0004-637x/726/2/67
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发表时间：
2010
期刊：
影响因子：
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通讯作者：
A. Sills
中科院分区：
文献类型：
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作者：
C. Lajoie;A. Sills
尽管为更好地理解双星演化做出了许多努力，但双星演化的某些方面仍然没有得到很好的限制。特别是，偏心双星的演化仍然难以捉摸，主要是因为圆形双星的罗氏叶形式论并不适用。在这里，我们报告了我们使用另一种方法对偏心双星中质量传递的平滑粒子流体动力学模拟的结果，在该方法中，我们只对具有适当边界条件的恒星的最外层进行建模。利用这项技术，结合适当松弛的模型恒星，我们表征了具有不同轨道参数的双星的质量转移幕。特别是，我们证明了这些事件可以用∼0.12Porb的半高宽高斯来描述，并且峰值速率出现在近星体之后，在轨道相∼0.58时，与恒星的偏心率和质量无关。观察到，这种聚积的物质在其中一颗恒星或两颗恒星周围形成了一个相当稀疏的包层。尽管在我们的模拟中没有模拟这个包层的命运，但我们证明了被转移的材料的恒定比例(∼5%)被从系统中弹出。我们用非保守的传质情景来讨论这一结果。我们建议，我们的结果可以结合到分析和双星群合成研究中，以帮助更好地理解偏心双星的演化和奇异恒星群的形成。
Despite numerous efforts to better understand binary star evolution, some aspects of it remain poorly constrained. In particular, the evolution of eccentric binaries has remained elusive mainly because the Roche lobe formalism derived for circular binaries does not apply. Here we report the results of our smoothed particle hydrodynamic simulations of mass transfer in eccentric binaries using an alternate method in which we model only the outermost layers of the stars with appropriate boundary conditions. Using this technique, along with properly relaxed model stars, we characterize the mass transfer episodes of binaries with various orbital parameters. In particular, we show that these episodes can be described by Gaussians with an FWHM of ∼0.12Porb and that the peak rates occur after periastron, at an orbital phase of ∼0.58, independently of the eccentricity and mass of the stars. The accreted material is observed to form a rather sparse envelope around either or both stars. Although the fate of this envelope is not modeled in our simulations, we show that a constant fraction (∼5%) of the material transferred is ejected from the systems. We discuss this result in terms of the non-conservative mass transfer scenario. We suggest that our results could be incorporated in analytical and binary population synthesis studies to help better understand the evolution of eccentric binaries and the formation of exotic stellar populations.