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arXiv 1904.00985astro-ph.EP
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用KH 15 D对准偏心双星周围的环双星盘

Alignment of a circumbinary disc around an eccentric binary with application to KH 15D

Jeremy L. Smallwood, Stephen H. Lubow, Alessia Franchini, Rebecca G. Martin

摘要:

我们分析了一个温和的倾斜circumbinary光盘,轨道偏心轨道的二进制通过平滑粒子流体动力学(SPH)模拟和线性理论的演变。我们发现,最初未对准的circumbinary光盘周围的偏心轨道二进制的对齐过程是显着不同的比周围的圆形轨道二进制,并涉及倾斜振荡。双星的偏心度越大,倾斜振荡就越大,阻尼这些振荡所需的时间也就越长。仅轻微倾斜的环双星盘在走向对齐之前可能会将其倾斜度增加几倍。SPH模拟的结果与线性理论的结果吻合得很好。本文研究了KH 15 D周围的环双星盘/环的性质。我们确定光盘属性的观测约束的基础上所施加的不断变化的二进制亮度。我们发现,目前的倾斜度是在一个局部最小值,并将大大增加之前设置为共面性。此外,交点岁差目前接近其最快的速度。最近的观测表明,B星的重现对遮蔽材料层的厚度施加了限制。我们的研究结果表明,光盘固体已经经历了大量的向内漂移和解决对光盘中平面。对于椎间盘肿块$\sim 0.001 M_\odot$,我们的模型表明椎间盘湍流水平较低,为$α\ll 0.001$。另一种可能性是盘/环包含很少的气体。

英文摘要:

We analyse the evolution of a mildly inclined circumbinary disc that orbits an eccentric orbit binary by means of smoother particle hydrodynamic (SPH) simulations and linear theory. We show that the alignment process of an initially misaligned circumbinary disc around an eccentric orbit binary is significantly different than around a circular orbit binary and involves tilt oscillations. The more eccentric the binary, the larger the tilt oscillations and the longer it takes to damp these oscillations. A circumbinary disc that is only mildly inclined may increase its inclination by a factor of a few before it moves towards alignment. The results of the SPH simulations agree well with those of linear theory. We investigate the properties of the circumbinary disc/ring around KH 15D. We determine disc properties based on the observational constraints imposed by the changing binary brightness. We find that the inclination is currently at a local minimum and will increase substantially before setting to coplanarity. In addition, the nodal precession is currently near its most rapid rate. The recent observations that show a reappearance of Star B impose constraints on the thickness of the layer of obscuring material. Our results suggest that disc solids have undergone substantial inward drift and settling towards to disc midplane. For disc masses $\sim 0.001 M_\odot$, our model indicates that the level of disc turbulence is low $α\ll 0.001$. Another possibility is that the disc/ring contains little gas.

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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