Occurrence of instability through the protostellar accretion disks by landing of low-mass condensations
Occurrence of instability through the protostellar accretion disks by landing of low-mass condensations
复制标题
低质量凝结着陆导致原恒星吸积盘发生不稳定
DOI：
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发表时间：
2016
期刊：
影响因子：
--
通讯作者：
M. Nejad
中科院分区：
文献类型：
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作者：
Mahjubeh Elyasi;M. Nejad
在坍缩的分子云核心的包络层内观察到低质量凝聚现象。在本研究中，我们研究了着陆lmc对原恒星吸积盘发生不稳定性的影响。我们考虑了一些区域，其中lmc的下降和着陆时间比轨道周期短。这样，我们就可以把着陆的lmc看作是初始的薄轴对称稳态自引力原恒星吸积盘（近似开普勒）在方位角方向上的密度凸起和沟槽。利用碰撞量的线性效应，我们得到了碰撞生长/衰减率的特征方程；我们对其进行数值求解以找出不稳定性的发生。我们还评估了最小生长时间尺度（MGTS）和增强的质量吸积率。结果表明，相对于原恒星吸积盘的外部区域，lmc在原恒星吸积盘内部区域的落入和降落会导致更快的不稳定模式和更小的吸积速率增强。此外，着陆点在方位角上破碎程度越高，不稳定的可能性越小，从而产生的质量吸积率增强值越大。
Low-mass condensations (LMCs) are observed inside the envelope of the collapsing molecular cloud cores. In this research, we investigate the effects of landing LMCs for occurrence of instability through the protostellar accretion disks. We consider some regions of the disk where duration of infalling and landing of the LMCs are shorter than the orbital period. In this way, we can consider the landing LMCs as density bumps and grooves in the azimuthal direction of an initial thin axisymmetric steady state self-gravitating protostellar accretion disk (nearly Keplerian). Using the linear effects of the bump quantities, we obtain a characteristic equation for growth/decay rate of bumps; we numerically solve it to find occurrence of instability. We also evaluate the minimum-growth-time-scale (MGTS) and the enhanced mass accretion rate. The results show that infalling and landing of the LMCs in the inner regions of the protostellar accretion disks can cause faster unstable modes and less enhanced accretion rates relative to the outer regions. Also, more fragmentation of landed LMCs in the azimuthal direction have less chance for instability, and then can produce more values of enhanced mass accretion rate.
DOI：
10.1088/0067-0049/188/1/139
发表时间：
2010-04
期刊：
The Astrophysical Journal Supplement Series
影响因子：
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作者：
R. Launhardt;D. Nutter;D. Ward-Thompson;T. Bourke;T. Henning;T. Khanzadyan;T. Khanzadyan;M. Schmalzl;S. Wolf;S. Wolf;R. Zylka
通讯作者：
R. Launhardt;D. Nutter;D. Ward-Thompson;T. Bourke;T. Henning;T. Khanzadyan;T. Khanzadyan;M. Schmalzl;S. Wolf;S. Wolf;R. Zylka