The early evolution of protostellar disks
The early evolution of protostellar disks
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原恒星盘的早期演化
DOI：
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发表时间：
1994
期刊：
影响因子：
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通讯作者：
J. Touma
中科院分区：
文献类型：
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作者：
S. Stahler;D. Korycansky;J. Touma
我们考虑的起源和初始生长的磁盘，形成在原恒星周围的旋转分子云核心崩溃。这些圆盘被假定为无粘性和无压力的，并且与它们的中心恒星相比质量很小。我们发现，有三个不同的组成部分，一个外盘，在冲击气体运动与可比的方位角和径向速度;和内盘，在那里的材料遵循近圆形轨道，但螺旋缓慢地向星星，因为相邻的物质所施加的阻力，和湍流环毗邻的前两个区域。在进化的早期，即，在下落物质开始与星星擦肩而过后不久，只剩下外盘，而到达原星星上的总质量加速率并没有减小。一旦外盘边界增长到超过恒星半径的2.9倍，首先是环，然后是内盘。此后，所有三个分量的半径扩展为t（exp 3）。环的质量随着时间的推移而增加，并且总是从云中落下的总质量的13%。与内盘和环的形成同时，对星星的吸积速率福尔斯下降。然而，原恒星的质量继续增加，渐近为t（exp 1/4）。我们计算了由于引力势能的释放而引起的内外盘辐射通量。来自内盘的通量占主导地位，并朝着恒星表面急剧上升。我们还确定了作为半径的函数的内盘的表面温度。总光度随时间缓慢下降，而来自环和内盘的贡献均随时间t（exp-2）下降。
We consider the origin and intital growth of the disks that form around protostars during the collapse of rotating molecular cloud cores. These disks are assumed to be inviscid and pressure free, and to have masses small compared to those of their central stars. We find that there exist three distinct components-an outer disk, in which shocked gas moves with comparable azimuthal and radical velocities; and inner disk, where material follows nearly circular orbits, but spirals slowly toward the star because of the drag exerted by adjacent onfalling matter, and a turbulent ring adjoining the first two regions. Early in the evolution, i.e., soon after infalling matter begins to miss the star, only the outer disk is present, and the total mass acceration rate onto the protostar is undiminished. Once the outer disk boundary grows to more than 2.9 times the stellar radius, first the ring, and then the inner disk appear. Thereafter, the radii of all three components expand as t(exp 3). The mass of the ring increase with time and is always 13% of the total mass that has fallen from the cloud. Concurrently with the buildup of the inner disk and ring, the accretion rate onto the star falls off. However, the protostellar mass continue to rise, asymptotically as t(exp 1/4). We calculated the radiated flux from the inner and outer disk components due to the release of gravitational potential energy. The flux from the inner disk is dominant and rises steeply toward the stellar surface. We also determine the surface temperature of the inner disk as a function of radius. The total disk luminosity decreases slowly with time, while the contributions from the ring and inner disk both fall as t(exp -2).