Mecanism of Outflow form Dynamically Contracting Molecular Cores

动态收缩分子核的流出机制

基本信息

批准号：
11640231
负责人：
TOMISAKA Kohji
金额：
$ 2.11万
依托单位：
National Astronomical Observatory Of Japam (2000-2001)Niigata University (1999)
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1999
资助国家：
日本
起止时间：
1999 至 2001
项目状态：
已结题

项目摘要

Dynamical contraction of interstellar molecular clouds is studied. 1. Tomisaka studied the mechanism of molecular outflow with the nested-grid axi-symmetric magnetohydrodynamical simulations. Rotations of the molecular cloud cores amplify the toroidal magnetic fields, which eject the gas as molecular outflows. From the simulations, we explored the followings : (1) Initial rotation speed specifies the epoch when the molecular outflow begins. That is, increasing the angular momentum, the outflow is launched immediate after the adiabatic core is formed. (2) When the initial poloidal magnetic field is strong (its energy is comparable to the thermal one), a U-shaped outflow is formed, in which gas is mainly outflowing through a region whose shape looks like a capital letter U at a finite distance from the rotation axis. (3) The other is a turbulent outflow in which magnetic field lines and velocity fields seem to be randomly oriented, which is realized when the initial magnetic energy is much smaller than the thermal one. In this case, globally the gas moves out almost perpendicularly from the disk and the outflow looks like a capital letter I. 2. Nakamura studied the gravitational collapse of a cloud supported by strong magnetic fields taking into account of the magnetic diffusion. (1) A model with large mass leads to fragmentation to a number of high-densitycores in the early phase. This corresponds to a cluster forming mode. (2) Incontrast, in a less massive cloud a bar grows and the bar breaks into fragments. In this case a binary system will appear.

研究了星际分子云的动态收缩。 1。Tomisaka研究了分子流出的机理，并使用嵌套的Axi对称磁性水动力学模拟。分子云芯的旋转扩大了环形磁场，该磁场将气体驱射为分子流出。从模拟中，我们探讨了以下内容：（1）初始旋转速度指定分子流出开始时的时期。也就是说，增加角动量，在形成绝热芯后立即发射流出。（2）当初始磁场磁场强（其能量与热的能量相当）时，形成了U形流出，其中气体主要通过一个区域流出，其形状看起来像是距旋转轴有限距离的大写字母U。（3）另一个是湍流流出的磁场线和速度场似乎是随机定向的，当初始磁能比热磁力小得多时，它可以实现。在这种情况下，在全球范围内，气体几乎从磁盘上垂直移出，流出看起来像是大写字母I。2。中村研究了云的重力塌陷，该云由强烈的磁场支持磁性扩散。（1）具有较大质量的模型导致碎片在早期阶段的许多高密度核。这对应于群集形成模式。（2）不对比，在一个较少的云中，一个条形生长，条将变成碎片。在这种情况下，将出现二进制系统。