ENABLING STAR FORMATION VIA SPONTANEOUS MOLECULAR DIPOLE ORIENTATION IN ICY SOLIDS
ENABLING STAR FORMATION VIA SPONTANEOUS MOLECULAR DIPOLE ORIENTATION IN ICY SOLIDS
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DOI：
10.3847/0004-637x/832/1/1
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发表时间：
2016-11
期刊：
影响因子：
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通讯作者：
A. Rosu-Finsen;J. Lasne;A. Cassidy;M. McCoustra;D. Field
中科院分区：
文献类型：
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作者：
A. Rosu-Finsen;J. Lasne;A. Cassidy;M. McCoustra;D. Field
它在这里示出了如何新的实验数据，固体CO的电性能，可以用来填补重要的空白，我们的理解星前核心的演变。尘埃颗粒与地幔的CO导致在这些核心的电离度减少了5和6之间的一个因素。从核心排出磁场的寿命，这是引力坍缩通常所必需的过程，从目前估计的几个百万年减少了类似的因素。这消除了一个主要的不一致，因为现在的寿命符合从观测中得出的星前核心的典型年龄，从几十万年到106年。随着时间尺度的缩短，核心也逃脱了银河系超新星遗迹的破坏。我们的研究结果提供了一个自然的机制，产生所谓的磁超临界核心，其中磁场本身不能防止引力坍缩。此外，我们发现星前核密度的最小值为≥（1.1 ± 0.1）× 104 H2 cm−3，与观测结果一致。
It is shown here how new experimental data, for the electrical properties of solid CO, can be used to fill important gaps in our understanding of the evolution of prestellar cores. Dust grains with a mantle of CO lead to a reduction in the degree of ionization in these cores by a factor of between 5 and 6. The lifetimes for expulsion of magnetic fields from cores, a process generally necessary for gravitational collapse, are reduced from current estimates of several megayears, by a similar factor. This removes a major inconsistency, since lifetimes now tally with typical ages of prestellar cores of a few hundred thousand to 106 yr, derived from observations. With the reduced timescales, cores also escape disruption by Galactic supernova remnants. Our results provide a natural mechanism for the generation of so-called magnetically supercritical cores, in which the magnetic field alone cannot prevent gravitational collapse. In addition, we find a minimum value for the density of prestellar cores of ≥(1.1 ± 0.1) × 104 H2 cm−3, in agreement with observations.