TIDAL THEORY FOR THE ORIGIN OF THE SOLAR NEBULA

被引:17
作者
KOBRICK, M [1 ]
KAULA, WM [1 ]
机构
[1] CALTECH,JET PROP LAB,PASADENA,CA 91103
来源
MOON AND THE PLANETS | 1979年 / 20卷 / 01期
关键词
D O I
10.1007/BF00897756
中图分类号
P1 [天文学];
学科分类号
0704 ;
摘要
There are two angular momentum (AM) problems associated with the formation of stars in general and the solar system in particular. The first is how to dispose of the AM possessed by turbulent protostellar clouds. Two-dimensional calculations of the gravitational infall of rotating gas clouds by several authors now indicate that stars are formed in groups or clusters rather than as single entities. Added evidence comes from observation of probable regions of star formation and young clusters, plus the fact that most stars are presently members of binaries or other multiples. Thus the first problem is solved by postulating the fragmentation of massive clouds with most of the AM ending up in the relative orbits. These clusters are notoriously unstable and evolve with the ejection of single stars like the Sun. The second problem is the uneven distribution of AM with mass in the solar system. It turns out that the collapse time for the majority of the infalling material is comparable to the time necessary for significant dynamical interaction of the protostellar fragment with its neighbors. It is found here through calculations utilizing very simplified numerical models that the last few tens of percent of infalling material can easily have sufficient AM transferred to it by the tidal action of passing protostars to form a solar nebula and ensure alignment of the solar spin. The most important parameter is the degree of central condensation: fragments without several tenths M⊙ in a central core tend to be torn apart by encounters, or at least stimulated into binary fission. A stabilizing central mass maintains its identity and acquires a rotating envelope of material. © 1979 D. Reidel Publishing Co.
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页码:61 / 101
页数:41
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