Self-Regulation of Star Formation in Low-Metallicity Clouds
Self-Regulation of Star Formation in Low-Metallicity Clouds
复制标题
低金属丰度云中恒星形成的自调节
DOI：
10.1086/309037
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发表时间：
2000
期刊：
影响因子：
--
通讯作者：
M. Tashiro
中科院分区：
文献类型：
--
作者：
R. Nishi;M. Tashiro
我们研究了低金属丰度云中氢分子的光解离过程，从而实现自我调节的星星形成过程。我们评估了温度在102 ~ 104 K之间的低金属丰度气体云中大质量星星的影响区域的尺度。一颗O型星星可以在整个宿主云中光解H2。如果金属丰度小于太阳金属丰度的10-2.5，则宿主云中冷却剂的消耗非常严重，使得云不能在自由落体时间内冷却，并且随后的星星形成几乎被淬灭。另一方面，如果金属丰度大于太阳金属丰度的约10-1.5，则通过光解离的星星形成调节是无效的。当这种转变发生时，典型的金属丰度约为太阳金属丰度的10-2。这表明在金属丰度大于太阳金属丰度的10-2之前，恒星不会有效地形成，我们认为这个值是发光物体（如星系）金属丰度的下限。
We investigate the process of self-regulated star formation via the photodissociation of hydrogen molecules in low-metallicity clouds. We evaluate the scale of the influence region for a massive star in low-metallicity gas clouds whose temperatures are between 102 and 104 K. A single O star can photodissociate H2 in the whole of the host cloud. If the metallicity is less than about 10-2.5 of the solar metallicity, the depletion of coolants in the host cloud is very serious, so that the cloud cannot cool in a free-fall time, and subsequent star formation is almost quenched. On the other hand, if the metallicity is greater than about 10-1.5 of the solar metallicity, star formation regulation via photodissociation is not efficient. The typical metallicity when this transition occurs is ~10-2 of the solar metallicity. This indicates that stars do not form efficiently before the metallicity becomes larger than about 10-2 of the solar metallicity, and we consider that this value is the lower limit of the metallicity of luminous objects such as galaxies.