Self-Regulation of Star Formation in Low Metallicity Clouds

Abstract

We investigate the process of self-regulated star formation via photodissociation of hydrogen molecules in low metallicity clouds. We evaluate the influence region's scale of a massive star in low metallicity gas clouds whose temperatures are between 100 and 10000 Kelvin. A single O star can photodissociate hydrogen molecules in the whole of the host cloud. If metallicity is smaller than about 10^{-2.5} of the solar metallicity, the depletion of coolant of the 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 contrary, if metallicity is larger 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 about 1/100 of the solar metallicity. This indicates that stars do not form efficiently before the metallicity becomes larger than about 1/100 of the solar metallicity and we considered that this value becomes the lower limit of the metallicity of luminous objects such as galaxies.

14 pages, including 5 figures, To appear in ApJ, Vol. 537

References in corpus (3)

• Photodissociative Regulation of Star Formation in Metal-Free Pregalactic Clouds
• Chemical Evolution of the Galactic Halo through Supernova-Induced Star Formation and Its Implication for Population III Stars
• Formation and Disruption of Cosmological Low Mass Objects

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