2002ApJ...566..302M -
Astrophys. J., 566, 302-314 (2002/February-2)
On the role of massive stars in the support and destruction of giant molecular clouds.
MATZNER C.D.
Abstract (from CDS):
We argue that massive stars are the dominant sources of energy for the turbulent motions within giant molecular clouds and that the primary agent of feedback is the expansion of H II regions within the cloud volume. This conclusion is suggested by the low efficiency of star formation and corroborated by dynamical models of H II regions. We evaluate the turbulent energy input rate in clouds more massive than 3.7x105 M☉, for which gravity does not significantly affect the expansion of H II regions. Such clouds achieve a balance between the decay of turbulent energy and its regeneration in H II regions; summed over clouds, the implied ionizing luminosity and star formation rate are roughly consistent with the Galactic total. H II regions also photoevaporate their clouds: we derive cloud destruction times somewhat shorter than those estimated by Williams & McKee. The upper mass limit for molecular clouds in the Milky Way may derive from the fact that larger clouds would destroy themselves in less than 1 crossing time. The conditions within starburst galaxies do not permit giant molecular clouds to be supported or destroyed by H II regions, and this may explain some aspects of the starburst phenomenon.
Abstract Copyright:
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Journal keyword(s):
ISM: H II Regions - ISM: Clouds - Stars: Formation
Simbad objects:
7
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