Thermal effects of H/sub 2/ molecules in rotating and collapsing spheroidal gas clouds
The thermal effect of H/sub 2/ molecules formed via the reactions H+e/sup -/..-->..H+H/sup -/, H+H/sup -/..-->..H/sub 2/+e/sup -/ has been studied for a range of uniform rotating spheroidal gas clouds undergoing pressure-free homologous collapse, with the goal of finding the Jeans mass, which governs star formation during the collapse of clouds to form galaxies. Initial conditions are those appropriate to a density perturbation which reaches maximum extension within various expanding Friedmann universes and then collapses. For collapsing spheres, H/sub 2/ cooling holds gas temperatures below 2000 K, up to densities of approx.10/sup 9/cm/sup -3/, and in the final stages of collape, the Jeans mass drops to approx.200 Msun. H/sub 2/ cooling is inhibited in the case of oblate clouds, while nonrotating prolate clouds thermally resemble spherical ones. It is found that, for prolate clouds which rotate sufficiently slowly about their long axes, the Jeans mass can become as small as 0.014 M/sub sun/ in the cases considered, suggesting an early period of formation of objects in the mass range of ordinary stars. The association of low rotation with efficient early star formation is suggestive of the supposed early history of elliptical galaxies. (AIP)
- Research Organization:
- Department of Astronomy, University of California, Berkeley
- OSTI ID:
- 7347418
- Journal Information:
- Astrophys. J.; (United States), Vol. 205:1
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
GENERAL PHYSICS
COSMIC GASES
DISTURBANCES
GALACTIC EVOLUTION
H1 REGIONS
ELECTRON-ATOM COLLISIONS
H2 REGIONS
ION-ATOM COLLISIONS
GRAVITATIONAL COLLAPSE
HYDROGEN
INTERSTELLAR SPACE
MASS
MOLECULES
ROTATION
STAR EVOLUTION
TEMPERATURE DEPENDENCE
ATOM COLLISIONS
COLLISIONS
COSMIC RADIO SOURCES
CRYOGENIC FLUIDS
ELECTRON COLLISIONS
ELEMENTS
FLUIDS
GASES
ION COLLISIONS
MOTION
NONMETALS
SPACE
640105* - Astrophysics & Cosmology- Galaxies
640102 - Astrophysics & Cosmology- Stars & Quasi-Stellar
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