Magnetic braking of self-gravitating, oblate interstellar clouds
Journal Article
·
· Astrophys. J.; (United States)
We obtain a characteristic time tau/sub J/ for loss of angular momentum by dense interstellar clouds, flattened along the common direction of the magnetic field and angular momentum vectors. By properly scaling the field with the gas density, we find that tau/sub J/ depends only on the present cloud temperature and the magnitude of the magnetic field at the time of cloud formation. The result is applied to dark and molecular clouds. Comparison of tau/sub J/ with the ambipolar-diffusion time, tau/sub B/, yields a ''critical'' density above which a dense cloud is expected to exhibit an angular velocity significantly larger than that due to Galactic rotation. At this density, the dynamical time scale is larger than tau/sub J/; hence, magnetic braking remains efficient up to that point. Observations support this conclusion.
- Research Organization:
- Departments of Physics and Astronomy, University of Illinois at Urbana-Champaign
- OSTI ID:
- 5929189
- Journal Information:
- Astrophys. J.; (United States), Journal Name: Astrophys. J.; (United States) Vol. 228:1; ISSN ASJOA
- Country of Publication:
- United States
- Language:
- English
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