A Detailed Examination of the Kinematics of Rotating Dark Clouds
Abstract
The velocity fields of eight molecular clouds, six of which are described in the literature as rotating, are analyzed using two-dimensional maps of high-quality carbon monoxide spectra. Using a simple analytical techniques, the directions along which significant velocity gradients occur across the clouds are identified. Kinematic models of the sources are developed from an examination of the relevant spatial-velocity diagrams, and in some cases with the aid of visual excitation and C-13O column density maps. The data strongly support the presence of rotation in only three of the six clouds originally believed to possess it. In particular, the kinematic models of the allegedly rotating globules B163 and B163 SW are shown to be ambiguous because of possible gross asymmetries in the mass distributions of the clouds. If these two sources are not rotating, then rapid rotation in dark clouds may be much rarer than previously suspected. However, it is found that rotation present in a number of clouds plays a major role in the energetics of those objects.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- April 1986
- DOI:
- 10.1086/164082
- Bibcode:
- 1986ApJ...303..356A
- Keywords:
-
- Angular Velocity;
- Astronomical Models;
- Molecular Clouds;
- Spectrum Analysis;
- Velocity Distribution;
- Astronomical Maps;
- Carbon Monoxide;
- Kinematics;
- Mass Distribution;
- Nebulae;
- Rotation;
- Spatial Distribution;
- Astrophysics;
- INTERSTELLAR: MOLECULES;
- NEBULAE: GENERAL