Turbulence in the dust cloud L134 - High-resolution observations of 6 centimeter formaldehyde absorption
Abstract
Observations of 6 cm formaldehyde absorption were made at high spatial and velocity resolution toward the central regions of the dust cloud Lynds 134. A least-squares fit to the hyperfine manifold of each spectrum yielded precise υLSR values at each position; these show no evidence of positional variation. This suggests that if previously observed smooth shifts in υLSR (which occur over a much larger portion of the cloud than observed here) are in fact due to rotation, this rotation is not carried into the most heavily obscured parts of the cloud.
The fit procedure also yielded precise values for the line velocity dispersion at each position. These vary significantly over the cloud core. These results are used to discuss turbulent models of the cloud velocity field. In the absence of an energy source, the resulting picture of the cloud must be regarded as highly improbable. One or more embedded T Tauri stars undergoing mass loss could account for the turbulent dissipation expected for the cloud, and the presence of such stars is not observationally excluded. The dynamical consistency of such a model remains to be established, however. We also briefly discuss the observations in terms of a systematic velocity field for the cloud. Subject headings: interstellar: molecules nebulae: individual- Publication:
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The Astrophysical Journal
- Pub Date:
- June 1980
- DOI:
- 10.1086/158046
- Bibcode:
- 1980ApJ...238..853D
- Keywords:
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- Centimeter Waves;
- Cosmic Dust;
- Formaldehyde;
- Interstellar Matter;
- Molecular Gases;
- Nebulae;
- Absorption Spectra;
- Astronomical Models;
- Data Processing;
- High Resolution;
- Least Squares Method;
- Spectral Line Width;
- Turbulence;
- Velocity Distribution;
- Astrophysics