A circumstellar disk in CEP A.
Abstract
NH3 observations towards the Cep A molecular cloud reveal a circumstellar torus to be the relic of a recent star forming process. The physical characteristics of the torus are derived by fitting synthetic line profiles to the data. The line shapes are consistent with Keplerian orbits around a central source and contraction (or expansion) of the torus. The radial velocity is about 0.8 km/s and the rotational motion about 0.8 km/s x the square root of R0/R, with a radius of about 0.35 pc the outer boundary. The disk is warm (kinetic temperature about 50 K) and massive (about 15 solar masses). It fits into the evolutionary scheme of a collapsing interstellar cloud, possessing sufficient angular momentum to form a large-scale rotating ring in its equatorial plane. A ratio beta between the initial rotational and gravitational energy of the protodisk of a few tenths is derived.
- Publication:
-
Astronomy and Astrophysics
- Pub Date:
- September 1984
- Bibcode:
- 1984A&A...138..205G
- Keywords:
-
- Gas Dynamics;
- Molecular Clouds;
- Protostars;
- Stellar Envelopes;
- Stellar Evolution;
- Ammonia;
- Astronomical Maps;
- Disks (Shapes);
- Gravitational Collapse;
- Molecular Spectra;
- Ring Structures;
- Astrophysics