Time-dependent Radio Sources in the Star-forming Region Cepheus A (East)
Abstract
Results are presented of monitoring of sources 8 and 9 of Cep A from November 2, 1988, to May 8, 1990, with emphasis on the appearance of a second new highly variable radio source. A number of possible mechanisms for the origin of the radiation from both sources is discussed, but the resulting interpretation of the spectra is in terms of gyrosynchroton emission from thermal electrons at a temperature of about 10 exp 8 K, in a magnetic field about 200 G, and a region of size about 1 AU. The fact that the frequency of the peak emission moves to higher frequencies as the flux density increases is explained as an increase in the magnetic field and/or temperature of the electrons. The high temperature is consistent with the conversion of magnetic field energy into thermal energy, and this mechanism could also be instrumental to the production of molecular outflows.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- December 1991
- DOI:
- 10.1086/170784
- Bibcode:
- 1991ApJ...383..280H
- Keywords:
-
- Pre-Main Sequence Stars;
- Radio Sources (Astronomy);
- Star Formation;
- Stellar Winds;
- Variable Stars;
- Electron Energy;
- Stellar Magnetic Fields;
- Stellar Spectra;
- Synchrotron Radiation;
- Time Dependence;
- Astrophysics;
- RADIO SOURCES: VARIABLE;
- STARS: FORMATION;
- STARS: PRE--MAIN-SEQUENCE;
- STARS: WINDS