Radio and white-light observations of the 1973 August 21 coronal transient.
Abstract
A coronal transient, which occurred on August 21, 1973, has been observed simultaneously in white light and at decameter radio wavelengths. The radio observations were obtained with a two-dimensional swept-frequency array (called the Teepee Tee). The white-light observations consist of a series of photographs taken by the High Altitude Observatory's coronagraph aboard Skylab. The radio emission associated with the transient was continuum in nature and lasted for almost 5 hours. The source of emission was observed to be cospatial with the lower part of one of the secondary white-light loops. A lower limit of 0.6 solar radius for the depth (extension along the line of sight) of this part of the transient was derived from considerations of radio-wave propagation in the corona. The radio source showed no dispersion of height with frequency, and, therefore, the emission is attributed to gyrosynchrotron radiation. Based on this assumption, the magnetic-field strength in the lower part of the loop is estimated to be in the 2.0-4.5-gauss range at a height of 2.1 solar radii from the center of the sun.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- June 1979
- DOI:
- 10.1086/157115
- Bibcode:
- 1979ApJ...230..575G
- Keywords:
-
- Radio Observation;
- Solar Corona;
- Solar Radio Emission;
- Visual Observation;
- Electron Density (Concentration);
- Graphs (Charts);
- Radio Emission;
- Stellar Mass Ejection;
- Solar Physics;
- Radio Radiation:Solar Corona;
- Solar Coronal Transients