Variation of the quiet sun at 21 cm: 1981 - 1987.
Abstract
Using the Very Large Array (VLA), the Green Bank 91 m telescope, the Arecibo 305 m telescope, and powerful maximum entropy image reconstruction techniques, the authors have imaged the Sun at λ ≈ 21 cm during the years 1981 - 1987. While the 21 cm radio brightness distribution is in qualitative agreement with past mapping efforts, several new results have emerged. Among these, the authors have noted a systematic decrease in the quiet Sun's brightness temperature at 21 cm as the Sun declined from sunspot maximum to sunspot minumum accompanied by systematic decrease in the Sun's radius at 21 cm. Simple modeling has shown that the observed variation in the quiet Sun's brightness temperature and radius at 21 cm could have resulted from a factor of ≈2 decrease in the electron number density in the solar transition region and low corona.
- Publication:
-
Solar and Stellar Coronal Structure and Dynamics
- Pub Date:
- 1988
- Bibcode:
- 1988sscd.conf..386B
- Keywords:
-
- Brightness Temperature;
- Electron Density (Concentration);
- Solar Corona;
- Solar Oscillations;
- Very Large Array (Vla);
- Decimeter Waves;
- Solar Atmosphere;
- Solar Radio Emission;
- Telescopes;
- Solar Physics;
- Brightness Temperature: Quiet Sun;
- Solar Radio Radiation: Quiet Sun;
- Solar Radio Radiation: Solar Activity Cycles;
- Solar Radio Radiation: Solar Transition Region;
- Solar Radio Radiation: Solar Corona