The Sun's Basal Corona
Abstract
Every solar minimum since 1947, the Sun's radio flux at 2.8 GHz, known as the F10.7 index, returns to the same value, around 66 solar flux units. While a significant fraction of this is likely optically thick chromospheric emission, recent EUV observations have shown that about a quarter of it is coronal. Coronal emission varies greatly over the solar cycle, so the fact that the coronal component of F10.7 does not seem to vary much from minimum to minimum implies that the Sun has a minimum heating level that results in a basal coronal. We present EUV and radio observations to address this question, and briefly compare the Sun's basal corona with the situation in other stars.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2018
- Bibcode:
- 2018AGUFMSH43F3724W
- Keywords:
-
- 7599 General or miscellaneous;
- SOLAR PHYSICS;
- ASTROPHYSICS;
- AND ASTRONOMYDE: 7899 General or miscellaneous;
- SPACE PLASMA PHYSICSDE: 7999 General or miscellaneous;
- SPACE WEATHER