Quiet and active solar emission analysed from the OSO IV spectroheliograms.
Abstract
OSO 4 spectroheliograms have been analyzed for intensities and fluxes of the quiet sun (Q) and active regions (AR) in 44 EUV lines from 29 atoms or ions. The flux ratios agreed well with earlier independent estimates. Limb brightening was always less than that expected from an optically thin solar atmosphere. There was no limb brightening for optically thick lines. Flux measurements made on 22 plages in 18 spectral lines gave rise to some quantitative relations between EUV fluxes and McMath plage indices. Emission measures in volume and height forms have been determined, and ratios of active-region to quiet-sun height emission measures are computed as a function of maximizing temperature.
- Publication:
-
Monthly Notices of the Royal Astronomical Society
- Pub Date:
- May 1977
- DOI:
- 10.1093/mnras/179.3.473
- Bibcode:
- 1977MNRAS.179..473A
- Keywords:
-
- Far Ultraviolet Radiation;
- Satellite Observation;
- Solar Activity Effects;
- Solar Limb;
- Solar Radiation;
- Spectroheliographs;
- Optical Thickness;
- Oso-4;
- Satellite-Borne Instruments;
- Solar Atmosphere;
- Spaceborne Astronomy;
- Solar Physics