The chromosphere above sunspot umbrae. I. Observations of the emission cores in the Ca II H- and K-lines.
Abstract
Summary. Photographic spectra of the Ca ii H- and K- lines in sunspot umbrae are analysed. The emission features in the line profiles may be classified into minimum emission profiles that also lack self-reversal, and profiles which change rapidly in time and exhibit self-reversals (umbral flashes) that are most often strongly asymmetric. Average intensity profiles from the minimum emission parts of the umbra and characteristic intensities of the more active parts of the umbra are given. Key words: chromosphere - sunspot umbra - Ca ii lines
- Publication:
-
Astronomy and Astrophysics
- Pub Date:
- April 1978
- Bibcode:
- 1978A&A....65...11M
- Keywords:
-
- Calcium;
- Chromosphere;
- Solar Spectra;
- Sunspots;
- Umbras;
- Electron Density Profiles;
- Emission Spectra;
- Fine Structure;
- H Lines;
- Infrared Astronomy;
- K Lines;
- Solar Physics;
- Line Profiles:Solar Chromosphere;
- Sunspots: Umbrae