An empirical view of the chromospheric temperature structure above a sunspot umbra
Abstract
OSO-8 observations of the chromospheric and transition region emission lines are used to develop a temperature-based model of the chromosphere above a sunspot. The data base included observations of Lyman-alpha, Lyman-beta, the resonance lines of singly-ionized Mg, and the resonance lines of singly-ionized Ca. Details of the line profiles are provided, and features of the derived plateau model of the chromosphere are discussed. Weak reversals and broad wings in the observed Ca II lines were accounted for by assuming a 5 km/sec broadening, thus implying greater significance for the Ca II/Mg II, K/H, and k/h intensity ratios than details of the line profile shapes. The L-alpha and L-beta intensities are noted to constrain the upper chromosphere and transition region pressure to lower values than in the average quiet solar corona.
- Publication:
-
The Physics of Sunspots
- Pub Date:
- 1981
- Bibcode:
- 1981phss.conf..152L
- Keywords:
-
- Chromosphere;
- Solar Temperature;
- Sunspots;
- Umbras;
- Calcium;
- Line Spectra;
- Lyman Spectra;
- Magnesium;
- Spectrum Analysis;
- Tables (Data);
- Solar Physics