On the Temperature Structure of Sunspot Umbrae
Abstract
From a high-resolution spectrum of a sunspot umbra (1.1 < λ < 2.3 μm) we derive models of the temperature stratification in the deep layers of the umbra. The observed spectrum is corrected for straylight using the HI Paschen line at gl = 1.282 μm. A method is described for the iterative fitting of empirical temperature models to spectral information, and the method is applied to the present data. We find that the observed profiles of 3 high-excitation lines of SiI and the observed continuum contrast between umbra and photosphere cannot be reproduced with a single one-component model of the umbral atmosphere: the Si I lines require a model that is 460 K hotter at gt0.5 = 3 than the continuum model. This indicates that hot and cool components coexist within the umbra. A temperature model derived from the relative intensity in the wings of 3 low-excitation lines of MgI, AlI, and SiI is not significantly different from the continuum model.
- Publication:
-
Solar Physics
- Pub Date:
- April 1984
- DOI:
- 10.1007/BF00146294
- Bibcode:
- 1984SoPh...91..195V
- Keywords:
-
- Solar Spectra;
- Solar Temperature;
- Sunspots;
- Umbras;
- Continuous Spectra;
- Line Spectra;
- Temperature Profiles;
- Solar Physics;
- Atmosphere;
- Stratification;
- Relative Intensity;
- Deep Layer;
- Continuum Model