Spectroscopic determination of intensities of umbral bright features and adjacent background
Abstract
Profiles of the Na I D doublet in three bright features (clusters of umbral dots), located in a relatively dark umbra, were analyzed by means of the 'local two-component modeling' to obtain the 'true' continuum intensities and temperatures of the bright features and their dark surroundings (background). The intensities of two central and one peripheral bright feature were 0.31 (background 0.11), 0.33 (0.13), and 0.40 (0.17), respectively. For the ratio of the object and background intensity (assumed to be constant, but unknown until now) the value of 2.6 +/- 0.2 was obtained.
- Publication:
-
Astronomy and Astrophysics
- Pub Date:
- July 1992
- Bibcode:
- 1992A&A...260..437S
- Keywords:
-
- Brightness Distribution;
- Solar Spectra;
- Sunspots;
- Umbras;
- Photosphere;
- Solar Atmosphere;
- Stellar Models;
- Solar Physics