Influence of NLTE calculations on the hydrogen lines in chromospheric models
Abstract
We present extensive NLTE calculations for a semi-empirical solar 1D chromosphere model based on the VAL C model. We report on a significant influence of nitrogen, oxygen, and sulfur on the emergent hydrogen emission with respect to LTE vs. NLTE calculations for these elements. Moreover, we present a model spectrum with 20 light and iron group elements computed in NLTE. We compare this to an observed solar spectrum and to a photospheric model spectrum. We find that the agreement for this model with the data is less good than the original VAL C model especially in the UV. This may imply the need of changes in the chromospheric temperature structure or may point to general problems of static 1D chromospheric models.
- Publication:
-
Astronomy and Astrophysics
- Pub Date:
- June 2006
- DOI:
- 10.1051/0004-6361:20053787
- Bibcode:
- 2006A&A...452.1083F
- Keywords:
-
- line: formation;
- Sun: chromosphere