The Chromosphere above Sunspot Umbrae II. The Interpretation of the H, K and IR Lines of CA II
Abstract
Summary. The chromospheres above sunspot umbrae are investigated by comparing calculated and observed profiles of the Ca ii H, K, and infra-red lines. Statistical steady state is assumed for the level populations. We test several model chromospheres in hydrostatic equilibrium. We distinguish between chromospheres which are optically thick and optically thin at the centre of the K line. In view of the observed intensity ratio 1K3/1H3 1.15 we are forced to adopt a thick model as reference chromosphere. Key words: chromosphere - sunspot umbra - Ca ii lines
- Publication:
-
Astronomy and Astrophysics
- Pub Date:
- April 1978
- Bibcode:
- 1978A&A....65...17K