The 1640.4 Å Halpha line of He II observed from Skylab.
Abstract
Profiles obtained from NRL Skylab solar spectra of the 1640.4 A feature identified as the H-alpha line of He II are discussed and compared with theoretical profiles derived assuming (1) collisional excitation and (2) radiative recombination as the dominant excitation mechanism. Relative intensities of this line as a function of altitude above and below the solar white-light limb are also given for a representative quiet sun region and for a polar coronal hole.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- July 1975
- DOI:
- 10.1086/181850
- Bibcode:
- 1975ApJ...199L..67F
- Keywords:
-
- H Alpha Line;
- Helium Ions;
- Skylab Program;
- Solar Spectra;
- Luminous Intensity;
- Molecular Collisions;
- Radiative Recombination;
- Solar Corona;
- Spaceborne Astronomy;
- Spectroheliographs;
- Solar Physics