Non-resonance lines of neutral calcium in the spectra of the sun and Procyon.
Abstract
Neutral calcium lines of moderately high excitation (2.5-3.0 eV) in the solar spectrum and in the spectrum of Procyon have been analyzed using precise oscillator strengths and estimates of hydrogen damping parameters based on measured parameters for broadening by helium. A conventional analysis based on an LTE model atmosphere and using all relatively unblended lines for which precise atomic data are now available, leads to extremely consistent values for calcium abundance and microturbulence. In the solar case several model atmospheres have been investigated and the derived abundance and microturbulence are found to depend somewhat on atmosphere. However, no significant differences are found between abundances derived from weak lines (equivalent width less than 100 mA) and those derived from moderately strong lines (equivalent width of 100-200 mA). This comparison indicates that the estimated damping parameters are approximately correct.
- Publication:
-
Astronomy and Astrophysics
- Pub Date:
- November 1981
- Bibcode:
- 1981A&A...103..351S
- Keywords:
-
- Binary Stars;
- Calcium;
- Neutral Particles;
- Solar Spectra;
- Spectrum Analysis;
- Abundance;
- Atmospheric Models;
- Damping;
- Helium Ions;
- Line Spectra;
- Nonresonance;
- Resonance Lines;
- Stellar Atmospheres;
- Stellar Structure;
- Turbulence Effects;
- Astronomy