Effects of acoustic and gravity waves on the curve of growth
Abstract
Unresolved motions, or `microturbulence', play a very important role in determining the Doppler width of the line-absorption coefficient. The concept of microturbulence was introduced because observed solar and stellar lines are broader than is explicable within the framework of other line-broadening mechanisms. By constructing a curve-of-growth in the presence of a dynamical model for simple acoustic and gravity waves, this paper evaluates the errors introduced by the use of kinematic models for line-broadening (microturbulence) into the determinations of non-thermal velocity fields and element abundances. Distinct differences between gravity and acoustic waves are apparent in the trend of the line asymmetry with the excitation potential as well as in the magnitude of the errors introduced by the temperature and pressure variations associated with the velocity field.
- Publication:
-
Solar Physics
- Pub Date:
- September 1987
- DOI:
- 10.1007/BF00148778
- Bibcode:
- 1987SoPh..112..211M
- Keywords:
-
- Doppler Effect;
- Gravity Waves;
- Solar Spectra;
- Sound Waves;
- Spectral Line Width;
- Stellar Spectra;
- Absorption Spectra;
- Abundance;
- Dynamic Models;
- Plasma Turbulence;
- Velocity Distribution;
- Astrophysics;
- Velocity Field;
- Acoustic Wave;
- Gravity Wave;
- Distinct Difference;
- Pressure Variation