Dynamical models for microturbulence
Abstract
Solar and stellar spectral lines are observed to be broadened by nonthermal motions. To account for this broadening, astronomical diagnostic spectroscopists introduce 'microturbulence', which is usually viewed as a statistical distribution of small-scale velocities whose only effect is to Doppler-broaden the line profile. However, insofar as microturbulence is a dynamical phenomenon, this usual picture is incomplete, since it is not based on a realistic description of the combined effects of small-scale velocity, temperature, and pressure variations on the detailed processes of spectra line formation. By using a number of schematic dynamical models for microturbulence, this paper shows that the temperature and pressure variations associated with velocity fields can lead to significant effects on the strength, shifts, and shapes of photospheric spectral lines.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- July 1981
- DOI:
- 10.1086/159031
- Bibcode:
- 1981ApJ...247..239C
- Keywords:
-
- Atmospheric Models;
- Atmospheric Turbulence;
- Dynamic Models;
- Stellar Atmospheres;
- Stellar Spectrophotometry;
- Doppler Effect;
- Line Shape;
- Photosphere;
- Pressure Effects;
- Spectral Line Width;
- Temperature Effects;
- Astrophysics