Line asymmetries and shifts in the presence of granulation and oscillations: The CLV of the Ki7699 resonance line

✍ Scribed by C. Marmolino; G. Roberti; G. Severino

• Publisher: Springer
• Year: 1987
• Tongue: English
• Weight: 607 KB
• Volume: 108
• Category: Article
• ISSN: 0038-0938
• DOI: 10.1007/bf00152074

✦ Synopsis

We study the effects of both the solar granulation and short-period oscillations on the solar profile of the KI 7699 resonance line and its center-to-limb variations.

The granular model we used is that of Nelson (1978). The wave field is obtained by adding two 30 s acoustic waves with opposite horizontal wavenumbers to allow for the center-to-limb calculations.

We find that the broadening and strengthening produced by our dynamical models do not fill the gap existing between the observations and the values computed in a static atmosphere. Then, either the granular model has to be revised (in particular its r.m.s, velocities are too low) or other types of motions, like gravity waves, have to be accounted for.

The upper part of the mean bisectors is affected by granulation and the lower part by waves. With some qualification concerning the data used for comparison, a satisfactory fit of the observed center-to-limb variations of the mean bisectors is obtained when both dynamical models are included and the granular velocities are increased by a factor 1.5.