Oscillations in sunspots near the solar limb.
Abstract
Using sunspot-spectrograms near the solar limb it is possible to determine the height of the formation of selected strong (chromospheric) lines by micrometric distance measurements. The authors have analysed the time sequences of Hα and Na D linespectra to check the possibility of a time variation in the height of formation of these lines. They have found periods in the 3 minutes range, but also longer periods. The amplitude of the height variation is in the range Δh(rms) = 100 - 200 km. This is a new method to study oscillations in sunspots, without making use of intensity or velocity variations.
- Publication:
-
Seismology of the Sun and Sun-Like Stars
- Pub Date:
- December 1988
- Bibcode:
- 1988ESASP.286..273M
- Keywords:
-
- Solar Activity Effects;
- Solar Limb;
- Solar Oscillations;
- Sunspots;
- Solar Spectra;
- Spectrograms;
- Spectrum Analysis;
- Solar Physics;
- Sunspots: Solar Oscillations