Frequencies of low-degree solar acoustic oscillations and the phase of the solar cycle
Abstract
A study of the solar total irradiance data of the Active Cavity Radiometer Irradiance Monitor (ACRIM) on the Solar Maximum Mission (SMM) satellite shows a small but formally significant shift in the frequencies of solar acoustic (p-mode) oscillations between the epochs of maximum and minimum solar activity. Specifically, the mean frequency of the strongest p-mode resonances of low spherical-harmonic degree (l = 0-2) is approximately 1.3 parts in 104 higher in 1980, near the time of sunspot maximum, than in ≡1985, near sunspot minimum. The observed frequency shift may be an 11-yr effect but the precise mechanism is not clear.
- Publication:
-
Solar Physics
- Pub Date:
- 1987
- DOI:
- 10.1007/BF00193064
- Bibcode:
- 1987SoPh..114...21W
- Keywords:
-
- Acoustic Frequencies;
- Helioseismology;
- Irradiance;
- P Waves;
- Solar Cycles;
- Solar Interior;
- Solar Maximum Mission;
- Spherical Harmonics;
- Sunspots;
- Solar Physics