Is the Sun a pulsar?
Tihany Geophysical Observatory, H-8237. Tihany, Hungary
WHILE investigating intensity variations of spectrum-lines of solar origin, periods which seem to describe the Sun's oscillation have been found. The observed period of 2.65 h is very close to 2.78 h, the predicted radial mode fundamental oscillation of the homogeneous model of the Sun. Thus some observations of the solar disk seem to confirm the existence of a radial mode pulsation, while others give no significant indication of such a period. External effects may not, however, have been filtered satisfactorily in all cases. Thus we tried to find an effect of magnetospheric origin that can be related in some way to the described observations. We report here observations of pulsations with period of 2 h 40 min.