ИСТИНА

Study of stars with saturation and solar-type activity allows us to indentify the age of the young Sun at the epoch of the cycle formation. This occurred when the Sun was rotated with the period of about 10 days and had the age of ≈ 1Gyr. Such a young Sun was covered by many spots whose total area was by 2 – 3 orders of magnitudes larger than the current value at the maximum of the contemporary cycle. The activity levels of the chromosphere and corona were quite high and similar to the Hyades one, but did not reach the saturation level. Available observational data on the magnetic fields of active G-type stars permit us to evaluate the upper limit of the total energy of flares that can happen on the young Sun as much as E=10^34 erg, occurrence frequency of such flares was 1 event per 5 years. We evaluate the mass loss of the young Sun as much as 10^{–11} M_Sun/yr, and the contribution of CME’s in this value was significantly higher than it is now. The duration of the cycle on the young Sun was apparently 7 – 8 years.