Rotational period variations in magnetic chemically peculiarstar HD 37776

Three decades of a precise photometric and spectroscopic monitoring of the young hot magnetic chemically peculiar star HD 37776 have revealed its continual rotational deceleration, increasing the period by a remarkable 18 s! The deceleration was interpreted as the rotational braking of the outer stellar layers due to the angular momentum loss in the stellar magnetosphere. Observational data have been recently supplemented by own new photometric data. We present here the results of the sophisticated analysis of all available observed data showing that the period reached its maximum of 1.538766 d in the year 2004, when the rotation period began to decrease. The nature of such unpredicted period changes and the paradox of the spin-down time are briefly discussed.