Cambridge, UK, Proceedings of the International Astronomical Union, Symposium No. 290: Feeding compact objects: Accretion on all scales, p. 317-318, 2 pp. 2013
We present a Resonant Switch (RS) model of twin peak high-frequency quasi-periodic oscillations (HF QPOs), assuming switch of twin oscillations at a resonant point, where frequencies of the upper and lower oscillations nu_U and nu_L become commensurableand the twin oscillations change from one pair of the oscillating modes (corresponding to a specific model of HF QPOs) to some other pair due to non-linear resonant phenomena. The RS model enables to determine range of allowed values of spin a and mass Mof the neutron star located at the atoll source 4U 1636-53 where two resonant points are observed at frequency ratios nu_U : nu_L = 3:2, 5:4.