VERTICAL OSCILLATION OF THIN ACCRETION DISCS AS A CANDIDATE PROCESS FOR QUASI-PERIODIC OSCILLATION

We draw attention to the importance of the characteristic periods of t he vertical oscillation of accretion discs. The periods and stability of the vertical oscillation of the thin accretion discs surrounding a neutron star are calculated numerically with the use of the OPAL opaci ties - newly presented radiative opacities. The periods of the oscilla tions are similar to the time-scale of quasi-periodic oscillations (QP Os) of X-rays. The vertical oscillation is also studied for other accr eting objects. It is suggested that the vertical oscillations of discs are the cause of QPOs.