[en] The general characteristics of the nonradial oscillations of a rotating star are summarized and compared with the observations of β Canis Majoris. It is shown that the existence of two periods very close to each other as well as a phase shift of a quarter-period between the broadening of the Unes and the corresponding radial velocity can be accounted for if the oscillation corresponds to a spherical harmonic of degree 2 in a rotating star. However, for free oscillations, the sign of the phase shift is opposite to the one observed when the periods are in the correct ratio, and vice versa.
Forced oscillations are briefly discussed, and, although they offer a possibility of removing this discrepancy, a quantitative analysis presents difficulties due to the proximity of the hypothetical companion.
