Abstract
η Carinae is a binary system formed by two massive stars, loosing mass through strong winds. The wind-wind interactions originate shocks that rise the plasma temperature to 10^{6-8} K, producing X-ray emission. Although the overall shape of the light curve can be explained and it is used to calculate the orbital eccentricity, the observed short quasi-periodic oscillations have not been explained yet. In our work we propose that these oscillations are produced by the nutation of the rotation axis of η Carinae, which is not be perpendicular to the orbital plane. Since in η Carinae, both the mass loss rate and the wind velocity are latitude dependent, the intensity of the emitted X-rays will be a function of the latitude at which the stellar surface intercepts the orbital plane. By assuming an angle of about 30° between the rotation axis and the perpendicular to the orbital plane, an nutation amplitude of about 5° and a nutation period of 22 days, we were able to reproduce very well the observed X-ray light curve.
