Bursts Excite Modes in the Neutron - Star Ocean ?

During a Type-I burst, the turbulent deflagation front may excite waves in the neutron star ocean with frequencies, ω ∼ 1 Hz. These waves are observed as highly coherent flux oscillations during the burst. The frequencies of these waves changes as the upper layers of the neutron star cool which accounts for the small variation in the observed QPO frequencies. In principle several modes could be excited but the fundamental buoyant r−mode exhibits significantly larger variability for a given excitation than all of the other modes.