2010MNRAS.403.1983R

We present the first description of mode trapping for subdwarf O (sdO) models. Mode trapping of gravity modes caused by the He/H chemical transition is found for a particular model, providing a selection effect for high-radial-order trapped modes. Low- and intermediate-radial-order p modes (mixed modes with a majority of nodes in the P-mode region) are found to be trapped by the C-O/He transition, but with no significant effects on the driving. This region also seems to have a subtle effect on the trapping of low-radial-order g modes (mixed modes with a majority of nodes in the G-mode region), but again with no effect on the driving. We found that for mode trapping to have an influence on the driving of sdO modes, (1) the mode should be trapped in a way that the amplitude of the eigenfunctions is lower in a damping region and (2) in this damping region significant energy interchange has to be produced.