HD 49933: A laboratory for magnetic activity cycles
  Seismic analyses of the CoRoT target HD 49933 have revealed a magnetic cycle. Further insight reveals that frequency shifts of oscillation modes vary as a function of frequency, following a similar pattern to that found in the Sun. In this preliminary work, we use seismic constraint to compute structure models of HD 49933 with the Asteroseismic Modeling Portal (AMP) and the CESAM code. We use these models to study the effects of sound-speed perturbations in near surface layers on p-mode frequencies. 
T. Ceillier, J. Ballot, R.A. Garcia, G.R. Davies, S. Mathur, T.S.   Metcalfe, D. Salabert
astro-ph.SR