Unveiling the kinematics of the MWC49A.s ionized disk and outflow with H-recombination line masers.

% MWC349A, the unique Hmaser source observed so far, is a massive star with an ionized outflow believed to be generated in its photoevaporating rotating circumstellar disk. We plan to use the unique spectral capabilities provided by HIFI to perform observations of basically all of the H alpha recombination lines (from H26alpha to H15alpha ) covered by this instrument. Spectral resolved profiles will reveal essential kinematics inormation of the inner regions of the ionized outflow and the rotating disk. The observed line profile will be compared with the prediction of our nonLTE 3D radiative transfer model to constrain key parameters of the diskoutflow system. From the model.s prediction we will stablish if the inner disk is rotating with a Keplerian law, the rotation of the outflow and likely the presence of radial motions (accretion/excretion) in the disk and the location of the lunching point of the outflow. These parameters will help to discriminate between the models proposed for the origin of the outflows and the evolutionary state (premain sequence or evolved Be stars) of the central star. truncated!, Please see actual data for full text [truncated!, Please see actual data for full text]