H{alpha} interferometric visibilities of o Aqr

The occurrence of a central quasi-emission feature in Mg II {lambda}4481 is also predicted by this best-fit disk model and the computed profile compares successfully with observations from 1999. To obtain consistency between the H{alpha} line profile modeling and the other constraints, it was necessary in the profile fitting to weight the line core (emission peaks and central depression) more heavily than the line wings, which were not well reproduced by our models.

This may reflect the limitation of assuming a single power law for the disk's variation in equatorial density. The best-fit disk density model for o Aqr predicts that H{alpha} is near its maximum strength as a function of disk density, and hence the H{alpha} equivalent width and line profile change only weakly in response to large (factor of ~5) changes in the disk density. This may in part explain the remarkable observed stability of o Aqr's H{alpha} emission line profile.