Steps toward an emerging model

Half-way through ingress by most estimates, but epsilon Aurigae continues to confound.  Middle of October, the star changed its rate of decline in brightness, from rapid to less rapid - see the visual light curve data link.  This change of slope seems to be more pronounced at shorter wavelengths, less pronounced at longer wavelengths.  Clues like these will help us define the nature of the eclipsing body more precisely.  If purely due to effective area, it says that the disk is slightly thinner-looking in bluer light, relative to red wavelengths.  Ultraviolet light curves during last eclipse seem consistent with this trend.
Persistent observers have seen the weak line of neutral potassium strengthing since spring 2009, showing steps in the process suggestive of rings lying outside the main disk body -- see attached image from HubbleSiteNews, and the Citizen Sky logo image at top of page.  Potassium is a tracer for small temperature and density changes in cool material associated with the disk.  A goal of the near-infrared interferometric observations is to demonstate the existence of this cooler disk of material.
Evidence from the ultraviolet and far-UV support the notion that a hot star exists in the center of the dusty disk.  Radiation from the hot star is capable of ionizing zones above and below the dusty disk, possibly giving rise to the H-alpha emission features seen in current spectra.  Additional optical interferometric observations may be able to demonstrate this association.
Thus we are beginning to see the outlines of an emerging, testable revised model for the binary star plus disk.  In coming weeks, we will begin to discuss facets of this.
Happy Thanksgiving to you and yours!