Variability in the Circumstellar Shell of $\pi$ Aqr: Clues to a Wind-Disk Connection?
Session 31 -- Massive Hot Stars
Display presentation, Tuesday, 31, 1994, 9:20-6:30

## [31.11] Variability in the Circumstellar Shell of $\pi$ Aqr: Clues to a Wind-Disk Connection?

K.S.Bjorkman, J.E.Bjorkman (U. Wisconsin), C.A.Grady (ARC)

The Be star $\pi$ Aqr has shown large variations in both its UV wind lines and its polarization over the past 5 years. Comparison of the changes in the UV wind lines with the timing of polarimetric outbursts, while not strictly simultaneous and therefore not conclusive, provides tantalizing indications of a connection between the equatorial disk and the wind. Such a connection would be predicted by the wind-compressed disk (WCD) model for Be star envelopes. We present the evidence for a wind-disk connection and discuss possible interpretations of the data in light of the WCD model and other proposed sources of variability in the circumstellar envelopes of Be stars.

This work has been supported by NASA contract NAS5-26777 and NASA grant NAG5-1790 to the University of Wisconsin.