AAS 196th Meeting, June 2000
Session 5. Be Star and Other Atmosphere Studies
Display, Monday, June 5, 2000, 9:20am-6:30pm, Empire Hall South

[Previous] | [Session 5] | [Next]

[5.06] Decoupling of Dense Clumps and Disk Formation in Hot Star Winds

J.E. Bjorkman, J. Zsargó (University of Toledo)

Radiatively-driven hot star winds are highly unstable, leading to the formation of high density, slowly moving components within a fast rarefied ambient wind. This clumpiness and the possibility that dense regions may move separately from the ambient wind has interesting theoretical and observational consequences. Recent, one dimensional simulations of clumps in the wind of \tau~Scorpii show that some unusual characteristics (hard X-ray emission and redshifted O~{\sc vi} absorption) of this early B star can be attributed to infalling clumps.

Here we extend this approach to 3 dimensions to investigate the effects of density fluctuations on the winds and disks of rapidly-rotating B stars. There is abundant observational evidence supporting the existence of circumstellar disks around such stars; however, there is as yet no completely satisfactory theoretical explanation. One of the most recent and originally promising theories is the Wind Compressed Disk (WCD) model, but numerical simulations incorporating nonradial radiation forces do not support WCD formation. However, if the dense clumps decouple from the underlying ambient wind, they may be able to orbit the star, possibly creating the equatorial disk.

We present a simple Lagrangian analysis that calculates the trajectory of dense blobs in the ambient wind. The parameters (mass and initial position of the clumps) are mapped to find the range of infalling, outflowing, and equator-crossing clumps. The density distribution of the clumps in the circumstellar envelope and the mass-flux onto the disk also will be presented, and the effects of the diffuse radiation field on the clump trajectories is being investigated.

The author(s) of this abstract have provided an email address for comments about the abstract: jon@physics.utoledo.edu

[Previous] | [Session 5] | [Next]