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Session 38 - Disks and Bipolar Outflows from Hot Stars.
Display session, Tuesday, June 11
During its outburst from 1840 to 1860 A. D., \eta Carinae was the second brightest star in the sky. The outburst produced a highly structured circumstellar nebula, whose hourglass-shaped inner part is known as the Homunculus. The distribution and morphology of the circumstellar material reveals the mass-loss history of the central massive star, yielding strong constraints on stellar evolution models of rotating, massive, post-main sequence stars. We model the circumstellar nebula using the astrophysical hydrocode ZEUS (developed by the Laboratory for Computational Astrophysics at the NCSA). We use the analytic model of Bjorkman amp; Cassinelli for the stellar wind structure from a rotating star, which naturally produces the density distribution required to explain the observed bipolar structure. The variations in the strength of the stellar wind, as the central star passes through the LBV phase, drive instabilities in the circumstellar gas that can explain the observed small-scale structure. We also investigate the effects of the predicted wind-compressed disks on the outflow.
Program listing for Tuesday