The homunculus of Eta Carinae: an interacting stellar winds paradigm

Abstract

We simulate the origin and evolution of the bipolar nebula surroundingEta Car using numerical two-dimensional gasdynamic models. Thegeneralized interacting stellar winds scenario, wherein a stellar windinteracts with an aspherical circumstellar environment, is adopted. Theeruption wind of 1840-1860, which is taken to be spherically symmetric,interacts with a preeruption toroidal density environment. Usingreasonable assumptions of initial conditions and eruption parametersbased on archival data, we have performed over 30 simulations in aneffort to bracket the initial parameters which produce models that bestmatch observations. We find that models with high pole-to-equatordensity contrasts (greater than 100) and toroidal density configurationsnicely account for the observed morphology and kinematics of thehomunculus.