Numerical Modeling of Eta Carinae Bipolar Outflows

Abstract

In this paper, we present two-dimensional gas dynamic simulations of the formation and evolution of the eta-Car bipolar outflows. Adopting the interacting nonspherical winds model, we have carried out high-resolution numerical simulations, which include explicitly computed time-dependent radiative cooling, for different possible scenarios of the colliding winds. In our simulations, we consider different degrees of non-spherical symmetry for the pre-outburst wind and the great eruption of the 1840s presented by the eta-Car wind. From these models, we obtain important differences in the shape and kinematical properties of the Homunculus structure. In particular, we find an appropriate combination of the wind parameters (that control the degree of non-spherical symmetry) and obtain numerical experiments that best match both the observed morphology and the expansion velocity of the eta-Car bipolar shell. In addition, our numerical simulations show the formation of a bipolar nebula embedded within the Homunculus (the little Homunculus) developed from a secondary eruptive event suffered by the star in the 1890s, and also the development of tenuous, high velocity ejections in the equatorial region that result from the impact of the eruptive wind of the 1840s with the pre-outburst wind and that could explain some of the high speed features observed in the equatorial ejecta. The models were, however, unable to produce equatorial ejections associated to the second eruptive event.

arXiv comment33 pages, 9 figures, accepted by the Astrophysical Journal

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Cited by in corpus (14)

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• Simulating the formation of $\eta$ Carinae's surrounding nebula through unstable triple evolution and stellar merger-induced eruption
• Emission lines from rotating proto-stellar jets with variable velocity profiles. I. Three-dimensional numerical simulation of the non-magnetic case
• Structure and Expansion Law of HII Regions in structured Molecular Clouds
• The three-dimensional structure of the Eta Carinae Homunculus
• Shell-Shocked: The Interstellar Medium Near Cygnus X-1
• The Structure of the Homunculus. III. Forming a Disk and Bipolar Lobes in a Rotating Surface Explosion
• On the bipolarity of Wolf-Rayet nebulae
• Revisiting 2D Numerical Models for the 19th century outbursts of $\eta$ Carinae
• 3D numerical model of the Omega Nebula (M17): simulated thermal X-ray emission
• Dissecting a SN impostor's circumstellar medium: MUSEing about the SHAPE of eta Car's outer ejecta
• Numerical simulations of the 1840s great eruption of $\eta$ Carinae: I. Revisiting the explosion scenario
• 3D numerical simulations of photodissociated and photoionized disks