Eta Carinae: Bullet Streams and Colliding Wind Shocks

Abstract

Eta Carinae, the most massive and most luminous star in our Galaxy, erupted in 1842 with an energy rivaling a supernova. It ejected approximately two solar masses of material to form an extended bipolar nebula (the homunculus), a variety of massive ``bullets'' (NN and NS knots and the South Bar) and the ``spikes'' (long narrow strings of bullets). We have performed spatial and spectral astrometry on all these features, but I shall concentrate on our observations and analysis of the spikes and homunculus. The spikes were emitted at various angles with respect to the axis of symmetry of the homunculus. These spikes may be an astrophysical realization of the recent magnetohydrodynamical (MHD) simulations of planetary nebulae by J. A. López, W. Steffen, G. García-Segura and collaborators. They use a wind and magnetic structure and, for certain values of their parameters, produce several features that resemble the spikes. We will discuss the properties of the spikes, the relation to the hydrodynamic (HD) and MHD simulations and speculate on the nature of eta Carinae.