  I examine some aspects of the interaction between the massive star Eta
Carinae and its companion, in particular during the eclipse-like event, known
as the spectroscopic event or the shell event. The spectroscopic event is
thought to occur when near periastron passages the stellar companion induces
much higher mass loss rate from the primary star, and/or enters into a much
denser environment around the primary star. I find that enhanced mass loss rate
during periastron passages, if it occurs, might explain the high eccentricity
of the system. However, there is not yet a good model to explain the presumed
enhanced mass loss rate during periastron passages. In the region where the
winds from the two stars collide, a dense slow flow is formed, such that large
dust grains may be formed. Unlike the case during the 19th century Great
Eruption, the companion does not accrete mass during most of its orbital
motion. However, near periastron passages short accretion episodes may occur,
which may lead to pulsed ejection of two jets by the companion. The companion
may ionize a non-negligible region in its surrounding, resembling the situation
in symbiotic systems. I discuss the relation of some of these processes to
other astrophysical objects, by that incorporating Eta Car to a large class of
astrophysical bipolar nebulae.
