The Caldwell Objects

stretch 16 billion km from the central star. HST's
high-resolution spectrograph also has resolved
individual gas blobs that can fade or disappear in
days or weeks. As more data are gathered, a new
picture of Eta Carinae is emerging from its
shroud of stellar mystery. Eta Carinae is most
likely a binary star, and the "napkin ring" is the
outer mantle of one of the binary's two stars,
which was shed some 1,000 or 2,000 years before
the system assumed its
92
present appearance. The material was stripped
from the star and yanked away by the gravity of
its stellar companion. Thus stripped of some of
its mass, this "naked" star became unstable,
leading to the powerful 1843 blast. The spectral
signature of the torus supports this theory, for it
is nitrogen-rich and oxygen- and carbon-poor,
implying that it contains processed material from
the star's interior.
At radio wavelengths, writes Davidson,
The Caldwell Objects 365