White Dwarf
The dense, hot core left behind after a low- or intermediate-mass star expels its outer layers. White dwarfs are composed mostly of electron-degenerate matter and no longer undergo fusion.
Source: chandra.harvard.edu
APODs including "White Dwarf"
The Eye of an Hourglass Nebula
09/02/1996
What's happening in the eye-like center of this planetary nebula? The geometry revealed in this Hubble Space Telescope view of the central part of an "etched hourglass nebula" known as MyCn 18 presents a puzzle. First, the axis of this central region does not line up well with the outer hourglass structure. Next, the hot star (the white spot to the left of center) which ejected this gaseous nebula as it evolved towards its white dwarf phase, is not exactly at the center of the "eye". These unexpected results leave astronomers looking for the missing pieces of the ejection process that created this unusual and beautiful structure.