NGC 4361, Corvus

A star in the end stage of its evolutionary life, it has thrown off its outer layers to expose the intensely hot core to form a short-lived (in cosmic terms) planetary nebula. The radiation of the core (central white-dwarf star) causes the thrown-off layers to fluoresce, often in the colours of hydrogen (red) and oxygen III (blue-green) as demonstrated by this planetary nebula. However this central star is special: having a surface temperature of 270,000 K, it is the hottest star known that is composed of atomic matter (as opposed to neutron stars which are composed of nuclear matter). Its distance from us is estimated to be about 3400 ly.