Q&A: Normal Stars, White Dwarf Stars, and Star Clusters
Can a black dwarf become a nebula and a black hole both?
The term "nebula" was in the past applied by astronomers to
all kinds of hazy patches in the sky, so many different types
of objects have the name "Nebula" attached to them. The Orion
Nebula, and the Eagle Nebula are regions where new stars are
forming, whereas a planetary nebula and the Crab Nebula are
caused by the last stages of a normal star's existence, and
the Andromeda Nebula is an entire galaxy of stars!
"Black dwarf" is a term that is sometimes used to describe a
white dwarf star that has cooled to become very cold and
dark. It will not turn into a black hole unless a large
amount of matter falls onto its surface from a nearby star.
Even in that case, it is more likely to explode and become a
supernova, which could leave behind a nebula.
For recent research on nebulas, see the latest image of N132D
on the Chandra web site.