Nebulae

thumb|right|upright=1.5|True color image of the Trifid Nebula, showing complex gas and plasma structure

type of interstellar cloud

astronomical object type

large, low-density cloud of partially ionized hydrogenium

cloud of ionized gas emitting light of various colors

remnants of an exploded star

nebulosity in astronomy

accumulation of gas, plasma and dust in a galaxy

small patches of nebulosity associated with newly born stars

torus, pancake or ring-shaped accumulation of matter in orbit around a star

interstellar cloud composed of neutral atomic hydrogen

any astronomical object that is not an individual star

type of astronomical object

astronomical object

nebula powered by the pulsar wind of a pulsar

distinctive nebular formation

Nebula with varying brightness

thumb|right|Cat's Eye Nebula (NGC 6543) thumb|Cat's Eye Nebula (NGC 6543) Nebulium was a proposed element found in astronomical observation of a nebula by William Huggins in 1864. The strong green emission lines of the Cat's Eye Nebula, discovered using spectroscopy, led to the postulation that an as yet unknown element was responsible for this emission. In 1927, Ira Sprague Bowen showed that the lines are emitted by doubly ionized oxygen (new style O; old style O), and no new element was necessary to explain them.

region of hydrogen gas in outer space large enough to shield gas from ionizing UV rays

nebula which surrounds a Wolf–Rayet star

molecular cloud with speed greater than 90 km/s

astrophotometrical unit for x-ray sources

extra-planar nebulae