- Betelgeuse (stars.astro.illinois.edu)
BETELGEUSE (Alpha Orionis). The great star Betelgeuse is one of the two that dominate mighty Orion of northern winter, the other Rigel, the pair respectively also called Alpha and Beta Orionis.
- Planetary nebula (Wikipedia)
A planetary nebula is a type of emission nebula consisting of an expanding, glowing shell of ionized gas ejected from red giant stars late in their lives.