planetary nebula
Dying star's halo
A planetary nebula is a shell of glowing gas expelled by a dying star, surrounding the hot stellar core that remains.
Despite the name, planetary nebulae have nothing to do with planets—early astronomers thought their round, hazy appearance resembled distant planets through telescopes.
These nebulae mark a late stage in the life cycle of medium-sized stars like our sun: The Ring Nebula is one of the most famous planetary nebulae.
Aged star with cooled, expanded envelope
- white dwarfExhausted star's compact corpse
- stellar windStar's ejected particle stream
- mass lossReduction in matter
- black dwarfHypothetical cold stellar corpse
main sequence · nucleosynthesis · photosphere · protoplanetary · ionizing radiation
Simplest atomic element
- heliumLightest noble gas
- oxygenElement eight, colorless gas
- nitrogenElement seven, colorless gas
- carbonSixth element, atomic symbol C
neon · ionization · plasma · gas · dust · heavy elements · atomic transitions · recombination
Hard outer covering
- ringClosed curve shape
- helixSpiraling three-dimensional curve
- dumbbellHandheld exercise weight
- cat's eyeChatoyant gemstone variety
bipolar · halo · knots · filaments · lobes · jets · symmetry · morphology
Renowned astronomer's surname
- telescopeInstrument magnifying faraway objects
- spectroscopyStudy of light-matter interaction
- MessierAstronomer's deep-sky catalog
- emissionDischarged substance or act
ionized · spectrum · infrared · ultraviolet · narrowband · deep sky · astrophotography · exposure
Delicate beyond earthly measure
- luminousEmitting or reflecting light
- iridescentShowing shifting spectral colors
- colorfulFull of varied hues
- glowingGiving off steady light
radiant · cosmic · celestial · otherworldly · spectacular · delicate · wispy · gossamer
red giant
Aged star with cooled, expanded envelope
- white dwarfExhausted star's compact corpse
- stellar windStar's ejected particle stream
- mass lossReduction in matter
black dwarf · main sequence · nucleosynthesis · photosphere · protoplanetary · ionizing radiation
hydrogen
Simplest atomic element
carbon · neon · ionization · plasma · gas · dust · heavy elements · atomic transitions · recombination · photoionization
shell
Hard outer covering
cat's eye · bipolar · halo · knots · filaments · lobes · jets · symmetry · morphology · layers
Hubble
Renowned astronomer's surname
- telescopeInstrument magnifying faraway objects
- spectroscopyStudy of light-matter interaction
- MessierAstronomer's deep-sky catalog
emission · ionized · spectrum · infrared · ultraviolet · narrowband · deep sky · astrophotography · exposure · filter
ethereal
Delicate beyond earthly measure
- luminousEmitting or reflecting light
- iridescentShowing shifting spectral colors
- colorfulFull of varied hues
glowing · radiant · cosmic · celestial · otherworldly · spectacular · delicate · wispy · gossamer · vibrant
planetary nebulasupernova
Exploding massive star
supernova remnant · hypernova · neutron star · black hole · kilonova
planets, planetary, nebula, exoplanet, dwarf planet, nebulae, interplanetary, nebulas, nebular