• Planetary nebula - Wikipedia, the free encyclopedia

    en.wikipedia.org/wiki/Planetary_nebula Planetary nebulae are generally faint objects; none are visible to the naked eye. The first planetary nebula discovered was the Dumbbell Nebula in the constellation ...
  • What is a Planetary Nebula? | Planetary Nebula Definition

    www.space.com/17715-planetary-nebula.html Planetary nebulae are the cloudy remnants of smaller stars that have shed their outer layers of gas, but haven't exploded into supernovas.
  • Planetary Nebula Sampler

    www.noao.edu/jacoby A planetary nebula forms when a star can no longer support itself by fusion reactions in its center. ... Here are several rather unusal examples of planetary nebulae.
    • Planetary Nebulae - SEDS Messier Database

      messier.seds.org/planetar.html Planetary Nebulae are typically small, faint nebulae, found between the stars as comparatively rare objects. Once thought to be strange, odd objects, evidence has ...
    • Planetary nebulae - Scholarpedia

      www.scholarpedia.org/article/Planetary_nebulae Physical and spectral properties of planetary nebulae. Planetary nebulae are typically one light year across and are expanding at a rate of about 20-50 km per second.
    • APOD Index - Nebulae: Planetary Nebulae

      apod.nasa.gov/apod/planetary_nebulae.html Editor's choices for the most educational Astronomy Pictures of the Day about planetary nebulae: APOD: 2005 June 12 - M2 9: Wings of a Butterfly Nebula
    • What is a planetary nebula? | Cool Cosmos

      coolcosmos.ipac.caltech.edu/ask/225-What-is-a-planetary-nebula- What is a planetary nebula? | Cool Cosmos ... William Herschel called these spherical clouds planetary nebulae because they were round like the planets.
    • HubbleSite - Picture Album: Nebulae: Planetary

      hubblesite.org/gallery/album/nebula/planetary Picture Album: Nebulae: Planetary . Results per page:
    • Planetary nebula - Simple English Wikipedia, the free ...

      simple.wikipedia.org/wiki/Planetary_nebula Planetary nebula are not very bright. None of them are bright enough to see without a telescope. The first one discovered was the Dumbbell Nebula.
    • NASA – A Planetary Nebula Gallery

      www.nasa.gov/mission_pages/chandra/multimedia/planetary_nebula.html A Planetary Nebula Gallery. 10.10.12 . This gallery shows four planetary nebulas from the first systematic survey of such objects in the solar neighborhood made with ...