planetary nebula
noun
: a usually compact luminous ring-shaped nebula that is composed of matter which has been ejected from a hot star at its center
Examples of planetary nebula in a Sentence
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Amateur astronomers can squint into an eight-inch Schmidt-Cassegrain telescope and learn how to identify a dwarf galaxy from a planetary nebula.
—
Mark Johanson, Outside, 18 Mar. 2026
The Cat's Eye Nebula is known as a planetary nebula, but that name is somewhat misleading, as these clouds of ionized gas don't have anything to do with planets.
—Brett Tingley, Space.com, 10 Mar. 2026
Finally, its now-inert core contracts down to form a white dwarf, while the prior ejecta get heated up and ionized, creating a planetary nebula.
—Big Think, 20 Feb. 2026
But the appearance of planetary nebulas has little to do with planets at all—these nebulas are actually roiling clouds of hot gas that emanate from dying sunlike stars and linger after their deaths.
—Joseph Howlett, Scientific American, 20 Jan. 2026
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Mark Johanson, Outside, 18 Mar. 2026
The Cat's Eye Nebula is known as a planetary nebula, but that name is somewhat misleading, as these clouds of ionized gas don't have anything to do with planets.
—Brett Tingley, Space.com, 10 Mar. 2026
Finally, its now-inert core contracts down to form a white dwarf, while the prior ejecta get heated up and ionized, creating a planetary nebula.
—Big Think, 20 Feb. 2026
But the appearance of planetary nebulas has little to do with planets at all—these nebulas are actually roiling clouds of hot gas that emanate from dying sunlike stars and linger after their deaths.
—Joseph Howlett, Scientific American, 20 Jan. 2026
See All Example Sentences for planetary nebula
Cite this Entry
“Planetary nebula.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/planetary%20nebula. Accessed 5 Apr. 2026.
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