planetary nebula


Definition of planetary nebula

: 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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It's long been known that most stars wind up producing a planetary nebula, but astronomers thought the sun — a ball of superheated gas with a diameter 109 times that of Earth — was too small to form a visible nebula. David Freeman /, NBC News, "Now we know what will happen when the sun dies," 10 May 2018 Even stars that are just a few percent less massive than the sun will not produce a planetary nebula. Jason Daley, Smithsonian, "The Sun Will Produce a Beautiful Planetary Nebula When It Dies," 9 May 2018 That’s the Stingray Nebula, considered the youngest planetary nebula—a title given to nebulae born of a dying star—which became visible late last century. National Geographic, "The Giant Squid Nebula and More Animals of the Cosmos," 20 Mar. 2018

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'planetary nebula.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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First Known Use of planetary nebula

1785, in the meaning defined above

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The first known use of planetary nebula was in 1785

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readily or continually undergoing change

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