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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Initial observations of the detailed map have already revealed around 500 planetary nebulas—dust and gas from dying stars—that reside in the galaxy.
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Margherita Bassi, Smithsonian Magazine, 23 June 2025
When this happens, a sun-like star's outer layers expand, transforming the star into a red giant, which eventually casts its outer layers adrift into space, forming a planetary nebula.
—Keith Cooper, Space.com, 8 July 2025
Normally, astronomers can only identify about 100 planetary nebulas in galaxies that lie outside of Earth’s neighborhood.
—Margherita Bassi, Smithsonian Magazine, 23 June 2025
The snapshot above showcases NGC 1514, a planetary nebula that resides roughly 1,500 light-years from Earth in the constellation Taurus.
—Sharmila Kuthunur, Space.com, 15 Apr. 2025
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Margherita Bassi, Smithsonian Magazine, 23 June 2025
When this happens, a sun-like star's outer layers expand, transforming the star into a red giant, which eventually casts its outer layers adrift into space, forming a planetary nebula.
—Keith Cooper, Space.com, 8 July 2025
Normally, astronomers can only identify about 100 planetary nebulas in galaxies that lie outside of Earth’s neighborhood.
—Margherita Bassi, Smithsonian Magazine, 23 June 2025
The snapshot above showcases NGC 1514, a planetary nebula that resides roughly 1,500 light-years from Earth in the constellation Taurus.
—Sharmila Kuthunur, Space.com, 15 Apr. 2025
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 4 Aug. 2025.
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