pro·​to·​star | \ ˈprō-tō-ˌstär How to pronounce protostar (audio) \

Definition of protostar

: a cloud of gas and dust in space believed to develop into a star

Examples of protostar in a Sentence

Recent Examples on the Web This creation story begins more than 4.5 billion years ago, when dust and gas from a giant molecular cloud gravitationally collapsed to create a protostar that would become our sun, surrounded by a spinning disk of gas and dust. Jonathan O'callaghan, Scientific American, "Asteroid Dust from Hayabusa2 Could Solve a Mystery of Planet Creation," 8 Dec. 2020 Masses of gas—mostly helium and hydrogen—within these stellar nurseries collapse under their own gravity and begin to heat up, forming a protostar. Jennifer Leman, Popular Mechanics, "What Are Stars?: A Guide," 13 June 2020 Because the dust in the nebulae obscures them, protostars can be difficult for astronomers to detect. Catherine Zuckerman, National Geographic, "Everything you wanted to know about stars," 20 Mar. 2019 One of these contracting masses of gas, known as a protostar, represents a star’s nascent phase. Catherine Zuckerman, National Geographic, "Everything you wanted to know about stars," 20 Mar. 2019 The forming star, or protostar, is about 11,000 light years away, in a much denser and more volatile region of the galaxy. Jay Bennett, Popular Mechanics, "Astronomers Catch Rare Sight of Incredibly Massive Star's Formation," 21 Aug. 2016 In the center, the material clumped together to form a protostar that would eventually become the sun. Valerie Strauss, Washington Post, "Facts about our sun and moon that you’re embarrassed to admit you don’t know," 9 Aug. 2017 This contact triggered a forceful explosion that hurled streams of dust, gas, and other protostars into interstellar space at speeds over 90 miles per second, according to a statement from the National Radio Astronomy Observatory (NRAO). Brigit Katz, Smithsonian, "Scientists Capture Beautiful, Explosive Collision of Young Stars," 12 Apr. 2017

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'protostar.' 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 protostar

1947, in the meaning defined above

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The first known use of protostar was in 1947

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Cite this Entry

“Protostar.” Dictionary, Merriam-Webster, Accessed 24 Feb. 2021.

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