protoplanet

American  

[proh-toh-plan-it] / ˈproʊ toʊˌplæn ɪt /

noun

Astronomy.

1. the collection of matter, in the process of condensation, from which a planet is formed.

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protoplanet British  

/ ˌprəʊtəʊˈplænɪt /

noun

1. a planet in its early stages of evolution by the process of accretion

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Etymology

Origin of protoplanet

First recorded in 1945–50; proto- + planet

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Example Sentences

See Examples For:

protoplanet

Instead, it was likely a differentiated body with an iron core surrounded by rocky material, similar to a small protoplanet or a differentiated asteroid.

From Science Daily ● Jun. 22, 2026

A giant collision between the young Earth and a smaller protoplanet has long been the prevailing theory for the Moon’s formation.

From Scientific American ● Nov. 2, 2023

The collision was so powerful, it broke apart that impacting protoplanet, nicknamed Theia, and sent huge amounts of material into orbit around Earth—material that eventually coalesced into the moon.

From National Geographic ● Nov. 1, 2023

But scientists have lacked smoking-gun evidence like a crater or pieces of the protoplanet, named Theia.

From New York Times ● Nov. 1, 2023

If a protoplanet gets to several Earth masses, it can grab a thick envelope of gas and become a gas giant like Jupiter or Saturn.

From Science Magazine ● Apr. 3, 2022

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