/proh"toh plan'it/, n. Astron.
the collection of matter, in the process of condensation, from which a planet is formed.
[1945-50; PROTO- + PLANET]

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      in astronomical theory, a hypothetical eddy in a whirling cloud of gas or dust that becomes a planet by condensation during formation of a solar system. As the central body, or protostar, of the system contracts and heats up, the increasing pressure of its radiation is believed to drive off much of the thinner material of the protoplanets, particularly those closer to the nascent star.

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Universalium. 2010.

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  • Protoplanet — [zu griech. prõtos „erster“] ist nach der verbreitetsten Theorie die Bezeichnung für den Vorläufer eines Planeten. Das Entwicklungsstadium steht in der Planetengeschichte zwischen den Planetesimalen und den fertigen Planeten. Inhaltsverzeichnis 1 …   Deutsch Wikipedia

  • Protoplanet — Protoplanet,   eine Materieverdichtung, die als Vorstufe eines Planeten angesehen werden kann. (Planetenentstehung) …   Universal-Lexikon

  • protoplanet — [prōt′ō plan΄it] n. in some cosmological theories, any of the hundreds of swirling clouds of dust and gas that form around a star and eventually evolve into individual planets protoplanetary [prōt΄ō plan′i ter΄ē] adj …   English World dictionary

  • Protoplanet — Protoplanets are moon sized planets, or larger embryos within protoplanetary discs. They are believed to form out of kilometer sized planetesimals that attract each other gravitationally and collide. According to planet formation theory,… …   Wikipedia

  • protoplanet — noun Date: 1949 a hypothetical whirling gaseous mass within a giant cloud of gas and dust that rotates around a sun and is believed to give rise to a planet • protoplanetary adjective …   New Collegiate Dictionary

  • protoplanet — noun astronomical objects, approximately the size of the Moon, formed from the mutual gravitational attraction of planetesimals; they are thought to collide with each other and slowly form planets …   Wiktionary

  • protoplanet — n. cloud of cosmic gas and dust that orbits a star and is in the process of condensing to form a planet (Astronomy) …   English contemporary dictionary

  • protoplanet — pro·to·planet …   English syllables

  • Protoplanet —    Planetesimal which is growing by attracting nebular material, and is in the process of becoming a planet …   The writer's dictionary of science fiction, fantasy, horror and mythology

  • protoplanet — |prōd.ə+ noun Etymology: prot + planet : a whirling gaseous eddy within a giant cloud of gas and dust rotating around a sun believed to give rise to a planet …   Useful english dictionary

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