protoplanet


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Related to protoplanet: protoplanetary, Protoplanet theory

protoplanet

(proh -toh-plan-it) An evolving planet in the process of accretion, together with any of its satellites forming by accretion at the same time in the vicinity of the planet. The dust cocoon around some T Tauri stars has the attributes of a protoplanetary system. In the one typical case, HL Tauri, it forms a flattened disk, radius 160 AU, containing about one Earth mass of dust; allowing for dust condensed into planetesimals and the system's gas content, it could condense into several planets. Infrared observations from the satellite IRAS show dust around over 40 slightly older stars, including Vega, indicating either a protoplanetary system or a swarm of comets. See also Beta Pictoris.

protoplanet

[′prōd·ō‚plan·ət]
(astronomy)
A precursor of one of the giant planets, which is believed to have formed, along with its satellites, from a minisolar nebula in a manner similar to that of the formation of the sun and planets.
References in periodicals archive ?
It took about 95,000 photographs of the dwarf planet and protoplanet and collected over 167 GB of scientific data.
According to the simulations, the protoplanet would have been twice as big as our Earth, which means the interaction was probably strong enough to smack Uranus (14 times bigger than Earth) sideways, but not enough to strip the planet's atmosphere.
A team of scientists under Stephanie Sallum in Tucson, Arizona used adaptive optics observations to record these protons and thereby detect the formation of the protoplanet, which orbits a relatively young star just two million years old.
It involves devastating collisions with other small protoplanets, as well as with a multitude of showering, tumbling worldlets.
If we assume that a protoplanet took about a million years to lose most of its volatile elements, then c is found to be ~[10.sup.-3].
Lastly, water, once it is formed, must be gathered together on a protoplanet before life can evolve--essential sequencing.
By that time, most of the iron and other heavy elements had already settled into the cores of each protoplanet, which merged inside Earth after the impact.
During the primary mission, Dawn orbited and accomplished all of its original objectives at Ceres and protoplanet Vesta, which the spacecraft visited from July 2011 to September 2012.
Dawn previously explored the protoplanet Vesta for 14 months, from 2011 to 2012, capturing detailed images and data about that body.
These impish nicknames arise from the fundamental basis of the theory: a Mars-sized protoplanet, named Theia by astronomers, crashed into the primordial Earth billions of years ago.
Dawn's exploration of protoplanet Vesta revealed to us that it was very similar to Earth than to typical asteroids.