dwarf planet


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dwarf planet,

a nonluminous body of rock or gas that orbits the sun and has a rounded shape due to its gravity. Unlike a planetplanet
[Gr.,=wanderer], a large nonluminous body of rock or gas that orbits the sun or another star, has a rounded shape due to gravity, and has cleared its orbit of smaller objects.
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, a dwarf planet is not capable of clearing its orbit of smaller objects by collision, capture, or other means. The known dwarf planets in the solar systemsolar system,
the sun and the surrounding planets, natural satellites, dwarf planets, asteroids, meteoroids, and comets that are bound by its gravity. The sun is by far the most massive part of the solar system, containing almost 99.9% of the system's total mass.
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 include CeresCeres
, in astronomy, a dwarf planet, the first asteroid to be discovered. It was found on Jan. 1, 1801, by G. Piazzi. He took three distinct observations; on the basis of these the mathematician Gauss calculated Ceres' orbit with such accuracy that it was found one year later
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, PlutoPluto,
in astronomy, a dwarf planet and the first Kuiper belt, or transneptunian, object (see comet) to be discovered (1930) by astronomers. Pluto has an elliptical orbit usually lying beyond that of Neptune.
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, and ErisEris,
in astronomy, the largest known dwarf planet. Eris, whose highly eccentric elliptical orbit ranges from 38 AU to 97 AU and is inclined more than 44°, is the largest known object of the Kuiper belt (see comet), with a diameter (1,445 mi/2,317 km) slightly larger than
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. All of these are significantly smaller in size and mass than Mercury. Eris, which is slightly larger than Pluto, is the largest known dwarf planet. Except for Ceres, all known dwarf planets follow orbits that lie or take them beyond Neptune into the outer reaches of the solar system.

Ceres and Pluto have been considered planets at time in the past. The discovery of other bodies in the asteroidasteroid,
 planetoid,
or minor planet,
small body orbiting the sun. More than 300,000 asteroids have been identified and cataloged; more than a million are believed to exist in the main belt between Mars and Jupiter, with many more in the Kuiper belt
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 belt led to the reclassification of Ceres in the mid-19th cent. as an asteroid. The discovery of other bodies beyond the orbit of Neptune that were similar in size to Pluto led to the declassification of Pluto as a planet in 2006, when the International Astronomical Union adopted the classification of dwarf planet.

dwarf planet

Any of the four terrestrial planets.
References in periodicals archive ?
Some scientists, like Brown, think that creating a class of dwarf planets was the right decision.
The new findings by astronomers at the California Institute of Technology (Caltech) also suggest that the red-tinged dwarf planet may be covered in a thin layer of methane, the remnants of an atmosphere that's slowly being lost into space.
NASA used data from the dwarf planet and its atmosphere to create this image that shows the layer of haze surrounding Pluto.
13 that reveal a white spot on the dwarf planet and the suggestion of craters.
The new findings also suggested that the red-tinged dwarf planet might be covered in a thin layer of methane, the remnants of an atmosphere that's slowly being lost into space.
This takes a big chunk out of the little heat that manages to make it all the way out to the dwarf planet in the far reaches of our solar system.
Just as genetic analyses are revealing details of life's long history, the New Horizons probe is bringing the fuzzy surface of the faraway dwarf planet Pluto into focus.
ySTANBUL (CyHAN)- Analyzing data from Herschel infrared observatory astronomers reports that dwarf planet Ceres, one of most amazing bodies of the solar system may have huge water reserves.
Washington, July 21 (ANI): While searching for rings around Pluto using the Hubble Space Telescope, NASA astronomers have discovered a fourth moon circling the dwarf planet.
The findings, along with other shreds of evidence, point to recent geological activity on Ceres that has led the team to believe that the dwarf planet could have had an ocean in the past.