Dwarf planet definition: A dwarf planet is an object in space that is like a small planet but does not completely... | Meaning, pronunciation, translations and examples The International Astronomical Union (IAU) defines a dwarf planet as a celestial body in direct orbit of the Sun that is massive enough for its shape to be controlled by gravitation but which has not cleared its orbital region of other objects. [4] Thus Stern and many other planetary geologists distinguish dwarf planets from classical planets, but since 2006 the IAU and the majority of astronomers have excluded bodies such as Eris and Pluto from the roster of planets altogether. noun Astronomy . Vesta, the next-most-massive body in the asteroid belt after Ceres, was once in hydrostatic equilibrium and is roughly spherical, deviating mainly because of massive impacts that formed the Rheasilvia and Veneneia craters after it solidified. In a draft resolution for the IAU definition of planet, both Pluto and Charon were considered planets in a binary system. Copyright © 2014 by Houghton Mifflin Harcourt Publishing Company. Alan Stern calls planetary-mass moons "satellite planets", one of three categories of planet, together with dwarf planets and classical planets. In 2006, a new and distinct class of celestial objects was named by the International Astronomical Union (IAU). Pluto is a relatively small planetoid, smaller than the Earth's moon. Currently, five dwarf planets, namely Ceres, Pluto, Eris, Haumea, and Makemake, have been discovered. A dwarf planet could be in for a bumpy ride as it travels - its path is full of other objects like asteroids. [62], NASA announced in 2006 that it would use the new guidelines established by the IAU. [45] The value of this parameter in Stern's model is proportional to the square of the mass and inversely proportional to the period. And membership is growing fast. Information and translations of dwarf planets in the most comprehensive dictionary definitions resource on the web. [43], Using this parameter, Steven Soter and other astronomers argued for a distinction between planets and dwarf planets based on the inability of the latter to "clear the neighbourhood around their orbits": planets are able to remove smaller bodies near their orbits by collision, capture, or gravitational disturbance (or establish orbital resonances that prevent collisions), whereas dwarf planets lack the mass to do so. dwarf planet synonyms, dwarf planet pronunciation, dwarf planet translation, English dictionary definition of dwarf planet. The half-dozen largest candidates have either been visited by spacecraft (Pluto and Ceres) or have at least one known moon (Pluto, Eris, Haumea, Makemake, Gonggong, Quaoar), which allows their masses and thus an estimate of their densities to be determined. And Pluto is a fascinating little world, no matter what you call it. [16], Eris (then known as 2003 UB313) was discovered in January 2005;[17] it was thought to be slightly larger than Pluto, and some reports informally referred to it as the tenth planet. More explicitly, the International Astronomical Union defines a dwarf planet as a celestial body in direct orbit of the Sun that is massive enough for its shape to be controlled by gravitation, but that unlike a planet has not cleared its orbital region of other objects. ", "Hubble Observes Planetoid Sedna, Mystery Deepens", California Institute of Technology, Retrieved 4-12-2015, "Astronomers Measure Mass of Largest Dwarf Planet", "Conversion of Absolute Magnitude to Diameter for Minor Planets", "Plutoid chosen as name for Solar System objects like Pluto", "Dawn Data Reveal Ceres' Complex Crustal Evolution", "2007 OR10: Largest Unnamed World in the Solar System", "The IAU draft definition of "planet" and "plutons, "Sounds of the solar system: probing Pluto's predicted score", "Comments & discussions on Resolution 5: The definition of a planet – Planets Galore", "Dos uruguayos, Julio Fernández y Gonzalo Tancredi en la historia de la astronomía:reducen la cantidad de planetas de 9 a 8 ...&Anotaciones de Tancredi", Division III (Planetary Systems Sciences): Triennial Report 2006–2009, "Ice Volcanoes and More: Dwarf Planet Ceres Continues to Surprise", "Regarding the criteria for planethood and proposed planetary classification schemes", 'How many dwarf planets are there in the outer solar system? [51] Researchers thought that the number of such bodies could prove to be around 200 in the Kuiper belt, with thousands more beyond. The question about planet versus dwarf planet led the IAU to create a committee to get the opinions of all of the professionals and scientists which later led to drafting a resolution about a planet’s definition that is called Resolution B5. Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. An extreme example of this is the Pluto–Charon system, where both bodies are tidally locked to each other. In most languages equivalent terms have been created by translating dwarf planet more-or-less literally: French planète naine, Spanish planeta enano, German Zwergplanet, Russian karlikovaya planeta (карликовая планета), Arabic kaukab qazm (كوكب قزم), Chinese ǎixíngxīng (矮行星), Korean waesohangseong or waehangseong (왜소행성; 矮小行星, 왜행성; 矮行星), but in Japanese they are called junwakusei (準惑星), meaning "quasi-planets" or "peneplanets". The largest TNOs that are not known to have moons are Sedna, 2002 MS4 and 2002 AW197. [56] Notably, Gonggong may have a larger diameter (1230±50 km) than Pluto's round moon Charon (1212 km). This definition was made on August 24, 2006 by the International Astronomical Union (IAU), and can be described as; a dwarf planet is a body orbiting the Sun that is big enough to round itself by its own gravity, but has not cleared its orbital path of other rival bodies. And membership is growing fast. This value can be used to estimate the capacity of a body to clear the neighbourhood of its orbit, where Λ > 1 will eventually clear it. Change your default dictionary to American English. Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free! What does dwarf planets mean? : a celestial body that orbits the sun and has a spherical shape but is not large enough to disturb other objects from its orbit. If the body has a massive nearby companion, then tidal forces cause its rotation to gradually slow until it is tidally locked, such that it always presents the same face to its companion. (dwôrf) A celestial body that orbits the sun, is large enough to have a nearly round shape, does not clear the neighborhood around its orbit, and is not a satellite of a planet. There is no defined upper limit, and an object larger or more massive than Mercury that has not "cleared the neighbourhood around its orbit" would be classified as a dwarf planet. Astronomers coined the term “dwarf planet” to reclassify Pluto, which would become a representative of this new club of heavenly bodies. They vary in size, orbit and composition. Dropping Charon from the list, the new proposal also removed Pluto, Ceres, and Eris, because they have not cleared their orbits.[20]. Pronunciation . Individual astronomers have recognized a number of such objects as dwarf planets or as highly likely to prove to be dwarf planets. The five bodies recognized or named as dwarf planets by the IAU: This page was last edited on 6 May 2021, at 05:58. 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