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Encyclopedia > Vulcanoid asteroid

Vulcanoids are hypothetical asteroids that may orbit in a dynamically stable zone between 0.08 and 0.21 astronomical units from the Sun, well within the orbit of Mercury. They take their name from the hypothetical planet Vulcan, which eighteenth-century astronomers fruitlessly searched for to explain the excess precession of Mercury's perihelion. The anomaly in Mercury's orbit later turned out to be an effect explained by general relativity, removing the need to postulate the existence of Vulcan. An asteroid is a small, solid object in our Solar System, orbiting the Sun. ... The astronomical unit (AU or au or a. ... The Sun (or Sol) is the star at the center of our Solar system. ... Atmospheric characteristics Atmospheric pressure trace Potassium 31. ... Vulcan was the name given to a small planet supposed to exist in an orbit between Mercury and the Sun, in a 19th century hypothesis which has now been superseded by Albert Einsteins theory of general relativity. ... An astronomer or astrophysicist is a scientist whose area of research is astronomy or astrophysics. ... There are two types of precession, torque-free and torque-induced, the latter being discussed here in more detail. ... This article is about several astronomical terms (apogee & perigee, aphelion & perihelion, generic equivalents based on apsis, and related but rarer terms. ... General relativity (GR) is the geometrical theory of gravitation published by Albert Einstein in 1915. ...


No Vulcanoids have ever been found, despite ground-based searches and more recent searches by NASA using high-altitude F-18 aircraft and Black Brant suborbital rockets. Such searches are extremely difficult due to the glare of the Sun. Additionally, the SOHO space-based solar observatory would be able to see any bright objects near the Sun (for example, it has seen hundreds of small comets). If Vulcanoids exist, for the expected albedo they may be no more than 60 km in diameter, since previous searches would have found anything larger. NASA Logo Listen to this article · (info) This audio file was created from the revision dated 2005-09-01, and does not reflect subsequent edits to the article. ... The F/A-18 Hornet is an all-weather fighter and attack aircraft. ... A Black Brant XII launching from Wallops Island. ... Comet Hale-Bopp, showing a white dust tail and blue gas tail (February 1997) A comet is a small astronomical object similar to an asteroid but composed largely of ice. ... The albedo is a measure of reflectivity of a surface or body. ...


Nevertheless, it is thought Vulcanoids could exist because the region of space being searched is gravitationally stable, and all similarly stable regions of the solar system have been found to contain objects. Also, the heavily cratered surface of Mercury means a population of Vulcanoids probably existed in the very early days of the solar system. Presentation of the solar system (not to scale) The solar system comprises our Sun and the retinue of celestial objects gravitationally bound to it. ...


Future searches for Vulcanoids will likely use small space-based telescopes, which can see very close to the Sun. SOHO is not the best instrument for the task, but suitable spacecraft have been proposed to look for near-Earth objects. Near-Earth objects (NEO) are asteroids, comets and large meteoroids whose orbit intersects Earths orbit and which may therefore pose a collision danger. ...


Vulcanoid asteroids, if they exist, would be a special subclass of Apohele asteroids. Apohele asteroids are a subclass of Aten asteroids. ...


References

  • Britt, Robert R. (Jan. 26, 2004) Elusive Vulcanoids: Search Reaches New Heights


The minor planetsedit
Vulcanoids | Main belt | Groups and families | Near-Earth asteroids | Jupiter Trojans
Centaurs | Damocloids | Comets | Trans-Neptunians (Kuiper belt · Scattered disc · Oort cloud)
For other objects and regions, see: Binary asteroids, Asteroid moons and the Solar system
For a complete listing, see: List of asteroids. For pronunciation, see: Pronunciation of asteroid names.

 
 

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