Vulcanoid asteroids are a special group of asteroids which may orbit close to the Sun, closer than the orbit of the planet Mercury. No vulcanoid has ever been discovered; it is not known if they ever existed. Because they would orbit so close to the Sun they could only be seen during twilight, or a solar eclipse. There very small size could make them impossible to see. This part of the Solar System is described as being gravitationally stable, and every other similar stable area has asteroids. If they do exist, vulcanoids would be made of material that would help explain the formation of the planets. If they do not exist, then theories about how the planets were formed might have to change. They are called vulcanoids after a planet, Vulcan, which early astronomers thought they had seen close to the Sun.
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- "Vulcanoids". The Planetary Society. http://www.planetary.org/programs/projects/vulcanoids/. Retrieved 2008-12-25.
- Britt, Robert Roy (2004). "Vulcanoid search reaches new heights". Space.com. http://www.msnbc.msn.com/id/4066544/. Retrieved 2008-12-25.
- "NASA Dryden, Southwest Research Institute Search for Vulcanoids". NASA. 2002. http://www.nasa.gov/centers/dryden/news/NewsReleases/2002/02-20.html. Retrieved 2008-12-25.
- Campins, H.; Davis, D. R.; Weidenschilling, S. J.; Magee, M. (1996). "Searching for Vulcanoids". Completing the Inventory of the Solar System, Astronomical Society of the Pacific Conference Proceedings 107: 85–96.
- Standage, Tom (2000). The Neptune File. Harmondsworth, Middlesex, England: Allen Lane, The Penguin Press. pp. 144–149. ISBN 0-713-99472-X.
☾ = moon(s) ∅ = rings
|Mercury||Venus||Earth ☾||Mars ☾|
|Jupiter ☾ ∅||Saturn ☾ ∅||Uranus ☾ ∅||Neptune ☾ ∅|
|Dwarf planets||Ceres||Pluto ☾||Haumea ☾||Makemake|
|Groups and families: Vulcanoids · Near-Earth asteroids · Asteroid belt
Jupiter Trojans · Centaurs · Neptune Trojans · Asteroid moons · Meteoroids · Pallas · Juno · Vesta · Hygiea · Interamnia · Europa
|See also the list of asteroids.|
|Kuiper belt – Plutinos: Orcus · Ixion – Cubewanos: Varuna ·
Quaoar · Huya
|Scattered disc: Sedna|
|Comets||Periodic comets and non-periodic comets
Damocloids · Oort cloud
|See also the list of solar system objects|