New moons make Uranus the champ.Astronomers have discovered two small bodies that are almost certainly moons of Uranus Uranus has twenty-seven known moons. The first two moons (Titania and Oberon) were discovered by William Herschel on March 13, 1787. Two more moons (Ariel and Umbriel) were discovered by William Lassell in 1851. . If the discovery is confirmed, this distant planet would have 20 known moons--more than any other planet in the solar system solar 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. . The former champion, Saturn, would become the runner-up, with 18 satellites. J.J. Kavelaars of McMaster University McMaster University, at Hamilton, Ont., Canada; nondenominational; founded 1887. It has faculties of humanities, science, social sciences, business, engineering, and health sciences, as well as a school of graduate studies and a divinity college. in Hamilton, Ontario, and his colleagues announced their finding in a July 27 circular of the International Astronomical Union “IAU” redirects here. For other uses, see IAU (disambiguation). The International Astronomical Union (IAU) unites national astronomical societies from around the world. . The team used the 3.5-meter Canada-France-Hawaii Telescope The Canada-France-Hawaii Telescope is located near the mountain top of Mauna Kea in Hawaii at an altitude of 4,204 meters (13,793 feet). It is a Prime Focus/Cassegrain configuration with a usable aperture diameter of 3.58 meters. atop Hawaii's Mauna Kea Mauna Kea (mou`nə kā`ə), dormant volcano, 13,796 ft (4,205 m) high, in the south central part of the island of Hawaii. It is the loftiest peak in the Hawaiian Islands and the highest island mountain in the world, rising c. to spy objects in the outer solar system's reservoir of comets, the Kuiper belt, as well as to search the vicinity of Uranus. A search within 100 million kilometers of the planet revealed only the two bodies. There's a small possibility, says Kavelaars, that these small bodies are not satellites of Uranus but escapees from the Kuiper belt that are orbiting the sun. However, both the location and the speed of the faint objects--they lie near Uranus and appear to move with the planet--make that possibility remote, he says. The researchers estimate that each body has a diameter less than 20 km and resides several million kilometers from the planet. Two years ago, using the 5-meter Hale Telescope on Palomar Mountain near Escondido, Calif., Kavelaars and his colleagues discovered the 16th and 17th moons of Uranus (SN: 12/6/97, p. 360). This past spring; Erich Karkoschka of the University of Arizona (body, education) University of Arizona - The University was founded in 1885 as a Land Grant institution with a three-fold mission of teaching, research and public service. in Tucson, found an 18th moon in images taken by the Voyager 2 spacecraft as it flew past the planet. The moons found by Kavelaars' team in 1997, as well as the objects announced in July, share an unusual trait. They are the only bodies with orbits inclined relative to the planet's equator. Kavelaars suggests that soon after Uranus formed, two chunks of debris that resided near the planet collided and broke into fragments. The fragments then passed through gas in Uranus' young, bloated atmosphere that slowed them down until they were captured by the planet's gravitational field. If the collision theory is correct, Uranus may have several more moons, but most would be too small and dim to detect, Kavelaars says. |
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