NationMaster - Encyclopedia: 4769 Castalia

The asteroid 4769 Castalia (previously known by the provisional designation 1989 PB) was the first asteroid to be directly imaged. It is an Apollo, Mars- and Venus-crosser asteroid. It was discovered on August 9, 1989 by Eleanor F. Helin (Caltech) on photographic plates taken at Palomar Observatory. It is named after Castalia, a nymph in Greek mythology. A 3D computer model of the different faces of Asteroid 4769 Castalia Copyright status Copyright © American Association for the Advancement of Science. ... A 3D computer model of the different faces of Asteroid 4769 Castalia Copyright status Copyright © American Association for the Advancement of Science. ... In physics, an orbit is the path that an object makes, around another object, whilst under the influence of a source of centripetal force, such as gravity. ... Jump to: navigation, search Near-Earth asteroids (NEAs) are asteroids whose orbit intersects Earths orbit and which may therefore pose a collision danger, as well as being most easily accessible for spacecraft from Earth. ... A Venus-crosser asteroid is an asteroid whose orbit crosses that of Venus. ... A Mars-crosser asteroid is an asteroid whose orbit crosses that of Mars. ... In geometry, the semi-major axis (also semimajor axis) a applies to ellipses and hyperbolas. ... The astronomical unit (AU or au or a. ... In astrodynamics, under standard assumptions any orbit must be of conic section shape. ... The orbital period is the time it takes a planet (or another object) to make one full orbit. ... Jump to: navigation, search A year is the time between two recurrences of an event related to the orbit of the Earth around the Sun. ... Inclination is one of the six orbital parameters describing the shape and orientation of a celestial orbit and is the angular distance of the orbital plane from the plane of the reference (usually planets equator or the ecliptic), stated in degrees. ... For the geometric term, see diameter. ... A kilometre (American spelling: kilometer) (symbol: km) is a unit of length equal to 1000 metres (from the Greek words khilia = thousand and metro = count/measure). ... Jump to: navigation, search Mass is a property of physical objects that, roughly speaking, measures the amount of matter they contain. ... Jump to: navigation, search The international prototype, made of platinum-iridium, which is kept at the BIPM under conditions specified by the 1st CGPM in 1889. ... Jump to: navigation, search Density (symbol: Ï - Greek: rho) is a measure of mass per unit of volume. ... Jump to: navigation, search An asteroid is a small, solid object in our Solar System, orbiting the Sun. ... Approximately 17% of all known asteroids are of an S-type (for stony) composition. ... The albedo is a measure of reflectivity of a surface or body. ... Eleanor Francis Helin is an American astronomer, principal investigator of the Near Earth Asteroid Tracking (NEAT) program of NASAs Jet Propulsion Laboratory. ... Jump to: navigation, search August 9 is the 221st day of the year in the Gregorian Calendar (222nd in leap years), with 144 days remaining. ... Jump to: navigation, search 1989 (MCMLXXXIX) is a common year starting on Sunday of the Gregorian calendar. ... The provisional designation of comets and asteroids are similar to each other: they both follow a pattern set in 1925 by the Minor Planet Center of the IAU. Historical designations At first, astronomers strove to assign symbols to the minor planets: 1 Ceres a stylized sickle 2 Pallas a lozenge... Jump to: navigation, search An asteroid is a small, solid object in our Solar System, orbiting the Sun. ... The Apollo asteroids are a group of near-Earth asteroids named after 1862 Apollo, the first asteroid of this group to be discovered. ... A Mars-crosser asteroid is an asteroid whose orbit crosses that of Mars. ... A Venus-crosser asteroid is an asteroid whose orbit crosses that of Venus. ... Jump to: navigation, search August 9 is the 221st day of the year in the Gregorian Calendar (222nd in leap years), with 144 days remaining. ... Jump to: navigation, search 1989 (MCMLXXXIX) is a common year starting on Sunday of the Gregorian calendar. ... Eleanor Francis Helin is an American astronomer, principal investigator of the Near Earth Asteroid Tracking (NEAT) program of NASAs Jet Propulsion Laboratory. ... California Institute of Technology The California Institute of Technology (commonly known as Caltech) is a private, coeducational university located in Pasadena, California, in the United States. ... Palomar Observatory is a privately-owned observatory located in San Diego County, California, 90 miles (145 km) southeast of Mount Wilson Observatory, on Palomar Mountain. ... Castalia, in Greek and Roman mythology was a nymph whom Apollo transformed into a fountain at Delphi, at the base of Mt. ... Jump to: navigation, search Hylas and the Nymphs by John William Waterhouse In Greek mythology, a nymph is any member of a large class of female nature spirits, sometimes bound to a particular location or landform. ... Jump to: navigation, search Greek mythology comprises the collected narratives of Greek gods, goddesses, heroes, and heroines, originally created and spread within an oral-poetic tradition. ...

General information

Castalia's orbit took it within eleven lunar distances of Earth, allowing it to be scanned with radar from the Arecibo Observatory by Scott Hudson (Washington State University) and Steven J. Ostro (JPL). The obtained data allowed astronomers to produce a three-dimensional computer model of it. In physics, an orbit is the path that an object makes, around another object, whilst under the influence of a source of centripetal force, such as gravity. ... In celestial navigation, lunar distance is in the angle of the Moons centre from the Sun or from the bright stars. ... Jump to: navigation, search Earth, also known as the Earth, Terra, and (mostly in the 19th century) Tellus, is the third-closest planet to the Sun. ... Jump to: navigation, search This long range radar antenna (approximately 40m (130ft) in diameter) rotates on a track to observe activities near the horizon. ... Jump to: navigation, search The Arecibo Observatory is located in Arecibo, Puerto Rico on the north coast of the island. ... Scott Hudson is a professor at the Washington State University. ... Jump to: navigation, search Washington State University Aerial View of Pullman Campus For the state of Washington in the United States, see Washington Washington State University (WSU) is a public research university in Pullman, Washington, United States. ... Steven J. Ostro is an astronomer at the Jet Propulsion Laboratory of the National Aeronautics and Space Administration. ... Jump to: navigation, search The Caltech Jet Propulsion Laboratory (JPL), in La CaÃ±ada Flintridge, near Pasadena, California, USA, builds and operates unmanned spacecraft for the National Aeronautics and Space Administration (NASA). ... An astronomer or astrophysicist is a scientist whose area of research is astronomy or astrophysics. ... A computer simulation or a computer model is a computer program which attempts to simulate an abstract model of a particular system. ...

Castalia was found to have a peanut shape, suggesting two 800 m diameter pieces held together by their weak mutual gravity. Since then radar measurements of other asteroids has indicated that this contact binary arrangement appears to be common.

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Category: Apollo asteroids Jump to: navigation, search Minor planets, or planetoids are minor bodies of the Solar system orbiting the Sun (or of other planetary systems orbiting other stars) that are larger than meteoroids (the largest of which might be taken to be around 10 meters or so across) but smaller than major... Vulcanoids are hypothetical asteroids that may orbit in a dynamically stable zone between 0. ... The asteroid belt is a region of the solar system falling roughly between the planets Mars and Jupiter where the greatest concentration of asteroid orbits can be found. ... Jump to: navigation, search Near-Earth objects (NEO) are asteroids, comets and large meteoroids whose orbit intersects Earths orbit and which may therefore pose a collision danger. ... Image of the Trojan asteroids in front of and behind Jupiter along its orbital path. ... The centaurs are a class of icy planetoids that orbit the Sun between Jupiter and Neptune, named after the mythical race of centaurs. ... Damocloids are asteroids such as 5335 Damocles and (16746) 1996 PW that have long-period highly eccentric orbits typical of periodic comets such as 1P/Halley, but without showing a cometary coma or tail. ... Photo of the comet Hale-Bopp above a tree. ... A trans-Neptunian object (TNO) is any object in the solar system which orbits the sun at a greater distance on average than Neptune. ... Artists rendering of the Kuiper Belt and more distant Oort cloud. ... The scattered disc (or scattered disk) is a distant region of our solar system, thinly populated by a subset of the family of trans-Neptunian objects known as scattered disk objects (SDOs). ... Jump to: navigation, search This image is an artists rendering of the Oort cloud and the Kuiper Belt. ... 243 Ida and its moon Dactyl An asteroid moon is an asteroid that orbits another asteroid. ... Jump to: navigation, search Presentation of the solar system (not to scale) The solar system is the retinue of objects gravitationally bound to our Sun. ... This is a list of numbered asteroids, in sequential order. ... This page alphabetically lists the first thousand asteroids to be numbered, which are mostly in the main belt. ...