1620 Geographos
A three-dimensional model of 1620 Geographos based on its light curve | |
Discovery | |
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Discovered by | Albert George Wilson, Rudolph Minkowski |
Discovery date | September 14, 1951 |
Designations | |
Named after | National Geographic Society |
1951 RA | |
Apollo, PHA,[1] Mars-crosser | |
Orbital characteristics[1] | |
Epoch March 6, 2006 (JD 2453800.5) | |
Aphelion | 1.663 AU (248.810 Gm) |
Perihelion | 0.828 AU (123.817 Gm) |
1.245 AU (186.314 Gm) | |
Eccentricity | 0.335 |
1.39 yr (507.665 d) | |
Average orbital speed | 25.92 km/s |
147.839° | |
Inclination | 13.341° |
337.293° | |
276.793° | |
Physical characteristics | |
Dimensions | 5.1×1.8 km[1] |
0.217 d (5.223 h)[1] | |
Albedo | 0.325[1] |
Temperature | ~249 K |
Spectral type | S[1] |
15.60[1] | |
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The asteroid 1620 Geographos /dʒiːoʊˈɡræfɒs/ was discovered on September 14, 1951, at the Palomar Observatory by Albert George Wilson and Rudolph Minkowski. It was originally given the provisional designation 1951 RA. Its name, a Greek word meaning "geographer" (geo– 'Earth' + graphos 'drawer/writer'), was chosen to honour geographers and the National Geographic Society.
Geographos is a Mars-crosser asteroid and a near-Earth object belonging to the Apollos. In 1994, during the asteroid's closest approach to Earth in two centuries at 5.0 Gm-which will not be bettered until 2586- a radar study of it was conducted by the Deep Space Network at Goldstone, California. The resultant images show Geographos to be the most elongated object in the solar system; it measures 5.1×1.8 km.
Geographos is an S-type asteroid, meaning that it is highly reflective and composed of nickel-iron mixed with iron- and magnesium-silicates.
Geographos was to be explored by the U.S.'s Clementine mission; however, a malfunctioning thruster ended the mission before it could approach the asteroid.
1620 Geographos is a potentially hazardous asteroid (PHA) because its minimum orbit intersection distance (MOID) is less than 0.05 AU and its diameter is greater than 150 meters. The Earth-MOID is 0.0304 AU (4,550,000 km; 2,830,000 mi).[1] Its orbit is well-determined for the next several hundred years.
References
External links
- Orbital simulation from JPL (Java) / Horizons Ephemeris
- NASA Asteroid Radar Research - Radar-Detected Asteroids: 1620 Geographos
- Large amplitude fast rotator (Yahoo Groups)
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