1620 Geographos
|
A three-dimensional model of 1620 Geographos based on its light curve | |
| Discovery | |
|---|---|
| Discovered by | Albert George Wilson, Rudolph Minkowski |
| Discovery date | 14 September 1951 |
| Designations | |
Named after | National Geographic Society |
| 1951 RA | |
| Apollo, PHA,[1] Mars-crosser | |
| Orbital characteristics[1] | |
| Epoch 13 January 2016 (JD 2457400.5) | |
| Uncertainty parameter 0 | |
| Observation arc | 23558 days (64.50 yr) |
| Aphelion | 1.6630 AU (248.78 Gm) |
| Perihelion | 0.82764 AU (123.813 Gm) |
| 1.2453 AU (186.29 Gm) | |
| Eccentricity | 0.33541 |
| 1.39 yr (507.61 d) | |
Average orbital speed | 25.92 km/s |
| 180.473° | |
| 0.70920°/day | |
| Inclination | 13.338° |
| 337.216° | |
| 276.879° | |
| Earth MOID | 0.029311 AU (4.3849 Gm) |
| Jupiter MOID | 3.45265 AU (516.509 Gm) |
| Physical characteristics | |
| Dimensions | 5.0×2.0×2.1 ± 0.15km[1] |
Mean radius | 1.28 ± 0.075 km |
| 5.22204 h (0.217585 d)[1] | |
| 0.3258 ± 0.051[1] | |
| Temperature | ~249 K |
| 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)
- 1620 Geographos at the JPL Small-Body Database
