1620 Geographos
From Wikipedia, the free encyclopedia
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Discovery
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| Discovered by | Albert Wilson, Rudolph Minkowski |
| Discovery date | September 14, 1951 |
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Designations
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| Alternative names | 1951 RA |
| Minor planet category |
Apollo, Mars-crosser |
| Epoch March 6, 2006 (JD 2453800.5) | |
| Aphelion | 248.810 Gm (1.663 AU) |
| Perihelion | 123.817 Gm (0.828 AU) |
| Semi-major axis | 186.314 Gm (1.245 AU) |
| Eccentricity | 0.335 |
| Orbital period | 507.665 d (1.39 a) |
| Average orbital speed | 25.92 km/s |
| Mean anomaly | 147.839° |
| Inclination | 13.341° |
| Longitude of ascending node | 337.293° |
| Argument of perihelion | 276.793° |
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Physical characteristics
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| Dimensions | 5.1×1.8 km[1] |
| Mass | ~2.6×1013 kg |
| Mean density | 2.0? g/cm³ |
| Equatorial surface gravity | ~0.0008 m/s² |
| Escape velocity | ~0.0015 km/s |
| Rotation period | 0.217 d (5.223 h)[1] |
| Albedo | 0.325[1] |
| Temperature | ~249 K |
| Spectral type | S[1] |
| Absolute magnitude | 15.60[1] |
The asteroid 1620 Geographos (pronounced /dʒiːoʊˈɡræfɒs/) was discovered on September 14, 1951 at the Palomar Observatory by Albert Wilson and Rudolph Minkowski. It was originally given the provisional designation 1951 RA. Its name means geographer and was chosen to honour the National Geographic Society.
Geographos is 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.
[edit] References
[edit] External links
- Orbital simulation from JPL (Java) / Horizons Ephemeris
- NASA Asteroid Radar Research - Radar-Detected Asteroids: 1620 Geographos
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