1620 Geographos

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1620 Geographos
1620Geographos (Lightcurve Inversion).png
A three-dimensional model of 1620 Geographos based on its light curve.
Discovery
Discovered by Albert George Wilson, Rudolph Minkowski
Discovery date September 14, 1951
Designations
Named after
National Geographic Society
1951 RA
Minor planet category Apollo, Mars-crosser
Orbital characteristics[1]
Epoch March 6, 2006 (JD 2453800.5)
Aphelion 248.810 Gm (1.663 AU)
Perihelion 123.817 Gm (0.828 AU)
186.314 Gm (1.245 AU)
Eccentricity 0.335
507.665 d(1.39 a)
25.92 km/s
147.839°
Inclination 13.341°
337.293°
276.793°
Physical characteristics
Dimensions 5.1×1.8 km[1]
Mass ~2.6×1013 kg
Mean density
2.0? g/cm³
~0.0008 m/s²
~0.0015 km/s
0.217 d (5.223 h)[1]
Albedo 0.325[1]
Temperature ~249 K
Spectral type
S[1]
15.60[1]

The asteroid 1620 Geographos /ˈɡræfɒs/ 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.

3D computer model of the different faces of Geographos. Image by Scott Hudson.

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