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2001 GO2

2001 GO2
Discovery
Discovered by Lincoln Laboratory ETS (now LINEAR)
Discovery site Socorro, New Mexico, USA
Discovery date April 13, 2001
Designations
MPC designation 2001 GO2
MPO 30455
Apollo Apollo
NEO
Orbital characteristics
Epoch 13 January 2016 (JD 2457400.5)
Uncertainty parameter 6
Observation arc 5d
Aphelion 1.17583 AU (175.902 Gm)
Perihelion 0.83753 AU (125.293 Gm)
1.00668 AU (150.597 Gm)
Eccentricity 0.16803
1.01 yr (368.92 d)
1.01 yr
Average orbital speed
29.474 km/s
305.54°
0° 58m 32.916s /day
Inclination 4.6199°
193.546°
265.48°
Earth MOID 0.00411326 AU (615,335 km)
Jupiter MOID 3.92432 AU (587.070 Gm)
Physical characteristics
Dimensions 35–85 m
24.3

2001 GO2 is a small asteroid that is a near-Earth object, an Earth coorbital, and an Apollo asteroid.

With an orbital period of 368.95 days, 2001 GO2 is in a near 1:1 orbital resonance with Earth, and also has about the same orbit around the Sun as Earth. Unlike most near-Earth asteroids that simply fly by when they approach Earth, the Earth catches up with this asteroid from behind so that the asteroid then pauses in the vicinity of Earth. While in the vicinity of Earth, the asteroid moves in a helical (corkscrew) pattern that resembles an orbit around the Earth, like the Earth has a new moon. But it is not really a moon, because the asteroid is not gravitationally bound to the Earth, and eventually the asteroid moves on away from Earth and continues its orbit around the Sun. 2001 GO2 was in this helical pattern from about 1997 to 2005, making the closest approach to Earth on 6 April 2001, and will not make another close approach until 2092.

The asteroid probably has a horseshoe orbit, but this has not been proven because the orbit was determined from only 5 days worth of observation. The Jupiter Tisserand invariant, used to distinguish different kinds of orbits, is 6.033.

Other asteroids that move in this helical pattern, some of which the Earth catches up with the asteroid, and others in which the asteroid catches up with Earth, are 2003 YN107, 2002 AA29, and (164207) 2004 GU9.



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