2002 AA29

Infobox Planet | discovery=yes | physical_characteristics = yes | bgcolour=#FFFFC0
name=2002 AA₂₉


discoverer=LINEAR
discovered=January 9, 2002
alt_names="none"
mp_category=Aten asteroid
epoch=November 22, 2002 (JD 2452600.5)
semimajor=149.588 Gm (1.000 AU)
perihelion=147.735 Gm (0.988 AU)
aphelion=151.442 Gm (1.012 AU)
eccentricity=0.012
period=365.222 d (1.00 a)
inclination=10.739°
asc_node=106.849°
arg_peri=91.594°
mean_anomaly=225.947°
avg_speed=29.784 km/s
dimensions=~0.06 km
mass=~2.3×10⁸ kg
density=2 ? g/cm³
surface_grav=~0.000 017 m/s²
escape_velocity=~0.000 032 km/s
rotation=? d
spectral_type=?
abs_magnitude=24.08
albedo=0.1 ?
single_temperature=~279 KAsteroid mp|2002 AA|29 (also written 2002 AA29) is a near-Earth asteroid discovered in January 2002 by the LINEAR asteroid survey, measuring about 60 metres across.

On January 8, 2003, the asteroid came within approximately 5.9 Gm (3.7 million miles) of Earth, its closest approach for almost a century.

The asteroid spends most of its time following a "horseshoe orbit" that makes it come near the Earth every 95 years as it follows Earth's orbit around the Sun. In about 600 years, it will appear to circle Earth in a quasi-satellite orbit. Calculations suggest mp|2002 AA|29 was in such a quasi-satellite orbit between about 550–600 A.D. but would have been too small to be observed visually then.

J. Richard Gott and Edward Belbruno from Princeton University have speculated that mp|2002 AA|29 might have formed together with Earth and Theia, the postulated planet that, according to the Giant Impact hypothesis collided with Earth in its early history.

The orbit of the asteroid is such that it would be relatively easy for a spacecraft to retrieve rock samples from it and bring them to Earth for analysis.

ee also

* Co-orbital moon
* Natural satellite
* Quasi-satellite
* Horseshoe orbit

External links

* [http://cfa-www.harvard.edu/mpec/K03/K03A17.html MPEC 2003-A17]
* [http://www.astro.uwo.ca/~wiegert/AA29/AA29.html Earth coorbital asteroid mp|2002 AA|29]
* [http://www.scielo.br/pdf/cam/v24n1/06v24n1.pdf Research paper describing horseshoe orbits.] Recommend starting at page 105!