(419624) 2010 SO16

2010 SO₁₆

Discovery
Discovered by	Wide-field Infrared Survey Explorer
Discovery date	17 September 2010
Orbital characteristics[1][2]
Epoch 13 January 2016 (JD 2457400.5)
Uncertainty parameter 0
Observation arc	1928 days (5.28 yr)
Aphelion	1.07791 AU (161.253 Gm)
Perihelion	0.92684 AU (138.653 Gm)
Semi-major axis	1.00237 AU (149.952 Gm)
Eccentricity	0.075351
Orbital period	1.00 yr (366.56 d)
Mean anomaly	304.409°
Mean motion	0° 58^m 55.596^s / day
Inclination	14.522°
Longitude of ascending node	40.420°
Argument of perihelion	108.804°
Earth MOID	0.0279159 AU (4.17616 Gm)
Jupiter MOID	3.90691 AU (584.465 Gm)
Jupiter Tisserand parameter	6.038
Physical characteristics
Dimensions	200–400 metres
Absolute magnitude (H)	20.5

(419624) 2010 SO₁₆ is a near-Earth asteroid discovered by the Wide-field Infrared Survey Explorer space telescope. The orbit was described by Christou Apostolos and David Asher at the Armagh Observatory in Northern Ireland.^[1] The object has a magnitude of 20.7 and is several hundred meters in diameter.

2010 SO₁₆ has a horseshoe orbit that allows it to stably share Earth's orbital neighborhood without colliding with it. It is one of a handful of known asteroids with an Earth-following orbit, a group that includes 3753 Cruithne, and the only known asteroid in an horseshoe orbit with Earth. It is, however, neither an Aten asteroid nor an Apollo asteroid because the semi-major axis of its orbit is neither less than nor greater than 1 AU, but oscillates between approximately 0.996 and 1.004 AU, with a period of about 350 yr.^[1] In its ~350 yr horseshoe cycle, it never approaches Earth more closely than about 0.15 AU, alternately trailing and leading.

According to various simulations 2010 SO₁₆ will remain in this orbit for at least 120,000 years and possibly for more than a million years, which is unusually stable compared to other similar objects.^[3] One reason for this stability is its low orbital eccentricity, $<0.084$.^[1]

A precovery of 2010 SO₁₆ may have been located in a 2005 Spitzer Space Telescope image.^[4]

See also

• 3753 Cruithne – a horseshoe companion of the Earth
• 2006 RH120 – a small asteroid that sometimes temporarily gets caught in Earth orbit
• 2002 AA29 – a horseshoe companion of the Earth
• Natural satellite

References

1. Christou; Asher (2011-03-31). "A long-lived horseshoe companion to the Earth". arXiv:1104.0036 [astro-ph.EP].
2. "419624 (2010 SO16)". JPL Small-Body Database. NASA/Jet Propulsion Laboratory. Retrieved 8 April 2016.
3. Asteroid Discovered in Horseshoe-Shaped Orbit, The Physics arXiv Blog, Technology Review, 4/05/2011
4. "New Tool Finds Buried Treasure in Spitzer Archives". NASA/JPL. 2014-04-03. Retrieved 2014-04-25.

External links

• JPL SO16 orbit simulation
• (419624) 2010 SO16 at the JPL Small-Body Database
  • Discovery · Orbit diagram · Orbital elements · Physical parameters