2015 SO2

2015 SO₂
Discovery
Discovered by	Črni Vrh Obs.
Discovery date	21 September 2015
Designations
MPC designation	2015 SO2
Minor planet category	NEO; Aten; Earth crosser;
Orbital characteristics
	Epoch 31 July 2016 (JD 2457600.5)
	Uncertainty parameter 1
Observation arc	342 days
Aphelion	1.10688036 AU (165.586945 Gm)
Perihelion	0.890962 AU (133.2860 Gm)
Semi-major axis	0.99892124 AU (149.436491 Gm)
Eccentricity	0.108076
Orbital period (sidereal)	1.00 yr (364.66602 d)
Mean anomaly	208.3767°
Mean motion	0° 59m 13.937s / day
Inclination	9.1750°
Longitude of ascending node	182.9293°
Argument of perihelion	290.0678°
Earth MOID	0.0191611 AU (2.86646 Gm)
Physical characteristics
Mean diameter	50–111 m[a]
Absolute magnitude (H)	23.9

2015 SO₂ (also written 2015 SO2) is an Aten asteroid that is a temporary horseshoe companion to the Earth, the ninth known Earth horseshoe librator.^[6] Prior to its most recent close encounter with our planet (2015 September 30) it was an Apollo asteroid.

^ List Of Aten Minor Planets
^ ^a ^b ^c "2015 SO2". JPL Small-Body Database. Jet Propulsion Laboratory. SPK-ID: 3728565. Retrieved 4 April 2016.
^ AstDys-2 on 2015 SO2 Retrieved 2015-11-28
^ NEODyS-2 on 2015 SO2 Retrieved 2015-11-28
^ Cite error: The named reference h was invoked but never defined (see the help page).
^ de la Fuente Marcos, Carlos; de la Fuente Marcos, Raúl (2016). "From horseshoe to quasi-satellite and back again: the curious dynamics of Earth co-orbital asteroid 2015 SO2". Astrophysics and Space Science. 361 (1): 16. arXiv:1511.08360. Bibcode:2016Ap&SS.361...16D. doi:10.1007/s10509-015-2597-8. S2CID 189842725.

[MPCatenlist-1] List Of Aten Minor Planets

[jpldata-2] "2015 SO2". JPL Small-Body Database. Jet Propulsion Laboratory. SPK-ID: 3728565. Retrieved 4 April 2016.

[AstDys-3] AstDys-2 on 2015 SO2 Retrieved 2015-11-28

[NEODyS-4] NEODyS-2 on 2015 SO2 Retrieved 2015-11-28

[h-5] Cite error: The named reference h was invoked but never defined (see the help page).

[dynamics-6] Fuente Marcos, Carlos; de la Fuente Marcos, Raúl (2016). "From horseshoe to quasi-satellite and back again: the curious dynamics of Earth co-orbital asteroid 2015 SO2". Astrophysics and Space Science. 361 (1): 16. arXiv:1511.08360. Bibcode:2016Ap&SS.361...16D. doi:10.1007/s10509-015-2597-8. S2CID 189842725.

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