(668643) 2012 DR30

(668643) 2012 DR₃₀ is a trans-Neptunian object and centaur with an extremely eccentric orbit that brings it from inner Oort cloud, the outermost region of the Solar System. It was discovered on 6 February 2008 by astronomers at Purple Mountain Observatory in Nanking, China.^[1] It measures approximately 188 kilometers (120 miles) in diameter.

(668643) 2012 DR₃₀

2012 DR30 in a precovery image taken by the Sloan Digital Sky Survey in 2000
Discovery[1]
Discovered by	PMO NEO Survey Program
Discovery site	Purple Mountain Obs.
Discovery date	6 February 2008
Designations
MPC designation	2012 DR30
Alternative designations	2012 DR30 2009 FW54
Minor planet category	TNO[2] centaur[3][4][5] damocloid distant[1]
Orbital characteristics[2][a]
Epoch 27 April 2019 (JD 2458600.5)
Uncertainty parameter 1
Observation arc	14.72 yr (5,375 d)
Aphelion	3192 AU 2049 AU (barycentric)
Perihelion	14.5 AU
Semi-major axis	1603.44 AU 1032 AU (barycentric)
Eccentricity	0.9909
Orbital period (sidereal)	64207 yr 33100 yr (barycentric)
Mean anomaly	0.0453°
Mean motion	0° 0m 0s / day
Inclination	77.986°
Longitude of ascending node	341.48°
Time of perihelion	≈ 16 March 2011[6]
Argument of perihelion	195.57°
Jupiter MOID	9.311 AU
Saturn MOID	5.45 AU[1]
Uranus MOID	3.32 AU[1]
TJupiter	0.9860
Physical characteristics
Mean diameter	185 km[4] 188 km[5]
Geometric albedo	0.076[5] 0.08 (approx.)[4]
Spectral type	BR–IR[5] B–V = 1.21[5]
Apparent magnitude	19.9[7]
Absolute magnitude (H)	7.1[2][1]

Description

Using an epoch of February 2017, it has the second-largest heliocentric semi-major axis of a minor planet not detected out-gassing like a comet.^[8] (2014 FE72 has a larger heliocentric semi-major axis.) 2012 DR₃₀ does have a barycentric semi-major axis of 1032 AU.^[9][a] For the epoch of July 2018 2012 DR₃₀ will have its largest heliocentric semi-major axis of 1644 AU.

Orbital evolution
Year[a] (epoch)	Barycentric Aphelion (Q) (AU)	Orbital period years
1950	2000	32000
2050	2049	33100

2012 DR₃₀ passed 5.7 AU from Saturn in February 2009 and came to perihelion in March 2011 at a distance of 14.5 AU from the Sun (inside the orbit of Uranus).^[2] In 2018, it will move from 18.2 AU to 19.1 AU from the Sun.^[7] It comes to opposition in late March. With an absolute magnitude (H) of 7.1,^[1] the object has a published diameter of 185 and 188 kilometers, respectively.^[4][5]

With an observation arc of 14.7 years,^[2] it has a well constrained orbit. It will not be 50 AU from the Sun until 2047. After leaving the planetary region of the Solar System, 2012 DR₃₀ will have a barycentric aphelion of 2049 AU with an orbital period of 33100 years.^[a] In a 10 million year integration of the orbit, the nominal (best-fit) orbit and both 3-sigma clones remain outside 12.2 AU (q_min) from the Sun.^[3] Summary of barycentric orbital parameters are:

• Semi-major axis: ~1032 AU^[a]
• aphelion: ~2049 AU^[a]
• period: ~33,100 yr^[a]

Archived data from the JPL SBDB and MPC.^[b][c]

Comparison

The orbits of Sedna, 2012 VP113, Leleākūhonua, and other very distant objects along with the predicted orbit of Planet Nine. The three sednoids (pink) along with the red-colored extreme trans-Neptunian object (eTNO) orbits are suspected to be aligned with the hypothetical Planet Nine while the blue-colored eTNO orbits are anti-aligned. The highly elongated orbits colored brown include centaurs and damocloids with large aphelion distances over 200 AU.

See also

• 2002 RN109
• 2005 VX3
• (308933) 2006 SQ372
• 2007 TG422
• 90377 Sedna
• List of hyperbolic comets
• Planet Nine

Notes

1. Given the orbital eccentricity of this object, different epochs can generate quite different heliocentric unperturbed two-body best-fit solutions to the semi-major axis and orbital period. For objects at such high eccentricity, the Sun's barycenter is more stable than heliocentric coordinates.^[10] Using JPL Horizons, the barycentric semi-major axis is approximately 1032 AU.^[9]
2. Archived JPL Small-Body Database Browser: (2012 DR30) from 15 October 2014.
3. Archived MPC object data for 2012 DR30 (2009 FW54) from 12 July 2013.