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(308933) 2006 SQ372 is a trans-Neptunian object and highly eccentric centaur on a cometary-like orbit in the outer region of the Solar System, approximately 123 kilometers (76 miles) in diameter. It was discovered through the Sloan Digital Sky Survey by astronomers Andrew Becker, Andrew Puckett and Jeremy Kubica on images first taken on 27 September 2006 (with precovery images dated to 13 September 2005).[1][8][9][10]

(308933) 2006 SQ372
308933-2006sq372 hst.jpg
Hubble Space Telescope image of 2006 SQ372 taken in 2009
Discovery [1][2]
Discovered byA. C. Becker
A. W. Puckett
J. Kubica
Discovery siteAPO
Discovery date27 September 2006
MPC designation(308933) 2006 SQ372
2006 SQ372
TNO[3] · centaur[2][4][5] · distant[1]
Orbital characteristics[3]
Epoch 23 March 2018 (JD 2458200.5)
Uncertainty parameter 1
Observation arc9.86 yr (3,602 days)
Aphelion1609.10 AU
Perihelion24.139 AU
816.62 AU
23336.64 yr (8,523,707 days)
0° 0m 0s / day
Neptune MOID1.499 AU[1]
Physical characteristics
Mean diameter
60–140 km[6]
122 km[5]
124 km[7]
0.08 (estimate)[7]
B–R = 1.62[5]
7.8[3] · 8.0[7]



Diagram of the orbit of 2006 SQ372

It has a highly eccentric orbit, crossing that of Neptune near perihelion but bringing it more than 1,500 AU from the Sun at aphelion.[4] It takes about 22,500 years to orbit the barycenter of the Solar System.[11] The large semi-major axis makes it similar to 2000 OO67 and Sedna.[11] With an absolute magnitude (H) of 8.1,[3] it is estimated to be about 60 to 140 km in diameter.[6] Michael Brown estimates that it has an albedo of 0.08 which would give a diameter of around 110 km.[7]

The object could possibly be a comet.[11] The discoverers hypothesize that the object could come from the Hills cloud,[11] but other scientists like California Institute of Technology's Michael Brown also consider other possibilities, including the theory "it may have formed from debris just beyond Neptune [in the Kuiper belt] and been 'kicked' into its distant orbit by a planet like Neptune or Uranus".[12]


The orbit of 2006 SQ372 currently comes closer to Neptune than any of the other giant planets.[1] More than half of the simulations of this object show that it gets too close to either Uranus or Neptune within the next 180 million years, sending it in a currently unknown direction.[13] This makes it difficult to classify this object as only a centaur or a scattered disc object. The Minor Planet Center, which officially catalogues all trans-Neptunian objects, lists centaurs and SDOs together.[2] (29981) 1999 TD10 is another such object that blurs the two categories.[14]

Baricentric orbital elements
  • aphelion (Q) = 1570 AU[15][a] (Heliocentric 2006 AU)
  • semimajor =736.67 AU[11][a] (Heliocentric 1015 AU)
  • period = 22,466 yr[11][a] (Heliocentric 32,347 yr)

Given the extreme orbital eccentricity of this object, different epochs can generate quite different heliocentric unperturbed two-body best-fit solutions to the aphelion distance (maximum distance) of this object.[b] With a 2005 epoch the object had an approximate period of about 22,000 years with aphelion at 1557 AU.[4] But using a 2011 epoch shows a period of about 32,000 years with aphelion at 2006 AU.[3] For objects at such high eccentricity, the Sun's barycentric coordinates are more stable than heliocentric coordinates.[11] Using JPL Horizons with an observed orbital arc of only 2.9 years, the barycentric orbital elements for epoch 2008-May-14 generate a semi-major axis of 796 AU and a period of 22,466 years.[11]


Sedna compared to some other very distant orbiting bodies including 2015 DB216 (orbit wrong), 2000 OO67, 2004 VN112, 2005 VX3, 2006 SQ372, 2007 TG422, 2007 DA61, 2009 MS9, 2010 GB174, 2010 NV1, 2010 BK118, 2012 DR30, 2012 VP113, 2013 BL76, 2013 AZ60, 2013 RF98, 2015 ER61

See alsoEdit


  1. ^ Solution using the Solar System Barycenter
  2. ^ Read osculating orbit for more details about heliocentric unperturbed two-body solutions


  1. ^ a b c d e "308933 (2006 SQ372)". Minor Planet Center. Retrieved 23 February 2018.
  2. ^ a b c "List Of Centaurs and Scattered-Disk Objects". Minor Planet Center. Retrieved 23 February 2018.
  3. ^ a b c d e "JPL Small-Body Database Browser: 308933 (2006 SQ372)" (2015-07-25 last obs.). Jet Propulsion Laboratory. Archived from the original on 12 December 2012. Retrieved 23 February 2018.
  4. ^ a b c Marc W. Buie. "Orbit Fit and Astrometric record for 308933" (2010-09-17 using 64 of 65 observations over 5.01 years). SwRI (Space Science Department). Retrieved 5 September 2008.
  5. ^ a b c d Johnston, Wm. Robert (30 December 2017). "List of Known Trans-Neptunian Objects". Johnston's Archive. Retrieved 23 February 2018.
  6. ^ a b "Asteroid Size Estimator". CNEOS NASA/JPL. Retrieved 23 February 2018.
  7. ^ a b c d Brown, Michael E. "How many dwarf planets are there in the outer solar system?". California Institute of Technology. Retrieved 23 February 2018.
  8. ^ "MPEC 2007-A27 : 2006 SQ372". IAU Minor Planet Center. 8 January 2007. Retrieved 26 May 2011.
  9. ^ Paul Gilster (18 August 2008). "An Icy Wanderer from the Oort Cloud". Retrieved 23 February 2018.
  10. ^ "First object seen from solar system's inner Oort cloud". New Scientist. 18 August 2008. Archived from the original on 28 August 2008. Retrieved 18 August 2008.
  11. ^ a b c d e f g h Kaib, Nathan A.; Becker, Andrew C.; Jones, R. Lynne; Puckett, Andrew W.; Bizyaev, Dmitry; Dilday, Benjamin; et al. (2009). "2006 SQ372: A Likely Long-Period Comet from the Inner Oort Cloud". arXiv:0901.1690. Bibcode:2009ApJ...695..268K. doi:10.1088/0004-637X/695/1/268.
  12. ^ "New "Minor Planet" Found in Solar System". National Geographic News. 19 August 2008. Archived from the original on 21 August 2008. Retrieved 18 August 2008.
  13. ^ Dr Chris Lintott (25 August 2008). "Sky survey yields new cosmic haul". BBC. Archived from the original on 6 September 2008. Retrieved 6 September 2008.
  14. ^ Kenneth Silber (11 November 1999). "New Object in Solar System Defies Categories". Archived from the original on 21 September 2005. Retrieved 7 September 2008.
  15. ^ Horizons output (23 January 2011). "Barycentric Osculating Orbital Elements for 2006 SQ372". Archived from the original on 25 February 2012. Retrieved 24 January 2011. (Horizons)

External linksEdit