2007 TG422

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2007 TG422
Discovered by SDSS Collaboration
A. C. Becker,
A. W. Puckett,
J. Kubica
Apache Point (705)
Discovery date 2007-10-03
MPC designation 2007 TG422
Orbital characteristics[4]
Epoch 13 January 2016 (JD 2457400.5)
Uncertainty parameter 2
Observation arc 2687 days (7.36 yr)
Aphelion 970 AU (Q)[3][a]
(Heliocentric 950 ± 7 AU)
Perihelion 35.579 AU (5.3225 Tm) (q)
503 AU (a)[3][a]
(Heliocentric 493 ± 4 AU)
Eccentricity 0.92779 (e)
11,300 yr[3][a]
(Heliocentric 10937 ± 120 yr)
0.33542° (M)
0.000090114°/day (n)
Inclination 18.587° (i)
112.95° (Ω)
285.80° (ω)
Jupiter MOID 30.8436 AU (4.61414 Tm)
Physical characteristics
Dimensions 343 km (assumed)[5]
150–340 km[4][6]
270 km[7][8]
0.04 (expected)[5]

2007 TG422, also written as 2007 TG422, is a scattered-disc object with a perihelion distance of 35.6 AU, which is just inside the gravitational influence of Neptune,[2] and an aphelion distance similar to 90377 Sedna's.


Mike Brown's website lists it as a possible dwarf planet with a diameter of 343 km based on an assumed albedo of 0.04.[5] The albedo is expected to be low because the object has a blue (neutral) color.[5] But if the albedo is higher the object could be much smaller. Assuming a generic trans-Neptunian albedo of 0.09, it is about 270 km in diameter.[7] But because its true albedo is unknown and it has an absolute magnitude (H) of 6.2,[4] it could be anywhere from about 150 to 340 km in diameter.[6]


Unstable[b] Heliocentric Solutions
2007/08/28[2] 932 10652
2012-Sep-30[10] 1099 13512
2017-Feb-16[4] 917 10399
2018-Jun-26 901 10143
970 11300
2007 TG422 orbit in magenta with hypothetical planet nine

2007 TG422 came to perihelion in 2005 at a heliocentric distance of 35.5 AU,[4] and is currently 37.2 AU from the Sun.[9] It will be in the constellation of Taurus until 2018. It comes to opposition 29 November 2017.

Given the orbital eccentricity of this object, different epochs can generate quite different heliocentric unperturbed two-body best-fit solutions to the aphelion (maximum distance from the Sun) of this object.[c] With a 2007 epoch the object had an approximate period of about 10,611 years with aphelion at 930 AU.[2] But using a 2012 epoch shows a period of about 13,512 years with aphelion at 1099 AU.[10] 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 5 years, the barycentric orbital elements for epoch 2008-May-14 generate a semi-major axis of 503 AU and a period of 11,300 years.[3] For comparison, probable dwarf planet Sedna has a barycentric semi-major axis of 506 AU and a period of 11,400 years.[3] Both (308933) 2006 SQ372 and (87269) 2000 OO67 take longer than Sedna and 2007 TG422 to orbit the Sun using barycentric coordinates.

2007 TG422 has been observed 98 times over seven years and has an uncertainty parameter of 2.[4] It has not been observed since 2015.[4]


Sedna compared to some other very distant orbiting bodies. Including 90377 Sedna, 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


  1. ^ a b c Solution using the Solar System's barycenter
  2. ^ Heliocentric solution unstable due to the changing position of Jupiter over Jupiter's 12 year orbit which perturbs the eccentricity of the two-body solution of the Sun+asteroid. Barycentric solutions are more stable for objects that take thousands of years to orbit the Sun.
  3. ^ Read osculating orbit for more details about heliocentric unperturbed two-body solutions


  1. ^ "MPEC 2008-D39: 2007 TG422, 2007 TH422, 2007 TJ422, 2007 UL126, 2007 VH305". IAU Minor Planet Center. 2008-02-26. Retrieved 2011-01-30.  (K07Tg2G)
  2. ^ a b c d Marc W. Buie. "Orbit Fit and Astrometric record for 07TG422" (2009-09-28 using 32 of 32 observations). SwRI (Space Science Department). Archived from the original on 2015-05-30. Retrieved 2011-01-30. 
  3. ^ a b c d e f Horizons output (2011-01-30). "Barycentric Osculating Orbital Elements for 2007 TG422". Archived from the original on March 28, 2014. Retrieved 2011-01-30.  (Horizons)
  4. ^ a b c d e f g h "JPL Small-Body Database Browser: (2007 TG422)" (2013-01-12 last obs). Retrieved 25 March 2016. 
  5. ^ a b c d e Michael E. Brown. "How many dwarf planets are there in the outer solar system? (updates daily)". California Institute of Technology. Archived from the original on 2011-10-18. Retrieved 2014-02-16. 
  6. ^ a b "Absolute Magnitude (H)". NASA/JPL. Archived from the original on 26 November 2009. Retrieved 2009-12-06. 
  7. ^ a b Dan Bruton. "Conversion of Absolute Magnitude to Diameter for Minor Planets". Department of Physics & Astronomy (Stephen F. Austin State University). Retrieved 2011-01-30. 
  8. ^ Assuming an albedo of 0.09
  9. ^ a b "AstDyS 2007TG422 Ephemerides". Department of Mathematics, University of Pisa, Italy. Retrieved 2016-09-01. 
  10. ^ a b JPL Epoch 2012-Sep-30 solution
  11. ^ Kaib, Nathan A.; Becker, Andrew C.; Jones, R. Lynne; Puckett, Andrew W.; Bizyaev, Dmitry; Dilday, Benjamin; Frieman, Joshua A.; Oravetz, Daniel J.; Pan, Kaike; Quinn, Thomas; Schneider, Donald P.; Watters, Shannon (2009). "2006 SQ372: A Likely Long-Period Comet from the Inner Oort Cloud". The Astrophysical Journal. 695 (1): 268–275. arXiv:0901.1690Freely accessible. Bibcode:2009ApJ...695..268K. doi:10.1088/0004-637X/695/1/268. 

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