2003 SS422 is a trans-Neptunian object located in the outermost region of the Solar System. It was discovered on 28 September 2003, by American astronomers at the Cerro Tololo Observatory in La Serena, Chile, and estimated to measure approximately 168 kilometers (104 miles) in diameter.[1][3]

2003 SS422
Discovery[1]
Discovered byCerro Tololo Obs.
Discovery siteCerro Tololo Obs.
Discovery date28 September 2003
Designations
2003 SS422
TNO[2] · extreme[3]
1:16 Resonant
distant[1]
Orbital characteristics[4]
Epoch 5 July 2021 (JD 2459400.5)
Uncertainty parameter 3[2]
Observation arc14.92 yr (5,448 days)
Aphelion356.788 AU
Perihelion39.574 AU
198.181 AU
Eccentricity0.8003140
2790 yr
1.770°
0° 0m 1.272s / day
Inclination16.773°
150.949°
206.824°
Physical characteristics
163 km (est. at 0.09)[3]
7.04[4]

Due to the object's high eccentricity and large perihelia, 2003 SS422 is an extreme trans-Neptunian object from the scattered disc (ESDO).[3] It was a lost minor planet until it was recovered in June 2021.[4]

Orbit and classification

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Based on an observation arc of 14.9 years with 26 observations in total, 2003 SS422 orbits the Sun at a distance of 39.6–356.8 AU once every 2790 years (1,019,048 days; semi-major axis of 198.2 AU). Its orbit has an eccentricity of 0.80 and an inclination of 17° with respect to the ecliptic.[2]

As of 2021, 2003 SS422 belongs to a small number of 21 high-eccentricity and large-perihelia objects (q > 38 AU) with a semi-major axis of larger than 150 AU,[5] which are the defining orbital parameters of the group of extreme scattered disc object, or ESDO. It is thought that objects cannot reach such orbits without some perturbing object outside the eight planets, which has led to the speculation of Planet Nine.

A study on dynamical classification of trans-Neptunian objects in 2024 identified 2003 SS422 as most likely in a 1:16 resonance with Neptune, in which the object completes a single orbit for every 16 Neptune makes.[6]

References

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  1. ^ a b c "2003 SS422". Minor Planet Center. Retrieved 5 March 2021.
  2. ^ a b c "JPL Small-Body Database Browser: (2003 SS422)" (2020-11-18 last obs.). Jet Propulsion Laboratory. Retrieved 5 March 2021.
  3. ^ a b c d Johnston, Wm. Robert (18 August 2020). "List of Known Trans-Neptunian Objects". Johnston's Archive. Retrieved 5 March 2021.
  4. ^ a b c "MPEC 2021-M14 : 2003 SS422". Minor Planet Center. 16 June 2021. Retrieved 16 June 2021.
  5. ^ "Query (search criteria): objects perihelion min. 38 AU and semimajor axis min. 150 AU (found: 25 objects)". Minor Planet Center. Retrieved 5 March 2021.
  6. ^ Volk, Kathryn; Malhotra, Renu (2024). "Machine Learning Assisted Dynamical Classification of Trans-Neptunian Objects". arXiv:2405.05185 [astro-ph.EP].
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