(19521) Chaos

19521 Chaos
19521 chaos hst.jpg
19521 Chaos as imaged by the Hubble Space Telescope in September 2001
Discovered byDeep Ecliptic Survey
Discovery date19 November 1998
(19521) Chaos
Named after
1998 WH24
TNO (cubewano)[1][2]
AdjectivesChaotian /kˈʃən/[3]
Orbital characteristics[6]
Epoch 13 January 2016 (JD 2457400.5)
Uncertainty parameter 3
Observation arc5902 days (16.16 yr)
Earliest precovery date17 October 1991
Aphelion50.636 AU (7.5750 Tm)
Perihelion40.957 AU (6.1271 Tm)
45.796 AU (6.8510 Tm)
309.92 yr (113199 d)
4.3931 km/s
0° 0m 11.449s / day
≈ 24 December 2033[4]
±10 days
Jupiter MOID35.8 AU (5.36 Tm)
Neptune MOID12.5 AU (1.87 Tm)[5]
Physical characteristics
Dimensions615± ? [7]
~665 [9]
3.985 d[citation needed]
B–V=0.95±0.03 [9]
V–R=0.63±0.03 [9]
V–I=1.25±0.04 [9]
4.8 [6]
5.0 [7][9]

19521 Chaos is a cubewano, a Kuiper-belt object not in resonance with any planet. It is a possible dwarf planet, but is likely not a solid body.[citation needed] Chaos was discovered in 1998 by the Deep Ecliptic Survey with Kitt Peak's 4 m telescope. Its albedo is 0.050+0.030
,[8] making it, with its absolute magnitude (H) of 4.8,[6] 600+140
in diameter.[8] It is named after the primeval state of existence in Greek mythology, from which the first gods appeared.


The orbit of Chaos (white) compared Pluto and the four giant planets: Jupiter, Saturn, Uranus, and Neptune with positions for 2019

19521 Chaos has an orbital period of approximately 309 years. Its orbit is longer, but less eccentric than the orbit of Pluto. 19521 Chaos's orbit is inclined approximately 12° to the ecliptic. Its orbit never crosses the orbit of Neptune. Currently, the closest approach possible to Neptune (MOID) is 12.5 AU (1.87 billion km).[5]

Chaos moves west to east (right to left) across the sky, discovered in Taurus in 1998, and precovered back to 1991
Distance from Earth (AU)

Chaos is at perihelion around Christmas 2033,[4] coming as close as 40 AUs from Earth. Its brightest magnitude will be 20.8.

Apparent magnitude from Earth

Physical characteristics[]

Size comparison between Pluto and Chaos

Chaos is a dark object, with an albedo estimated at 5%, implying a diameter of 600 km. It rotates slowly in 3.985 days.[citation needed] According to Brown, it is a likely dwarf planet.[7]


  1. ^ "MPEC 2008-O05 : Distant Minor Planets (2008 AUG. 2.0 TT)". Minor Planet Center. 17 July 2008. Retrieved 8 January 2011.
  2. ^ Buie, Marc W. (9 November 2004). "Orbit Fit and Astrometric record for 19521". Space Science Department. SwRI. Retrieved 28 September 2008.
  3. ^ Thayer (1994). Gray World, Green Heart.[full citation needed]
  4. ^ a b JPL Horizons Observer Location: @sun (Perihelion occurs when deldot changes from negative to positive. Uncertainty in time of perihelion is 3-sigma.)
  5. ^ a b "(19521) Chaos = 1998 WH24 orbit". IAU Minor Planet Center. Retrieved 10 February 2018.
  6. ^ a b c "19521 Chaos (1998 WH24)". JPL Small-Body Database Browser (2007-12-14 last obs). Retrieved 11 April 2016.
  7. ^ a b c Brown, Michael E. "How many dwarf planets are there in the outer solar system? (updates daily)". California Institute of Technology. Retrieved 25 December 2018.
  8. ^ a b c d Vilenius, E.; Kiss, C.; Mommert, M.; Müller, T.; Santos-Sanz, P.; Pal, A.; et al. (2012). ""TNOs are cool": A survey of the trans-Neptunian region VI. Herschel / PACS observations and thermal modeling of 19 classical Kuiper belt objects". arXiv:1204.0697v1. doi:10.1051/0004-6361/201118743. Cite journal requires |journal= (help)
  9. ^ a b c d e Doressoundiram, A.; Peixinho, N.; de Bergh, C.; Fornasier, S.; Thébault, Ph.; Barucci, M.A.; Veillet, C. (October 2002). "The color distribution in the Edgeworth-Kuiper Belt". The Astronomical Journal. 124 (4): 2279–2296. arXiv:astro-ph/0206468. Bibcode:2002AJ....124.2279D. doi:10.1086/342447.

External links[]