19521 Chaos
19521 Chaos is a cubewano, a Kuiper-belt object not in resonance with any planet. Chaos was discovered in 1998 by the Deep Ecliptic Survey with Kitt Peak's 4 m telescope. Its albedo is 0.050+0.030
−0.016, making it, with its absolute magnitude (H) of 4.8, equivalent to a single spherical body 600+140
−130 km in diameter.
19521 Chaos as imaged by the Hubble Space Telescope in September 2001 | |
| Discovery | |
|---|---|
| Discovered by | Deep Ecliptic Survey |
| Discovery date | 19 November 1998 |
| Designations | |
MPC designation | (19521) Chaos |
| Pronunciation | /ˈkeɪ.ɒs/ |
Named after | Chaos |
Alternative designations | 1998 WH24 |
Minor planet category | TNO (cubewano) |
| Adjectives | Chaotian /keɪˈoʊʃən/ |
| Symbol | (astrological) |
| Orbital characteristics | |
| Epoch 13 January 2016 (JD 2457400.5) | |
| Uncertainty parameter 3 | |
| Observation arc | 5902 days (16.16 yr) |
| Earliest precovery date | 17 October 1991 |
| Aphelion | 50.636 AU (7.5750 Tm) |
| Perihelion | 40.957 AU (6.1271 Tm) |
Semi-major axis | 45.796 AU (6.8510 Tm) |
| Eccentricity | 0.10567 |
Orbital period (sidereal) | 309.92 yr (113199 d) |
Average orbital speed | 4.3931 km/s |
Mean anomaly | 337.2998° |
Mean motion | 0° 0m 11.449s / day |
| Inclination | 12.0502° |
Longitude of ascending node | 50.0239° |
| ≈ 23 December 2033 ±10 days | |
| 58.4097° | |
| Jupiter MOID | 35.8 AU (5.36 Tm) |
| Neptune MOID | 12.5 AU (1.87 Tm) |
| TJupiter | 5.884 |
| Physical characteristics | |
| Dimensions | 612 km (est. at 0.05) 600+140 −130 km ~665 |
| 0.050+0.030 −0.016 | |
| B–V=0.95±0.03 V–R=0.63±0.03 V–I=1.25±0.04 | |
| 4.8 5.0 | |
On 20 November 2020, Chaos occulted a magnitude 16.8 star. Three observers detected the occultation, finding that the object is likely smaller than 600 km in diameter. Another occultation was recorded on 14 January 2022; full results on size, shape, geometric albedo, and the spin-axis orientation have not been released. A further occultation occurred on 28 September 2023, with a shadow crossing most of North America. This occultation was observed by over 30 observers; preliminary analysis suggests that Chaos is a binary (possibly a contact binary).