(19521) Chaos
This object has a more recent orbit available here
Object
Object | (19521) Chaos |
Diameter(1) | 600 km |
Dynamic class(1) | cubewano |
Absolute magnitude | 4.64 |
G slop | 0.15 |
(1) Data from the johnston archive list.
Orbital elements
Epoch (Julian date) | 2459800.5 |
Semi major axis | 45.755453 ± 0.003144 au |
Eccentricity | 0.103175178 ± 0.000044141 |
Inclination | 12.018360203 ± 0.000036995 ° |
Longitude of ascending node | 49.899934 ± 0.000134 ° |
Argument of perihelia | 55.659452 ± 0.012847 ° |
Mean anomaly | 347.178107 ± 0.011612 ° |
Orbital period | 309.51 yr |
Ephemeris & Observations
Ephemeris version | NIMAv8 |
Observation file |
omc_ast_NIMAv8.txt |
bsp file | 19521_Chaos_nima_v8.bsp |
Date of first observation | 1991-10-17 |
Date of last observation | 2021-01-11 |
Number of observations used in the fit | 259 |
Number of rejected observations | 3 |
Number of DES observations | 0 |
Number of MPC observations | 167 |
Number of unpublished observations | 95 |
RMS of observations | 0.291 arcsec |
Residuals

Residuals in right ascension and declination compared to NIMAv8 ephemeris.
Colours indicate the estimated precision in arcsec used as weights in the fitting process.
Orbit quality
date | σα (arcsec) | σδ (arcsec) |
2022-01 | 0.052 | 0.012 |
2022-07 | 0.028 | 0.021 |
2023-01 | 0.053 | 0.016 |
2023-07 | 0.040 | 0.023 |
2024-01 | 0.058 | 0.020 |
2024-07 | 0.055 | 0.025 |
2025-01 | 0.068 | 0.025 |
2025-07 | 0.074 | 0.027 |
2026-01 | 0.084 | 0.030 |
Ephemeris comparison

Difference between NIMAv8 and JPL16 in right ascension (weighted by cos δ) and in declination.
Gray area represents the 1-σ uncertainty of NIMA ephemeris. Green dots represent the DES observations.