(21900) Orus
This object has a more recent orbit available here
Object
| Object | (21900) Orus |
| Diameter(1) | 59 km |
| Dynamic class(1) | trojan |
| Absolute magnitude | 10.09 |
| G slop | 0.15 |
(1) Data from the johnston archive list.
Orbital elements
| Epoch (Julian date) | 2459800.5 |
| Semi major axis | 5.124205 ± 0.000000 au |
| Eccentricity | 0.037837072 ± 0.000000015 |
| Inclination | 8.468547139 ± 0.000000589 ° |
| Longitude of ascending node | 258.554261 ± 0.000005 ° |
| Argument of perihelia | 180.775314 ± 0.000017 ° |
| Mean anomaly | 339.727459 ± 0.000016 ° |
| Orbital period | 11.60 yr |
Ephemeris & Observations
| Ephemeris version | NIMAv8 |
| Observation file |
omc_ast_NIMAv8.txt |
| bsp file | 21900_Orus_nima_v8.bsp |
| Date of first observation | 1951-11-08 |
| Date of last observation | 2022-12-16 |
| Number of observations used in the fit | 3581 |
| Number of rejected observations | 11 |
| Number of DES observations | 14 |
| Number of MPC observations | 3159 |
| Number of unpublished observations | 299 |
| RMS of observations | 0.103 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 | 0.005 | 0.002 |
| 2022-07 | 0.003 | 0.002 |
| 2023-01 | 0.005 | 0.003 |
| 2023-07 | 0.005 | 0.003 |
| 2024-01 | 0.010 | 0.005 |
| 2024-07 | 0.008 | 0.004 |
| 2025-01 | 0.014 | 0.007 |
| 2025-07 | 0.011 | 0.005 |
| 2026-01 | 0.016 | 0.007 |
Ephemeris comparison
Difference between NIMAv8 and JPL37 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.