(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 | 10.00 |
| G slop | 0.15 |
(1) Data from the johnston archive list.
Orbital elements
| Epoch (Julian date) | 2458600.5 |
| Semi major axis | 5.125316 ± 0.000001 au |
| Eccentricity | 0.036299694 ± 0.000000097 |
| Inclination | 8.468462691 ± 0.000009629 ° |
| Longitude of ascending node | 258.559938 ± 0.000050 ° |
| Argument of perihelia | 179.594263 ± 0.000169 ° |
| Mean anomaly | 238.739988 ± 0.000207 ° |
| Orbital period | 11.60 yr |
Ephemeris & Observations
| Ephemeris version | NIMAv1 |
| Observation file |
omc_ast_NIMAv1.txt |
| bsp file | 21900_Orus_nima_v1.bsp |
| Date of first observation | 1951-11-08 |
| Date of last observation | 2018-11-08 |
| Number of observations used in the fit | 1398 |
| Number of rejected observations | 4 |
| Number of DES observations | 29 |
| Number of MPC observations | 1373 |
| Number of unpublished observations | 0 |
| RMS of observations | 0.491 arcsec |
Residuals
Residuals in right ascension and declination compared to NIMAv1 ephemeris.
Colours indicate the estimated precision in arcsec used as weights in the fitting process.
Orbit quality
| date | σα (arcsec) | σδ (arcsec) |
| 2018-01 | 0.031 | 0.023 |
| 2018-07 | 0.049 | 0.035 |
| 2019-01 | 0.036 | 0.025 |
| 2019-07 | 0.057 | 0.037 |
| 2020-01 | 0.045 | 0.029 |
| 2020-07 | 0.063 | 0.038 |
| 2021-01 | 0.058 | 0.035 |
| 2021-07 | 0.067 | 0.033 |
| 2022-01 | 0.076 | 0.038 |
Ephemeris comparison
Difference between NIMAv1 and JPL26 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.