(2241) Alcathous
This object has a more recent orbit available here
Object
| Object | (2241) Alcathous |
| Diameter(1) | 115 km |
| Dynamic class(1) | trojan |
| Absolute magnitude | 8.64 |
| G slop | 0.15 |
(1) Data from the johnston archive list.
Orbital elements
| Epoch (Julian date) | 2458600.5 |
| Semi major axis | 5.179885 ± 0.000000 au |
| Eccentricity | 0.067236631 ± 0.000000050 |
| Inclination | 16.627531106 ± 0.000006684 ° |
| Longitude of ascending node | 267.998040 ± 0.000009 ° |
| Argument of perihelia | 292.243631 ± 0.000062 ° |
| Mean anomaly | 346.975303 ± 0.000056 ° |
| Orbital period | 11.79 yr |
Ephemeris & Observations
| Ephemeris version | NIMAv3 |
| Observation file |
omc_ast_NIMAv3.txt |
| bsp file | 2241_Alcathous_nima_v3.bsp |
| Date of first observation | 1950-06-19 |
| Date of last observation | 2021-04-24 |
| Number of observations used in the fit | 2580 |
| Number of rejected observations | 16 |
| Number of DES observations | 0 |
| Number of MPC observations | 2595 |
| Number of unpublished observations | 1 |
| RMS of observations | 0.452 arcsec |
Residuals
Residuals in right ascension and declination compared to NIMAv3 ephemeris.
Colours indicate the estimated precision in arcsec used as weights in the fitting process.
Orbit quality
| date | σα (arcsec) | σδ (arcsec) |
| 2021-01 | 0.008 | 0.008 |
| 2021-07 | 0.010 | 0.010 |
| 2022-01 | 0.010 | 0.010 |
| 2022-07 | 0.023 | 0.021 |
| 2023-01 | 0.019 | 0.018 |
| 2023-07 | 0.034 | 0.029 |
| 2024-01 | 0.028 | 0.023 |
| 2024-07 | 0.039 | 0.029 |
| 2025-01 | 0.036 | 0.025 |
Ephemeris comparison
Difference between NIMAv3 and JPL73 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.