(588) Achilles
This object has a more recent orbit available here
Object
| Object | (588) Achilles |
| Diameter(1) | 130 km |
| Dynamic class(1) | trojan |
| Absolute magnitude | 8.67 |
| G slop | 0.15 |
(1) Data from the johnston archive list.
Orbital elements
| Epoch (Julian date) | 2458600.5 |
| Semi major axis | 5.209480 ± 0.000001 au |
| Eccentricity | 0.146565583 ± 0.000000071 |
| Inclination | 10.319130805 ± 0.000007857 ° |
| Longitude of ascending node | 316.535517 ± 0.000036 ° |
| Argument of perihelia | 133.358886 ± 0.000042 ° |
| Mean anomaly | 238.460897 ± 0.000050 ° |
| Orbital period | 11.89 yr |
Ephemeris & Observations
| Ephemeris version | NIMAv2 |
| Observation file |
omc_ast_NIMAv2.txt |
| bsp file | 588_Achilles_nima_v2.bsp |
| Date of first observation | 1906-02-22 |
| Date of last observation | 2019-08-10 |
| Number of observations used in the fit | 1712 |
| Number of rejected observations | 42 |
| Number of DES observations | 0 |
| Number of MPC observations | 1754 |
| Number of unpublished observations | 0 |
| RMS of observations | 0.700 arcsec |
Residuals
Residuals in right ascension and declination compared to NIMAv2 ephemeris.
Colours indicate the estimated precision in arcsec used as weights in the fitting process.
Orbit quality
| date | σα (arcsec) | σδ (arcsec) |
| 2019-01 | 0.023 | 0.020 |
| 2019-07 | 0.031 | 0.028 |
| 2020-01 | 0.025 | 0.022 |
| 2020-07 | 0.036 | 0.030 |
| 2021-01 | 0.034 | 0.029 |
| 2021-07 | 0.046 | 0.031 |
| 2022-01 | 0.054 | 0.038 |
| 2022-07 | 0.057 | 0.026 |
| 2023-01 | 0.087 | 0.035 |
Ephemeris comparison
Difference between NIMAv2 and JPL69 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.