(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 ± 0.000000 au |
| Eccentricity | 0.146565570 ± 0.000000053 |
| Inclination | 10.319128882 ± 0.000005474 ° |
| Longitude of ascending node | 316.535526 ± 0.000027 ° |
| Argument of perihelia | 133.358882 ± 0.000030 ° |
| Mean anomaly | 238.460890 ± 0.000033 ° |
| Orbital period | 11.89 yr |
Ephemeris & Observations
| Ephemeris version | NIMAv1 |
| Observation file |
omc_ast_NIMAv1.txt |
| bsp file | 588_Achilles_nima_v1.bsp |
| Date of first observation | 1906-02-22 |
| Date of last observation | 2018-12-07 |
| Number of observations used in the fit | 1510 |
| Number of rejected observations | 50 |
| Number of DES observations | 0 |
| Number of MPC observations | 1560 |
| Number of unpublished observations | 0 |
| RMS of observations | 0.719 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 | 0.016 | 0.014 |
| 2018-07 | 0.023 | 0.020 |
| 2019-01 | 0.017 | 0.015 |
| 2019-07 | 0.026 | 0.021 |
| 2020-01 | 0.021 | 0.017 |
| 2020-07 | 0.030 | 0.023 |
| 2021-01 | 0.028 | 0.022 |
| 2021-07 | 0.036 | 0.023 |
| 2022-01 | 0.041 | 0.027 |
Ephemeris comparison
Difference between NIMAv1 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.