(617) Patroclus
This object has a more recent orbit available here
Object
Object | (617) Patroclus |
Diameter(1) | 140 km |
Dynamic class(1) | trojan |
Absolute magnitude | 8.23 |
G slop | 0.15 |
(1) Data from the johnston archive list.
Orbital elements
Epoch (Julian date) | 2459800.5 |
Semi major axis | 5.210104 ± 0.000000 au |
Eccentricity | 0.139867839 ± 0.000000058 |
Inclination | 22.062061509 ± 0.000005684 ° |
Longitude of ascending node | 44.358477 ± 0.000015 ° |
Argument of perihelia | 308.184374 ± 0.000028 ° |
Mean anomaly | 303.031918 ± 0.000030 ° |
Orbital period | 11.89 yr |
Ephemeris & Observations
Ephemeris version | NIMAv5 |
Observation file |
omc_ast_NIMAv5.txt |
bsp file | 617_Patroclus_nima_v5.bsp |
Date of first observation | 1906-10-17 |
Date of last observation | 2022-09-02 |
Number of observations used in the fit | 3561 |
Number of rejected observations | 19 |
Number of DES observations | 0 |
Number of MPC observations | 3580 |
Number of unpublished observations | 0 |
RMS of observations | 1.819 arcsec |
Residuals

Residuals in right ascension and declination compared to NIMAv5 ephemeris.
Colours indicate the estimated precision in arcsec used as weights in the fitting process.
Orbit quality
date | σα (arcsec) | σδ (arcsec) |
2022-01 | 0.033 | 0.021 |
2022-07 | 0.056 | 0.029 |
2023-01 | 0.044 | 0.018 |
2023-07 | 0.065 | 0.039 |
2024-01 | 0.050 | 0.029 |
2024-07 | 0.052 | 0.048 |
2025-01 | 0.050 | 0.045 |
2025-07 | 0.045 | 0.039 |
2026-01 | 0.053 | 0.048 |
Ephemeris comparison

Difference between NIMAv5 and JPL82 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.