(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 0.146565581 ± 0.000000058
Inclination 10.319135159 ± 0.000006149 °
Longitude of ascending node 316.535501 ± 0.000026 °
Argument of perihelia 133.358900 ± 0.000032 °
Mean anomaly 238.460896 ± 0.000050 °
Orbital period 11.89 yr

Ephemeris & Observations

Ephemeris version NIMAv3
Observation file (documentation) omc_ast_NIMAv3.txt
bsp file 588_Achilles_nima_v3.bsp
Date of first observation 1906-02-22
Date of last observation 2020-09-01
Number of observations used in the fit 2059
Number of rejected observations 56
Number of DES observations 0
Number of MPC observations 2067
Number of unpublished observations 48
RMS of observations 0.616 arcsec

Residuals

residual plot

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)
2020-01 0.012 0.011
2020-07 0.008 0.008
2021-01 0.008 0.009
2021-07 0.019 0.015
2022-01 0.025 0.024
2022-07 0.036 0.023
2023-01 0.060 0.036
2023-07 0.048 0.024
2024-01 0.075 0.042

Ephemeris comparison

residual plot

Difference between NIMAv3 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.