(15440) Eioneus


Object

Object (15440) Eioneus
Diameter(1) 63 km
Dynamic class(1) trojan
Absolute magnitude 9.70
G slop 0.15
(1) Data from the johnston archive list.

Orbital elements

Epoch (Julian date) 2460800.5
Semi major axis 5.289302 ± 0.000000 au
Eccentricity 0.021802459 ± 0.000000012
Inclination 28.763011076 ± 0.000000141 °
Longitude of ascending node 120.549587 ± 0.000000 °
Argument of perihelia 285.813285 ± 0.000022 °
Mean anomaly 85.594868 ± 0.000018 °
Orbital period 12.16 yr

Ephemeris & Observations

Ephemeris version NIMAv3
Observation file (documentation) omc_ast_NIMAv3.txt
bsp file 15440_Eioneus_nima_v3.bsp
Date of first observation 1951-11-28
Date of last observation 2025-06-07
Number of observations used in the fit 4717
Number of rejected observations 66
Number of DES observations 0
Number of MPC observations 4325
Number of unpublished observations 0
RMS of observations 0.122 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)
2024-01 0.019 0.008
2024-07 0.015 0.006
2025-01 0.025 0.006
2025-07 0.018 0.004
2026-01 0.026 0.001
2026-07 0.022 0.001
2027-01 0.025 0.007
2027-07 0.024 0.005
2028-01 0.022 0.009

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.

Previous NIMA versions