(28978) Ixion
This object has a more recent orbit available here
Object
Object | (28978) Ixion |
Diameter(1) | 617 km |
Dynamic class(1) | plutino |
Absolute magnitude | 3.60 |
G slop | 0.15 |
(1) Data from the johnston archive list.
Orbital elements
Epoch (Julian date) | 2458200.5 |
Semi major axis | 39.713214 ± 0.000984 au |
Eccentricity | 0.242209267 ± 0.000007235 |
Inclination | 19.580706130 ± 0.000244282 ° |
Longitude of ascending node | 70.991081 ± 0.000368 ° |
Argument of perihelia | 298.576718 ± 0.003977 ° |
Mean anomaly | 284.990480 ± 0.003992 ° |
Orbital period | 250.27 yr |
Ephemeris & Observations
Ephemeris version | NIMAv8 |
Observation file |
omc_ast_NIMAv8.txt |
bsp file | 28978_Ixion_nima_v8.bsp |
Date of first observation | 1982-07-17 |
Date of last observation | 2019-09-28 |
Number of observations used in the fit | 430 |
Number of rejected observations | 18 |
Number of DES observations | 0 |
Number of MPC observations | 174 |
Number of unpublished observations | 274 |
RMS of observations | 0.204 arcsec |
Residuals

Residuals in right ascension and declination compared to NIMAv8 ephemeris.
Colours indicate the estimated precision in arcsec used as weights in the fitting process.
Orbit quality
date | σα (arcsec) | σδ (arcsec) |
2019-01 | 0.062 | 0.024 |
2019-07 | 0.058 | 0.030 |
2020-01 | 0.079 | 0.029 |
2020-07 | 0.077 | 0.036 |
2021-01 | 0.098 | 0.034 |
2021-07 | 0.099 | 0.043 |
2022-01 | 0.120 | 0.040 |
2022-07 | 0.124 | 0.050 |
2023-01 | 0.145 | 0.046 |
Ephemeris comparison

Difference between NIMAv8 and JPL15 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.