(1208) Troilus
This object has a more recent orbit available here
Object
Object | (1208) Troilus |
Diameter(1) | 100 km |
Dynamic class(1) | trojan |
Absolute magnitude | 8.99 |
G slop | 0.15 |
(1) Data from the johnston archive list.
Orbital elements
Epoch (Julian date) | 2458600.5 |
Semi major axis | 5.252322 ± 0.000000 au |
Eccentricity | 0.091363682 ± 0.000000075 |
Inclination | 33.540993326 ± 0.000006308 ° |
Longitude of ascending node | 48.547237 ± 0.000007 ° |
Argument of perihelia | 295.613145 ± 0.000059 ° |
Mean anomaly | 222.455300 ± 0.000060 ° |
Orbital period | 12.04 yr |
Ephemeris & Observations
Ephemeris version | NIMAv3 |
Observation file |
omc_ast_NIMAv3.txt |
bsp file | 1208_Troilus_nima_v3.bsp |
Date of first observation | 1931-12-31 |
Date of last observation | 2021-01-18 |
Number of observations used in the fit | 2716 |
Number of rejected observations | 16 |
Number of DES observations | 0 |
Number of MPC observations | 2730 |
Number of unpublished observations | 2 |
RMS of observations | 3.185 arcsec |
Residuals

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) |
2021-01 | 0.012 | 0.012 |
2021-07 | 0.018 | 0.020 |
2022-01 | 0.020 | 0.015 |
2022-07 | 0.040 | 0.024 |
2023-01 | 0.034 | 0.021 |
2023-07 | 0.046 | 0.043 |
2024-01 | 0.041 | 0.037 |
2024-07 | 0.041 | 0.051 |
2025-01 | 0.043 | 0.053 |
Ephemeris comparison

Difference between NIMAv3 and JPL56 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.