(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 | 9.00 |
G slop | 0.15 |
(1) Data from the johnston archive list.
Orbital elements
Epoch (Julian date) | 2459800.5 |
Semi major axis | 5.252617 ± 0.000000 au |
Eccentricity | 0.092684491 ± 0.000000056 |
Inclination | 33.543437260 ± 0.000006167 ° |
Longitude of ascending node | 48.553280 ± 0.000007 ° |
Argument of perihelia | 295.567718 ± 0.000037 ° |
Mean anomaly | 320.927814 ± 0.000039 ° |
Orbital period | 12.04 yr |
Ephemeris & Observations
Ephemeris version | NIMAv5 |
Observation file |
omc_ast_NIMAv5.txt |
bsp file | 1208_Troilus_nima_v5.bsp |
Date of first observation | 1931-12-31 |
Date of last observation | 2023-07-02 |
Number of observations used in the fit | 3187 |
Number of rejected observations | 17 |
Number of DES observations | 0 |
Number of MPC observations | 3202 |
Number of unpublished observations | 2 |
RMS of observations | 2.941 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) |
2023-01 | 0.030 | 0.019 |
2023-07 | 0.041 | 0.039 |
2024-01 | 0.037 | 0.033 |
2024-07 | 0.037 | 0.046 |
2025-01 | 0.039 | 0.048 |
2025-07 | 0.036 | 0.042 |
2026-01 | 0.043 | 0.054 |
2026-07 | 0.039 | 0.032 |
2027-01 | 0.053 | 0.041 |
Ephemeris comparison

Difference between NIMAv5 and JPL65 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.