(1871) Astyanax


Object

Object (1871) Astyanax
Diameter(1) 34 km
Dynamic class(1) trojan
Absolute magnitude 11.32
G slop 0.15
(1) Data from the johnston archive list.

Orbital elements

Epoch (Julian date) 2460800.5
Semi major axis 5.220447 ± 0.000000 au
Eccentricity 0.033394976 ± 0.000000054
Inclination 8.611912081 ± 0.000005869 °
Longitude of ascending node 145.766487 ± 0.000042 °
Argument of perihelia 166.756043 ± 0.000112 °
Mean anomaly 36.699007 ± 0.000103 °
Orbital period 11.93 yr

Ephemeris & Observations

Ephemeris version NIMAv7
Observation file (documentation) omc_ast_NIMAv7.txt
bsp file 1871_Astyanax_nima_v7.bsp
Date of first observation 1971-03-24
Date of last observation 2025-07-04
Number of observations used in the fit 2764
Number of rejected observations 166
Number of DES observations 20
Number of MPC observations 2882
Number of unpublished observations 28
RMS of observations 0.465 arcsec

Residuals

residual plot

Residuals in right ascension and declination compared to NIMAv7 ephemeris.
Colours indicate the estimated precision in arcsec used as weights in the fitting process.

Orbit quality

date σα (arcsec) σδ (arcsec)
2024-01 0.028 0.021
2024-07 0.039 0.027
2025-01 0.031 0.019
2025-07 0.038 0.022
2026-01 0.037 0.020
2026-07 0.040 0.020
2027-01 0.048 0.025
2027-07 0.043 0.020
2028-01 0.059 0.029

Ephemeris comparison

residual plot

Difference between NIMAv7 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.

Previous NIMA versions