(5145) Pholus


Object

Object (5145) Pholus
Diameter(1) 107 km
Dynamic class(1) Centaur
Absolute magnitude 6.96
G slop 0.15
(1) Data from the johnston archive list.

Orbital elements

Epoch (Julian date) 2460400.5
Semi major axis 20.284180 ± 0.000025 au
Eccentricity 0.573579989 ± 0.000000270
Inclination 24.711054849 ± 0.000015623 °
Longitude of ascending node 119.334415 ± 0.000017 °
Argument of perihelia 354.619372 ± 0.000089 °
Mean anomaly 128.300316 ± 0.000257 °
Orbital period 91.36 yr

Ephemeris & Observations

Ephemeris version NIMAv2
Observation file (documentation) omc_ast_NIMAv2.txt
bsp file 5145_Pholus_nima_v2.bsp
Date of first observation 1977-07-22
Date of last observation 2024-05-19
Number of observations used in the fit 394
Number of rejected observations 4
Number of DES observations 0
Number of MPC observations 396
Number of unpublished observations 2
RMS of observations 0.569 arcsec

Residuals

residual plot

Residuals in right ascension and declination compared to NIMAv2 ephemeris.
Colours indicate the estimated precision in arcsec used as weights in the fitting process.

Orbit quality

date σα (arcsec) σδ (arcsec)
2024-01 0.008 0.007
2024-07 0.008 0.007
2025-01 0.007 0.007
2025-07 0.008 0.008
2026-01 0.009 0.009
2026-07 0.012 0.009
2027-01 0.014 0.010
2027-07 0.018 0.011
2028-01 0.020 0.012

Ephemeris comparison

residual plot

Difference between NIMAv2 and JPL23 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