C/2020 U4 PanSTARRS
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Comet C/2020 U4 was discovered on 22 October 2020, about 1.5 yr before its perihelion passage; later a series of prediscovery images was found going back to 9 November 2019. This comet was observed until 11 September 2024 (as in February 2025).

Comet had its closest approach to the Earth on 30 November 2021 (4.47 au); a bit more than four months before the perihelion passage.

Solution given here is based on data span over 4.84 yr in a range of heliocentric distances: 8.24 au – 5.35 au (perihelion) – 8.26 au. Orbits based on pre-perihelion and post-perihelion data independently were also obtained.

This Oort spike comet suffers small planetary perturbations during its passage through the planetary system; however, they lead to escape the comet from the solar system on hyperbolic barycentric orbit.
solution description
number of observations 1060
data interval 2019 11 09 – 2024 09 11
data type perihelion within the observation arc (FULL)
data arc selection entire data set (STD)
range of heliocentric distances 8.24 au – 5.35 au (perihelion) – 8.26 au
detectability of NG effects in the comet's motion NG effects not determinable
type of model of motion GR - gravitational orbit
data weighting YES
number of residuals 2099
RMS [arcseconds] 0.37
orbit quality class 1a+
orbital elements (heliocentric ecliptic J2000)
Epoch 2022 04 11
perihelion date 2022 04 07.99468108 ± 0.00017150
perihelion distance [au] 5.35368071 ± 0.00000112
eccentricity 1.00135167 ± 0.00000169
argument of perihelion [°] 69.535005 ± 0.000022
ascending node [°] 120.013703 ± 0.000015
inclination [°] 167.035856 ± 0.000004
reciprocal semi-major axis [10-6 au-1] -252.47 ± 0.32
Upper panel: Time distribution of positional observations with corresponding heliocentric (red curve) and geocentric (green curve) distance at which they were taken. The horizontal dotted line shows the perihelion distance for a given comet whereas vertical dotted line — the moment of perihelion passage.
Middle panel(s): O-C diagram for a given solution (sometimes in comparison to another solution available in CODE), where residuals in right ascension are shown using magenta dots and in declination by blue open circles.
Lowest panel: Relative weights for a given data set(s).