C/2020 H5 Robinson
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Comet C/2020 H5 was discovered on 22 April 2020 by ATLAS-HKO (Haleakala), that is about 7.5 months before its perihelion passage. was observed until the 11 May 2024. Several prediscovery images of this comet were found going back to the mid-December 2015.

Comet had its closest approach to the Earth on 11 April 2021 (8.48 au), about 4 months after its perihelion passage.

Preferred GR solution given here is based on data span over 8.41 yr in a range of heliocentric distances: 13.59 au – 9.34 au (perihelion) – 11.60 au; also orbit based on pre-perihelion data is presented.

This long-period comet (original semimajor axis of about 7,000–7,500 au) suffers small planetary perturbations during its passage through the planetary system that lead to a more tight future orbit (semimajor axis of about 4,000 au).
solution description
number of observations 278
data interval 2015 12 14 – 2024 05 11
data type perihelion within the observation arc (FULL)
data arc selection entire data set (STD)
range of heliocentric distances 13.59 au – 9.35 au (perihelion) – 11.6 au
detectability of NG effects in the comet's motion NG effects not determinable
type of model of motion GR - gravitational orbit
data weighting NO
number of residuals 133
RMS [arcseconds] 0.40
orbit quality class 1a
orbital elements (barycentric ecliptic J2000)
Epoch 1706 10 05
perihelion date 2020 12 10.44969194 ± 0.01893072
perihelion distance [au] 9.34802131 ± 0.00011181
eccentricity 0.99870820 ± 0.00005908
argument of perihelion [°] 326.335823 ± 0.001010
ascending node [°] 210.617745 ± 0.000076
inclination [°] 70.174097 ± 0.000057
reciprocal semi-major axis [10-6 au-1] 138.19 ± 6.32
file containing 5001 VCs swarm
2020h5pa.bmi
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.
Six 2D-projections of the 6D space of original swarm including 5001 VCs. Each density map is given in logarithmic scale presented on the right in the individual panel.