C/2020 H6 ATLAS
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Comet C/2020 H6 was discovered on 22 April 2020, about 1.3 yr before its perihelion passage. This comet was observed until 8 January 2024 (as in February 2025).

Comet had its closest approach to the Earth on 30 April 2021 (3.86 au); about six months before its perihelion passage.

The preferred NG solution ('bd') given here is based on data span over 3.72 yr in a range of heliocentric distances: 6.22 au – 4.70 au (perihelion) – 7.80 au. Orbits based on pre-perihelion and post-perihelion data independently are also presented.

This Oort spike comet suffers moderate planetary perturbations during its passage through the planetary system that lead to a significantly more tight future orbit (semimajor axis of about 2,000 au).
solution description
number of observations 792
data interval 2020 04 22 – 2021 08 23
data arc selection data generally limited to pre-perihelion (PRE)
range of heliocentric distances 6.22 au – 4.71au
type of model of motion NC - non-gravitational orbits for symmetric CO-g(r)-like function
data weighting YES
number of residuals 1561
RMS [arcseconds] 0.32
orbit quality class 1a
orbital elements (barycentric ecliptic J2000)
Epoch 1717 03 01
perihelion date 2021 09 30.34411152 ± 0.00526670
perihelion distance [au] 4.70569498 ± 0.00003792
eccentricity 1.00003471 ± 0.00002317
argument of perihelion [°] 20.300184 ± 0.000663
ascending node [°] 213.635586 ± 0.000004
inclination [°] 79.934525 ± 0.000015
reciprocal semi-major axis [10-6 au-1] -7.38 ± 4.92
file containing 5001 VCs swarm
2020h6pc.bmi
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).
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.