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 (heliocentric ecliptic J2000)
Epoch 2021 09 23
perihelion date 2021 10 01.05772888 ± 0.00498804
perihelion distance [au] 4.70291221 ± 0.00000793
eccentricity 1.00069143 ± 0.00000916
argument of perihelion [°] 20.345378 ± 0.000699
ascending node [°] 213.706493 ± 0.000004
inclination [°] 79.967245 ± 0.000015
reciprocal semi-major axis [10-6 au-1] -147.02 ± 1.95
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).
non-gravitational parameters
A1 [10-8au/day2] 4.1901 ± 0.8097
A2 [10-8au/day2] -1.1827 ± 0.4714
A3 [10-8au/day2] 0 (assumed)
m -2.00
n 3.000
k -2.6000
r0 [au] 10.000
α 0.0100