C/2021 D2 ZTF
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Comet C/2021 D2 was discovered on 19 February 2021 by Palomar Mountain--ZTF, that is almost a year before its perihelion passage.

Comet had its closest approach to the Earth on 7 February 2022 (2.54 au), about four days after its perihelion passage.

The preferred NG solution given here is based on data span over 2.17 yr in a range of heliocentric distances: 4.46 au – 2.95 au (perihelion) – 5.10 au.

This Oort spike comet suffers small planetary perturbations during its passage through the planetary system that lead to escape the comet from the planetary zone on a hyperbolic orbit (see future barycentric orbits).
solution description
number of observations 561
data interval 2021 02 19 – 2022 01 29
data arc selection data generally limited to pre-perihelion (PRE)
range of heliocentric distances 4.46 au – 2.95au
type of model of motion NC - non-gravitational orbits for symmetric CO-g(r)-like function
data weighting YES
number of residuals 1107
RMS [arcseconds] 0.49
orbit quality class 1a+
orbital elements (barycentric ecliptic J2000)
Epoch 1720 03 25
perihelion date 2022 02 02.20502478 ± 0.00473944
perihelion distance [au] 2.94546595 ± 0.00004428
eccentricity 0.99992259 ± 0.00002234
argument of perihelion [°] 125.016952 ± 0.000889
ascending node [°] 305.696387 ± 0.000113
inclination [°] 83.844866 ± 0.000109
reciprocal semi-major axis [10-6 au-1] 26.28 ± 7.59
file containing 5001 VCs swarm
2021d2p4.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.