C/2021 Y1 ATLAS
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Comet C/2021 Y1 was discovered on 26 December 2021 by ATLAS-MLO (Mauna Loa), that is a year and five months before its perihelion passage. Next, two series of pre-discovery images taken by M Holbroook at Pleasant Groves Observatory on two days in November (8 and 24) were found.
Comet had its closest approach to the Earth on 12 December 2022 (1.69 au), about 5.5 months before its perihelion passage.
The preferred NG solution given here is based on data span over 1.61 yr in a range of heliocentric distances: 5.91 au – 2.032 au (perihelion) – 2.11 au. However, even this NG solution exhibits some trends in [O-C] within a few months before perihelion passage. Thus, we also offer the solution 'd5' for past orbital study.
This Oort spike comet suffers rather small planetary perturbations during its passage through the planetary system that lead to escape the comet from the planetary zone on a hyperbolic orbit.
Comet had its closest approach to the Earth on 12 December 2022 (1.69 au), about 5.5 months before its perihelion passage.
The preferred NG solution given here is based on data span over 1.61 yr in a range of heliocentric distances: 5.91 au – 2.032 au (perihelion) – 2.11 au. However, even this NG solution exhibits some trends in [O-C] within a few months before perihelion passage. Thus, we also offer the solution 'd5' for past orbital study.
This Oort spike comet suffers rather small planetary perturbations during its passage through the planetary system that lead to escape the comet from the planetary zone on a hyperbolic orbit.
| solution description | ||
|---|---|---|
| number of observations | 1869 | |
| data interval | 2021 11 08 – 2023 06 16 | |
| data type | perihelion within the observation arc (FULL) | |
| data arc selection | entire data set (STD) | |
| range of heliocentric distances | 5.91 au – 2.03 au (perihelion) – 2.11 au | |
| type of model of motion | NS - non-gravitational orbits for standard g(r) | |
| data weighting | YES | |
| number of residuals | 3666 | |
| RMS [arcseconds] | 0.33 | |
| orbit quality class | 1a | |
| previous orbit statistics, both Galactic and stellar perturbations were taken into account | ||
|---|---|---|
| no. of returning VCs in the swarm | 5001 | * |
| no. of escaping VCs in the swarm | 0 | |
| no. of hyperbolas among escaping VCs in the swarm | 0 | |
| previous reciprocal semi-major axis [10-6 au-1] | 21.97 – 22.45 – 22.92 | |
| previous perihelion distance [au] | 497 – 511 – 523 | |
| previous aphelion distance [103 au] | 86.7 – 88.6 – 90.5 | |
| time interval to previous perihelion [Myr] | 8.76 – 9.04 – 9.35 | |
| percentage of VCs with qprev > 20 | 100 | |
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.
| previous_g orbit statistics, here only the Galactic tide has been included | ||
|---|---|---|
| no. of returning VCs in the swarm | 5001 | * |
| no. of escaping VCs in the swarm | 0 | |
| no. of hyperbolas among escaping VCs in the swarm | 0 | |
| previous reciprocal semi-major axis [10-6 au-1] | 24.53 – 25.01 – 25.48 | |
| previous perihelion distance [au] | 54 – 61 – 69 | |
| previous aphelion distance [103 au] | 78.5 – 79.9 – 81.5 | |
| time interval to previous perihelion [Myr] | 7.65 – 7.85 – 8.08 | |
| percentage of VCs with qprev > 20 | 100 | |