C/2021 T4 Lemmon
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Comet C/2021 T4 was discovered on 7 October 2021 by Mt. Lemmon Survey, that is a year and ten months before its perihelion passage. comet is still observed (as in April 2025).
Comet had its closest approach to the Earth on 20 July 2023 (0.541 au), eleven days before its perihelion passage.
Currently, the preferred NG solution given here is based on pre-perihelion data span over 1.96 yr in a range of heliocentric distances from 7.65 au to 1.49 au.
This Oort spike comet suffers notable planetary perturbations during its passage through the planetary system that lead to more tight future orbit of about 1,000 au.
Comet had its closest approach to the Earth on 20 July 2023 (0.541 au), eleven days before its perihelion passage.
Currently, the preferred NG solution given here is based on pre-perihelion data span over 1.96 yr in a range of heliocentric distances from 7.65 au to 1.49 au.
This Oort spike comet suffers notable planetary perturbations during its passage through the planetary system that lead to more tight future orbit of about 1,000 au.
| solution description | ||
|---|---|---|
| number of observations | 1316 | |
| data interval | 2021 08 07 – 2023 07 23 | |
| data arc selection | data generally limited to pre-perihelion (PRE) | |
| range of heliocentric distances | 7.65 au – 1.49au | |
| detectability of NG effects in the comet's motion | comet with determinable NG~orbit | |
| type of model of motion | GR - gravitational orbit | |
| data weighting | YES | |
| number of residuals | 2609 | |
| RMS [arcseconds] | 0.46 | |
| orbit quality class | 1a+ | |
| orbital elements (heliocentric ecliptic J2000) | ||
|---|---|---|
| Epoch | 2023 09 13 | |
| perihelion date | 2023 07 31.53928361 | ± 0.00002098 |
| perihelion distance [au] | 1.48327792 | ± 0.00000041 |
| eccentricity | 0.99986966 | ± 0.00000049 |
| argument of perihelion [°] | 329.822654 | ± 0.000028 |
| ascending node [°] | 257.884813 | ± 0.000015 |
| inclination [°] | 160.777082 | ± 0.000005 |
| reciprocal semi-major axis [10-6 au-1] | 87.87 | ± 0.33 |
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.