C/2017 M4 ATLAS
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Comet C/2017 M4 was discovered on 21 June 2017 by Asteroid Terrestrial-impact Last Alert System (ATLAS) Team, that is about months after its perihelion passage.
Some prediscovery images of this comet were found: taken on 16 June 2017 by Pan-STARRS 1 telescope (Haleakala).
Solutions given here are based on data spanning over 4.46 yr in a range of heliocentric distances: 6.09 au – 3.252 au (perihelion) – 9.19 au.
NG orbits using full data-arc as well as independently using pre-perihelion and post-perihelion data are determinable.
See also Królikowska and Dones 2023.
| solution description | ||
|---|---|---|
| number of observations | 2854 | |
| data interval | 2017 06 16 – 2018 11 13 | |
| data arc selection | data generally limited to pre-perihelion (PRE) | |
| range of heliocentric distances | 6.09 au – 3.31au | |
| type of model of motion | NC - non-gravitational orbits for symmetric CO-g(r)-like function | |
| data weighting | YES | |
| number of residuals | 5658 | |
| RMS [arcseconds] | 0.37 | |
| orbit quality class | 1a | |
| previous orbit statistics, both Galactic and stellar perturbations were taken into account | ||
|---|---|---|
| no. of returning VCs in the swarm | 3716 | * |
| no. of escaping VCs in the swarm | 1285 | |
| no. of hyperbolas among escaping VCs in the swarm | 0 | |
| previous reciprocal semi-major axis [10-6 au-1] | 15.61 – 17.37 – 19.12 | |
| previous perihelion distance [au] | 1900 – 2500 – 3000 | R |
| previous aphelion distance [103 au] | 103 – 114 – 126 | |
| time interval to previous perihelion [Myr] | 11 – 13 – 14 | R |
| percentage of VCs with qprev > 20 | 100 | |
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).
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).
| previous orbit statistics, here only the Galactic tide has been included | ||
|---|---|---|
| no. of returning VCs in the swarm | 359 | |
| no. of escaping VCs in the swarm | 4642 | * |
| no. of hyperbolas among escaping VCs in the swarm | 0 | |
| previous reciprocal semi-major axis [10-6 au-1] | 12.03 – 14.20 – 16.40 | |
| previous perihelion distance [au] | 35 – 40 – 45 | |
| previous aphelion distance [103 au] | 120 – 140 – 170 | |
| time interval to previous perihelion [Myr] | 3.97 ± 3.9 | |
| percentage of VCs with qprev > 20 | 100 | |