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 3284
data interval 2017 06 16 – 2021 11 30
data type perihelion within the observation arc (FULL)
data arc selection entire data set (STD)
range of heliocentric distances 6.09 au – 3.25 au (perihelion) – 9.19 au
type of model of motion NS - non-gravitational orbits for standard g(r)
data weighting YES
number of residuals 6492
RMS [arcseconds] 0.48
orbit quality class 1a+
next 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
next reciprocal semi-major axis [10-6 au-1] 125.43 – 126.43 – 127.43
next perihelion distance [au] 3.2709 – 3.272 – 3.273
next aphelion distance [103 au] 15.69 – 15.82 – 15.94
time interval to next perihelion [Myr] 0.694 – 0.703 – 0.711
percentage of VCs with qnext < 10100
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).
next 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
next reciprocal semi-major axis [10-6 au-1] 125.41 – 126.41 – 127.40
next perihelion distance [au] 3.2736 – 3.2745 – 3.2755
next aphelion distance [103 au] 15.69 – 15.82 – 15.94
time interval to next perihelion [Myr] 0.695 – 0.703 – 0.711
percentage of VCs with qnext < 10100