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
detectability of NG effects in the comet's motion comet with NG effects strongly manifested in positional data fitting
type of model of motion GR - gravitational orbit
data weighting YES
number of residuals 5658
RMS [arcseconds] 0.40
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] 39.78 – 40.71 – 41.34
previous perihelion distance [au] 54 – 68 – 83
previous aphelion distance [103 au] 48.3 – 49.1 – 50.2
time interval to previous perihelion [Myr] 2.62 – 2.65 – 2.68
percentage of VCs with qprev > 20100
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).
previous 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] 51.68 – 52.11 – 52.54
previous perihelion distance [au] 3.091 – 3.101 – 3.112
previous aphelion distance [103 au] 38.07 – 38.38 – 38.7
time interval to previous perihelion [Myr] 2.62 – 2.66 – 2.69
percentage of VCs with qprev < 10100