C/2017 M4 ATLAS
more info


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 CT - non-gravitational orbits for assymetric CO-g(r)-like function
data weighting YES
number of residuals 6492
RMS [arcseconds] 0.47
orbit quality class 1a+
orbital elements (barycentric ecliptic J2000)
Epoch 2322 06 18
perihelion date 2019 01 17.71323277 ± 0.00069821
perihelion distance [au] 3.24177096 ± 0.00000992
eccentricity 0.99963864 ± 0.00000466
argument of perihelion [°] 167.362831 ± 0.000222
ascending node [°] 65.857368 ± 0.000029
inclination [°] 105.702364 ± 0.000019
reciprocal semi-major axis [10-6 au-1] 111.47 ± 1.44
file containing 5001 VCs swarm
2017m4ct.bpl
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).
Six 2D-projections of the 6D space of future swarm including 5001 VCs. Each density map is given in logarithmic scale presented on the right in the individual panel.