C/2016 A1 PANSTARRS
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Comet C/2016 A1 was discovered on 1 January 2016 with Pan-STARRS 1 telescope (Haleakala), that is about almost 2 yr before its perihelion passage, and was next observed until 15 February 2020.

Comet had its closest approach to the Earth on 17 January 2018 (4.397 au); about 2 months after its perihelion passage.

Solutions given here are based on data spanning over 4.12 yr in a range of heliocentric distances: 7.31 au    5.328 au (perihelion) – 7.90 au.

This Oort spike comet suffers small planetary perturbations during its passage through the planetary system that lead to a more tight future orbit (see future barycentric orbit).

See also Królikowska and Dones 2023.

solution description
number of observations 974
data interval 2016 01 01 – 2017 11 22
data arc selection data generally limited to pre-perihelion (PRE)
range of heliocentric distances 7.31 au – 5.33au
detectability of NG effects in the comet's motion NG effects not determinable
type of model of motion GR - gravitational orbit
data weighting YES
number of residuals 1911
RMS [arcseconds] 0.35
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] 32.73 – 33.35 – 33.96
previous perihelion distance [au] 1420 – 1500 – 1580
previous aphelion distance [103 au] 57.5 – 58.5 – 59.5
time interval to previous perihelion [Myr] 4.77 – 4.91 – 5.06
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] 33.31 – 34.00 – 34.69
previous perihelion distance [au] 15 – 16.6 – 18.5
previous aphelion distance [103 au] 57.6 – 58.8 – 60
time interval to previous perihelion [Myr] 4.87 – 5.01 – 5.17
percentage of VCs with 10 < qprev < 2098
percentage of VCs with qprev > 202