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 1195
data interval 2017 11 26 – 2020 02 15
data arc selection data generally limited to post-perihelion (POS)
range of heliocentric distances 5.33 au – 7.9au
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 3212
RMS [arcseconds] 0.39
orbit quality class 1a+
orbital elements (barycentric ecliptic J2000)
Epoch 2325 03 14
perihelion date 2017 11 22.56184556 ± 0.00047163
perihelion distance [au] 5.32986854 ± 0.00000243
eccentricity 0.99930325 ± 0.00000276
argument of perihelion [°] 10.189611 ± 0.000057
ascending node [°] 128.129479 ± 0.000006
inclination [°] 121.19926 ± 0.000009
reciprocal semi-major axis [10-6 au-1] 130.73 ± 0.52
file containing 5001 VCs swarm
2016a1ra.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.