C/1986 P1-A Wilson
more info
Comet C/1986 P1-A was discovered on 5 August 1986 by Christine Wilson (Mount Palomar, California, USA), that is 8.5 months before its perihelion passage. This comet was last observed in mid-April 1989. Splitting event observed in comet Wilson was occured after perihelion passage.
Comet had its closest approach to the Earth on 1 May 1987 (0.623 au), less than two weeks after perihelion passage. According to Minor Planet Center, the main component A of this comet exhibits nongravitational acceleration in the time interval 5 August 1986 – 11 April 1989. Therefore, the non-gravitational orbit from the whole observational arc (spanning over 2.68 yr in a range of heliocentric distances: 3.64 au – 1.200 au (perihelion) – 7.83 au.) are given here as preferred orbit.

This Oort spike comet suffers large planetary perturbations during its passage through the planetary system; these perturbations lead to a more tight future orbit with semimajor axis of about 1,300 au.
See also Królikowska and Dybczyński 2010, Królikowska 2014 and Królikowska 2020.

solution description
number of observations 687
data interval 1986 08 05 – 1989 04 11
data type perihelion within the observation arc (FULL)
data arc selection entire data set (STD)
range of heliocentric distances 3.64 au – 1.20 au (perihelion) – 7.83 au
type of model of motion NS - non-gravitational orbits for standard g(r)
data weighting YES
number of residuals 1361
RMS [arcseconds] 1.11
orbit quality class 1a
orbital elements (barycentric ecliptic J2000)
Epoch 2294 11 11
perihelion date 1987 04 19.78395339 ± 0.00011968
perihelion distance [au] 1.20210995 ± 0.00000172
eccentricity 0.99907772 ± 0.00000282
argument of perihelion [°] 238.307237 ± 0.000142
ascending node [°] 111.721429 ± 0.000040
inclination [°] 147.19316 ± 0.000028
reciprocal semi-major axis [10-6 au-1] 767.22 ± 2.35
file containing 5001 VCs swarm
1986p1n1.bpl
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.
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.