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Comet C/2015 R3 was discovered on 12 September 2015 with Pan-STARRS 1 telescope (Haleakala), that is about 1.6 yr after its perihelion passage. After some time pre-discovery data were found going back to 5 March 2013. This comet was rarely observed until 28 September 2016.

Comet had its closest approach to the Earth on 8 May 2015 (4.939 au), a week after its perihelion passage.

We recommended GR solution spanning over 3.57 yr in a range of heliocentric distances from 5.57 au – 4.90 au (perihelion) – 8.54 au as the preferred orbit( solution 'b1'), because radial component of NG~acceleration is negative in solution 'bc'.

This Oort spike comet suffers small planetary perturbations during its passage through the planetary system that lead to a more tight future orbit with a semimajor axis larger than 10000 au (see future barycentric orbits).
solution description
number of observations 36
data interval 2015 09 12 – 2016 09 28
data arc selection data generally limited to post-perihelion (POS)
range of heliocentric distances 6.56 au – 8.54au
detectability of NG effects in the comet's motion comet with determinable NG~orbit
type of model of motion GR - gravitational orbit
data weighting YES
number of residuals 65
RMS [arcseconds] 0.46
orbit quality class 1b
orbital elements (barycentric ecliptic J2000)
Epoch 2322 03 10
perihelion date 2014 02 12.45806581 ± 0.01290923
perihelion distance [au] 4.90157601 ± 0.00009839
eccentricity 0.99873203 ± 0.00005571
argument of perihelion [°] 271.984174 ± 0.001125
ascending node [°] 36.413501 ± 0.000118
inclination [°] 83.562104 ± 0.000277
reciprocal semi-major axis [10-6 au-1] 258.69 ± 11.36
file containing 5001 VCs swarm
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.