C/2015 R3 PANSTARRS
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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 44
data interval 2013 03 05 – 2016 09 28
data type perihelion within the observation arc (FULL)
data arc selection entire data set (STD)
range of heliocentric distances 5.57 au – 4.90 au (perihelion) – 8.54 au
type of model of motion NC - non-gravitational orbits for symmetric CO-g(r)-like function
data weighting YES
number of residuals 83
RMS [arcseconds] 0.52
orbit quality class 1a
orbital elements (barycentric ecliptic J2000)
Epoch 2321 11 10
perihelion date 2014 02 12.47800874 ± 0.01250660
perihelion distance [au] 4.90113392 ± 0.00005817
eccentricity 0.99887337 ± 0.00003947
argument of perihelion [°] 271.979771 ± 0.001081
ascending node [°] 36.413765 ± 0.000088
inclination [°] 83.56133 ± 0.000164
reciprocal semi-major axis [10-6 au-1] 229.87 ± 8.05