C/2012 A1 PANSTARRS
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Comet C/2012 A1 was discovered on 2 January 2012, that is 1.9 yr before perihelion passage, and next observed 3.2 yr during four oppositions in a range of heliocentric distances: 8.73 au – 7.603 au (perihelion) – 8.12 au.
Comet had its closest approach to the Earth on 22 December 2013 (6.642 au, about three weeks after perihelion passage, see figure).
C/2012 A1 suffers a slight planetary perturbations during its passage through the planetary system.
See also Królikowska and Dybczyński 2017.

solution description
number of observations 330
data interval 2012 01 02 – 2015 03 09
data type perihelion within the observation arc (FULL)
data arc selection entire data set (STD)
range of heliocentric distances 8.73 au – 7.60 au (perihelion) – 8.12 au
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 653
RMS [arcseconds] 0.40
orbit quality class 1a+
orbital elements (heliocentric ecliptic J2000)
Epoch 2013 12 14
perihelion date 2013 12 02.21813125 ± 0.00117263
perihelion distance [au] 7.60253338 ± 0.00000787
eccentricity 1.00164070 ± 0.00000730
argument of perihelion [°] 191.934807 ± 0.000071
ascending node [°] 277.971479 ± 0.000007
inclination [°] 120.910023 ± 0.000014
recip semi-major axis [10-6 au-1] -215.81 ± 0.96
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