C/2011 Q2 McNaught
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Comet C/2011 Q2 was discovered on 26 August 2011 by Robert H. McNaught (Siding Spring), that is almost 5 months before its perihelion passage. It was observed until 26 April 2012.
Comet had its closest approach to the Earth on 26 January 2012 (2.271 au), a week after its perihelion passage.
Solution given here is based on data spanning over 0.665 yr in a range of heliocentric distances: 2.43 au – 1.349 au (perihelion) – 1.94 au.
This Oort spike comet suffers notable planetary perturbations during its passage through the planetary system that cause a tighter future orbit with original semimajor axis of about 1,000 au (see future barycentric orbits).
See also Królikowska 2020.

solution description
number of observations 105
data interval 2011 08 26 – 2012 04 26
data type perihelion within the observation arc (FULL)
data arc selection entire data set (STD)
range of heliocentric distances 2.43 au – 1.35 au (perihelion) – 1.94 au
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 202
RMS [arcseconds] 0.22
orbit quality class 1b
orbital elements (heliocentric ecliptic J2000)
Epoch 2011 09 13
perihelion date 2012 01 19.79252990 ± 0.00113764
perihelion distance [au] 1.34955367 ± 0.00000331
eccentricity 1.00000028 ± 0.00001889
argument of perihelion [°] 34.630658 ± 0.000583
ascending node [°] 287.369175 ± 0.000122
inclination [°] 36.86687 ± 0.000087
reciprocal semi-major axis [10-6 au-1] -0.20 ± 14.00
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.