C/2006 HW51 Siding Spring
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Comet C/2006 HW51 was discovered on 23 April 2006 with Siding Spring; that is about 5 months before its perihelion passage. It was observed until 7 August 2007 (see picture).
Comet had its closest approach to the Earth on 3 May 2006 (2.280 au), 10 days after its discovery.
Here, two solutions based on entire data set (a6 and n5) are very similar quality, and in Królikowska and Dybczyński 2013 we recomended pure GR solution for past and future orbital evolution. Both these solutions are based on data spanning over 1.29 yr in a range of heliocentric distances: 2.87 au – 2.259 au (perihelion) – 4.04 au. Here, we chose the NG solution as preferred;see Królikowska 2020.
This Oort spike comet suffers tiny planetary perturbations during its passage through the planetary system (compare original and future barycentric orbits for preferred orbit).

solution description
number of observations 164
data interval 2006 04 23 – 2006 08 29
data arc selection data generally limited to pre-perihelion (PRE)
range of heliocentric distances 2.88 au – 2.29au
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 316
RMS [arcseconds] 0.29
orbit quality class 2a
orbital elements (barycentric ecliptic J2000)
Epoch 1706 02 07
perihelion date 2006 09 29.57033673 ± 0.00073192
perihelion distance [au] 2.25937873 ± 0.00000740
eccentricity 0.99994388 ± 0.00001398
argument of perihelion [°] 0.103955 ± 0.000271
ascending node [°] 228.162952 ± 0.000112
inclination [°] 45.856953 ± 0.000065
reciprocal semi-major axis [10-6 au-1] 24.84 ± 6.19
file containing 5001 VCs swarm
2006hwpa.bmi
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 original swarm including 5001 VCs. Each density map is given in logarithmic scale presented on the right in the individual panel.