C/2003 A2 Gleason
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Comet C/2003 A2 was discovered on 10 January 2002 by Arianna E. Gleason using the Spacewatch II telescope at the Kitt Peak National Observatory when the comet was a year and 10 months before its perihelion passage. This comet was observed 3.2 yr during its four oppositions in a narrow range of heliocentric distances: 11.9 au – 11.43 au (perihelion) – 11.70 au. However, there is a long pause around perihelion lasting over 7 months (from 1 April to 11 November of 2002).
Comet had its closest approach to the Earth on 14 February 2004 (10.451 au).
This Oort spike comet suffers minor planetary perturbations during its passage through the planetary system that lead to a more tight future orbit (see future barycentric orbit).
See also Królikowska and Dybczyński 2017.

solution description
number of observations 149
data interval 2002 01 08 – 2005 03 31
data type significantly more measurements before perihelion (PRE+)
data arc selection entire data set (STD)
range of heliocentric distances 11.9 au – 11.43 au (perihelion) – 11.7 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 297
RMS [arcseconds] 0.53
orbit quality class 1a
orbital elements (heliocentric ecliptic J2000)
Epoch 2003 11 17
perihelion date 2003 11 05.81062855 ± 0.01495097
perihelion distance [au] 11.42703480 ± 0.00005608
eccentricity 1.00693241 ± 0.00002946
argument of perihelion [°] 346.667136 ± 0.000552
ascending node [°] 154.544251 ± 0.000153
inclination [°] 8.061448 ± 0.000057
recip semi-major axis [10-6 au-1] -606.67 ± 2.56
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