C/2001 Q4 NEAT
more info
Comet C/2001 Q4 was discovered on 24 August 2001 by Near-Earth-Asteroid Tracking Team (Jet Propulsion Laboratory), that is about 2.8 yr before its perihelion passage. It was observed until 18 August 2004.
Comet had its closest approach to the Earth on 6 May 2004 (0.321 au), ten days before its perihelion passage.
C/2001 Q4 is a comet with non-gravitational effects strongly manifested in positional data fitting. Preferred orbital solution given here is based on data spanning over 4.98 yr in a range of heliocentric distances from 10.11 au to 8.82 au; however data taken around perihelion passage are excluded (see figure).
This Oort spike comet suffers rather large planetary perturbations during its passage through the planetary system; these perturbations lead to escape the comet from the planetary zone on a hyperbolic orbit (see future barycentric orbits).
More details in Królikowska, Dybczyński and Sitarski and Królikowska 2020.

solution description
number of observations 692
data interval 2001 08 24 – 2006 08 18
data arc selection only data taken in large heliocentric distance (DIS)
range of heliocentric distances 10.11 au – 0.96 au (perihelion) – 8.82 au
type of model of motion NN - non-gravitational orbits for dedicated g(r)-like function
data weighting YES
number of residuals 1369
RMS [arcseconds] 0.57
orbit quality class 1a+
next orbit elements (barycentric ecliptic J2000)
no. of returning VCs in the swarm 0
no. of escaping VCs in the swarm 5001
no. of hyperbolas among escaping VCs in the swarm 5001 *
next recip semi-major axis [10-6 au-1] -679.41 ± 2.42
next perihelion distance [au] 0.488 ± 0.005
synchronous stop epoch [Myr] 0.692 S
percentage of VCs with q < 10100
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