C/2009 O4 Hill
more info
Comet C/2009 O4 was discovered on 30 July 2009 by R. E. Hill (Catalina Sky Survey); that is about 5 months before its perihelion passage. The comet was observed only before perihelion until 14 December 2009.
Comet had its closest approach to the Earth on 19 September 2009 (1.819 au), about 1.5 month after its discovery.
Solution given here is based on data spanning over 0.375 yr in a narrow range of heliocentric distances from 3.04 au to 2.57 au.
This Oort spike comet suffers small planetary perturbations during its passage through the planetary system; however, these perturbations lead to escape the comet from the solar system on hyperbolic orbit (see future barycentric orbits).
See also Królikowska and Dybczyński 2013 and Królikowska 2020.

solution description
number of observations 785
data interval 2009 07 30 – 2009 12 14
data type observed only before perihelion (PRE)
data arc selection entire data set (STD)
range of heliocentric distances 3.04 au – 2.57au
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 1522
RMS [arcseconds] 0.39
orbit quality class 1b
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] -55.20 ± 4.77
next perihelion distance [au] 250.033 ± 9.183
synchronous stop epoch [Myr] 1.708 S
percentage of VCs with q > 20100
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