C/2007 N3 Lulin
more info
Comet C/2007 N3 was discovered on 11 July 2007 with Lulin Sky Survey (Taiwan); that is about 1.5 years before its perihelion passage. It was observed until 1 January 2011 (see picture).
Comet had its closest approach to the Earth on 24 February 2009 (0.411 au), about 1.5 month after its perihelion passage.
Preferred solution given here is based on data spanning over 3.48 yr in a range of heliocentric distances: 6.38 au – 1.212 au (perihelion) – 7.82 au.
This Oort spike comet suffers rather large planetary perturbations during its passage through the planetary system and these perturbations lead to more tight future orbit with semimajor axis of about 1,200 au (see future barycentric orbits).
For more details see Królikowska and Dybczyński 2013 and Królikowska 2020.

solution description
number of observations 3927
data interval 2007 07 11 – 2011 01 01
data type perihelion within the observation arc (FULL)
data arc selection entire data set (STD)
range of heliocentric distances 6.38 au – 1.21 au (perihelion) – 7.82 au
type of model of motion NT - non-gravitational orbits for asymmetric, standard g(r)
data weighting YES
number of residuals 7740
RMS [arcseconds] 0.35
orbit quality class 1a+
orbital elements (heliocentric ecliptic J2000)
Epoch 2009 01 09
perihelion date 2009 01 10.64006812 ± 0.00000630
perihelion distance [au] 1.21225654 ± 0.00000007
eccentricity 0.99997680 ± 0.00000045
argument of perihelion [°] 136.862766 ± 0.000042
ascending node [°] 338.535489 ± 0.000041
inclination [°] 178.373633 ± 0.000004
recip semi-major axis [10-6 au-1] 19.14 ± 0.37
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
non-gravitational parameters
A1 [10-8au\day-2] 0.086948 ± 0.008132
A2 [10-8au\day-2] -0.021692 ± 0.006961
A3 [10-8au\day-2] -0.13336 ± 0.0019
m -2.15
n 5.093
k -4.6142
r0 [au] 2.808
α 0.1113
ΔT [days] 11.3370 ± 1.945