C/1999 N4 LINEAR
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C/1999 N4 was discovered as an apparently asteroidal object by LINEAR team on 12 July 1999 (ten months before perihelion passage), and soon reported as cometary by observers [IAUC 7226, 1999 July 17]. Later, pre-discovery detection from 27 August 1998 by LINEAR was found.

This comet made its closest approach to the Earth on 4 June 2000 (4.589 au), twelve days after perihelion.

Solutions given here are based on data spanning over 3.7 yr in a range of heliocentric distances: 7.14 au – 5.505 au (perihelion) – 7.49 au.

NG orbit is possible to obtained using the full data arc; however uncertainties of NG parameters are notable, especially for A2 (see solutions ac and bc differing only in data weighting).

This Oort spike comet suffered slight planetary perturbations during its passage through the planetary system.

See also Królikowska and Dones 2023, Królikowska and Dybczyński 2017,and Królikowska 2014.
solution description
number of observations 345
data interval 1998 08 27 – 2002 05 06
data type perihelion within the observation arc (FULL)
data arc selection entire data set (STD)
range of heliocentric distances 7.14 au – 5.50 au (perihelion) – 7.49 au
type of model of motion NC - non-gravitational orbits for symmetric CO-g(r)-like function
data weighting YES
number of residuals 659
RMS [arcseconds] 0.57
orbit quality class 1a
orbital elements (heliocentric ecliptic J2000)
Epoch 2000 05 16
perihelion date 2000 05 23.74555367 ± 0.00440039
perihelion distance [au] 5.50473962 ± 0.00000912
eccentricity 1.00420409 ± 0.00000996
argument of perihelion [°] 90.430316 ± 0.000508
ascending node [°] 345.901402 ± 0.000056
inclination [°] 156.922907 ± 0.00001
reciprocal semi-major axis [10-6 au-1] -763.72 ± 1.81
Upper panel: 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.
Middle panel(s): O-C diagram for a given solution (sometimes in comparison to another solution available in CODE), where residuals in right ascension are shown using magenta dots and in declination by blue open circles.
Lowest panel: Relative weights for a given data set(s).
non-gravitational parameters
A1 [10-8au/day2] 1.5209 ± 0.3836
A2 [10-8au/day2] -1.6428 ± 0.7408
A3 [10-8au/day2] 0 (assumed)
m -2.00
n 3.000
k -2.6000
r0 [au] 10.000
α 0.0100