Solar System
Dynamics &
Planetology
Group 		C/2002 L9 NEAT




data set of C/2002 L9

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General description

C/2002 L9 was discovered on 13 June 2002 by the NEAT as an apparently asteroidal object. Later, its cometary apperance was reported [IAUC 7931, 2002 July 2]. Later, a few pre-discovery detections by LINEAR were found.

This comet made its closest approach to Earth on 30 July 2003 (6.365 au), eight months before perihelion.

Solution given below is based on data span over 4.6 yr in a range of heliocentric distances: 8.23 au – 7.033 au (perihelion) – 9.48 au.

Comet suffered a very slight planetary perturbations during its passage through the planetary system.


Figure caption: 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.



SSDP Cometary Note C2002L9A2-001

Comet C/2002 L9 NEAT

number of observations 323
number of residuals 634
data interval 2002 June 6 — 2007 Jan. 11
rms [arcsec] 0.49
orbit quality class 1a+

Osculating orbital elements (heliocentric; ecliptic J2000.0)

Epoch (TT) 20040425.0 = JD 2453120.5
time of perihelion passage (TT) 20040406.052495 ± 0.000771
perihelion distance 7.03303845 ± 0.00000591
eccentricity 0.99850170 ± 0.00000615
argument of perihelion [deg] 231.431509 ± 0.000050
longitude of the ascending node [deg] 110.457237 ± 0.000011
inclination [deg] 68.445540 ± 0.000011
inverse semimajor axis [10-6 au-1] 213.04 ± 0.88

Note: Epoch is given in a format: yyyymmdd.d, time of perihelion passage in a format of yyyymmdd.dddddd.

data set of C/2002 L9

Figure caption: Six 2D-projections of the 6D space of original swarm (5001 VCs) of C/2002 L9. Each density map is given in logarithmic scale presented on the right in the individual panel.
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Original orbital elements (barycentric; at 250 au from the Sun)

Epoch (TT) 16950224
time of perihelion passage (TT) 20040405.561118 ± 0.000769
perihelion distance 7.03551955 ± 0.00000600
eccentricity 0.99974285 ± 0.00000627
argument of perihelion [deg] 231.448525 ± 0.000050
longitude of the ascending node [deg] 110.454062 ± 0.000011
inclination [deg] 68.399334 ± 0.000011
inverse semimajor axis [10-6 au-1] 36.55 ± 0.89

Note: Values of uncertainties of original/future orbital elements were derived using a swarm of 5001 osculating orbits of VCs (including the nominal osculating orbit given above) for original/future orbital evolution calclulations and then by fitting the distribution of a given orbital element of original/future swarm of VCs to Gaussian distribution.

Original barycentric positions and velocities of 5001 VCs at 250 au from the Sun are given here   (data format), i.e. before entering the planetary zone.

Future orbital elements (barycentric; at 250 au from the Sun)

Epoch (TT) 23131023
time of perihelion passage (TT) 20040406.791856 ± 0.000764
perihelion distance 7.03670088 ± 0.00000604
eccentricity 0.99945273 ± 0.00000627
argument of perihelion [deg] 231.480567 ± 0.000050
longitude of the ascending node [deg] 110.436611 ± 0.000011
inclination [deg] 68.407644 ± 0.000011
inverse semimajor axis [10-6 au-1] 77.77 ± 0.89


Future barycentric positions and velocities of 5001 VCs at 250 au from the Sun are given here   (data format), i.e. after leaving the planetary zone.





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