C/2002 J4 NEAT

Solar System
Dynamics &
Planetology
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C/2002 J4 NEAT

General description

C/2002 J4 was discovered on 13 May 2002 by the NEAT as an apparently cometary object. Additional observations confirmed its cometary apperance. At once, pre-discovery detections made by LONEOS and LINEAR on 4—8 May were found [IAUC 7899, 2002 May 13].

This comet made its closest approach to Earth on 29 June 2003 (2.824 au), three months before perihelion.

Solution given below is based on data span over 4.4 yr in a range of heliocentric distances: 5.74 au – 3.634 au (perihelion) – 9.38 au.

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 C2002J4A5-001

Comet C/2002 J4 NEAT

number of observations	232
number of residuals	451
data interval	2002 May 4 — 2006 Oct. 1
rms [arcsec]	0.48
orbit quality class	1a+

Osculating orbital elements (heliocentric; ecliptic J2000.0)

Epoch (TT)	20031008.0	= JD 2452920.5
time of perihelion passage (TT)	20031003.151072	± 0.000235
perihelion distance	3.63378023	± 0.00000105
eccentricity	1.00001831	± 0.00000356
argument of perihelion [deg]	230.705722	± 0.000035
longitude of the ascending node [deg]	70.881227	± 0.000014
inclination [deg]	46.521834	± 0.000015
inverse semimajor axis [10^-6 au^-1]	-5.04	± 0.98

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

Figure caption: Six 2D-projections of the 6D space of original swarm (5001 VCs) of C/2002 J4. 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)	17000817
time of perihelion passage (TT)	20031003.506725	± 0.000244
perihelion distance	3.63841226	± 0.00000105
eccentricity	0.99987674	± 0.00000360
argument of perihelion [deg]	230.676162	± 0.000035
longitude of the ascending node [deg]	70.946574	± 0.000015
inclination [deg]	46.492041	± 0.000016
inverse semimajor axis [10^-6 au^-1]	33.88	± 0.99

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)	23030708
time of perihelion passage (TT)	20031003.306849	± 0.000243
perihelion distance	3.63811716	± 0.00000106
eccentricity	1.00098246	± 0.00000360
argument of perihelion [deg]	230.766608	± 0.000036
longitude of the ascending node [deg]	70.872660	± 0.000015
inclination [deg]	46.480076	± 0.000016
inverse semimajor axis [10^-6 au^-1]	-270.05	± 0.99