C/2003 WT42 LINEAR older solution

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C/2003 WT₄₂ LINEAR

General description

Comet C/2003 WT₄₂ was discovered on 19 November 2003 by LINEAR as an apparently asteroidal object; observations raported in mid-January 2004 [IAUC 8270, 2004 January 16] demostrated the cometary appearance. Three images of this object were found on LINEAR exposures taken on 30 October 2003. Comet passed perihelion in April 2006 (see below).

C/2003 WT₄₂ was observed 4.6 yr during five oppositions in a range of heliocentric distances: 8.26 au – 5.191 au (perihelion) – 7.66 au.

Comet had its closest approach to Earth on 3 February 2006 (4.403 au, about two months before perihelion).

Balistic solution given below reveals some trends in (O-C) where most prominent are in the last opposition. It seems that there are any NG effects detectable on the basis of positional data.

New solution based on dedicated approach to data weighting is available here, where trends in (0-C) are less noticeable.

Nakano solution [ Nakano Notes 1636] also gives trends in (O-C) in the last opposition, however many of observations taken in this opposition are discarded (for example all data after 2008 March 31). His solution is based on 2382 observations (arc: 2003 October 30 to 2008 March 31; rms = 0.60 arcsec) and gives 1/a_origin = +0.000029, 1/a_future = +0.000183).

Solution based on first three oppositions also gives very similar original 1/a (see here).

Figure caption: 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. Lower panel: O-C diagram for the gravitational solution shows some trends in right ascension (magenta dots) and declination (blue open circles), mainly in the last apparitions.

SSDP Cometary Note C2003WT_W-001 – older solution

Comet C/2003 WT₄₂ LINEAR

number of observations	2564
number of residuals	5057
data interval	2003 Oct. 30 — 2008 May 25
rms [arcsec]	0.53
orbit quality class	1a+

Osculating orbital elements (heliocentric; ecliptic J2000.0)

Epoch (TT)	20060415.0	= JD 2453840.5
time of perihelion passage (TT)	20060410.766380	± 0.000181
perihelion distance	5.19092643	± 0.00000115
eccentricity	1.00256857	± 0.00000168
argument of perihelion [deg]	92.467227	± 0.000021
longitude of the ascending node [deg]	48.453841	± 0.000008
inclination [deg]	31.410656	± 0.000003
inverse semimajor axis [10^-6 au^-1]	-494.82	± 0.32

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

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

Epoch (TT)	17000419
time of perihelion passage (TT)	20060411.899174	± 0.000185
perihelion distance	5.18222200	± 0.00000123
eccentricity	0.99976466	± 0.00000168
argument of perihelion [deg]	92.604965	± 0.000021
longitude of the ascending node [deg]	48.434857	± 0.000008
inclination [deg]	31.434392	± 0.000003
inverse semimajor axis [10^-6 au^-1]	45.41	± 0.32

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)	23140220
time of perihelion passage (TT)	20060410.407036	± 0.000184
perihelion distance	5.18238436	± 0.00000116
eccentricity	0.99896550	± 0.00000168
argument of perihelion [deg]	92.354949	± 0.000021
longitude of the ascending node [deg]	48.405111	± 0.000008
inclination [deg]	31.423890	± 0.000003
inverse semimajor axis [10^-6 au^-1]	199.62	± 0.32

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.