Comet C/2001 Q4 NEAT

Solar System
Dynamics &
Planetology
Group

C/2001 Q4 NEAT

General description

The Catalogue of Cometary Orbit (Marsden & Williams, 2008, 17^thEd.; MWC08) gives non-gravitational(NG) orbit based on significantly less number of observations (1106) and shorter arc (2001 Aug. 04 — 2004 June 11). In June 2013, 2681 observations were available at IAU Minor Planet Center Web Pages, however, osculating orbit is the same as in MWC08. Since MWC08 gives NG orbit, thus orbital quality class is not given there. NG osculating orbit given at JPL Small-Body Database Browser is based on 2567 observations.

In Królikowska and Dybczyński (2010) the symmetric NG model based on full data interval is given where some trends in O-C variations are reported. Therefore, two types of orbits are given here:

the non-gravitational orbit based on full data interval (SSDP Cometary Note C2001Q4N5-001 given just below). This model gives NG orbit of 1a+ class with evident trends in O-C time variations. Since the asymmetric model gives τ = 0.73 ± 0.45 day, and no decrease in rms, thus the symmetric model is included here. O-C time variations for this solution are here where magenta points show residuals in right ascension, blue – in declination.
the non-gravitational osculating orbit based on data taken at larger distances, i.e. observations taken around perihelion were excluded (from 15 April 2004 to 25 July 2004, shown by grey dots in figure given on the right) (SSDP Cometary Note C2001Q4W5-001, see below); more recommended for studying the past and future dynamical evolution of this comet. For more details see Królikowska, Dybczyński and Sitarski (2012) .

Figure caption: Time distribution of positional observations with corresponding heliocentric (red points) and geocentric (green points) 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. The observations not taken for the orbit determination given in SSDP Cometary Note C2001Q4W1-001 are shown by grey dots. The same figure in the new window

SSDP Cometary Note C2001Q4N5-001

Comet C/2001 Q4 NEAT (non-gravitational solution)

number of observations	2681
number of residuals	5316
data interval	2001 Aug. 24 — 2006 Aug. 18
rms [arcsec]	0.56
orbit quality class	1a+

Osculating orbital elements (heliocentric; ecliptic J2000.0)

Epoch (TT)	20010730.0	= JD 2452120.5
time of perihelion passage (TT)	20040516.066603	± 0.000023
perihelion distance	0.96136124	± 0.00000034
eccentricity	1.00056075	± 0.00000079
argument of perihelion [deg]	1.213428	± 0.000050
longitude of the ascending node [deg]	210.200138	± 0.000008
inclination [deg]	99.564090	± 0.000011
inverse semimajor axis [10^-6 au^-1]	-583.29	± 0.82

Nongravitational parameters [10^-8 au/day²]

A₁ = 1.6506 ± 0.0140

A₂ = 0.06241 ± 0.00610

A₃ = 0.00141 ± 0.00511

Notes: 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)	17050831
time of perihelion passage (TT)	20040516.039333	± 0.000036
perihelion distance	0.96047294	± 0.00000035
eccentricity	0.99994184	± 0.00000077
argument of perihelion [deg]	1.322963	± 0.000050
longitude of the ascending node [deg]	210.315484	± 0.000008
inclination [deg]	99.749234	± 0.000011
inverse semimajor axis [10^-6 au^-1]	60.56	± 0.81

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)	22941221
time of perihelion passage (TT)	20040515.816463	± 0.000020
perihelion distance	0.96128328	± 0.00000017
eccentricity	1.00066754	± 0.00000044
argument of perihelion [deg]	1.204925	± 0.000015
longitude of the ascending node [deg]	210.355822	± 0.000008
inclination [deg]	99.556828	± 0.000005
inverse semimajor axis [10^-6 au^-1]	-694.43	± 0.46

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.

SSDP Cometary Note C2001Q4W5-001

Comet C/2001 Q4 NEAT (non-gravitational solution based on the data taken at larger distances from the Sun)

number of observations	1518 (observations taken around perihelion were excluded: from 15 April 2004 to 25 July 2004)
number of residuals	3012
data interval	2001 Aug. 24 — 2006 Aug. 18
rms [arcsec]	0.52
orbit quality class	1a+

Osculating orbital elements (heliocentric; ecliptic J2000.0)

Epoch (TT)	20010730.0	= JD 2452120.5
time of perihelion passage (TT)	20040516.066034	± 0.000057
perihelion distance	0.96137487	± 0.00000086
eccentricity	1.00057161	± 0.00000094
argument of perihelion [deg]	1.212369	± 0.000069
longitude of the ascending node [deg]	210.199931	± 0.000015
inclination [deg]	99.563785	± 0.000015
inverse semimajor axis [10^-6 au^-1]	-594.58	± 0.97

Nongravitational parameters [10^-8 au/day²]

A₁ = 1.2132 ± 0.0267

A₂ = 0.03323 ± 0.00721

A₃ = 0.17907 ± 0.00920

Note: Epoch is given in a format: yyyymmdd.d, time of perihelion passage in a format of yyyymmdd.dddddd.
Most recommended model for studying the origin and future of this comet. For more details see model DIST2 in Paper 3 .

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

Epoch (TT)	17051010
time of perihelion passage (TT)	20040516.038651	± 0.000062
perihelion distance	0.96048645	± 0.00000086
eccentricity	0.99995266	± 0.00000093
argument of perihelion [deg]	1.321905	± 0.000068
longitude of the ascending node [deg]	210.315277	± 0.000016
inclination [deg]	99.748930	± 0.000015
inverse semimajor axis [10^-6 au^-1]	49.29	± 0.96

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

Epoch (TT)	22941221
time of perihelion passage (TT)	20040515.816211	± 0.000057
perihelion distance	0.96129547	± 0.00000076
eccentricity	1.00067356	± 0.00000074
argument of perihelion [deg]	1.205484	± 0.000046
longitude of the ascending node [deg]	210.355622	± 0.000015
inclination [deg]	99.556892	± 0.000007
inverse semimajor axis [10^-6 au^-1]	-700.67	± 0.77

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.

General description

SSDP Cometary Note C2001Q4N5-001

Comet C/2001 Q4 NEAT (non-gravitational solution)

Osculating orbital elements (heliocentric; ecliptic J2000.0)

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

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

SSDP Cometary Note C2001Q4W5-001

Comet C/2001 Q4 NEAT (non-gravitational solution based on the data taken at larger distances from the Sun)

Osculating orbital elements (heliocentric; ecliptic J2000.0)

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

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

Solar System Dynamics & Planetology Group, 2013. All rights reserved