C/2001 C1 LINEAR

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Planetology
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C/2001 C1 LINEAR

General description

C/2001 C1 was discovered on 1 February 2001 by the LINEAR [IAUC 7578, 2001 February 2]. Later, S. Nakano linked this comet with an asteroid 2000 HR₈₁ detected by LONEOS on 29 April 2000 [MPEC 2001-H23, 2001 April 21].

This comet made its closest approach to Earth on 7 May 2002 (4.410 au), 1.3 months after perihelion.

Solution given below is based on data span over 2.2 yr in a range of heliocentric distances: 7.24 au – 5.105 au (perihelion) – 5.16 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 C2001C1A2-001

Comet C/2001 C1 LINEAR

number of observations	223
number of residuals	436
data interval	2000 Apr. 29 — 2002 July 3
rms [arcsec]	0.67
orbit quality class	1a

Osculating orbital elements (heliocentric; ecliptic J2000.0)

Epoch (TT)	20020327.0	= JD 2452360.5
time of perihelion passage (TT)	20020328.292956	± 0.002413
perihelion distance	5.10462770	± 0.00001150
eccentricity	0.99991178	± 0.00001068
argument of perihelion [deg]	219.936408	± 0.000274
longitude of the ascending node [deg]	33.711279	± 0.000013
inclination [deg]	68.951920	± 0.000050
inverse semimajor axis [10^-6 au^-1]	17.28	± 2.09

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/2001 C1. 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)	16960906
time of perihelion passage (TT)	20020328.801115	± 0.002426
perihelion distance	5.11002022	± 0.00001152
eccentricity	0.99991858	± 0.00001070
argument of perihelion [deg]	219.952566	± 0.000276
longitude of the ascending node [deg]	33.760054	± 0.000013
inclination [deg]	68.910831	± 0.000050
inverse semimajor axis [10^-6 au^-1]	15.93	± 2.09

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)	23050118
time of perihelion passage (TT)	20020328.849382	± 0.002426
perihelion distance	5.10851053	± 0.00001163
eccentricity	1.00109569	± 0.00001070
argument of perihelion [deg]	220.006765	± 0.000276
longitude of the ascending node [deg]	33.711913	± 0.000013
inclination [deg]	68.913424	± 0.000050
inverse semimajor axis [10^-6 au^-1]	-214.48	± 2.09