C/1999 K5 LINEAR

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C/1999 K5 LINEAR

General description

C/1999 K5 was discovered as an apparently asteroidal object by LINEAR team on 20 May 1999 (1.1 yr before perihelion passage), and soon reported as cometary by several observers. Later pre-discovery detection from 15 May 1999 by 2MASS was found.

This comet made its closest approach to Earth on 18 June 2000 (2.885 au), 16 days before perihelion.

Solution given below is based on data span over 2.8 yr in a range of heliocentric distances: 5.00 au – 3.255 au (perihelion) – 6.36 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 C1999K5A2-001

Comet C/1999 K5 LINEAR

number of observations	250
number of residuals	492
data interval	1999 May 15 — 2002 Mar. 18
rms [arcsec]	0.51
orbit quality class	1a+

Osculating orbital elements (heliocentric; ecliptic J2000.0)

Epoch (TT)	20000625.0	= JD 2451720.5
time of perihelion passage (TT)	20000704.392540	± 0.000322
perihelion distance	3.25538203	± 0.00000088
eccentricity	1.00167918	± 0.00000306
argument of perihelion [deg]	241.487043	± 0.000043
longitude of the ascending node [deg]	106.381812	± 0.000011
inclination [deg]	89.473112	± 0.000024
inverse semimajor axis [10^-6 au^-1]	-515.82	± 0.94

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/1999 K5. 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)	16980208
time of perihelion passage (TT)	20000703.418653	± 0.000333
perihelion distance	3.25370073	± 0.00000086
eccentricity	0.99993034	± 0.00000308
argument of perihelion [deg]	241.511845	± 0.000044
longitude of the ascending node [deg]	106.284045	± 0.000011
inclination [deg]	89.488511	± 0.000024
inverse semimajor axis [10^-6 au^-1]	21.41	± 0.95

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)	23070217
time of perihelion passage (TT)	20000704.013847	± 0.000326
perihelion distance	3.26343066	± 0.00000093
eccentricity	0.99874785	± 0.00000310
argument of perihelion [deg]	241.555903	± 0.000043
longitude of the ascending node [deg]	106.352565	± 0.000011
inclination [deg]	89.570567	± 0.000024
inverse semimajor axis [10^-6 au^-1]	383.69	± 0.95