C/1999 H3 LINEAR

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Planetology
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C/1999 H3 LINEAR

General description

C/1999 H3 was discovered as an apparently asteroidal object by LINEAR on 22 April 1999 (about four months before perihelion passage). Next day was reported as cometary object by observers from Klet and Ondrejov [IAUC 7151, 1999 April 23].

This comet made its closest approach to Earth on 6 March 2000 (3.185 au), about 7.5 months after perihelion.

Solution given below is based on data span over 2.9 yr in a range of heliocentric distances: 3.66 au – 3.501 au (perihelion) – 8.48 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 C1999H3N2-001

Comet C/1999 H3 LINEAR

number of observations	877
number of residuals	1722
data interval	1999 Apr. 22 — 2002 Mar. 20
rms [arcsec]	0.51
orbit quality class	1a

Osculating orbital elements (heliocentric; ecliptic J2000.0)

Epoch (TT)	19990810.0	= JD 2451400.5
time of perihelion passage (TT)	19990818.241961	± 0.000870
perihelion distance	3.50080910	± 0.00000249
eccentricity	1.00269373	± 0.00000619
argument of perihelion [deg]	101.912685	± 0.000199
longitude of the ascending node [deg]	332.723748	± 0.000035
inclination [deg]	115.840364	± 0.000012
inverse semimajor axis [10^-6 au^-1]	-769.46	± 1.77

Nongravitational parameters [10^-8 au/day²]

A₁ = 4112 ± 193

A₂ = 3007 ± 228

A₃ = -509.0 ± 72.0

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 H3. Each density map is given in logarithmic scale presented on the right in the individual panel.
The same figure in the new window

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

Epoch (TT)	16950803
time of perihelion passage (TT)	19990817.116521	± 0.001361
perihelion distance	3.50442230	± 0.00000377
eccentricity	0.99956311	± 0.00001359
argument of perihelion [deg]	101.831498	± 0.000316
longitude of the ascending node [deg]	332.721955	± 0.000075
inclination [deg]	115.908160	± 0.000011
inverse semimajor axis [10^-6 au^-1]	124.67	± 3.88

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)	23020203
time of perihelion passage (TT)	19990817.978459	± 0.000410
perihelion distance	3.50201708	± 0.00000330
eccentricity	1.00003511	± 0.00000368
argument of perihelion [deg]	101.885230	± 0.000090
longitude of the ascending node [deg]	332.815367	± 0.000010
inclination [deg]	115.893722	± 0.000015
inverse semimajor axis [10^-6 au^-1]	-10.02	± 1.05