C/1981 G1 Elias

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C/1981 G1 Elias

General description

Comet C/1981 G1 was discovered by Jonathan H. Elias (Cerro Tololo Interamerican Observatory) on 3 April 1981 (IAUC 3592), 4.5 months before perihelion, and was last seen on 14 April 1983.

The comet made its closest approach to the Earth on 22 March 1982 (4.12 au), that was seven months after perihelion.

Solution given below is based on data span over 2.03 yr in the range of heliocentric distances: 4.86 au – 4.74 au (perihelion) – 6.62 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 C1981G1A1-001

Comet C/1981 G1 Elias

number of observations	27
number of residuals	47
data interval	1981 Apr. 3 — 1983 Apr. 14
rms [arcsec]	1.32
orbit quality class	1a

Osculating orbital elements (heliocentric; ecliptic J2000.0)

Epoch (TT)	19810824.0	= JD 2444840.5
time of perihelion passage (TT)	19810818.228010	± 0.006418
perihelion distance	4.74252441	± 0.00003683
eccentricity	1.00067550	± 0.00005090
argument of perihelion [deg]	310.241141	± 0.000783
longitude of the ascending node [deg]	176.705296	± 0.000122
inclination [deg]	115.310230	± 0.000144
inverse semimajor axis [10^-6 au^-1]	-142.44	± 10.73

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/1981 G1. 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)	16750430
time of perihelion passage (TT)	19810819.497508	± 0.006416
perihelion distance	4.73791979	± 0.00003626
eccentricity	0.99934341	± 0.00005003
argument of perihelion [deg]	310.302998	± 0.000786
longitude of the ascending node [deg]	176.647202	± 0.000123
inclination [deg]	115.293045	± 0.000143
inverse semimajor axis [10^-6 au^-1]	138.58	± 10.56

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.

Figure caption: Six 2D-projections of the 6D space of future swarm (5001 VCs) of C/1981 G1. Each density map is given in logarithmic scale presented on the right in the individual panel.
The same figure in the new window

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

Epoch (TT)	22860206
time of perihelion passage (TT)	19810818.713272	± 0.006353
perihelion distance	4.73088984	± 0.00003647
eccentricity	1.00007299	± 0.00004999
argument of perihelion [deg]	310.115795	± 0.000791
longitude of the ascending node [deg]	176.670277	± 0.000123
inclination [deg]	115.296625	± 0.000143
inverse semimajor axis [10^-6 au^-1]	-15.43	± 10.57