C/1987 W3 Jensen-Shoemaker

Solar System
Dynamics &
Planetology
Group

General description

Comet C/1987 W3 was discovered by Carolyn S. and Eugene M. Shoemaker (with the 0.46-m Schmidt telescope at Palomar) on 24 November 1987 (IAUC 4503), when the comet was about two months before its perihelion passage. It was next announced (IAUC 4505) that the same comet was discovered by Poul Jensen on an earlier exposure taken by Karl Augustesen on 25 October (with the 0.45-m Schmidt telescope at the Copenhagen Observatory's Brorfelde station). Later, two more pre-discovery observations from September were found. The comet was last seen on 29 April 1990.

C/1987 W3 made its closest approach to the Earth on 17 October 1987 (2.47 au), that was three months before its perihelion passage.

Solution given below is based on data span over 2.60 yr in the range of heliocentric distances: 3.51 au – 3.33 au (perihelion) – 7.77 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 C1987W3A1-001

Comet C/1987 W3 Jensen-Shoemaker

number of observations	34
number of residuals	65
data interval	1987 Sep. 24 — 1990 Apr. 29
rms [arcsec]	1.22
orbit quality class	1a

Osculating orbital elements (heliocentric; ecliptic J2000.0)

Epoch (TT)	19871231.0	= JD 2447160.5
time of perihelion passage (TT)	19880118.808909	± 0.002680
perihelion distance	3.33281436	± 0.00001639
eccentricity	1.00477970	± 0.00002465
argument of perihelion [deg]	194.736359	± 0.000546
longitude of the ascending node [deg]	198.345564	± 0.000086
inclination [deg]	76.715895	± 0.000095
inverse semimajor axis [10^-6 au^-1]	-1434.13	± 7.38

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/1987 W3. 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)	16850706
time of perihelion passage (TT)	19880119.288960	± 0.002646
perihelion distance	3.32264693	± 0.00001598
eccentricity	0.99991866	± 0.00002412
argument of perihelion [deg]	195.061575	± 0.000542
longitude of the ascending node [deg]	198.376791	± 0.000087
inclination [deg]	76.786374	± 0.000095
inverse semimajor axis [10^-6 au^-1]	24.48	± 7.26

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)	22860318
time of perihelion passage (TT)	19880118.036179	± 0.002735
perihelion distance	3.32893198	± 0.00001617
eccentricity	1.00120357	± 0.00002420
argument of perihelion [deg]	194.587361	± 0.000546
longitude of the ascending node [deg]	198.345776	± 0.000087
inclination [deg]	76.707904	± 0.000095
inverse semimajor axis [10^-6 au^-1]	-361.55	± 7.27