Comet Kohoutek

C/1973 E1 (Kohoutek)

A color photograph of the comet Kohoutek taken on 11 January 1974.
Discovery
Discovered by	Luboš Kohoutek
Discovery date	7 March 1973
Alternative designations	"Comet of the Century"
Orbital characteristics A
Epoch	24 December 1973
Perihelion	0.1424 AU
Eccentricity	1.000008 (dropped below 1 in 1977)
Inclination	14.3
Last perihelion	28 December 1973

Comet Kohoutek, formally designated C/1973 E1, 1973 XII, and 1973f, was first sighted on 7 March 1973 by Czech astronomer Luboš Kohoutek. It attained perihelion on 28 December that same year.

Comet Kohoutek is a long-period comet; its previous apparition was about 150,000 years ago, and its next apparition will be in about 75,000 years. At its apparition in 1973 it had a hyperbolic trajectory (e > 1) due to gravitational perturbations from giant planets. Due to its path, scientists theorized that Kohoutek was an Oort-cloud object. As such, it was believed that this was the comet's first visit to the inner Solar System, which would result in a spectacular display of outgassing. Infrared and visual telescopic study have led many scientists to conclude, in retrospect, that Kohoutek is actually an Edgeworth/Kuiper-belt object, which would account for its apparent rocky makeup and lack of outgassing.

Before its close approach, Kohoutek was hyped by the media as the "comet of the century". However, Kohoutek's display was considered a let-down, possibly due to partial disintegration when the comet closely approached the Sun prior to its Earth flyby. Since this was probably the comet's first visit to the inner Solar System, it would have still contained large amounts of frozen volatiles since its creation. Although it failed to brighten to levels expected, it was still a naked-eye object. Its greatest visual magnitude was −3, when it was at perihelion, 0.14 AU (21,000,000 km; 13,000,000 mi) from the Sun. Its orbital inclination is 14.3°. Its best viewing was in the night sky after perihelion, when it had dimmed to fourth magnitude. The comet also sported a tail up to 25° long, along with an anti-tail.