Comet 46 P/Wirtanen
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Figure 1: Comet 46P/Wirtanen imaged with the MPG/ESO 2.2 m Telescope in September 1996. The dust coma and the already developed dust tail are visible |
Comet 46 P/Wirtanen was discovered on 15 January 1948 at Lick Observatory by Carl A. Wirtanen. Two close approaches to Jupiter in 1972 (0.28 AU) and 1984 (0.46 AU) changed the orbit from an initial perihelion distance of 1.63 AU and a period P = 6.71 years to a period P = 5.46 years and a perihelion distance of 1.06 AU.
The comet belongs to the Jupiter family comets, which represents a large group of the short-period comets in the Solar System. Their orbits with an aphelion around Jupiter orbit make them in principle observable along their entire orbit. Except in 1980, Comet Wirtanen was observed during all its apparitions. However, only the coordinated observation campaign in 1996/1997 made this object to one of the best monitored comets
Assuming an albedo of .04 a radius of about 700 m was derived. For its small size the nucleus is fairly active and produces about 1028 molecules s-1.
