VLT Observes Comet Wirtanen at Aphelion
Comet Wirtanen was discovered in 1948 at the Lick Observatory (California, USA) by Carl A. Wirtanen . It is a socalled "Jupiter-type" comet, meaning that its orbit is strongly influenced by this planet. At the present time, the orbital period is about 5.45 years. The perihelion (the point in the orbit that is nearest the Sun) is at 159 million kilometres (1.06 AU) from the Sun, i.e. just outside the orbit of the Earth. The aphelion is at a distance of about 768 million km (5.13 AU), near the orbit of Jupiter. The inclination of the orbit (angle between the orbit of the comet and that of the Earth) is moderate, about 12°.
This video clip shows a sequence of five frames, illustrating the motion of Comet Wirtanen during the present observations with the VLT.