Friday, May 22, 2009
Split Comet Schwassmann-Wachmann 3
Comet Schwassmann-Wachmann 3 broke up into several fragments in 1995. Its orbit period is 5.4 years, so came closest to the Sun again in 2001 and 2006. Bill Reach and colleagues used the Spitzer Space Telescope to observe this comet in infrared wavelengths in May 2006. The faint band connecting the fragments is a trail of debris that traces their orbit about the Sun. These astronomers detected 55 fragments along this comet's orbit, several of which are seen above. The color image of two brighter components show their dusty tails in red with a hint of green to show that CO2 gas is emitted from the sunward-facing parts of the comet nuclei. These fragments comae and tails are generated as the icy cometary nuclei warm and sublimate (evaporate) in the sunlight, whose weak pressure also sweeps the dust away in the anti-sunward direction. A preprint by Reach et al on these Spitzer observations is also available.