Comet 73P/Schwassmann-Wachmann 3 (SW3) Bulletin Board

Michael L. Sitko, University of Cincinnati & Space Science Institute

Comets remain our most direct link to the original material that our solar system formed. However, the surfaces of comets undergo significant weathering during every passage into the inner solar system. Thus what we see is often not representative of the bulk composition. In 2005, The Deep Impact mission blasted a small amount of material from the surface of Comet 9P/Tempel 1 in order to probe for the more pristine material, an event that was watched by many ground-based and space-based telescopes around the world. Another way to sample their interiors is to observe recently-fragmented comets, where the deep interior has been recently exposed.

In 1995, Comet Schwassmann-Wachmann 3 (SW3) fragmented into a number of individual pieces, some of which were observed in its subsequent return into the inner solar system in 2000.

SW3 fragmenting in 1995

3 components returned in 2000

Anticipating their return in 2006, a number of investigators have planned a series of ground-based and space-based observational programs to investigate these objects. The number of fragments recovered in this visitation is 7 so far – the brightest of which will be visible to the naked eye in May, when it passes less than 0.1 AU from the Earth.

I am involved in 3 of these programs, and will be posting some results from these and other programs as they become available.

3 of the 7 fragments so far recovered by 2006

For more information, contact:

Mike Sitko

Dept. of Physics, University of Cincinnati sitko@physics.uc.edu Phone: 513.556.0642

& Space Science Institute, Boulder, CO sitko@spacescience.org