Probing the Interaction Between Comets and the Solar Wind

Dennis Bodewits, R. Hoekstra, and A.G.G.M. Tielens *

KVI Atomic Physics
Zernikelaan 25
9747 AA Groningen
The Netherlands

*Kapteyn Astronomical Institute/SRON

Comets are bright emitters in X-ray and Far-Ultraviolet (XUV). The main driver of this emission is charge exchange between solar wind ions and neutrals in the cometary coma. We study these reactions in the laboratory and use our results to model cometary XUV emission.

Recent observations show that cometary XUV emission depends on properties of both the comet (mass loss, composition, distance to the sun) and the solar wind (speed, composition). The understanding of their interaction requires a deep insight in the atomic processes that constitute it. Unfortunately, there are still many gaps in our knowledge about some of the crucial charge exchange reactions in cometary atmospheres. Two examples are collisions involving Hydrogen-like highly charged ions and collisions between solar wind ions and atomic oxygen.

An interdisciplinary effort is therefore called for to turn the next generation cometary XUV observations into valuable, remote diagnostics for studying solar system plasmas.