posted on Feb, 27 2011 @ 06:38 PM
This seems to say that comets do become magnetic....
While the solid nucleus of comets is generally less than 50 km (31 mi) across, the coma may be larger than the Sun, and ion tails have been observed
to extend one astronomical unit (150 million km) or more. The observation of antitails contributed significantly to the discovery of solar
wind. The ion tail is formed as a result of the photoelectric effect[dubious – discuss] of solar ultra-violet radiation acting on particles in
the coma. Once the particles have been ionized, they attain a net positive electrical charge which in turn gives rise to an "induced magnetosphere"
around the comet. The comet and its induced magnetic field form an obstacle to outward flowing solar wind particles. As the relative orbital speed of
the comet and the solar wind is supersonic, a bow shock is formed upstream of the comet, in the flow direction of the solar wind. In this bow shock,
large concentrations of cometary ions (called "pick-up ions") congregate and act to "load" the solar magnetic field with plasma, such that the
field lines "drape" around the comet forming the ion tail.