This is Comet Hale-Bopp observed with a narrow-band interference filter
at 360nm. In this range are several line emissions of OH+ ions.
But also the scattered continuum radiation of the large dust particles is present.
From pure continuum observations we know that
the inner part of this image is dominated by the already known dust shells,
but the outer regions show strong plasma activity
in form of fine structured turbulent rays and envelopes.
An interesting question is, does the plasma shows interaction
with these dust shells?
This comet gives us for the first time the opportunity, to study the OH+
plasma, its motion and creation, close to the nucleus and even in front of it.
More informations can be found on the special project page of the
Max-Planck-Institut für Aeronomie.