A three colour image of Comet Wirtanen, taken from observations on Pik
Terskol, which shows the three cometary components - dust, neutral gas and
ions. Using different filters on the telescope, the cometary water (H2O)
ions appear red, the dust is green and neutral CN gas is blue.
This shows Wirtanen's ion tail (here H2O+) for the first time. It appears
as a straight,
red diffuse band to the left side (anti-sunward direction). The blue sphere
is the very
extended neutral CN coma. In contrast to this, the dust is much more
and dominates the near nucleus region, here seen as a yellowish green
colour. This image illustrates that 46P/Wirtanen is dust poor and about 2-3
times less dusty than Comet Halley.
Photo Max-Planck-Institut fur Aeronomie, courtesy T. Credner, K. Jockers,
Last Update: 1 September 2019