HI and HII Regions (3) ...
The adjacent right Limber Observatory
image shows a three-dimensional map of the Trifid Nebula in which the vertical direction is
proportional to the amount of H-alpha emission.
This map indicates clearly the yellow spike of the hot central star and that the emission is coming
from three highly ionized
gas clouds (red and yellow regions) separated by cooler un-ionized ribbons (blue and
green regions).
