Deep red lines in Orion

[will-henney]

We only see a few of the lines in Orion, and they are very noisy. Here are some screenshots so I do not forget about them.

The [C I] 8727 line for comparison

This one is much brighter than the other DRLs by factor of 10 to 30, unlike in NGC 346 where they are roughly equal

DRL 9113 is the brightest in Orion

Note however that its spatial distribution is not clearly outside the ionization front. It is a very broad band at the Bar that seems to straddle both sides.

DRL 6814 is unique to Orion (not seen in NGC 346)

This one does have a clear distribution that is concentrated outside the ionization front, similar to the Raman wings of Ha

DRL 9029 is only marginally detected in Orion

Even though it is the brightest in NGC 346. Only really detected in Orion S. You can just about imagine it at the bar as well.

Ca I] 9095 for comparison

This traces the ionization front and the very near neutral side

[will-henney]

In #4 I show that 9113 may be blended in M17 with ionized lines. This might explain why it is spatially broad at the Orion Bar