NGC 3199: What a Wolf-Rayet Star Can Do

A.K.A.: RCW48, GUM28
OTA: CDK24” f/6.5
Camera: Moravian C3-61000 Pro, 2x2 binned at capture
Observatory: Heaven's Mirror, Chile

Exposures:
R: 15  x 300 sec
G: 9 x 300
B: 11 x 300
H: 14 x 1800 sec
O: 15 x 1800
S: 23 x 1800
Total Exposure time used:16 hours
Image Width: 30 arc-minutes

Processing Tools:
1.    Commercial: PixInsight, Topaz (Studio2, Photo AI2), Aurora HDR, Luminar Neo, 3DLUT Creator, Photo Director
2.    Pixinsight Addons: NoiseXTerminator, BlurXTerminator, StarXTerminator, Normalize Scale Gradient
3.    My Scripts: NB_Assistant, AC_Restar, Subframe Weighting Tool (Excel w/ J. Hunt)

Target Description:
In this image, the West is down, and the South is toward the left. An annotated Image Showing WR18 is Image C (righthand column below).

There's a considerable discussion of NGC 3199 by Toala et al. (2017) at https://arxiv.org/pdf/1708.02177.pdf. Considering many data types and sources, they conclude that the nebula resulted from fashioning a pre-existing interstellar nebula by a Wolf-Rayet star, W18s, strong winds, and ionizing UV radiation. W18 star lies just above the obvious yellow star, just south of the nebula's center.

At the bottom of the image are radial rays that point back to the WR star; they are more evident in the Ha image of the above authors. Those rays are attributed to the shadowing by clumps in the gas (Bok Globules?) blocking some UV radiation but allowing some through to ionize the clouds farther away. (The authors hypothesize several interesting interactions occurred between the star and its surroundings. The article's Discussion is an easy read.

Processing Description:
These are SHO "true color" images where the R,G,B were used to isolate the emission lines from their continuums, pixel by pixel. Every image requires slightly different processing. But this time, I switched many things around, and the results suggest it's a better approach.

Distance: 7200 light-years
Apparent Magnitude: 6.7
Average Surface Magnitude: 15
Pixel Span at Target: 13 billion km

Alex Woronow