NGC 7538 – Going Deep in a Starless Contrast Map

OTA: CDK17
Camera: FLI Proline 16803, 9 micron pixels, 0.64 arcsec/pxl
Observatory: Benard Miller, NM

EXPOSURES:                
R: 15 x 900
G: 14 x 900
B: 14 x 900
L: 26 x 1200
H: 17 x 1800
S: 18 x 1800
O: 10 x 1800
Total exposure    34 hours

Image Width: 13 arc-minutes
Processed by Alex Woronow (2022): PixInsight, Topaz, My Scripts & Blanshen’s Icons


NGC 7538 hosts a substantial population of Young Stellar Objects, massive protostars, and dense cold clouds likely to condense into massive protostars—13 of which have masses greater than 40 solar masses, and the total cloud mass is estimated to be about 400,000 solar masses.


My image shows the central region to be highly fragmented, as one would expect in an area of such tremendous chaos from star formation and cloud collapse. However, what I also find interesting is that the fragmentation drops off abruptly at the edges of the central cloud into a more tranquil, probably less dense, cloud region. (No masking was done in the processing of this image.) Also, notice at the left and bottom margins of the fragmented region, the structures turn to lie rather concentric to the cloud center. This may indicate the bow shocks propagating outward from star birth/death events in the heart of the nebula. These features and their juxtapositionings, locations, and extents indicate they are not artifacts, but features representative of cloud processes. A further indication that they are not artifacts is that they do not tangle, as physical domains should not, but a random pattern of artifacts is prohibited from doing.
My image-processing paradigm emphasized edges and borders as defined by contrasts in brightness, hue, and, somewhat redundantly, color. The violence of star-birth and star-death shock waves, supersonic winds, and the like fragmented and sculpted this cloud's textures into the complexity shown in this image.

By the way, one pixel’s width on this image equals 0.5 trillion km at the cloud’s distance. Therefore, even the finest details in the image are not very small!

Cheers,
Alex Woronow