Sharpless 140 is an emission nebula/star-forming region visually located in the constellation Cepheus. The red parts of the image are the emissions of ionized
hydrogen, resulting from the highly energetic massive new stars recently formed in the region. The dark part in the lower half of the image is LDN 1204 (1204 in the catalog named Lynd's Dark
Nebulae), a dust cloud obscuring light from reaching us from the far side of the nebula. This region is very similar to the area in this
image, in that it is primarily composed of an obscuring dark nebula between us and a bright emission nebula.
The glow in the upper right corner is from a very bright star, just off the frame. And, no, those darker blobs in the dark nebula aren't places where the flat field correction failed; they're
structure that's there.
This area is about 2900 light years from us. At that distance, the emission nebula shown is about 32 light years across.
Copyright 2023, 2024 Mark de Regt