This image shows NGC 281 with assorted embedded Bok globules, NGC 281A molecular cloud, IC 1490 central open cluster and HD 5005 bright star.
My image is OSC LRGB, which shows much less detail than narrowband images of this target, but still shows the major features of the nebula.
The large dark nebula (NGC 281A) is a molecular cloud made up predominantly of molecular hydrogen, but also dust and other gases. New generations of solar systems are being forged within its cold interior. Once these young stars' fusion engines switch on they will irradiate their surroundings - heating up, ionizing and eroding away the remaining dark material from which they formed.
Originally the whole Pac-Man nebula would have been one large dark molecular cloud - the stars that formed early on at its center having progressively hollowed out the center of the nebula. The gas in and around this central region is ionized by the copious UV radiation emitted by the central open star cluster (IC 1490), causing it to glow.
The massive multiple-star system at the center of the star cluster, know as HD 5005, is by far the brightest source of ionizing radiation within the cluster.
Backlit by the glow of ionized gas within the nebula, several small isolated black patches of material are evident. These are known as "Bok globules" after Bart Bok, a dutch astronomer who first observed and studied them. Most Bok globules contain one or more protostars that will eventually become visible once the globule dissipates.
The very informative text courtesy of
http://www.beskeen.com , many thanks Paul.
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