NGC 7635 - 2018 Closeup (Gary Imm)

NGC 7635 - 2018 Closeup

This image is a zoomed in view of the Bubble Nebula, located 7,000 light years away in the constellation of Cassiopeia. The bubble diameter is about 7 light years across. The bubble is caused by a stellar wind emitted from the progenitor star, which is the brightest star inside of the bubble (left of center). This star is a Wolf-Rayet star, which is an O-type star that is nearing supernova stage. These stars expel a significant amount of mass in this stage, resulting in the expanding gas bubble which is contained by the molecular cloud which surrounds it.

The cloud has been shaped by the gas velocity into orangish dust pillars which all point back to the source star. The pillars are similar to the iconic columns in the “Pillars of Creation” Eagle Nebula. As seen with the structures in the Eagle Nebula, the Bubble Nebula pillars are being illuminated by the strong ultraviolet radiation from the brilliant star inside the bubble. The brightest pillars, located on the back side of the bubble, can be seen shining through the bubble and appearing face-on to us, just above the source star.

Note the shape of the bubble, which is not perfectly symmetric due to differences in the density of the surrounding gaseous material and to the gas expulsion radial direction. Although the shape of the bubble is fairly symmetric, I find it interesting that the lighting of the bubble is not symmetric. The brightest outer surfaces of the bubble seem to correspond to the locations of the brightest dust cloud pillars (to the lower left in the image). The lighting distribution may be due to the off center location of the progenitor star, or to a distribution of dust in and around the Bubble, or perhaps even because of reflected light from the closer dust cloud pillars.

The refractors!
Cloudy Nights
ZWO ASI1600MM/QHY163M
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