NGC 7635 revisited

 

 

 

 

 

 

NGC 7635 is an emission nebula located in the constellation Cassiopeia. This nebula emits, mainly, in H alpha and Oxygen III. The central bubble is one out of the three shells of emitting gas that surround the hot, O6.5 class, star SAO 20575 (also known as BD+60°2522). Amazingly, this star, which originated the bubble and fuels its emission with its enormous radiation output, is not located at the center of the bubble, due to its movement. It is the star located half way between the center and its lower left border. This star is about 4 million years old (just one thousandth of our Sun’s age) and is expected to explode as supernova in about 15 million years (give or take a couple million…). By coincidence, this nebula lies superimposed to a region where another supernova exploded many thousands of years ago. Its gas wisps were faint enough to remain undiscovered until 2005. These remains are out of this image (just a few arc minutes left of the left border).

 

This image has been taken with narrowband filters (Halpha, [OIII] and [SII]) and has been color mapped to a modified Hubble Palette as well as to the natural colors. This is yet another result of the ongoing collaboration with Christian Sasse.