Wednesday, 18 October 2017

IC59 & IC63: The Gamma Cassiopeiae Nebulae

Gamma Cassiopeiae, the middle star of the famous W-shaped constellation, is a hot giant with a surface temperature of 25,000°C (compared to 5,500°C for our Sun) and a mass fifteen times our Sun's. The star shines at us with an incredible luminosity of 40,000 Suns and only looks ordinary from our point of view because it lies at the respectable distance of 610 light-years. It's burning its core hydrogen at an excruciatingly high rate and will most certainly explode as a supernova one day. Already now this star's known as an eruptive variable that may lighten up abruptly to even become the brightest star in its constellation.

Such a big and powerful star must have a tremendous impact on its environment and that's indeed what we find. If you are the proud owner of a ten-inch or larger telescope and have access to a nice and dark sky, point it towards this star and then slightly towards north-east to put Gamma Cassiopeiae just outside of the field of view. This way this bright star will not impair your search for the faint nebulae that surround it too much. These may not be the most spectacular objects you've ever come across and even with my binoscope they were not so easy to detect. But if you try to grasp what it is exactly that you're seeing, you'll surely be impressed. The extreme radiation from Gamma Cassiopeiae is literally tearing neighbouring dust clouds to pieces. The leading edges of these clouds are glowing because of the immense heat and are evaporating as we speak! In a few thousands of years these clouds will have been blown away completely. 

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