Because it's such a big star, it's blowing a big wind, like a super solar wind. This gas is slamming into and compressing the material floating in between stars, lighting it up. This image shows the result: taken by NASA's Wide-field Infrared Survey Explore, what you see as green is undisturbed dust, but the yellow shows where this material is getting rammed by the star and its wind. It's very similar to the bow wave you see off the front of a ship as it moves through water... but on a somewhat larger scale.
And while this structure was born in violence - a supernova is as nasty as it gets in the Universe, pretty much - and glows from violence, it's amazingly delicate-looking and wondrous. From a safe distance, the Universe can be really lovely... from a very safe distance.