The material thrown out by such stellar catastrophes is full of heavy elements needed for planet building and life itself.
It's the only way these elements can be accessed. Otherwise they would remain locked in the cores of stars.
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There's that hydrogen alpha band filter again. Very special construction, 7 layers of glass, the last very, very thin and difficult to make.
This image is the kind of astronomy we like. Forget those big NASA orbiting telescopes, forget those monstrous ground-based compensating optics constructs. This is the kind of thing amateurs can do, if they are really dedicated.
When a supernova occurs, is the rate of expansion of the remaining ‘star stuff’ constant and dependent on the force of the initial explosion?
In other words, in the supernova pictured above, was the width of the debris equal to only 75 light years 50,000 years ago? And, will the width of the debris equal 300 light years, 100,000 years from now?
It would seem that if there is no gravitational pull (other stars) to slow it down, the debris will expand at a constant rate. No?
Have a good holiday.