older Hubble images, and it appears to have been a red giant about 10 times more massive than our sun. The apparent magnitude of the supernova peaked at about 13. Since M95 is about 37 million light years away, its absolute magnitude is about -17.
In our night sky, perhaps the most famous red giant is the star Betelgeuse. At some point in the next several millennia Betelgeuse will go supernova itself. Betelgeuse is only 650 light years away, so when it goes off, what might we see? Given the absolute magnitude of the recent supernova, if Betelgeuse exploded with the same brightness it would have an apparent magnitude of about -11. That is brighter than any star or planet in our sky, but it isn’t quite as bright as a full moon.
So even if Betelgeuse does explode this year as some Mayan fans fear, it won’t be the end of the world. It will just be a short lived beacon in our night sky, casting shadows on moonless nights.
Shadows from a supernova. How cool would that be!