What caused the recent supernova in the Pinwheel Galaxy?

[swampwiz]

https://earthsky.org/todays-image/supernova-in-m101-pinwheel-galaxy-closest-in-a-decade-how-to-see/

 

[russ_watters]

Holy cow, I've been working on imaging that galaxy while experimenting with my equipment. Weather didn't cooperate last night, bit I was planning to try again tonight. Discovering a supernova would be awesome, but I'm not sure I would notice, lol.

 

[russ_watters]

On second thought, there's a decent chance I would have noticed. One of the issues I was working on/experimenting with is color balance/exposures. My result is below (similar orientation as the discovery photo), which has some weird color artifacts in overexposed stars. Since I was working on that and since I shot different colors on different days, I likely would have noticed an oddly colored star, showing up in red and green but not blue, for example.

And here's a clip of a single subframe I just took with a different scope, with the supernova still visible/circled:

 

[Vanadium 50]

So, are you going to measure the light curve?

 

[pinball1970]

This amateur astronomer caught it unknowingly. Nice kit!

https://www.cbsnews.com/sanfrancisc...ngly-records-rare-supernova-bursting-to-life/

He does say, "right now.." When he meant, "right now (for us) 21 million years ago (for them)."