The Crab Nebula as electron-capture

This morning UC Santa Barbara (our lady of the mines) found the star which gave rise to a weird 2018 supernova in galaxy NGC 2146, 21 million light-years away, which wasn't Type I or Type II. The researchers say that the same sort of explosion created the Crab Nebula AD 1054.

This sort was theorised in 1980, as the "electron-capture" supernova. The star would be smaller than the Type II core-collapse monsters at 10 solar masses. As for the Type I: such is just a scaled-up nova so irrelevant; their stars never go above 8 masses anyway.

This electron-capture means I think that protons are taking that electron and becoming neutrons, in the reverse of beta-decay. The classical Type II would implode when the nuclear fusion gets to iron. The EC implodes at oxygen + neon + magnesium. Yep, here we go again with potential condensates: 16, 20, and now 24. But anyway, not every under-10 star qualifies; before totally blowing up, they will be blasting a lot of mass out in a cloud like Betelgeuse just did.

They'll actually be weak as explosions - but the light will shine on the dust-cloud, which may have been what the Asians saw in AD 1054.

I went looking through mine own blog and - the AD 1052 spike. It might be from our own Sun; I have been warning against taking flares as novae. But...