"AFAIK Type I SN are not cyclic because the main actor is ripped apart during this action
"
"Novae can be cyclic. Type I SN blow up the White Dwarf - there's nothing left of it. So when you have one of those, it won't happen again
"
"I think we're looking at B and O V stars as being the only ones that can go supernova. Even a 7 solar mass star is only early B V."
D'oh! You are correct, it is "ordinary" nova binaries that can be cyclic. And if 1.44M F5V is too small for SN, so would 3.3M (mid A-range). I wuz not thinking clearly. This is all stuff which gets confused rather easily.
I've always loved the story of Chandrasekhar. He was a promising self-taught physics grad, granted a fellowship at Oxford or something. To pass the time on the ship from India to Britain he calculated the theory which became his signature work.
This guy accomplished more in a week or so of spare time than any of us will in our whole lives.
Suitably humbled at the thought, the narrator continues. I can't find a reference that clearly says what the original mass (or range of masses) would be in order to end up at the C limit in Dwarf stage. Many googles later…
HyperPhysics: White Dwarfs and Electron Degeneracy indicates that all stars 4M or less are too small to fuse Carbon. It doesn't say how much of that mass is lost when the carbon core collapses into degenerate matter.
Therefore at 4M it can't develop an iron core that could collapse into a neutron star. It would seem, though, that stars above that limit might still be too small to fuse all the way to iron.
The
HyperPhysics: Astrophysics Index shows stars 4-8M becoming either neutron stars or black holes, which seems to ignore masses large enough to fuse Carbon but insufficient to fuse large quantities of heavier elements leading to a massive Fe core.
As previously stated, 4M is too small to form NS, as that would put the boundary in the A range.
Death of High Mass Stars indicates an initial mass of 5M will produce a neutron star, which again seems too low by far (either the largest As or smallest Bs). This could be a limit for Type I SN, that a smaller star would not produce a WD massive enough to fuse Iron under the added mass from a companion's envelope.
Any thoughts on that?
The Hyperphysics Index also shows the possibility of collapse into a neutron star without a supernova event. It hardly seems possible to have a quiescent change when such energies are involved. On the other hand, if 4M - 8M stars form Red SGs but collapse without SN event into WD, that would make sense.
Also, Blue SGs can go straight to Type II SN (SN1987A) without a Red SG phase. I think between these two lines of evolution maybe that's what was meant. Chalk that up to sloppy editing; someone should write them a courteous email.
Following the link shown as
HyperPhysics: "Red Supergiant" indicates that a mass of 15M will form a Red Supergiant in the triple alpha phase. It also implies that a Red Supergiant can become either a NS or a BH. I suspect 15M might be the limit for Black Hole formation. We have to more than double the mass of iron in the core from 1.44M to ~3.3M, so maybe it takes a near doubling of the initial mass. 8M snd 15M could be those initial conditions.
All those Astro-Eggheads need to get their data straight for us armchair Einsteins.