@chuchi I know in order for a star to supernova it has to be massive enough. Though I too don't really recall if iron is the direct cause of it. I know not all stars reach the iron core but I am pretty sure that it can have an iron core and not supernova
I am genuinely not trying to argue with you, just to be clear, and I am not 100% myself, just going off my memory. Which, HAHA, can fucking fail me at times.
But, as I recall it, a star has to be of certain mass and the core of certain heat in order to create iron. And then, when it does, obviously, it continues to do so and it starts 'chugging' so to speak. And the integrity of the core begins to fail as the gravity becomes imbalanced and then it collapses and goes supernova. I might be wrong in it, and I'm about to head to bed so I won't check for myself, but I'm pretty sure that iron cores go to supernova .. I wanna say most of the time.
Smaller masses don't reach certain heats and thus don't create certain fusions in the core or something along those lines. Those types go the route you described, ending up as white dwarfs, but I guess there's a chance of some random anomalies as well. And then those just kinda simmer out over time.
And then there's... neutron stars that had a certain mass and certain heat but didn't create iron in the core so they ended up being ridiculously dense or something... I can't remember exactly. But those are pretty cool too. \o/
In the event that I am incorrect, I apologize in advance. I'm not trying to stir the pot, just offering what I am fairly certain to be correct. Although I realize I might not be, and in the event of such, I will gracefully go throw myself off the roof. I mean, gracefully accept that and change my knowledge accordingly. C: