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From: Joseph W. <joe...@gm...> - 2013-02-13 17:00:46
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Hi there, I'm curious about what you've seen, and I was wondering if you could send me your infiles. Something that I've found to be useful in looking at convective related issues is to plot out the convective zones. One thing that I've noticed in massive stars is how quickly the convective structure of the star can change once you hit a nuclear threshold. Say you have a massive star with a large convective core that's burning hydrogen. The convective core insures that there is a fresh supply of hydrogen. Then the interior of the star hits stars burning helium. What ends up happening is that you end up with carbon ash in the center of the star, and since this ash isn't radiating this causes the center to suddenly becomes convectively stable. Once the center of the star stops mixing, the nuclear burning shell quickly burns up the the remaining unburned material, creating more ash, which causes the radiative shell to move outward, and you can very quickly have the convective core disappear. Now if you put in overshooting or Ledoux, then the interaction between the burning and the mixing is different. Once you hit more nuclear thresholds, things get very complicated, as you have an interaction between nuclear burning and convection, and I've seen runs where there are bursts of convection which move material around and change the nuclear burning which changes the convective regions, and there are situations in which I suspect are chaotic. I haven't seen how and if this affects the H-R diagram, so I'm quite interested in running your models and seeing what happens. In addition, my quick impression is that the code is "misbehaving" but it's misbehaving for reasons that telling us something deep and significant about how stars work. |