I've corrected a couple mistakes and fixed some serious audio issues. Please see the updated version here: ru-vid.com/group/PLyu4Fovbph6d9PJ25kXjmEDSAXQp76Mpl
Since you start with a few solar masses of protons, and turn half of them into neutrons, you need to get rid of more than 10^(33+23) electrons, or else you’ll have too much charge. Fusion positrons will do that. But you also need to shed lepton number ( it’s conserved): enter….or exit really… the neutrino. For every proton that becomes a neutron, a neutrino has to leave the star.
Why don't heavy stars fuze iron even at the net energy loss? Why heavy stars don't overshoot the iron peak? Iron cores have enough gravitational energy to spend on iron fusion but they don't.
to lift 64,000 tons up a kilometer seems outrageous from 1 gram of matter. In chemistry I saw what 1 gram was, one cubic centimeter of water. But the numbers of the cno cycle in density are so out of normal we just have trouble susing exactly what that means. That is why I am so much a proponent of molten salt thorium reactors, to replace our oil dependency now. Now that Goodenough and Bragga have discovered a million mile lithium battery in solid state glass that will not burn down and degrade over time like lithium ion electrolyte batteries, "hey we can do this". For the next thousand years at least.
Why don't Ni(p,γ)Cu or Ni(α,γ)Zn processes happen in heavy stars during Si burn but before core collapse begins? Assume stellar core has grav-energy to spend.
Eta Carina explosion with duel bubbles is how I imaged, as child of 8, the big bang explosion happened with a positive good universe and a negative bad universe that was supported by an Star Trek episode What of Lazarus, where good Lazarus was dedicated to keeping the negative Lazarus out of our positive universe by locking himself in a membrane between the two universes... then I became aware of the inflation model so remodeled my vision of the starting event which physicist said was neither big nor made a bang.
I love your lectures going just somewhat deeper in the matter, without getting too tecdhnical for me to follow. Hope for clear skies when I visit my mother wehere the is less light pollution than over here in the west of the netherlands.
Curiously the total mass of each category is roughly the same until the very largest stars. Perhaps because most modest mass stars are still extant while most high mass stars are already defunct.
Fascinating. Exceptionally well presented for the average layman like myself adding significantly to my understanding on the subject. I always look at Betelgeuse at night.
I’m confused. At 38:48 he mentions that the atomic number of Iron is 56. I thought the atomic number of Iron is 26, with its mass being ~56. Am I misunderstanding something?
that's probably what he meant; ive noticed a few minor errors here and there. if only youtube let you edit videos... annotations could work, if someone were to put in the time...
I know. I wish I could. I try to do them in one sitting, with zero edits. As though I'm giving an actual lecture. I do have a few flubs, so I do appreciate the patience.
Awesome stuff, but also the second lecture with a horrible noise that scared the crap out of me. Your audio is pretty low so I had to crank it up pretty high and at 3:30 mark I almost died
Ah Betelgeuse I find it interesting that the only reason it is so prominently visible is due to it having been launched out of the Orion Nebula at high velocity probably due to gravitational interactions when it was a newborn star otherwise it would be hidden away behind all the gas and dust like its siblings in the Orion Nebula. Eta Carinae is a interesting system of uncertain stage one of those extremely rare behemoths with over a hundred solar masses even its smaller companion is at least 30 solar masses in other words crazy massive stars. Personally the weirdest and perhaps most fascinating stars are the monstrous WNh stars since their CNO cycle burning and rapid rotations drive internal convection rapidly burning through their entire envelope of hydrogen and beyond losing nearly all their angular momentum to extreme outflows. Depending on circumstances they might not even produce Supernovae instead dying with a whimper by collapsing straight into a black hole without a gamma ray burst since they have no angular momentum left to lose though that remains speculative since these stars are too rare. Weirdly enough WNh stars are still fusing hydrogen in their cores because of this effectively never existing as a typical main sequence spectral type. I think its thought these develop straight into Luminous Blue Variables which in turn evolve into more conventional Wolf Raynet Stars. Have you done any video on the Wolf Raynet class? The stars covered here are the less massive "low mass" supernovae progenitors alternating between the red and blue super giant phases with the transitional yellow hyper giant phase. And then there are those population III stars from the Early universe which are though to be able to die via pair instability supernovae as the photo disintegration is able to dominate. Massive stars are complicated....
dragrath: hmmm did you know sn 1987a was not a rayet star. seems it was just a blue giant. I would dearly love for our stellar astro-phycists to explain exactly simply to me how the rings were formed as it dynamited into a supernova. And what the glint was that was spotted some close distance away by the Harvard-Smithsonian telescope shortly after the burst, that then went quickly away. Something happened during detonation that was almost superluminal and I am not sure if it was a relativity space/time view from our angle or was really super-luminal in nature.
@@PaulHigginbothamSr you know, look up few papers on it. If you find something close to what you need. Write the author. The PI's and grad students are usually pretty responsive.
