Something that i have been interested in lately is the helium flash, i understand that it happens when the core contracts and heats up to where it can fuse helium into other nuclei. What happens to the star, does it swell up, is luminosity greatly increased in a short amount of time, when will it happen and what will happen to our planet when the helium flash happens. Is there a CNO cycle going on right now in our star, what happens to that cycle once the helium flash begins. I just find the life of stars fascinating, and the more i learn about it i see more of the complexity of how stars works in practice. Most of this is just glossed over in most mainstream science media, "stars burn hydrogen into helium, then helium into carbon until the final step of the stars life when the fusion product is iron" and thats sort of all that is said about stars, like it explains the whole life of a star and that its a rather dull and boring place to understand.
The helium flash is interesting in that it happens in lower mass stars, less than twice the mass of our sun. Heavier stars get steadily hotter in the core and can smoothly transition to helium burning, but ls massive stars don't. Th helium builds up in the core and becomes degenerate, held up by electron pressure rather than heat. The core ends up denser than it 'should' be for its temperature. If you heat the core up, it doesn't expand until thermal pressure equals degeneracy pressure. So, when the temperature DOES reach fusion point and helium fusion starts, the core gets hotter but doesn't expand. Without expansion it can't cool. Since fusion rate relates to temperature (to the 40th power!) the fusion rate rises exponentially. By the time the core starts to expand about 6% of it has fused (in just a few minutes!) Oddly enough, since the star is so massive, this energy takes time to gt to the surface and there's not much change visible from afar. What gets ME is 'silicon fusion', talked about like it's a simple process when rally it's a star's core getting so hot nuclei almost can't exist.
3:40 Mass loss from the sun steadily drags Earth IN? I would have thought it would cause it to spiral outwards. What am I missing? 4:45 Three helium nuclei into oxygen? Th first step of the triple alpha process is endothermic, but does it also produce a gamma ray as shown in the diagram?
Thanks for the catch!!!! I'll fix that for the extended version. And yes the drag would pull it in just like the ISS is falling down due to the tenuous atmosphere.
Utterly brilliant short talk Jason Kendall, thank you for the insight.
I love watching your videos. I’ve watched a few where it clicked in my brain and I finally understood what I was seeing.
That's great to hear!
Something that i have been interested in lately is the helium flash, i understand that it happens when the core contracts and heats up to where it can fuse helium into other nuclei. What happens to the star, does it swell up, is luminosity greatly increased in a short amount of time, when will it happen and what will happen to our planet when the helium flash happens.
Is there a CNO cycle going on right now in our star, what happens to that cycle once the helium flash begins. I just find the life of stars fascinating, and the more i learn about it i see more of the complexity of how stars works in practice.
Most of this is just glossed over in most mainstream science media, "stars burn hydrogen into helium, then helium into carbon until the final step of the stars life when the fusion product is iron" and thats sort of all that is said about stars, like it explains the whole life of a star and that its a rather dull and boring place to understand.
The helium flash is interesting in that it happens in lower mass stars, less than twice the mass of our sun. Heavier stars get steadily hotter in the core and can smoothly transition to helium burning, but ls massive stars don't. Th helium builds up in the core and becomes degenerate, held up by electron pressure rather than heat. The core ends up denser than it 'should' be for its temperature. If you heat the core up, it doesn't expand until thermal pressure equals degeneracy pressure.
So, when the temperature DOES reach fusion point and helium fusion starts, the core gets hotter but doesn't expand. Without expansion it can't cool. Since fusion rate relates to temperature (to the 40th power!) the fusion rate rises exponentially. By the time the core starts to expand about 6% of it has fused (in just a few minutes!)
Oddly enough, since the star is so massive, this energy takes time to gt to the surface and there's not much change visible from afar.
What gets ME is 'silicon fusion', talked about like it's a simple process when rally it's a star's core getting so hot nuclei almost can't exist.
Great explanation.
Thanks! I'm always working on new videos.
3:40 Mass loss from the sun steadily drags Earth IN? I would have thought it would cause it to spiral outwards. What am I missing?
4:45 Three helium nuclei into oxygen?
Th first step of the triple alpha process is endothermic, but does it also produce a gamma ray as shown in the diagram?
Thanks for the catch!!!! I'll fix that for the extended version.
And yes the drag would pull it in just like the ISS is falling down due to the tenuous atmosphere.
Sweet
Arthur Eddington must have felt like a god being the first human to discover stellar fusion.
Hey jason love your chenel the only chanel in all you tube hou amaze me 🤌🏻 thenk you for yor work . 😊