Great Qualitative Tutorial on Stellar Evolution ! . . . would love to see this upgraded to a *strictly* Quantitative treatment (and comprehensive with many different starting points).
I vaguely remember doing this (as I was taking my Physics GCSE around the time of this video). Sadly, Mr Jon Sheppard (the narrator, and my teacher) died on 29 December 2018. He was 38 years old.
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.
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.
@@LardGreystoke research isn't done on RUclips but there are lectures of advanced topics on RUclips, such as perturbation theory in Cosmology, or quantum field theory in curved spacetimes, why not stellar evolution?
I have noticed astrophysicists often use the term "clouds of dust and gas" but when you delve in to what is meant by dust they can never answer and always end up with "it is really just a cloud of gas". Would you agree? If not what exactly is meant by "dust"? On earth dust usually means a small particle barely visible to the human eye, which may contain a mixture of elements or compounds. But there is no such thing as Hydrogen dust!
I know you didn't ask me but my understanding is that heavy elements (those beyond iron) are only formed by supernovae. This means that the original stars in the universe were indeed formed out of clouds of hydrogen and some helium, but after this first generation the heavier elements were formed, and so newer generation stars (our sun is a 3rd generation star) are also formed with small amounts of these heavier elements, which simply didn't exist for the formation of earlier stars. This is the 'dust', along with other trace materials like maybe the remains of planets or comets. It's pretty inconsequential (probably), so that's why we tend to just ignore it.
@@porcuspine2368 brilliant answer, thanks for that. I never thought about the fact that the remnants of supernovae also may contribute to the matter that forms new stars. This suggest that there could possibly be some gold, silver, platinum, tungsten, etc, inside the sun! Amazing!!!
The most concise and well illustrated explanation I have heard of the H-R diagram. Superb!!
HR is a dynamic space, not a photography. This video helped me understand better the different types of stars and their different evolutions.
Excellent video!
In a word.... fabulous.
Great Qualitative Tutorial on Stellar Evolution ! . . . would love to see this upgraded to a *strictly* Quantitative treatment (and comprehensive with many different starting points).
Very well explained !
Really great bcz I have been confused in this for real long time.... excellent explanation
I vaguely remember doing this (as I was taking my Physics GCSE around the time of this video).
Sadly, Mr Jon Sheppard (the narrator, and my teacher) died on 29 December 2018. He was 38 years old.
Brilliant video
Life saver!
Thank you!
Thanks a lot :)
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.
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.
Why are all these stellar evolution videos entry level?
Because most advanced research isn't done on RUclips?
Sounds like you're volunteering to create an advanced level video treatment of the HR diagram?? I'd love the link once you upload!
@@LardGreystoke research isn't done on RUclips but there are lectures of advanced topics on RUclips, such as perturbation theory in Cosmology, or quantum field theory in curved spacetimes, why not stellar evolution?
I have noticed astrophysicists often use the term "clouds of dust and gas" but when you delve in to what is meant by dust they can never answer and always end up with "it is really just a cloud of gas". Would you agree? If not what exactly is meant by "dust"? On earth dust usually means a small particle barely visible to the human eye, which may contain a mixture of elements or compounds. But there is no such thing as Hydrogen dust!
I know you didn't ask me but my understanding is that heavy elements (those beyond iron) are only formed by supernovae. This means that the original stars in the universe were indeed formed out of clouds of hydrogen and some helium, but after this first generation the heavier elements were formed, and so newer generation stars (our sun is a 3rd generation star) are also formed with small amounts of these heavier elements, which simply didn't exist for the formation of earlier stars. This is the 'dust', along with other trace materials like maybe the remains of planets or comets. It's pretty inconsequential (probably), so that's why we tend to just ignore it.
@@porcuspine2368 brilliant answer, thanks for that.
I never thought about the fact that the remnants of supernovae also may contribute to the matter that forms new stars. This suggest that there could possibly be some gold, silver, platinum, tungsten, etc, inside the sun!
Amazing!!!