What Are the Stars? - by G Srinivasan

Explore the fascinating world of stars in this comprehensive lecture by Professor G Srinivasan, part of a summer course on gravity, astrophysics, and cosmology. Delve into topics such as the structure of stars, hydrostatic equilibrium, Eddington's theory, mass-luminosity relationships, and nuclear fusion processes. Learn about the Sun's interior, energy production mechanisms, and the factors that determine stellar lifetimes. Discover the intricacies of quantum tunneling, nuclear cycles, and fusion reactions that power stars. Gain insights into the historical development of stellar physics, including Eddington's contributions and the resolution of early puzzles in the field. Suitable for advanced undergraduates and graduate students in physics and astronomy, this lecture offers a deep dive into the nature of stars and their place in the universe.

Time: AM
A Journey through the Universe
What are the stars? Lecture-03
Stars as globes of perfect gas
Gravitational Force
Hydrostatic Equilibrium
Boyle's Law
Equation of Hydrostatic Equilibrium
What are the stars?
Eddington's theory of stars
Radiation Pressure
Hydrostatic Equilibrium
The interior of the Sun
Mass - Luminosity relation
Mass - Luminosity relation calculated by Eddington
Luminosity of a star depends only on its mass!
Why are the stars as they are?
To Eddington this 'agreement' was most annoying! "What business have they on a curve reserved for a perfect gas?", he exclaimed.
"Our mistake was that in estimating the congestion in the stellar ball-room we had forgotten that crinolines are no longer infashion" - Eddington
Eddington was obscure about two things:
The Bohr radius
Lifetime of stars
Element & Relative Masspercent
Why does the Sun shine?
Virial Theorem applied to the Sun
How long will the heat last?
Sir Arthur Eddington 24 August, 1920
Mass Deficit
Proton - proton collision
Maxwell-Boltzmann Distribution
Alpha decay of radioactive nuclei
Quantum Tunnelling
Energy production in the Sun
Why doesn't the Sun blow up?
The Safety Valve
Nuclear cycles
To burn or not to burn? That is the question
Fusion reactions
The composition of the core when nuclear reactions finally stop
Q&A