Explore the fascinating world of astrophysics in this comprehensive lecture on diffuse stars, part of a series on neutron stars and black holes. Delve into the nature of stars, their formation, and internal processes as explained by renowned physicist G Srinivasan. Learn about Eddington's theory of stars, gravitational pressure, hydrostatic equilibrium, and the mass-luminosity relation. Discover why stars have specific masses and compositions, and understand the nuclear reactions that power them. Investigate concepts like quantum tunneling, fusion reactions, and the proton-proton cycle. Gain insights into the Sun's energy production, lifetime, and core composition. This lecture provides a solid foundation for understanding stellar physics and sets the stage for exploring more advanced topics in astrophysics.
Neutron Stars and Black Holes - Lecture 1: Diffuse Stars
International Centre for Theoretical Sciences via YouTube
Overview
Syllabus
Time: AM
Neutron Stars and Black Holes Lecture - 01
Momentous discoveries during last three years
What are neutron stars? How are they formed?
Topics
What are the stars? Why are they as they are?
Gaseous Stars
Stars as globes of perfect gas
Gravitational Pressure
Gravitational Pressure = P Gravity approximate GM2/R4
Hydrostatic Equilibrium
Boyle's Law
Equation of Hydrostatic Equilibrium
What are the stars?
Eddington's theory of stars
Radiation Pressure
How hot is the Sun?
Virial Theorem
Virial Theorem applied to the Sun
The interior of the Sun
Mean-free-path is approximate 0.5 cm. Radius approximate 1 million km.
In the Sun, photons take ~ 30,000 years to escape! In massive stars, it will take a million years or more!
Mass - Luminosity relation
Mass - Luminosity relation calculated by Eddington L proportional M3
Why are the stars as they are?
"Our mistake was that in estimating the congestion in the stellar ball-room we had forgotten that crinolines are no longer in fashion" - Eddington
Why are the masses of stars in an incredibly narrow range between 0.5-30 M sun?
Eddington was obscure about two things:
Why are the atoms as they are?
Atoms are as they are because they obey the rules of atomic physics.
Lifetime of stars
Why does the Sun shine?
How long will the heat last?
Sir Arthur Eddington
Mass Deficit
Proton - proton collision
Maxwell-Boltzmann Distribution
Alpha decay of radioactive nuclei
Quantum Tunnelling
Energy production in the Sun
Proton - proton reaction
Why doesn't the Sun blow up?
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
Taught by
International Centre for Theoretical Sciences
