Online Lecture notes for module 210PHY412

Part II – Stellar structure and evolution (Prof. S. Smartt)

This course is taught as a half-module for PHY412 Astrophysics in the Department of Physics and Astronomy at Queen's. It is a 4th year MSci course, which is compulsory for students on the Physics with Astrophysics pathway and optional for other Physics and Physics and Applied Mathematics students.

Lecture 1: The observed properties of stars (powerpoint file)

  1. Introduction and learning outcomes for the module.
  2. The observable properties of stars
  3. Recap of previous concepts – basic stellar parameters, the HR diagram, colour magnitude diagrams, absolute magnitudes
  4. Observed mass-luminosity relations 
  5. Star clusters – open clusters and globulars


Lecture 2: The equations of stellar structure I  (powerpoint file)

  1. Introduction to the equations describing stellar structure, basic assumptions
  2. The equation of hydrostatic support
  3. The equation of mass conservation
  4. Accuracy of the hydrostatic assumption
  5. Accuracy of the spherical symmetry assumption
  6. The dynamical timescale


Lecture 3: The equations of stellar structure II  (powerpoint file)

  1. The minimum value for central pressure of a star
  2. The Virial Theorem
  3. Minimum mean temperature for a star and the Sun
  4. The physical state of stellar material
  5. Radiation and gas pressure


Lecture 4: The equations of stellar structure III  (powerpoint file)

  1. Energy generation in stars
  2. Source of energy generation
  3. Equation of energy production
  4. Method of energy transport 
  5. Convection and conditions for convection


Lecture 5: The equations of stellar structure IV  (powerpoint file)

  1. The equation of radiation transport
  2. Summary of the four equations of stellar structure
  3. Solving these equations: boundary conditions, and use of mass as an independent variable
  4. Temporal evolution of the models
  5. Influence of convection


Lecture 6: Nuclear reactions in stellar interiors  (powerpoint file)

  1. Binding energy of atomic nuclei
  2. Occurrence of fusion reactions: quantum tunnelling and the Gamow Peak
  3. Hydrogen burning – PP chain
  4. Energy production and neutrino emission
  5. The CNO Cycle
  6. He burning – the triple-a reaction
  7. Later stages of nuclear burning and statistical equilibrium – carbon, oxygen, silicon burning
  8. The s-process and r-process


Lecture 7: The structure of main-sequence stars – homologous stellar models   (powerpoint file)

  1. Equation of state of an ideal gas
  2. Mean molecular weight
  3. Opacity and approximate form for opacity
  4. Homologous stellar models
  5. Comparing the homologous series with observed parameters: mass-luminosity and luminosity-temperature relations


Lecture 8: Polytropes and simple models  (powerpoint file)

  1. What is a simple stellar model
  2. Polytropic models
  3. Derivation of the Lane-Emden equation
  4. Analytical and computational solutions of the Lane-Emden equation
  5. Comparison with real models
  6. How does a polytropic model of the Sun compare with the detailed Standard Solar model?


Lecture 9:  General stellar evolution  (powerpoint file)

  1. Computation of realistic stellar models
  2. Examples of results from stellar evolution calculations
  3. Visualising stellar evolution with SCLOCK
  4. Discussions of the differences between low, intermediate and high mass stars
  5. Influence of input physics – convection and overshooting
  6. Comparisons of the stellar codes with observations: observational HR diagrams of stellar clusters


Lecture 10: Evolution of solar-type stars  (powerpoint file)

  1. The main-sequence lifetime
  2. End of H-burning, ascent of the red giant branch.
  3. Tip of the red giant branch and the He flash
  4. He-burning on the AGB
  5. Pulsations and formation of Planetary nebulae



Assignment Class I

Discussion of the assignment (tbd)



Lecture 11: Evolution of high mass stars  (powerpoint file)

  1. Typical evolution of 10, 25 and 100 solar mass stars
  2. H-burning and main-sequence lifetimes
  3. The Eddington luminosity
  4. Post main-sequence evolution
  5. Structure of massive stars before collapse
  6. The influence of mass-loss: formation of Wolf-Rayet stars
  7. The IMF – massive stars are rare


Lecture 12: End states of stars: white dwarfs, neutron stars and black holes  (powerpoint file)

  1. White dwarfs – the final state of low and intermediate mass stars
  2. Electron degeneracy pressure
  3. Chandrasekhar limit
  4. Neutron stars and pulsars
  5. Very massive stars and black holes
  6. Observed masses for neutron stars and black holes 


Lecture 13: Supernovae I   (powerpoint file)

  1. What is a supernova – historical note
  2. The different types of supernovae observed
  3. Typical lightcurves and spectra of supernovae
  4. Massive stars and core-collapse supernovae
  5. Stellar evolution and progenitor stars


Lecture 14: Supernovae II  (powerpoint file)

  1. Type Ia supernovae - thermonuclear explosions
  2. Progenitor models for type Ia SNe
  3. Supernova surveys and the accelerating Universe
  4. Detection of dark energy with Type Ia SNe



Assignment Class II

Sample exam questions and various mathematical problems to aid understanding and learning.