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The Physics of Stars - PHY00058H

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  • Department: Physics
  • Module co-ordinator: Dr. Charles Barton
  • Credit value: 10 credits
  • Credit level: H
  • Academic year of delivery: 2020-21

Module summary

This module allows you to take all the physics and mathematical skills and knowledge you have acquired in the previous years and apply them to practical physical systems - typically stars. You will begin from a simple perspective to solve practical problems and, as needed, apply more rigorous physical models to find solutions. For example, you can calculate from a simple model and basic physics what the interior temperature of the Sun should be to fuse two protons if these protons fused when they were in contact at about 1 femtometre. You could then check the answer with your intuition, realise it is wrong, and improve it with a semiclassical calculation using the deBroglie wavelength. Finally, the physics and mathematics of sub-barrier fusion will be correctly applied to more fully understand stellar fusion and energy generation.

Related modules

Co-requisite modules

  • None

Prohibited combinations

  • None

Additional information

Please note, students taking this module should have completed the modules listed a prerequisites (Electromagnetism and Optics - PHY00002I and Mathematics II PHY00030I) or the appropriate equivalent modules.

Module will run

Occurrence Teaching cycle
A Spring Term 2020-21

Module aims

You will take all the physics and mathematical skills and knowledge you have acquired in the previous years and apply them to practical physical systems - typically stars. Your knowledge of the underlying fundamental physics, ability to create simple models and apply theories, and experience with solving quantifiable problems will be used to explore some of the most interesting aspects of stellar evolution, stellar structure, and nucleosynthesis. There is a balance between physics and astrophysics throughout this module.


Module learning outcomes

  • Describe and apply the physical principles underlying gravitational collapse of a dust cloud to form a protostar.
  • Describe and derive aspects of energy production and heat transport mechanisms within the stellar interior.
  • Describe stellar evolution to and from the main sequence and the conditions of hydrostatic equilibrium.
  • Calculate fusion rates and describe element synthesis within stellar environments as well as explain the abundance of elements within the universe.
  • Describe the endpoints of stellar evolution as a function of stellar mass.
  • Calculate and apply the appropriate classical or relativistic kinematics as well as the ideal or quantum mechanical gas description to the electron and ion components of the stellar interior.

Module content


  • Big Bang nucleosynthesis and gravitational contraction – The synthesis of light elements and hydrostatic equilibrium of non-relativistic and ultra-relativistic particles.
  • Star Formation and the Sun– The Jean’s Criteria, contraction of a protostar, conditions for stardom, pressure, density, temperature, and solar radiation.
  • Links to radiation transport laser plasma measurements of opacities relevant to stellar physics
  • Stellar Nucleosynthesis and Stellar Life Cycles – Stellar mass and the extent of thermonuclear fusion, burning cycles, neutron capture, the rate and endpoint of stellar evolution, abundances of chemical elements.
  • Hertzsprung-Russell Diagram – Luminosity, surface temperature, star clusters, tracks and variable stars.
  • Properties of Matter within stars – Ideal gas law, density of states, internal energy, pressure, ideal classical gas, electrons in stars, degenerate electron gases, density-temperature diagram.
  • Properties of Radiation within stars – Photon gas, radiation pressure, the Saha Equation, ionization in stars and stellar atmospheres, pair production and photodisintegration.
  • Heat transfer in stars – heat transfer via random motion of particles and photons, convection, temperature gradients in stars.
  • Thermonuclear fusion in stars – barrier penetration, cross sections, reaction rates, H burning, the p-p chain, CNO cycle, He burning, C production and consumption, advanced burning to Fe-Ni region.
  • Stellar structure– pressure, temperature and density inside stars, Modelling the Sun, minimum and maximum masses of stars.
  • Endpoints of stellar evolution– white dwarfs, collapse of stellar cores, neutron stars, black holes.
  • Helioseismology– pressure and gravity waves, normal modes of oscillation, observations of our Sun from Earth and satellite missions.

Lecture notes
Students are expected to take their own notes during lectures. A set of skeleton notes will be made available online at the end of the course.


Task Length % of module mark
The Physics of Stars PPQs
N/A 14
University - closed examination
The Physics of Stars Exam
1.5 hours 86

Special assessment rules



Task Length % of module mark
University - closed examination
The Physics of Stars Exam
1.5 hours 86

Module feedback

Physics Practice Questions (PPQs) - You will receive the marked scripts via your pigeon holes. Feedback solutions will be provided on the VLE or by other equivalent means from your lecturer. As feedback solutions are provided, normally detailed comments will not be written on your returned work, although markers will indicate where you have lost marks or made mistakes. You should use your returned scripts in conjunction with the feedback solutions.

Exams - You will receive exam marks from eVision. Detailed model answers will be provided on the internet. You should discuss your performance with your supervisor.

Advice on academic progress - Individual meetings with supervisor will take place where you can discuss your academic progress in detail.


Indicative reading

Stellar Physics

Phillips A C: The Physics of Stars (Wiley, 2nd Ed 1999)***

Kippenhahn R and Weigert A: Stellar Structure and Evolution (Springer-Verlag)*

The information on this page is indicative of the module that is currently on offer. The University is constantly exploring ways to enhance and improve its degree programmes and therefore reserves the right to make variations to the content and method of delivery of modules, and to discontinue modules, if such action is reasonably considered to be necessary by the University. Where appropriate, the University will notify and consult with affected students in advance about any changes that are required in line with the University's policy on the Approval of Modifications to Existing Taught Programmes of Study.

Coronavirus (COVID-19): changes to courses

The 2020/21 academic year will start in September. We aim to deliver as much face-to-face teaching as we can, supported by high quality online alternatives where we must.

Find details of the measures we're planning to protect our community.

Course changes for new students