PHY3070 Stars from Birth to Death 2024-25
Dr P. Loren-Aguilar
Delivery Weeks: T1:01-11
Level: 6 (NQF)
Credits: 15 NICATS / 7.5 ECTS
Enrolment: 66 students (approx)


The study of stellar systems encompasses a wide range of physics, including gravitation, quantum mechanics, and thermodynamics. This module takes these fundamental physical concepts, learned in the core modules, and uses them to derive the properties of stars. The basic internal structure of stars is described in the first sections, while later sections deal with the ageing and death of both high- and low-mass objects. The final sections describe how stars form.

Module Aims

This module aims to develop familiarity with topics at the forefront of current astrophysical research, such as star formation and a detailed understanding of the physics that govern stellar structure and evolution.

Intended Learning Outcomes (ILOs)

A student who has passed this module should be able to:

Syllabus Plan

  1. General Properties of stars
    1. Definition of a star
    2. Observable quantities
    3. Distance determination
    4. Mass determination
    5. Luminosity and effective temperature
    6. Black body radiation
    7. Magnitude, colors and spectral types
  2. Basic approach: Dimensional analysis
    1. Hydrostatic Equilibrium
    2. Virial theorem
    3. Characteristic timescales
      1. Dynamical or 'free fall' timescale
      2. Thermal timescale or Kelvin-Helmholz timescale
      3. Nuclear timescale
      4. Stellar lifetime on the Main Sequence
    4. Mass-luminosity relationship
  3. Stellar structure equations
    1. Coordinates and mass distribution
      1. Eulerian description
      2. Lagrangian description
    2. Hydrostatic equilibrium
    3. Equation of motion for spherical symmetry
    4. Energy conservation
    5. Energy transport mechanisms
      1. Radiative transport of energy
      2. Convective transport of energy
      3. Conductive transport of energy
  4. Thermodynamical properties of matter
    1. Ideal gas with radiation
      1. Fully ionized matter
      2. Partial ionisation
    2. Degenerate electron gas
      1. Consequence of Pauli's principle
      2. Complete degenerate electron gas
      3. Partial degeneracy
    3. Effect of degeneracy on stellar evolution
    4. Non ideal effects
  5. Nuclear reactions and main burning phases in stars
    1. Basics of thermonuclear reactions
      1. Mass excess
      2. Binding energy
      3. Coulomb barrier
      4. Tunnel effect or quantum tunneling
      5. Cross sections and reaction rates
    2. Major nuclear burning phases in stars
      1. Hydrogen burning
      2. Helium burning
      3. Advanced stages
    3. Ultimate stages
  6. Energy transport properties
    1. Opacity of stellar matter
      1. Bound-bound absorption
      2. Bound-free absorption
      3. Free-free absorption
      4. Electron scattering (Thomson scattering)
  7. Principles of stellar evolution
    1. Polytropes
      1. The Lane-Emden equation
      2. The polytropic equation of state
      3. Analytical solutions to the Lane-Emden equation
      4. Masses and radii of polytropes
    2. Numerical models
      1. Contraction toward the Main Sequence
      2. Evolution on the Main Sequence
      3. Final stages: the death of stars
        White dwarfs; Supernovae, Remnants of supernovae: Neutron stars, black holes
  8. Instabilities and stellar pulsations
    1. Stability considerations
    2. Stellar pulsations
      1. Special case of Cepheids
      2. Basics of stellar pulsation theory
  9. Star formation
    1. Properties of interstellar medium and clouds
    2. The Jeans length and mass
      1. Gravitational instability criterion
    3. Fragmentation process
  10. Massive star formation
    1. Spherical accretion and the Eddington limit
    2. The role of rotation
  11. Binary star evolution
    1. The lagrange points
    2. The Roche lobe
    3. Detached binaries
    4. Semi-detached binaries
    5. Contact binaries
  12. Protostellar discs
    1. Kinematical and thermal structure
    2. The source of viscosity
    3. The inner disc and the sublimation radius
    4. Magnetospheric accretion

Learning and Teaching

Learning Activities and Teaching Methods

Description Study time KIS type
20×1-hour lectures 20 hours SLT
2×1-hour problems/revision classes 2 hours SLT
5×6-hour self-study packages 30 hours GIS
4×4-hour problem sets 16 hours GIS
Reading, private study and revision 82 hours GIS


Weight Form Size When ILOS assessed Feedback
0% Guided self-study 5×6-hour packages Fortnightly 1-13 Discussion in class
0% 4 × Problems sets 4 hours per set Fortnightly 1-13 Solutions discussed in problems classes.
60% Final Examination 2 hours 30 minutes January 1-13 Mark via MyExeter, collective feedback via ELE and solutions.
40% One piece of independent research in one of the topics in the module 2 hours 30 minutes Week 11 1-13 Mark via MyExeter


The following list is offered as an indication of the type & level of information that students are expected to consult. Further guidance will be provided by the Module Instructor(s).

Core text:

Supplementary texts:


Further Information

Prior Knowledge Requirements

Pre-requisite Modules Introduction to Astrophysics (PHY1022), Mathematics for Physicists (PHY1026) and Thermal Physics (PHY2023)
Co-requisite Modules none


Re-assessment is not available except when required by referral or deferral.

Original form of assessment Form of re-assessment ILOs re-assessed Time scale for re-assessment
Whole module Written examination (100%) 1-13 August/September assessment period

Notes: Re-assessment is not available except when required by referral or deferral.

KIS Data Summary

Learning activities and teaching methods
SLT - scheduled learning & teaching activities 22 hrs
GIS - guided independent study 128 hrs
PLS - placement/study abroad 0 hrs
Total 150 hrs
Summative assessment
Coursework 0%
Written exams 100%
Practical exams 0%
Total 100%


IoP Accreditation Checklist
  • N/A this is an optional module
Availability unrestricted
Distance learning NO
Keywords Physics; Star; Mass; Energy; Properties; Timescales; Evolution; Transport; Stages; Burning.
Created 10-Mar-23
Revised 02-Mar-16