MODULE TITLE

Stars

 

CREDIT VALUE

15

MODULE CODE

PHY3063

MODULE CONVENER

Prof. T. Naylor

 

 

DURATION

TERM

1

2

3

Number Students Taking Module (anticipated)

24

WEEKS

T1:01-11

 

DESCRIPTION – summary of the module content (100 words)

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 – intentions of the module

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) (see assessment section below for how ILOs will be assessed)

 On successful completion of this module you should be able to:

Module Specific Skills and Knowledge:

  1. describe the fundamental properties of stars;
  2. use the equation of hydrostatic equilibrium to estimate the core properties of stars;
  3. calculate the dynamical, thermal, and nuclear timescales of stars;
  4. describe the main nuclear reactions that power high and low mass stars;
  5. describe how radiation is transported from the stellar core to the surface;
  6. discuss post-main sequence evolution for high and low mass stars;
  7. describe the physics of compact stars and derive the mass-radius relationship for white dwarfs;
  8. discuss the terminal stages of stellar evolution;
  9. calculate the Jeans mass and describe the process of star formation;

Discipline Specific Skills and Knowledge:

  1. solve mathematical problems;
  2. apply quantum and classical mechanics, and thermal physics to stellar systems;

Personal and Key Transferable / Employment Skills and Knowledge:

  1. develop self-study skills;
  2. solve problems.

SYLLABUS PLAN – summary of the structure and academic content of the module

  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 (given in hours of study time)

Scheduled Learning & Teaching activities  

22 hours

Guided independent study  

128 hours

Placement/study abroad

0 hours

 

DETAILS OF LEARNING ACTIVITIES AND TEACHING METHODS

 Category 

 Hours of study time 

 Description 

Scheduled Learning & Teaching activities

20 hours

20×1-hour lectures

Scheduled Learning & Teaching activities

2 hours

2×1-hour problems/revision classes

Guided independent study

30 hours

5×6-hour self-study packages

Guided independent study

16 hours

4×4-hour problem sets

Guided independent study

82 hours

Reading, private study and revision

 

ASSESSMENT

 

 FORMATIVE ASSESSMENT - for feedback and development purposes; does not count towards module grade

Form of Assessment

Size of the assessment e.g. duration/length

ILOs assessed

Feedback method

Guided self-study

5×6-hour packages

1-13

Discussion in class

4 × Problems sets

4 hours per set

1-13

Solutions discussed in problems classes.

SUMMATIVE ASSESSMENT (% of credit)

Coursework

0%

Written exams

100%

Practical exams

0%

 

DETAILS OF SUMMATIVE ASSESSMENT

Form of Assessment

 

% of credit

Size of the assessment e.g. duration/length

 ILOs assessed 

Feedback method

Final Examination

100%

2 hours 30 minutes

1-13

Mark via MyExeter, collective feedback via ELE and solutions.

 DETAILS OF RE-ASSESSMENT (where 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

RE-ASSESSMENT NOTES  

See Physics Assessment Conventions.

 

RESOURCES

 

 INDICATIVE LEARNING RESOURCES -  The following list is offered as an indication of the type & level of information that you are expected to consult. Further guidance will be provided by the Module Convener.

Core text:

  • Not applicable

Supplementary texts:

ELE:

CREDIT VALUE

15

ECTS VALUE

7.5

PRE-REQUISITE MODULES

Introduction to Astrophysics (PHY1022), Mathematics for Physicists (PHY1026) and Thermal Physics (PHY2023)

CO-REQUISITE MODULES

none

NQF LEVEL (FHEQ)

6

AVAILABLE AS DISTANCE LEARNING

NO

ORIGIN DATE

01-Oct-10

LAST REVISION DATE

N/A

KEY WORDS SEARCH

Physics; Star; Mass; Energy; Properties; Timescales; Evolution; Transport; Stages; Burning.

Module Descriptor Template Revised October 2011