Stellar Physics I

  Dr L. Fletcher
10 lectures, starting 12th October 2005


The aim of this ten-lecture level 3/4 course is to explain and understand the structure of main-sequence stars in terms of basic physical principles. Topics covered include (Part I) basic observations, observational correlations and order-of-magnitude estimates (Part II) simplified stellar models (including polytropic models) and (Part III) the derivation of the equations of stellar structure, and introduction of related concepts of radiative transfer, opacity and convection

Books
There are two recommended textbooks for this course:
The Physics of Stars, 2nd Edition, A. C. Phillips (Wiley)
An Introduction to the Theory of Stellar Structure and Evolution, Dina Prialnik, (Cambridge University Press).

Additional books to read if you can get hold of them (they are currently out of print) are:
Astrophysics I - Stars, Bowers and Deeming (Jones and Bartlett)
Structure and Evolution of the Stars, Schwartzschild (Dover).

 

Course Summary

Here is a pdf of the summary slides I showed at the tutorial on 10/05/06, describing the things you should be able to derive, describe or calculate. They are roughly in the order in which they appear in the notes. Consider this as a checklist for examinable coursework.

Course Outline

Stellar Physics I will cover the following topics:

Stellar Observations: distances, luminosities, surface temperatures, masses and their relationships - HR / ML diagrams - stellar classes - range of values and requirements of energy source

Star Formation: Jeans' mass - protostar contraction time (Kelvin-Helmholtz) -

Stellar Structure: equations (hydrostatic, state and energy flow) of quasistatic structure - solutions for prescribed density and polytropic models - Lane Emden equation - central temperature

Stellar Luminosity: radiative and convective energy transport - photon diffusion time and luminosity - opacity and temperature gradient - KH lifetime and the need for internal energy source

Nuclear Processes and Nucleosynthesis: nuclear reaction rates and quantum Coulomb barrier penetration - reaction cycles for different masses

Lecture Notes

Below you will find pdf versions of the slides I have shown during the lectures. You will receive the handouts during the lectures themselves; however in the versions posted on the web I have implemented corrections which have been brought to my attention . You should therefore look at these to correct errors in the handouts.


Lecture 1 - Observable Quantities
notes: Lecture 1 (pdf)
Other Handouts:[Aims and Objectives ]
Websites: [ Spectral Types (applet), The Hipparcos Satellite]

Lecture 2 - Important timescales, and the Virial Theorem
notes: Lecture 2 (pdf)
Websites: [ More about the Virial Theorem, ]

Lecture 3 - Estimates of pressure and temperature, Jeans mass and stellar collapse
notes: Lecture 3 (pdf)
Websites: [ Star Formation Simulations ]

Lecture 4 - Minimum and Maximum Stellar Mass, Lower limit to central pressure
notes: Lecture 4 (pdf)

Lecture 5 - Simplified stellar models, The Lane-Emden Equation and its solutions for n=0,1
notes: Lecture 5 (pdf)
Websites: [ Vik Dhillon's notes on solutions of the LE equation , Lane-Emden equation from Mathworld]

Lecture 6 - Energy Generation and Basics of Nuclear Fusion in Stars
notes: Lecture 6 (pdf)

Lecture 7 - Introduction to Radiative Transport
notes: Lecture 7 (pdf)

Lecture 8 - Pressure balance in Radiative Equilibrium; Breakdown in Radiative Transport
notes: Lecture 8 (pdf)

Lecture 9 - Polytropic relationship for an adiabatic gas and the onset of convection
notes: Lecture 9 (pdf)

Lecture 10 - Homology, comparison with observations
notes: Lecture 10 (pdf)

Question Sheets

Question Sheet 1 (pdf)    Model Answers (pdf)

Question Sheet 2 (pdf)    Model Answers (pdf)