Introduction to Stellar Physics

Introduction to Stellar Physics

Course CodeB72003H   

Course Name:Introduction to Stellar Physics     


Level: Undergraduate

Pre-requisite: Advanced mathematics, English language, Basic Astronomy, Atomic physics, thermodynamics and statistical theory of physics

Lecture Time: 16 weeks, 2 sessions/week, 2 hours/session 60 hours

Instructors: Null

Course Description

Fairly well understanding of the observational properties of stars, the fundamentals of stellar atmospheres. Well understandings of the structure and evolution, formation and final fate of stars with different masses.

1       Stellar astrometry, proper motions ,distance and brighnesses of stars(3 hrs)
a) The positions of stars: Coordinate systems, the motion of the earth, domain of observation
(1 hr)
b) Proper motion(0.5 hrs)
c) The distance to the Sun, tridiagonal parallax of stars(0.5 hrs)
d) Brightness of stars: Visual magnitude, color indices, atmospheric extinction, black body radiation, absolute magnitude(1 hr)

2       Stellar luminosity, effective temperature, and color-magnitude diagram(3 hrs)
a) The Hertsprung-Russel Diagram(HRD)
:Nearby stars, open and globular star clusters(1 hr)
b) Photometric parallax: Star clusters, individual stars (1 hr)
c) Luminosity: The concept, Solar luminosity, stellar luminosity and bolometric corrections (1 hr)

3       Stellar radii, radiu-mass relation, and Exercise 1(3 hrs)
a) Stellar radii measurements: Interferometer, moon osculation (1 hr)
b) Radius-mass relation: Binary stars, Doppler effect, orbital parameters of binary systems, mass-luminosity relation (1 hr)
c) Exercise 1 (1 hr

4       Spectral classification of stars, understandings of stellar spectra, the concept of stellar populations (3 hrs)
a) Effective temperature of stars(0.5 hrs)
b) Spectral classification: Spectral class, luminosity class, the spectra of white dwarfs(1 hr)
c) Understandings of Stellar spectra: Solar Spectrum, line identification, spectral class based on lines( 1 hr )
d) Stellar populations (1 hr )

5       Stellar rotation, magnetic fields, exercise 2 ( 3 hrs )
a) Stellar rotation (1 hr )
b) Magnetic fields in stars: Concept, Laman effect (1 hr )
c) Exercise 2 (1 hr )

6       Peculiar stars, Supernovae and interstellar extinctions (3 hrs )
a) Peculiar stars: type A peculiar stars, internal diffusion processes, metallic lines, Barium line stars, T Tauri stars (1 hr )
b) Supernovae, Novae (1 hr )
c) Interstellar extinctions: interstellar dust, interstellar gas ( 1 hr )

7       Basics of rative transfer, radiative processes in stellar atmosphere, source function (3 hrs )
a) Basics of radiative transfer: radiation intensity Iλ
,radiative energy transport, source function, emission and absorption lines (1 hr )
b) Radiative transfer in stellar atmospheres: equation of radiative transfer, surface intensity, flux and effective temperature, anisotropy of flux and radiation, energy density of radiation. ( 1 hr )
c) Source function: source function of solar atmosphere, radiative equilibrium, gray model for atmosphere ( 1 hr )

8       Absorption coefficient of continuum, the effects of non-gray atmosphere, pressure stratifications (3 hrs )
a) Absorption coefficient of continuum: absorption processes, Boltzmann equations, Saha equation, the absorption coefficient in solar atmosphere, absorption coefficients in types A and B stars (2 hrs)
b) The effects of non-gray atmospheres: Balmier jump, non-gray atmosphere and temperature (1 hr )

9       Line formation, spectral analysis, exercise 3( 4 hrs )
a) line formation: optical thin lines, line absorption coefficients, line profiles, widening of spectral lines, equivalent widths, growth curve ( 2hrs )
b) Spectral analysis: Balmier Jump, Strongen color indices, growth curve analysis ( 1 hr )

10    Non-local thermal equilibrium, chromosphere, corona and stellar winds ( 3 hrs )
a) The physics of local and non-local thermal equilibrium, basic equations (0.5 hrs )
b) Chronmosphere, corona and stellar winds
( 0.5 hrs )
c) Pressure stratification: hydrostatic equilibrium, pressure and gravity, electron pressure, radiative pressure ( 1 hr )
d) Exercise 4 ( 1 hr )

11    Conservation laws and stellar structure, hydrostatic equilibrium, thermal equilibrium ( 3 hrs )
a) The physical basis of hydrostatic equilibrium and the fundamental equations of stellar structure. ( 1 hr )
b) The equilibrium transfer of internal energy: Virial theorem ( 1 hr )
c) Thermal equilibrium inside stars and energy transfer ( 0.5 hrs )
d) The preliminary mass-luminosity relation ( 0.5 hrs )

12    The basics of stellar convection theory ( 3 hrs )
a) The energy transfer mechanisms: How does convection happen? The criteria of convective stability (1 hr )
b) The mixing length theory and its applications ( 2 hrs )
i. The fundamental image, mathematics and energy exchange processes of convection in stars;
ii. The mixing length: the choice of parameter
iii. The Cos and Cons of mixing length theory: the problem of convective overshooting, and Lithium abundances

13    Opacity, energy source, nucleosynthesis and energy generation mechanisms, Exercise 4 ( 3 hrs )
a) “Input physics”in the framework of stellar structure ( 2 hrs )
i. Opacity
ii. Nuclear energy generation rates, gravitational potential and internal energy
iii. Nuclear reaction-the internal drive of evolution
b) Exercise 5 ( 1 hr )

14    The basic equations of stellar structure, understanding stellar structure using order of magnitude analysis (3 hrs )
a) Building the equations for stellar structure (2 hrs )
i. Temperature gradient and energy transfer
ii. Conservation of inertia and pressure gradient, the mathematics of stellar oscillations
iii. The equations of stellar structure: the physics and mathematics of structure, evolution and short timescale problems
iv. Order of magnitude analysis based on non-
b) Exercise 5 ( 1 hr )

15    Solving the structure equations, the model of main sequence stars ( 3 hrs )
a) The Schwarzschild method
史瓦西方法 ( 1 hr )
b) The Henney method ( 1 hr )
c) Sketching the picture of stellar evolution, the astronomical concept of classifying stars by masses ( 1 hr )

16    Evolution of low mass stars ( 3 hrs )
a) A prototype low mass star-The Sun: the standard model of the Sun, the Solar neutrino problem ( 1 hr )
b) From the main sequence to Red Giant: a basic picture (0.5 hrs )
c) The process of degeneracy and corresponding equation of state, “intermediate mass” and “low mass” stars. ( 0.5 hrs )
d) Heliu flash and the Horizontal and asymptotic branches, planetary nebulae and white dwarf ( 1 hr )

17    Evolution of massive stars, late stages and the fate of massive stars ( 3 hrs )
a) “massive”and “intermediate mass” stars, observational facts ( 1 hr )
b) The physical problems of stellar evolution: mixing of matter, the blue loop, and advanced nuclear reactions ( 1 hr )
c) The final stage of evolution and type II supernovae ( 1 hr )

18    Observational constraints of stellar theory, pulsating variable stars (3 hrs)
a) Observational constraints of stellar theory (revisited): the HRD of star clusters, the remanants of stellar evolution ( 1 hr )
b) Observations:Perio-luminosity relation, the physics and applications (0.5 hrs )
c) The classical cepheids and classical problems ( 0.5 hrs )
d) The excitation mechanism of oscillations, the instability stripes in HRD ( 1 hr )

19    The basics of star formation, initial mass function, exercise 5 ( 3 hrs )
a) The rough picture, observation and theory of star formation process ( 0.5 hrs )
b) Stellar convection and Hayashi line: Physics of proto stars and red giants ( 1 hr )
c) The initial mass function (0.5 hrs)
d) Exercise and Q&A ( 1 hr )

20    Examination ( 3 hrs )
Grading standard
Class room performance 30%
Exercises 40 %
Final examination 30 %

Reference materials

Francis LeBlanc, An Introduction to Stellar Astrophysics, Wiley, 2010.
B. W. Carroll and D. A. Ostlie, An Introduction to Modern astrophysics, Wesley, 1996

Text books:
Introduction to stellar astrophysics, Volume 1, II, III (Bohm-Vitense, Cambridge University Press, 1997) 

Professors: Licai Deng et al.