Stellar Structure and Evolution
2012–2013 term Ia
Lecturer: Prof.dr. S.C. (Scott) Trager
ZG 158, x6625, sctrager@astro.rug.nl
http://www.astro.rug.nl/~sctrager/teaching/stellar_structure/
Stellar_Structure__Fall_2012.html
Required text: “Evolution of Stars and Stellar Populations” by M. Salaris &
S. Cassisi (Wiley 2005)
Recommended text: “Stellar Structure and Evolution” by R. Kippenhahn &
A. Weigert (Springer-Verlag 1990)
Useful text: “Principles of Stellar Evolution and Nucleosynthesis, 2nd Edition” by D. D. Clayton (University of Chicago Press 1983)
Useful text: “Introduction to Stellar Astrophysics, volume 3: Stellar Structure and Evolution” by E. Böhm-Vitense (Cambridge University Press
1992)
Useful text: “Structure and Evolution of the Stars” by M. Schwarzschild (Princeton/Dover 1958/1965)
Course Requirements:
For Masters students:
• Four problem sets (5% of final mark each)
• Calculation of a stellar model (computer project; 30% of final mark)
• Final exam (50% of final mark)
For Bachelors students:
• Four problem sets (10% of final mark each)
• Final exam (60% of final mark)
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Outline of Course:
1. Basic observational data
• Hertzsprung-Russell diagrams
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distances: parallaxes (Hipparchos), RR Lyrae, Cepheids
membership: proper motions, radial velocities, chemistry
theoretical to observed transformations: atmospheres, IRFM
chemical composition
convection theory, diffusion
• Ages
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Sun: meteoritic and geological radiochronology
HR diagram matching techniques
age spreads; when do stars appear on the HR diagram?
radioactive decay (Th/Eu and U/Th)
• Masses and IMF
– masses from stellar observations: Sun, binaries
– Mass-luminosity relation
– IMF: Salpeter vs. Scalo; low-mass IMF, high-mass IMF
• Radii
– Solar radius
– Interferometry
– Eclipsing binaries
• Elemental abundances
– Sun: X, Y, Z
∗ photosphere vs. models (helioseismology) vs. meteorites
– He abundances, ∆Y /∆Z
• Rotation
– line profiles (note: starspots)
– angular momentum conservation, transport
2. Equation of state
• Basics
• Ideal gas
• Radiation
• Degeneracy
• Saha equation
• Coulomb effect
3. Equations of stellar structure
• Mass conservation
• Differential equations of hydrodynamics and hydrostatics
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• Radiative and convective energy transport
– Opacity
∗ mean opacities: Rosseland mean
∗ electron scattering
∗ free-free
∗ bound-free
∗ bound-bound (line transitions)
∗ conduction
– Convection
∗ Schwarzschild criterion
∗ mixing-length theory
∗ depth of convection zone
• Energy generation
– Nuclear reactions
∗ basics: terminology, binding energies, reactions
∗ reaction rates
– Gravitational energy
– Neutrino losses
• Uniqueness of solutions: Vogt-Russell “theorem”
• Virial theorem
• Time scales
4. Stellar evolution
• General picture of stellar evolution
• The mass–luminosity relation
• Pre-main-sequence contraction, comparison with observations
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homologous contraction
convective (Hayashi), radiative phases
Hayashi track, birthplace
energy generation
• H-burning phases
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Nuclear reactions: pp, CNO
Low-mass stars and the Sun: the lower Main Sequence
Massive stars: the upper Main Sequence
The lowest mass stars
Post-MS evolution
∗ Intermediate- and high-mass stars
∗ Low-mass stars
∗ He flash
– Dependence of RGB features on physical and chemical parameters
• He-burning phases
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– Nuclear reactions: 3α, C-burning
– Zero-age horizontal branch (ZAHB)
– Core He-burning
∗ Low-mass stars
∗ Massive stars
– Variable stars
• Advanced evolutionary phases
– Asymptotic giant branch (AGB)
– White dwarfs
∗ white dwarf classifications
∗ Chandrasekhar limit
∗ electron conduction and WD cooling
– Supernovae (if time)
∗ Core collapse (Type II supernovae)
∗ Type Ia supernovae
– Neutron stars
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Schedule
S&C:
T04.09 Overview of course; Basic observational data
W05.09 Equation of state (1); requirements for computer stellar model described
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F07.09 Equation of state (2). First problem set handed out
T11.09 Equation of state (3)
W12.09 Equations of stellar structure (1): mass and hydrostatic equilibrium
3.1.1–3.1.2
F14.09C Werkcollege
T18.09 Equations of stellar structure (2): Energy transport (i)
3.1.3–3.1.4
W19.09 Equations of stellar structure (3): Energy transport (ii)
F21.09 Equations of stellar structure (4): Energy generation. First problem
set due. Second problem set handed out
3.1.6–3.1.7
T25.09 No class (Scott away)
W26.09 Equations of stellar structure (5): Virial theorem, time scales of stellar
evolution
3.1.9
F28.09C Werkcollege
T02.10 Overview of stellar evolution
4.1, 5.7
W03.10 Pre-main-sequence evolution
4.2–4.3
F05.10 H-burning phases (1): main sequence. Second problem set due.
Third problem set handed out
5.1–5.6
T09.10 H-burning phases (2): post-MS evolution
5.8–5.10
W10.10 He-burning phases
6.1–6.5
F15.10C Werkcollege
T16.10 Advanced evolutionary phases: AGB, white dwarfs
7.1–7.4
W17.10 Supernovae and neutron stars Third problem set due. Fourth
problem set handed out
7.5–7.7
F19.10C Werkcollege
T23.10 Buffer day: catch up and/or stellar model workshop
W24.10 Course review
F26.10 No class (Scott away). Fourth problem set due in Scott’s mailbox
by 17.00
W31.10 Stellar model due in Scott’s mailbox by 17.00
M05.11 09.00-12.00 Exam, ZG161
Key: M=Monday; T=Tuesday; W=Wednesday; F=Friday; C=Werkcollege
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