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Astronomy 201a (Fall 2012): Stellar and Planetary Astrophysics

Although I won't have polished lecture notes available electronically, I will attempt to summarize the material covered in each lecture and provide links to the handouts and problem-set materials.

  1. Tues., September 4: Introductory lecture. Overview of course syllabus, some general philosophy, and the importance of stars to astronomy. Begin discussion of kinetic and thermodynamic properties of gases.
    Reading: Rose, Chapter 1. Pols, Chapter 1 (online).
    Problem Set 1: due Thurs., September 13.
    Useful physical and astronomical constants
    Clayton Figure 1-1 (flowchart: the role of the star in astrophysics);
    Comparative H-R Diagrams (one observational, one quasi-theoretical).

  2. Thurs., September 6: Continue discussion of kinetic and thermodynamic properties of gases: moments of distribution functions, equilibrium statistics (M-B, B-E, F-D), and adiabatic invariants.
    Reading: Collins, Chapter 1. Pols, Chapter 3. Rose, Chapter 3.

  3. Tues., September 11: Continue discussion of kinetic and thermodynamic properties of gases: radiation pressure, electron degeneracy, ion crystallization, electron plasma screening, and pair production.
    Reading: Collins, Chapter 1. Pols, Chapter 3. Rose, Chapter 3.
    Equation of state T versus rho diagram showing many different regimes of parameter space.

  4. Thurs., September 13: Start discussion of energy sources in stars: gravitational contraction and definition of dynamical time scale. Then introduce virial theorem and the Kelvin-Helmholtz thermal time scale. Also begin discussing nuclear energy generation via fusion in stellar cores.
    Reading: Collins, Chapter 3. Pols, Chapters 2, 6.
    Binding energy curve for all known atomic nuclei.
    Problem Set 1 due.

  5. Tues., September 18: Nuclear energy generation: derive cross sections, reaction rates, and properties of the Gamow peak. Begin discussion of important nuclear burning cycles.
    Reading: Pols, Chapter 6. Collins, Chapter 3. Rose, Chapter 6.
    Problem Set 2: due Thurs., September 27.
    Energy generation rates as a function of core temperature.
    Summary of main hydrogen burning reaction chains.
    Clayton Figure 7-3 (chart of nuclei that participate in major burning stages)

  6. Thurs., September 20: End discussion of nuclear energy generation: photodisintegration, neutron capture, and radioactive decay. (For context, HERE is a periodic table.) Begin talking about equations of spherical stellar structure.
    Reading: Pols, Chapter 6. Collins, Chapter 3. Rose, Chapter 6.

  7. Tues., September 25: Continue presenting equations of stellar structure. Radiation transport mechanisms: derive temperature gradients due to radiative diffusion and heat conduction. Begin mixing-length theory of convection.
    Reading: Pols, Chapter 5. Collins, Chapter 4.
    Plot of Rosseland mean opacity versus temperature and density.

  8. Thurs., September 27: Finish discussion of mixing-length theory of convection. Begin full problem of time-steady spherically symmetric stellar interiors.
    Reading: Pols, Chapter 7. Collins, Chapter 4.
    Problem Set 2 due.

  9. Tues., October 2: Stellar structure models: explore the constant-density "homology" approximation, then derive the Lane-Emden equation for polytropic equations of state.
    Reading: Pols, Chapters 4 and 7. Collins, Chapters 2 and 4. Rose, Chapter 2.7-2.9.
    Collection of mass-radius relationships for stars and planets.
    Summary of properties of polytropes.
    Problem Set 3: due Thurs., October 11.

  10. Thurs., October 4: Finish discussion of polytropes and examine various example cases of polytropic indices that correspond to realistic stellar or planetary conditions. Investigate Eddington limit and Eddington's "standard" stellar model.
    Reading: Same as last lecture.
    Finalize project topics.

  11. Tues., October 9: Discuss stellar rotation, oblateness, and 3D generalizations of the spherical stellar structure equations. Begin discussion of tidal deformation by a close companion.
    Reading: Collins, Chapter 7. Rose, Chapter 9.3-9.4.
    Summary plots of Roche model oblateness and von Zeipel gravity darkening.

  12. Thurs., October 11: Finish discussion of tidal deformation and tidal heating. Begin stellar pulsation with the equations of time-dependent hydrodynamics, wave propagation in stars, and the Baker one-zone model.
    Reading: Collins, Chapter 8. Rose, Chapter 8. Pols, Chapters 7.5 and 10.4.
    Problem Set 4: due Tues., October 23.
    Problem Set 3 due.

  13. Tues., October 16: Conclude stellar pulsations and seismology with discussion of the full non-radial pulsation (NRP) problem.
    Reading: Same as last lecture. (The NRP material will be highly reminiscent of Chapter 7.1 of my 1996 PhD Thesis.)

  14. Thurs., October 18: Finish pulsations. Discuss star formation: ISM thermal instabilities, turbulence, and the Jeans criterion.
    Reading: Collins, Chapter 5. Pols, Chapter 9.
    ISM thermal stability diagram for star formation.

  15. Tues., October 23: Finish star formation with a derivation of the initial mass function. Begin pre-main-sequence stellar evolution with discussion of the Hayashi track.
    Reading: Collins, Chapter 5. Pols, Chapter 9.
    Problem Set 4 due.
    Problem Set 5: due Thurs., November 1.

  16. Thurs., October 25: Continue pre-main-sequence evolution: Henyey track, accretion disk physics, and properties of T Tauri stars.
    Reading: Collins, Chapter 5. Rose, Chapter 9.2. Pols, Chapter 9.

  17. Tues., October 30: Finish pre-main-sequence evolution. Begin post-main-sequence stellar evolution: main sequence lifetimes, core/envelope separation.
    Reading: Same as last lecture.
    Luminosity versus time for young stars, brown dwarfs, and planets (by Adam Burrows).
    Flowchart of stellar evolution stages after the main sequence.

  18. Thurs., November 1: Continue discussion of post-main-sequence stellar evolution: mirror/bounce effect (cores collapse while envelopes expand); low-mass core cooling versus high-mass core heating.
    Reading: Collins, Chapter 5. Pols, Chapters 10 and 11.
    Problem Set 5 due.

  19. Tues., November 6: Finish post-main-sequence stellar evolution. Begin discussing stellar death, supernovae, and compact remnants.
    Reading: Pols, Chapters 12 and 13. Rose, Chapters 11 and 13.
    Problem Set 6: due Thurs., November 15.

  20. Thurs., November 8: Finish discussing stellar death, supernovae, and compact remnants. Begin radiative transfer and stellar atmosphere theory (partial review of Ay150).
    Reading: For stellar death: same as last lecture. Radiative transfer: Collins, Chapters 9 and 10.

  21. Tues., November 13: Continue radiative transfer and stellar atmosphere theory: the gray atmosphere, radiative equilibrium, Eddington's approximations, departures from plane-parallel geometry.
    Reading: Collins, Chapters 9 and 10 (and skim chapters 11 and 12).

  22. Thurs., November 15: Begin discussion of spectral line formation and broadening (partial review of Ay150): Non-LTE Einstein coefficients, Schuster reversing layer model of line formation.
    Reading: Collins, Chapters 13 and 14.
    Problem Set 6 due.

  23. Tues., November 20: Finish discussion of spectral line formation and broadening: derivation of line profile function for various kinds of broadening mechanisms, and discussion of curve of growth.
    Reading: Same as last lecture.
    Summary plot of line broadening functions and the curve of growth.

  24. Thurs., November 22: Thanksgiving holiday.

  25. Tues., November 27: Discuss chromospheres and coronal heating.

  26. Thurs., November 29: Discuss acceleration of stellar winds.
    H-R Diagram highlighting different types of stellar mass loss.
    Term Project due.

  27. Tues., December 4: (No lecture on this day. I'll be away at a conference between December 4 and 7, but I'll try to keep up on email during that time.)

  28. December 5-12: Reading Period.

  29. December 13-21: Final Exam Period.
    In class, we agreed on Monday, December 17, 11:00-12:30 as the date and time of the final exam. I've reserved the classroom A-101 for this time.

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