• Tuesday and Thursday: 4:10 - 5:25; room Physics 38
  
  • Please note that I will need to be away for a few class periods this term. To make up time, we will occasionally need to meet at other times; we will arrange these in advance by mutual agreement.

• Office: A323 Zaffarano, Lab: A529 Zaffarano
  
• Office Hours: whenever you need me (I'm in my lab most of the time)
  
• Telephone: 294-9728 (office), 294-1150 (lab), 292-6060 (home; not after 10pm, please)
• e-mail: sdk@iastate.edu

Books: Required

• Stellar Interiors: Physical Principles, Structure and Evolution
  C. Hansen, S. Kawaler, & V. Trimble (New York: Springer) 2004.
  Note: This is the main book for this course.
  The first edition (1994) may be available at reduced price somewhere, but the new edition is sufficiently different and updated that you should use the new one.

• Understanding Stellar Evolution
  Henny J.G.L.M. Lamers and Emily M. Levesque (Bristol: IoP Press) 2017.
  This is a newer text that covers similar material in a brief but very clear way. This book is part of the AAS/IoP Astronomy eBooks Series, and as such, is a FREE book for ISU students and faculty. You can download the book as a PDF or in Kindle or ePub format, using the link above while connected to the ISU network. Many other titles in astronomy are availble through ISU's library - click here for more info.

• Introduction to Stellar Astrophysics, Volume 2: Stellar Atmospheres
  Erika Bohm-Vitense (Cambridge, Cambridge University Press)
  Not needed until last part of the course, but please do get it as soon as you can. This brief book contains a nice overview of the input physics and techniques used in stellar spectral analysis.

Books: Recommended

• Astrophysical Recipes: The art of AMUSE
  Simon Portegies Zwart and Steve McMillan (Bristol: IoP Press) 2018.
  Another eBook from IoP/AAS, Chapter 3 on stellar evolution presents a very brief overview of computational stellar structure and evolution from a computational standpoint, and includes code to help with computing your own models with MESA.

• Stellar Structure and Evolution
  R. Kippenhahn and A. Weigert (Berlin: Springer) 1990
• Structure and Evolution of the Stars
  M. Schwarzschild, (New York: Dover) 1958, 1965
  NOTE: This book is now (unfortunately) out-of-print, though it has the best succinct explanation of the basic physics at work in stars that I've been able to find. I usually can find a few used copies (ain't the Internet wonderful...). So if you would like a copy, please let me know. They usually cost between $10 and $15.
• Principles of Stellar Evolution and Nucleosynthesis
  D. Clayton, (Chicago: Univ. of Chicago) 1968, 1984

• Principles of Stellar Structure
  J. P. Cox and R. T. Giuli (New York: Gordon and Breach) 1968 Note: if you find a first-edition copy of this huge two volume set, I will be impressed! A reprinted version is available (edited by A. Weiss) and a good value.
• Black Holes, White Dwarfs, and Neutron Stars
  S. Shapiro and S. Teukolsky (New York: Wiley) 1983
• The Internal Constitution of the Stars
  A. Eddington (Cambridge: Cambridge Univ.) 1926, 1988
  NOTE: I'm on the hunt for a first edition (1926) of this book at a reasonable price...
• Theory of Stellar Pulsation
  J. P. Cox (Princeton: Princeton Univ.) 1980

FINAL EXAM: The final exam will be worth 30% of your total grade.

PROBLEM SETS: Approximately 5 problem sets will be assigned this term. You may (and are encouraged to) work together on these problems. However, each student is expected to turn in his/her own paper with his/her own work. Identical answers to essay-type questions, or to interpretation of numerical results, will be severely frowned upon. Problems will frequently require computer solutions (just like in real life). Therefore you are all strongly encouraged to have a Mac or a Unix/Linux computer available (Windows is mostly useless for computational work); if you don't I can help set you up on a lab computer. Taken together, the problem sets account for 20% of your total grade.

COMPUTATIONS: Stellar evolution and stellar atmosphere "theory" is mostly numerical experimentation using more-or-less standard modeling codes. With the abundance of computing equipment available to you, we can make extensive use of several stellar strucure, evolution, (and perhaps atmosphere) codes that run on almost any modern computer (Linux PCs and Macs). One that is now becoming an 'industry standard' is MESA. MESA installation is now easy on any Unix system (especially OSX on Macs), and running it is relatively easy after you make it up the somewhat steep learning curve.

Expect to be running these codes with an eye towards solving real problems in addition to supporting analytical exercises. In addition, some of the problem sets will require numerical solutions using tools that you will have to develop on your own... either by writing your own code (Python, Fortran, C, C++, whatever), or by intelligent use of packages such as Mathematica.

PRESENTATIONS AND PROJECT By the end of this course, you will be expected to have the ability to read, critically and intelligently, any Astrophysical Journal-level paper on stellar structure and evolution or stellar atmospheres. To develop this skill, we will have presentations throughout the course, and a term project.

Presentations: To help hone your presentation and analysis skills, every Thursday one of the students will give a short (10 minute) presentation of a recently posted or published paper in stellar astrophysics - i.e. a 'Journal Club' talk. Each student will do 1-2 such talks during the semester.

Project: In addition, as a term project, you will spend some more time carefully reading and critically analyzing a recent paper from the literature. You will then need to reproduce a key element of the paper's research with your own computation, or test the paper's conclusion with a new calculation or other piece of quasi-original research.

I will have more to say about the Project early in the course, including where to find recommended papers for you to analyze. As this will take some time to prepare, I will expect all students to have chosen their paper by mid-February. Of course, I will do all I can to help (including providing relevant computer codes if available), and you will be encouraged to contact the author(s) of the chosen paper for suggestions..

The presentations and project (and a general assessment of your class participation) will account for the remaining 10% of your total grade.

1. Preliminaries (1.5 weeks)
   • Observational motivation
   • Mechanical structure: time scales, order-of-magnitude estimates
   • Thermal structure: energy transport, generation, time scales
   • The Equations of Stellar Structure
   • The overall problem: simple solutions and homology
2. Equation of State of Stellar Material (1 week)
   • Basic thermodynamics
   • Ideal gas
   • Ionization and nonideal effects
   • Degeneracy and partial degeneracy
   • non-ideal effects
3. Energy Transport in Stellar Interiors (1 week)
   • Radiative transport in the diffusion approximation
   • Opacity
   • Conduction by degenerate electrons
   • Convection and the mixing length kludge
   • Semiconvection and convective overshoot
   • Realistic convection models
4. Stellar Energy Sources (1 week)
   • Energy from the gravitational field
   • Nuclear reactions: general background
   • Hydrogen burning: the p-p chain and neutrinos
   • Electron screening
   • The CNO cycles
   • Equilibrium burning
   • Helium burning via the triple-a process
   • Heavier species: the s- and r- processes
5. Stellar Models (1 week)
   • The differential equations
   • The Vogt Russell theorem
   • Simple solutions: numerical techniques and polytropes
   • Real models: structure and evolution
6. Stellar Evolutionary Stages: An Overview (1.5 weeks)
   • Pre-main sequence and star formation
   • Main sequence systematics
   • Late stages: low, intermediate, and high masses
   • Interacting binary stars
   • Pulsating variable stars
   • Supernovae
7. The Sun: A Stellar Prototype (0.5 week)
   • ZAMS structure
   • Hydrogen depletion
   • The Sun today: neutrinos
   • Solar seismology
   • The future of the Sun
8. Stellar Atmospheres and Spectra (3 weeks)
   • the Transfer Equation
   • line and continuum processes
   • opacity sources in LTE
   • line profiles - broadening mechanisms
   • the Curve of Growth
   • non-LTE and statistical equilibrium
   • modern stellar atmosphere simulation codes
   • interpretation of stellar spectra: T, P, abundances

9. Stellar Pulsation and Asteroseismology (1 week)
   • Theory: radial pulsation
   • Driving and damping of pulsations
   • Radial pulsators: Cepheids, RR Lyra stars, and Miras
   • Theory: nonradial pulsation
   • Nonradial pulsators: solar-like pulsators, red giants, and white dwarfs
   • Asteroseismology in the Space Age