## ASTR 702 – Stellar Structure and Evolution – Fall 2014

**Instructor:** Dr. Maura McLaughlin

**Contact details:** Maura dot McLaughlin at mail dot wvu dot edu, 304-293-4812

**Office hours:** Just stop by, or by appointment in G59 White Hall

**Class times:** M/W 0930-1045 in 105 White Hall

**Aim:** The goal of this course is to give you a good working understanding of stellar properties, how stars generate energy, and how stars are born and die. We will become familiar with the properties (e.g. temperatures, ages, chemical compositions) of stars and the different states of matter that make up stars. We will understand hydrostatic equilibrium, nuclear fusion and energy transport. We will follow the lifecycles of different types of stars and understand the properties of the different end-points.

We will concentrate on understanding the physics of stars using simple calculations covering a very large range of physical principles. Many of our calculations will be order-of-magnitude and back-of-the-envelope as we will aim to simply understand principles without getting bogged down in minutiae. Secondary goals of the course are to understand what the current important problems in the field are, and to be able to interpret and communicate scientific results that are related to the topics we will cover in the course.

While this course is designed to prepare students for careers as astrophysicists, the physics we will cover has a very broad range of applications, and the approach to problems should help in tackling difficult problems in many areas of physics.

**Prerequisites:** If you have an undergraduate degree in Physics or Astronomy and have had classes in electromagnetism, thermodynamics, quantum mechanisms, and modern physics you should be prepared for this course.

**Text:** The required textbook for this course is

*Stellar Interiors* by Hansen, Kawaler and Trimble

The other three main textbooks that I will use are

*An Introduction to the Theory of Stellar Structure and Evolution* by Prialnik
*Principles and Stellar Evolution and Nucleosynthesis* by Clayton
*Black Holes, White Dwarfs and Neutron Stars* by Shapiro and Teukolsky

The first is an advanced undergraduate book and is excellent for a big-picture view of the topics covered. The second is a graduate text which is essential for a detailed look at stellar nucleosynthesis. The last one covers many things about compact objects which are glossed over in the Hansen text.

Other texts that may be useful are

*Introductory Astronomy and Astrophysics* by Zeilik and Gregory
*Introduction to Stellar Structure* by Chandrasekhar
*Radiative Processes in Astrophysics* by Rybicki and Lightman

All of the above mentioned texts are on reserve at the library.

I have have MANY introductory astronomy texts in my office (free samples from publishers) that you are MORE than welcome to borrow if you would like to brush up on the basics.

**Website:** http://astro.wvu.edu/courses/ASTR702 will be updated regularly with the syllabus, homework assignments and solutions. As this is the first time that this course has been taught, the syllabus will evolve over the course of the semester.

**Homeworks and Exams:** Homework will be assigned every one or two weeks, to be due one week later. I encourage you to talk with each other about the homework, but the actual solutions must be completely your own. There will be a midterm and a final exam. These obviously must be done completely on your own!

Late homeworks will not be accepted, but I will drop your lowest homework.

**Attendance:** There is no specific attendance requirement for this course. However, since we will have lots of class discussions and since I will pull material from several different sources for the lectures, you will likely do much better in the course if you attend.

**Grading:** Your grade will be comprised of the following parts:

- 50% Homeworks
- 20% Midterm exam
- 30% Final exam

You will get at least the following letter grades for the following percentage grades in this course.

- 85-100% A
- 70-85% B
- 60-70% C
- 50-60% D
- < 50% F

**Syllabus:**

1) What is a star? What are our astronomical observables? Overview of the HR diagram and the life cycles of stars. Overview of the Galaxy and the Universe. (1 week)

2) Basic underlying principles such as hydrostatic equlibrium, perfect gas equation of state, virial theorum, stability of self-gravitating spheres. (1 week)

2) Characteristic timescales of evolution, maximum mass of planets and minimum mass for stellar ignition, maximum stellar mass, dimensional analysis and homology relations. (1 week)

3) Energy generation, nuclear reactions, tunneling, p-p chain, CNO cycle, neutrinos. (2 weeks)

4) Basic physical processes of the gas and radiation inside stars, chemical compositions, equations of state, radiation pressure, degeneracy pressure, Saha equation. (1 week)

5) Heat transfer through radiation, conduction and convection, blackbody radition, opacity, Rosseland mean. (2 weeks)

6) Equations of stellar structure, polytropes, Chandrasekhar mass, Eddington luminosity, boundary condidtions, Lane-Emden equation. (2 weeks)

7) Pre-main sequence evolution, Hayashi track, observations and theories. (1 week)

8) End-points of low-mass, intermediate mass and high-mass stars. (1 week)

9) General relativity, black holes and neutron stars. (1 week)

10) The Sun (if we have time! 1 week)

11) Special topics or catch-up. (1 week)

**Lecture notes:**

Lecture 1 : Introduction and Astronomical Observables |

Lecture 2 : Astronomical Observables and the Milky Way |

Lecture 3 : The Sun/Protostars |

Lecture 4 : Opacities/Protostars |

Lecture 5 : Star formation |

Lecture 6 : Post main sequence evolution |

Lecture 7 : Supernovae and neutron stars |

Lecture 8 : Black Holes |

**Links:**

Hipparcos Satelilte

Spectral Type Applet

HR Diagram Applet

HR Diagram Simulator