HAVERFORD COLLEGE

DEPARTMENT OF ASTRONOMY

Stellar Structure and Evolution

(office hours to be announced)

Textbook: "Stellar Structure and Evolution" by Dina Prialnik. While the entire textbook will be assigned reading, it will be supplemented by several texts on reserve in the Strawbridge Observatory Library and lecture notes.

Course Description:

The study of the structure and evolution of stars is unusual in that it draws on many other fields: observational astronomy, atomic and nuclear physics, thermodynamics and statistical physics, electrodynamics, hydrodynamics (including magnetohydrodynamics and turbulence), gravitation and general relativity, condensed matter physics, computation physics, plasma physics, and more. In this respect it is an ideal topic for drawing together everything you've learned in astronomy and physics, and will undoubtedly force you to learn a great deal more. Of course, this one semester class won't, in any sense, be comprehensive. One could take several courses on stars and still leave many topics untouched. A principal goal of the course is to provide an overall introduction to the field so that by the end of the term you should be able to grasp, in fundamental physical terms, why stars exist, why they shine as brightly as they do, and how they will die. The remnants of "dead" stars (i.e., white dwarfs, neutron stars, and black holes) involve the properties of matter under extreme conditions which require the consideration of both quantum physics and relativity. For example, we will deduce that the ratio of the radius of a white dwarf to the radius of a neutron star is, up to factors of order unity, just the ratio of the neutron mass to the electron mass, a fascinating result! For those of you who go on to do graduate study in astrophyiscs, this course is only a first step. Hopefully the course will help make the study of stellar structure a little less intimidating the next time you encounter it. However, by the end of the term you should already be able to make your way through some of the literature on stars. Those of you who do not pursue further study in astronomy or physics will, hopefully, leave with a deeper understanding of the fundamental physical principles that underlie the Cosmos.

Most of the written work in the second half of the semester will be devoted to a class project to construct a detailed stellar model from first principles. This will involve generating simple starting models, constructing accurate opacity tables, transforming the stellar structure equations into finite difference equations, and, eventually, generating computer code to generate solutions. This isn't just a computer project. Figuring out what to put into the computer will be a major part of the project.

Course Structure:

About 1/2 to 2/3 of the class time will be devoted to lecture and the remaining to a "workshop" style seminar; however, it is expected that there will be considerable student input during the lectures. Workshops will be devoted to student presentations (see "special assignment" below), general class discussion, and problem solving. Student input will be important for setting the agenda for the workshops. The workshop/seminar is a collective way to study, and it is imperative that participants complete the assigned readings before coming to class.

Assignments, Exam, and Term Project:

There will be 6 homework assignments due roughly every other week. The last two assignments will be exclusively on the term project. A penalty equivalent to 2% to 3% per day will be deducted from papers handed in late. Occasional in-class problem sessions will serve as a reminder to come to class prepared. The primary exam will consist of a comprehensive take-home problem set that will be due about a month before the end of class. Course grades will be determined from performance on homework (approx. 30%), class performance, including the special assignment (approx. 25%), and the exam and class project (approx. 45%).

Special Assignment:

Sometime during the semester, each student will report on some type of non-main sequence star, e.g., white dwarf, carbon star, T-Tauri star, etc. In addition to a 15-minute presentation to the class, the presenter will prepare and distribute a short (2 page maximum), typewritten summary prior to the presentation. You will be asked to decide on your topic in the first few weeks of class, so begin to give the matter some thought. Your old Kutner text, the text by Carroll & Ostlie, the text by Zeilik & Gregory, the Shu text, and the first volume of Bohm-Vitense are useful resources. In addition, you have access to the entire collection in the Strawbridge Observatory Library.

Tentative Course Outline:

Topic

Reading in Textbook

(these will be supplemented with other readings)

Week 1

Introductory Review of Stars

Chapter 1 (review your Astro 205 text as necessary)

Weeks 2 and 3

Radiative Transport and Stellar Atmospheres

Chapter 3, sections 3.1, 3.4, 3.5, 3.7, and Appendix 1

Week 4

Convective Transport

Chapter 3, section 3.6, and Chapter 6,
sections 6.5 and 6.6.

Week 5

Stellar Interiors

Chapter 2 and Chapter 3, sections 3.2 and 3.3.

Week 6

Nuclear Processes in Stars

Chapter 4

Week 7

Equations of Stellar Structure

Chapter 5

Week 8

Equations of Stellar Structure and Simple Models

Chapters 5 and 6

Week 9

Degenerate Stars

Lecture and outside reading only

Weeks 10 and 11

Stellar Evolution

Chapters 7 and 8

Week 12

Exotic Stars

Chapter 9

Week 13

Exotic Stars/Star Formation

Chapters 9 and 10

Week 14

Star Formation

Chapter 10