AST 352K

General Stellar Astronomy

Spring 2000

TTH 11:00 a.m. - 12:30 p.m.
RLM 15.216B
Unique No. 43840


PROFESSOR: Chris Sneden
Office: RLM 15.218
Phone: 471-1349 (office); 343-0004 (home)
E-mail: chris@verdi.as.utexas.edu
Office Hours: TTH 2:00 - 3:00 p.m. (subject to change)

TA: Greg Doppmann
Office: RLM 16.308 (for AST 152M)
Phone: 471-3453
E-mail: greg@astro.as.utexas.edu
Office Hours:
GRADER: Jodie Martin
E-mail: jodie@astro.as.utexas.edu

Text:
None! Notes, suggested readings on reserve in libraries.

Course Grading:
Homework Sets 40% of grade
Hour Tests (3 of them) 40%
Class Presentation 20%
Final Exam 0% (last Hour Test during the final exam period)

 

Subject Matter, Goals, and Miscellaneous Comments

What is it? Who am I speaking to?
Astronomy 352K is a junior/senior-level introduction to stellar astronomy and astrophysics, with emphasis on observational and empirical methods for studying stars via the light they emit. It is designed mainly for upper-division astronomy majors, but it is also suitable for students majoring in closely related fields such as physics or engineering.

Prerequisites?
The prerequisites for AST 352K are Physics 316 (E&M) or its equivalent, and its prerequisite Physics 301 (Mechanics), as well as the math required for these courses. Astronomy draws on such a wide variety of areas in physics that we cannot expect you to have prior preparation in all of them, and will introduce physical ideas and laws as needed. (Examples include the theory of radiation, atomic structure, and statistical mechanics.) We will usually be interested mainly in applying physical principles, rather than in deep and lengthy derivations, and in general the mathematical manipulations expected of you (e.g., on homework sets) will be pretty straightforward.

Background?
We do not assume that you have a strong previous background in astronomy, although many of the students will have previously either taken other upper-division astronomy courses or at least had an introductory astronomy course such as AST~307. If you find that there are gaps in your background, please ask me to explain or elaborate (either in class or during office hours); you might also find it helpful to consult one of the many fine introductory textbooks that are widely available (I can lend you one of them).

Overlap with other courses?
There is a small amount of overlap between AST~352K and AST~358 (Galactic Astronomy), AST~353 (Stellar Structure), and AST~352L (Positional, Kinematical, and Dynamical Astronomy). We will try to avoid excessive redundancy, but that is inevitable in some subject areas, since not all members of the present class will have taken these other courses.

Textbook?
Nope. This is because I find no single text satisfactory enough to justify asking you to spend $50--100. Instead, I will put various texts on reserve in the Peridier library, and I will recommend readings from them. In addition, my class notes will be placed on reserve in both the Peridier and PMA libraries.

Your presentation?
Students generally benefit from the experience of researching a specific topic in some depth. Toward the latter part of this course you will be asked to give a short (10 minute) presentation on a topic that deals with some interesting aspect of stellar astronomy. Your presentation will be an oral explanation of a poster on the subject that you have prepared for the occasion. Your grade will be determined from a combination of astronomical content, presentation style and effort, and the quality of the poster that accompanies your presentation. You will individually prepare and give this small talk on some narrow stellar astronomy topic, but in the context of a broader topic to be addressed by a group of students. There will be three or four broad areas drawn from the latter topics in the preliminary syllabus given below, each of which will be assigned to a group of three to five students. The members of the group will work together to decide how to divide up the larger topic into individual presentations, and will also serve as a pool of informed people in the same general area, and can (ought to!) provide an audience for "practice" presentations that (ought to!) take place prior to the formal presentation in class. Groups that work together well and give uniformly high-quality presentations will get "bonus" points added to their grade, giving students an incentive to help each other.

My bias in this course?
I regard this course as a vital link between the basic, often elegant physics and mathematics that you have ingested at UT for the past two-three years, and the real, often messy world of astronomical research. Astrophysics combines elements from all areas of physics to offer coherent theoretical models for how the solar system, galaxy, and universe
are constructed and how they have and will evolve. If you are looking for that in this course, forget it. Theoretical astrophysics cannot really derive rational models for an object without appealing to observational astronomy. I am not an astrophysicist as the term is usually meant (that is, I am not a theorist). I am an observational astronomer, and proud of it. And observational astronomy is what you will find covered in this course. Not how is the universe constructed, but how does one practically assemble the basic data about particular astronomical objects (stars) that can be gainfully used in constructing the story of the universe?

Homework and your approach to it?
The homework sets are the keys to what I want to get done in this course. I intend to be (perhaps irritatingly) vague in some of the assignments that I give to you. This is admitted at the beginning to be totally deliberate. Real astronomical research usually does not admit cookbook approaches to interesting problems, and I want you to get used to that. Such an approach is also a signal on my part that I encourage interactions with you outside class. Feel free to discuss with me the course material, problem sets, or any other astronomical topic that come to mind. On the first page I give the formal office hours, but you of course may set up appointments with me at other rational times of day. Notice also that I give my work number (for which I have an answering machine), email address (to which I attend regularly), and my home phone number. I would not give out my home phone number (OK, it's true that we are the
only Snedens in the Austin telephone directory) if I did not expect calls in the evening whenever you need to. I want to help you do well in this course, but I need you to make contact! Don't be shy: remember that the truly stupid question is the unasked one.

Caveat Emptor?
I finish with two warnings, one applicable to all faculty members here and one specific to me. First, in this department you deal with professional astronomers. The good part is that you get very close to current research, and that can be very exciting. The bad part is that we tend to travel a lot (most obviously to observatories in remote and exotic locales), and it is entirely possible that I may need to excuse myself from class a couple of times during the semester. However, all classes will meet, and if I must be out of town I will have a substitute lecturer for class. [At present I have only a trip planned during spring break.] Second, I am currently chairman of this department. This means that inevitably I am pulled in many different teaching/service/research directions simultaneously, and frankly I am very busy. However, this should not become your problem! I expect you to work in this class, and you should expect no less of me. Do not feel the slightest hesitation in pushing me to make time for you outside of class; politely in the beginning, but more firmly if I do not respond. Interaction on this course can only help.

 

Preliminary Course Outline (subject to revision)

  1. Introduction and Vital Observational Statistics of Stars: positions, distances, magnitudes, etc.

  2. The Basic Quantities of Radiation: intensity, flux, blackbodies

  3. Interpreting Stellar Magnitudes: luminosity, & effective temperature; stellar photometry & color indices; effects of the Earth's atmosphere

  4. The Heart of Observational Stellar Physics: spectroscopy, stellar spectral types; excitation & ionization equilibria; the Hertzsprung-Russell diagram

  5. Further Extractions from Spectroscopy: radial velocity & proper motion; interstellar extinction; binary stars & the measurement of stellar masses; the Mass-Luminosity relation

  6. Variable Stars: Cepheids, RR Lyraes, Long-Period Variables; white dwarf pulsators; close binary systems (mass-exchange & contact binaries; cataclysmic variables; novae; etc.)

  7. Star Clusters: young clusters/pre-MS evolution; Main Sequence turnoffs & cluster ages; globular clusters; etc.

  8. Stellar Atmospheres: radiative transfer; basic principles of model atmospheres; spectral lines & abundance determinations; stellar winds; stars of peculiar composition.