Astronomy 102: Stars and Galaxies

Fall 2003

Vanderbilt University

Prof. Robert Knop

Syllabus

Note: this Syllabus is under construction and subject to change.

MWF, 10:00-11:00 AM, BSB 1220 (MRBIII 1220)
Labs: M-Th 7:00-10:00 PM, 25th St. Garage Observing Facility

• Textbook
• Course Staff
• Prerequisites (and About the Math)
• Course Description and Unifying Concepts
• Format of the Course
• Grading
• Course Schedule

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Textbook

21st Century Astronomy, by Hester et. al., W. W. Norton & Company, 2002.

This course will focus on Parts I and III of the text. You may find some of the material in Part II to be helpful for the laboratory.

Reading assignments from this text, supplemented by additional material that will be made available on this website or elsewhere on the web, will be indicated for each day of class. You are expected to complete the reading assignment before lecture on the indicated day. Doing so will help you better follow the lecture, and therefore will help you better learn the material, which in turn will make it easier for you to do well on homework sets and exams.

A suggestion on reading the text: look at the pictures! They're not just there to make the book look pretty. Often, you can learn as much or even more from looking at the pictures and reading their captions than you can from reading the exposition in the text. Many concepts in science, and in particular in astronomy, are very visual, and the diagrams and images in the text can express them in ways that is more natural than the text.

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Course Staff

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Prerequisites (and About the Math)

Math 133 (Algebra & Trigonometry) or equivalent. You will do some mathematics on homework and exams, and in the laboratory. You should understand scientific notation ("powers of ten" notation) and be able to use a calculator to compute numerical values for problems which involve large numbers. You must be able to perform and understand simple algebraic equations and manipulations.

Students uncomfortable with math may find themselves thinking that there is "too much" math in this course, or that the math is "too hard". Remember that the admissions requirement for Vanderbilt include two units of algebra and one unit of plane geometry. None of the math you will do in this class will be more advanced than that. Mathematics is the language of science, and a full exploration of introductory astronomy requires some basic math.

There is a Math Review available on the course's web page which you may find helpful. It also describes the standards I will be using in grading e.g. with significant figures. Early in the semester, I will hold some additional review sessions for students worried about math; I will do this after the first couple of homework sets are due, so that you will have the opportunity to determine first hand if you find the math in this course challenging.

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Course Description and Unifying Concepts

The purpose of this course is to introduce you to Astronomy. Additionally, as this is only one of two science courses many of you will take at Vanderbilt, the course strives to expose you to the manner in which science is done, and to help you understand the scientific way of thinking.

Many of you who are not accustomed to thinking in the scientific mode will find this course challenging. Of course, such challenges are the very reason one attends a liberal-arts college like Vanderbilt; to learn about the full spectrum of human intellectual endeavor, and to be exposed to different modes of thinking.

This course may be different from some science courses you have had in the past. In particular, simple memorization of terms and concepts will not get you through the course. Yes, there is a fair amount of material in the course. However, the most important thing is not to be able to reguritate the facts; rather, it is more important to understand the concepts and the reasoning, and to be able to think through the implications and results of the material.

To help you provide a framework in which to understand the astronomical material of the course, I will present many of the concepts and topics of this course in the context of four unifying themes:

A Sense of Scale

One can find a surprising amount of insight into astronomy and the Universe we live in simply by having a grasp of the scales involved. This does not just mean spatial scale (e.g., how far are the stars compare to the size of the solar system, how big is the Galaxy), although that is an important part of it. Also important are time scales (what do we mean when we say a star is "short-lived"?), and size scales (what is a "high-mass" star and how does it compare to, say, a "dwarf" galaxy?)

Energy: Forms of Energy, Transport of Energy

Energy is one of the most important concepts in physical science. Often, an important part of understanding an astronomical object or process involves asking the questions: How much energy is there? Where does this energy come from? How does this energy get from where it came from to where it's observed? One form of energy that is particularly important to astronomy will receive special focus: light.

The Conflict of Gravity and Motion

Many of the structures we see in the Universe can be viewed as a balance between the attractive force of gravity and the motion that would tend to make things move away from each other. One can describe the solar system in this manner, the orbits of stars in the Galaxy, and even the structure of stars themselves (where it is the atoms that make up the stars which are in motion, providing the pressure that holds up a star). By considering the balance between the two, one can understand what will happen if there is an imbalance, and one can also understand why astronomers believe that most of our Galaxy is made up of dark matter.

How Do We Know?/How Does Astronomy (Science) Work?

Some attention will be given to astronomical techniques and measurements, as well as a more broad-based view of how the process of science decides that something is "wrong" or "likely to be right".

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Format of the Course

The course has two integral parts: a lecture and a laboratory. Note that the lab is note a separate course, but is part of the same course as the lecture. The lab is described in greater detail in the labs portion of this website. The page "How the Labs Work" is the syllabus for the laboratory portion of the course. You will only receive one grade for Astronomy 102, which combines your lecture and lab grades. However, you cannot pass the course without adequately completing the labs.

As discussed on the lab's web page, there will be work you will need to do for the laboratory outside of the actual lab meetings. While it would be possible to complete all of the necessary work for the lab during the designated lab meeting times, realistically several lab meetings will get canceled due to weather. Consequently, you will be expected to perform some observations and calculations on your own time.

Exams

There will be four in-class examinations in addition to the final. You will have the length of the class meeting (50 minutes) to complete an exam. You must complete each examination alone, without consulting others. In-class examinations must be taken in class on the day they are administered. Exams will primarily focus on the most recent material, i.e. the material after that covered on the previous exam up through what was discussed on the Monday before the exam. More details will be given as each exam approaches. Since any part of this course builds on what has gone before, you may need to know some earlier material in order to complete a later exam. You will find that it is usually difficult to study for the material of each exam in isolation.

The final will be cumulative, covering the entire course. It will focus a little bit more on the material introduced after Exam 4, but will include questions on any material in the course. It will be administered at the standard designated time for this course.

Homework Assignments

There will be ten homework assignments, due every Friday starting the first full week of the course (except on days of an exam, and during Thanksgiving Break). Late homework will not be accepted. A homework assignment will cover the material covered in the course up through the Wednesday of the week it is due. Each homework assignment will have three problems which are due. However, there will be one or more extra "review" problems in each homework assignment. You do not have to do these extra review problems, and they will not be graded if you do them. They will be provided simply to give you more practice with the material. Solutions for these extra review problems will be posted at the same time as solutions to the regular homework problems, after the homework has been returned.

Each homework problem will be worth 10 points. You will be given five of these points simply for trying the homework problem. In other words, even if you get the homework problem completely wrong, you will get half credit for making an honest, concerted effort to understand and answer the problem. Do not try to abuse this! Simply writing down the question and quickly pulling something lame out of the air will not earn you the five points; only evidence of true, serious thought about the problem will earn them.

Watch the Announcements page on the course website for updates about homework and exam. The actual homework assigments will be found on the Homework & Exams page.

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Grading

Your grade will be based on the following:

Homework Assignments (9)	20%
In-class Examinations (4)	35%
Final Examination	20%
Laboratory Activities	25%

The grading of the labs is discussed on the page "How the Labs Work".

Your worst exam will be de-weighted; it will only contribute half as much weight to your course grade as each of the other two exams. (If you're keeping track of the numbers, this means that each of your better three exams will be worth 10% of your grade, and your worst exam will be worth only 5% of your grade.)

The final distribution of course grades will probably have an average between 2.7 and 2.9 (on the standard 4.0 scale).

Distribution of Graded Material

Because this is a large class, it is not practical to return graded material during lecture. Unless you specifically request otherwise, all graded material will be returned to you, sorted alphabetically, in open-access "student mailboxes". They are located on the 9th floor of the Physics Building, across from the service elevator next to room SC6902. If you prefer your work returned more privately, send me an E-mail message to make different arrangements.

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Course Schedule

Reading assignments should be completed before the lecture on the indicated day. Where just a chapter or section is listed, you should read the entire chapter or section. Where a page range is also given, you only need to read the specific pages in the indicated section. (Page ranges mean you should start with the section or subsections that begin on the first page, and stop before any section or subsection that would go beyond the indicated page range Note that sometimes a section which starts on the last page does not spill over to the next page, in which case you should read that section. In other words, just use your good sense.) You are, of course, always welcome to read more than is assigned!

Except where noted otherwise, reading assignments are in "21st Century Astronomy".

Regularly check the Announcements page to see if there have been any changes or additions to the reading assignments.

Date	Topic	Reading Assignment
W 8/27	Intro & Overview
F 8/29	The Celestial Sphere; Angular Distances	Math Review; Chapter 1
M 9/1	The Celestial Sphere; Seasons	Sections 2.1-2.2, pp.19-28; Section 2.3 pp.33-34, 37-42
W 9/3	The Ecliptic; Phases of the Moon	Sections 2.4-2.5
F 9/5	Our Solar System	Sections 3.1-3.2, pp.54-59 (all of each page)
M 9/8	Gravity: Newtonian Dynamics	Sections 3.3-3.4
W 9/10	Gravity: Universal Gravitation	Section 3.4; box p. 79
F 9/12	The Conflict of Gravity and Motion in our Solar System	Section 3.5
M 9/15	Parallax	Section 12.2, subsection on parallax (pp. 304-308)
W 9/17	The Stars in our Galaxy	The Stars in our Galaxy
F 9/19	EXAM 1
M 9/22	Light	Sections 4.1-4.2
W 9/24	Flux & Luminosity; Distances	Section 4.6
F 9/26	Forms of Energy; Conservation of Energy; Energy & Atoms	Section 4.4
M 9/29	Energy & Atoms Spectroscopy; The Doppler Shift	Section 4.4
W 10/1	Extrasolar Planets	Section 5.6; The "Other Planetary Systems" section from astronomynotes.com.
F 10/3	Binary Stars	Section 12.3 pp.316-319
M 10/6	Measuring the Galaxy's Rotation	Section 18.1-18.2
W 10/8	Galactic Rotation; Dark Matter	Section 17.4
F 10/10	EXAM 2
M 10/13	The Expansion of the Universe	Sections 19.1-19.2
W 10/15	The Big Bang; The Whole Universe	Sections 19.3-19.4
F 10/17	The Shape of the Universe; Dark Energy	Sections 19.5-19.6
M 10/20	(Fall Break)
W 10/22	Cosmology	(Chapter 19)
F 10/24	Blackbody Radiation; Flux/Luminosity Review	Section 4.5; Sections 12.1-12.3 pp.303-314
M 10/27	Flux / Luminosity / Temperature / Size / Distance
W 10/29	The H-R Diagram	Section 12.3 pp.312-316, pp.319-326 (skip p.320)
F 10/31	Classification of Stars
M 11/3	Energy Generation in Stars; Fusion	Section 13.2 pp.330-333; Section 13.3
W 11/5	Structure of Stars: Gravity vs. Pressure	Section 13.1-13.2 pp.328-330 [1]
F 11/7	EXAM 3
M 11/10	Structure of Stars; Heat Transport	Section 13.2 pp.333-337
W 11/12	Stellar Evolution	The Life and Times of Stars [2]
F 11/14	Red Giants	TBA; Section 15.5 pp.387-392 [2] [3]
M 11/17	Planetary Nebulae; White Dwarves; Novae	Section 15.5 pp.392-397
W 11/19	Supernovae	Section 15.5 pp.397-398; Section 16.3 pp.406-416
F 11/21	Neutron Stars & Black Holes	Section 16.4 (p. 409-416), 16.6 (p. 419-430)
M 11/24	(Thanksgiving)
W 11/26	(Thanksgiving)
F 11/28	(Thanksgiving)
M 12/1	The Cycle of Star Formation and Death; Chemical Enrichment	Section 14.1; Sections 14.3-14.4
W 12/3	Star Clusters; Stellar Populations	Section 16.5
F 12/5	EXAM 4
M 12/8	Other Galaxies	Sections 17.1-17.2 [4]
W 12/10	Wrap-Up and Summary

Note 1: you may also want to read the unassigned parts of Chapter 13. This goes into greater detail about the Sun than you will be responsible for, but it's an interesting look at the only star we can study in close.

Note 2: You may want to read Chapters 15 and 16 in the text. They go into much more detail about all the various stages of stellar evolution than you will be required to know for the course. However, if you are interested, there's a lot of fascinating stuff that goes on with stars. What's more, at least quickly reading all of the various stages may help you have a clearer picture of the overview that you will be responsible for in the course.

Note 3: If you haven't read the rest of Chapter 15, there will be some terms in the assigned reading you aren't familiar with. Basically, all of the following terms refer to stars which are late in their life and have evolved off of the main sequence: Red Giants, Horizontal Branch Stars, Asymptotic Giant Branch (AGB) stars, Supergiants. Don't worry about the fine points of the differences between them. All of these are generically "giant" stars, although certain stars will only go through some of these phases. A "post-AGB star" is a star that's just past all of these various stages.

Note 4: If you're interested in why spiral galaxies have spiral arms, also read Section 17.3