Ay 20
Basic Astronomy and the Galaxy

(Fall Term 2015-2016)

Instructor: Professor Lynne Hillenbrand (218 Cahill, 395-6587, lah@astro )
Office Hours: by arrangement, or any time my office door is open

Class Time:

The class meets in 219 Cahill on M 9-10 am ; W 9-10 am; and F 2-3 pm

TA : graduate student Jacob Jencson (255 Cahill, jj@astro )
Office Hours: Monday 2-3pm likely in the 219 classroom (also by arrangement)

Textbook: An Introduction to Modern Astrophysics by Bradley W. Carroll and Dale A. Ostlie.

This is available on reserve in the library, but if you plan on taking other courses in astronomy at any time in the future, the text is a highly recommended purchase.

Other suitable books at our level are the following, if you would like supplemental reference material.
-- Fundamental Astronomy by H. Karttunen et al.
-- Astronomy: A Physical Perspective by M.L. Kutner
-- Astrophysics in a Nutshell by D. Maoz

The course syllabus


This is the sophomore level general introduction to astronomy and astrophysics at Caltech that is required for Ay majors, and serves as a pre-requisite course to our upper level Ay 101 and Ay 102 courses.

Ay20 (basic astronomy and the galaxy) is recommended before Ay21 (galaxies and cosmology), but this sequencing is not required.


Grading will be based on weekly homework sets, an oral midterm, and a written closed-book final exam.
On homeworks, you may discuss problems with your classmates since the point is for everyone to learn the material. However, the work you turn in must be your own, and you should be aware that final grades will have a component reflecting your performance relative to the class.

Announcements and Current Events

***This just in, relevant to week 9 material: Discovery of most distant object in the solar system

A research paper on formation of the solar system in a star cluster (look at sections 1 and 2 for an overview with some more details than I mentioned in class)

Hopefully you saw the 27 September total lunar eclipse visible from pasadena

Homework Assignments

Problem sets will be roughly weekly, and the class voted on Tuesday as the due day. The cutoff time for having your solutions in my mailbox (around the corner from the classroom, to the right) is 6pm.

PS 1 - due 6 October

PS 2 - due 13 October
NOTE: as discussed in class, problem 4a is extra credit, and probably should be completed last in the sequence rather than first!

PS 3 - due 20 October

PS 4 - due 27 October
NOTE: the last two problems require some calculation and then some plotting, so allow yourself sufficient time for the latter. and please try to use a real programming language / tool that makes decent plots (rather than e.g. ms/excel)

PS 5 - due 3 November

PS 6 - due 10 November

PS 7 - due 17 November

PS 8 - due 24 November

PS 9 - due 1 December
NOTE: there is a second page

Material from Class

Copies in .pdf of the material shown in class are below or can be sent by email upon request. These are provided for the benefit of Ay20 student education, and are not meant for general distribution since some of the figures and other info is gathered from original references that are not always attributed.

week 1 intro and classical astronomy (22 MB)

week 2 part 1 magnitudes, colors, spectral lines (6 MB)

week 2 part 2 telescopes and instruments (20 MB)

week 3 star basics (14 MB)

weeks 4 and 5 stellar physics (20 MB)

week 6 ism and star/planet formation (19 MB)

week 7 orbits and binaries (7 MB)

week 8 stellar evolution and remnants (19 MB)

week 9 solar system (15 MB)

week 10 galaxy (38 MB)

Supplemental Material

Broaden your horizons with the Astronomy Picture of the Day

Current images of the Sun

Refresher on basic geometric optics

Get to know Planck's Law

Applet for the Maxwell-Boltzmann distribution

Applets from Cornell on stellar parallax, binary stars, and stellar evolution

Model stellar atmospheres with GrayStar or older version.
(click "model" towards the bottom then change some of the parameters and see what happens)

An eclipsing binary simulator illustrating lightcurves and projected orbits for different binary configurations.

Another binary simulator illustrating radial velocity curves for the particular case of planets, i.e. large mass ratio binary systems.

Artist's rendition of the evolution of a close, and then interacting, binary system.

The crab pulsar movie.

Last updated October 4, 2015 by LAH