Astronomy 16: Modern Astrophysics
Prof. David Cohen
Tu., Th. 11:20 to 12:35
SC 113 (seminar room)
We have a lab on Thursday night (8 pm in SC 187), and a pre-lab assignment and information (see Assignments section, below) that involves choosing a star to observe.
The last colloquium of the semester — and the only astronomy colloquium — is this Friday, December 6 at 12:30 in SC 199. I would like everyone to come. The talk is by Prof. Eliza Kempton, from Grinnell College, and it is about measuring the properties of atmospheres of exoplanets.
We'll have one more homework assignment; out early in the week; due on Wednesday, December 11.
Look over important images (and their explanations) about the Milky Way: The Milky Way in the infrared; and about stellar evolution and end-states: the expanding Crab Nebula in images taken 30 years apart, and a combined X-ray and optical movie of the Crab Nebula Pulsar.
And the slides from Tuesday's class. I've added some annotations/explanations to some of them.
For Thursday's class, finish up Ch. 24, but you can/should just skim secs. 19.5 and 19.6. Don't skip them; you should read them carefully enough to see what quantities can be measured and what other important quantities have to be inferred from the measured quantities and some complicated geometry. All this is with the overall goal of measuring how the orbital speed of objects (really the average of all the stars and gas in a given region) vary with radius (distance form the center of the Galaxy). You should not have to understand every equation in these sections, but you should get enough out of them to be able to understand some simple cases, like the tangent point method on p. 457; and you should be able to explain Fig. 19.15.
Also for Thursday's class, look over the Xeroxed figure from Ch. 17 on the pulsating star, and answer the questions (nothing to hand in) at the bottom. This will give more context to our upcoming delta Scuti lab.
For Tuesday's class, we'll be discussing the first three sections of Ch. 19, with the remainder of the chapter to be discussed on Thursday.
Please read the pre-lab information for our upcoming lab. You should choose a star to observe by Sunday, and email Eric and David with your information (as described in the pre-lab information). Note: Here's the catalog interface for choosing stars.
We'll discuss the Milky Way galaxy on Tuesday in class. Please read Ch. 19 before coming to class.
Check the departmental colloquium schedule. You should come to these talks. They are typically Friday at 12:30 in Rm. 199, and include free pizza (!) You will be required to come to astronomer Eliza Kempton's talk on Friday, December 6, which will be on the atmospheres of extrasolar planets.
There are telescope public viewings the second Tuesday of each month, at the Peter van de Kamp Observatory on the roof of the Science Center. The next one is on December 10, at 8 PM. Astro 16 students are welcome to come and help out. It is also an excellent opportunity to show your friends the observatory and the view of astronomical objects through our telescope.
This page is maintained by David Cohen
cohen -at- astro.swarthmore.edu
Last modified: December 4, 2013