Physics 341
Principles of Astrophysics
Fall 2009

Description

Astrophysics is the application of physical principles to astronomical systems. In Physics 341 and 342 you will learn how to use gravity, electromagnetism, and atomic, nuclear, and gas physics to understand planets, stars, galaxies, dark matter, and the Universe as a whole. Gravity is the dominant force in many astronomical systems, and it will be our focus in Physics 341.

Some astrophysical systems are described by equations that are fairly easy to solve, and we will certainly study them. However, many interesting systems cannot be solved exactly. Nevertheless, we can often use physical insight and approximate calculations to understand the salient features of a system without sweating the details. One goal of the course is to develop that skill. As you will see, it will take us very far (through the whole Universe, in fact!) Another goal is to learn about recent advances in astrophysics, a very dynamic field of research.

Prerequisites for this class are two semesters of physics and two semesters of calculus. I will briefly review physical principles as we need them, but assume that you have seen them before. I will also assume familiarity with vector calculus. Some of the assignments may involve a bit of computation that can be done with programs like Excel, Google Spreadsheets, Maple, Matlab, or Mathematica.

The main textbook we will use for both Physics 341 and 342 is An Introduction to Modern Astrophysics (2nd edition) by Bradley W. Carroll and Dale A. Ostlie (affectionately known as the Big Orange Book). It provides a broad survey of astrophysics and covers the basics well. I will also draw from other sources as well, letting you know when I do.

Contact Information

Prof. Saurabh W Jha
Room 315, Serin Physics Building (across Allison Road from the classroom), Busch campus
Email: nosaurabhspam@nospam.physics.rutgers.edu
Phone: 732-445-5500 ext. 6979

Office hours: Wednesdays 2-3:30pm, or by appointment

Grading Policy

Grading will be based on problem sets (70%), the take-home final exam (25%), and an in-class quiz on October 15 (5%). A final grade of 90% or higher will guarantee you an A.

Weekly problem sets will be handed out on Thursdays, and will be due the following Thursday in class. Problem sets can also be turned in to my mailbox on the second floor of Serin by Thursday at 4:30pm (the door is locked after that), or by emailing me your solutions before 4:30pm. It is your responsibility to meet the deadline! No late assignments will be accepted. No exceptions. I will drop your two lowest problem set scores in calculating your final grade. While that means you could skip two problem sets and still get a perfect score, experience has shown it is much better for your grade to turn in all of them and have the lowest scores dropped.

You are encouraged to work in groups on the problem sets, but your write-up of the solutions must be your own. You must write down the names of your collaborators on your write-up. You must also cite any external sources you use (other than the class notes I post or the texbook). You may not refer to notes, assignments, or solutions, from previous years of Physics 341 or 342.

The take-home final will be due at 4pm on December 11.

Schedule: Topics and Assignments

This syllabus may be modified as the semester progresses. PDF versions of the lecture notes are available by clicking on the links in the Date column. Links are also available for the assignments and solutions. Some of these require the username and password given out in class (e-mail me if you need them).

Resources

Here are some web resources you may find illuminating or indispensable:

• a list of useful constants, in cgs units
• the Astronomy Picture of the Day
• public observing nights at the Robert A. Schommer Observatory (on the 4th floor of Serin) on the 2nd and 4th Thursday of every month (when the weather is clear)
• binary star applets:
  • a binary star orbit Java applet written by Prof. Mike Guidry, University of Tennessee
  • another binary star orbit applet, by Prof. Joachim Köppen, University of Strasbourg (click "primary" to see the orbit relative to one of the stars)
  • yet another binary star applet, by Prof. Terry Herter, Cornell (here you can change the orientation and see the Doppler shifts)
  • an eclipsing binary applet, also by Prof. Terry Herter, Cornell (note the defintion of the inclination angle is flipped compared to the other applet and what we used in class)
• three-body links:
  • chaos in the three-body problem, a Flash applet by Prof. David Harrison, University of Toronto. In class I showed 3 planets, starting at x=0.6, with the mass of Sun 1 first set to zero (to show the closed orbits) and then set to 1.0 (showing the chaos)
  • remarkable three-body motions, by Prof. Eugene Butikov at St. Petersburg State University. Collection 6 is what I showed in class, but I found collections 2, 4, and 5, also quite... remarkable
  • Langrange points applet, by Prof. Robert Vanderbei at Princeton University. In class I showed the "instances" (use the drop down menu) L1-L5 M/m=2 (try changing the "warp" to 40, with dt = 1.0E-6; also set the frame rotation rate = 289.5 to switch to a frame that rotates with the binary period) and instance L1-L5 M/m=40 (in which L4 and L5 are stable, use dt = 1.0E-6 and change the warp from 20 to 200 to 2000; a frame rotation rate of 423.4 will keep the stars approximately fixed). Prof. Vanderbei has many other simulations, including really neat ones that are in 3-d if you cross your eyes!

Other Items

Students with disabilities should consult the department policy.

Students will be held to the Rutgers policy on academic integrity.

Astrophysics at Rutgers • Department of Physics and Astronomy • Rutgers University

Last updated: November 5, 2009 swj