ASTRONOMY 353 - SPRING 2011
ASTROPHYSICS

Unique No. 48305

Course Web Page

Course information including important announcements, homework assignments, homework solutions, and lecture notes will be made available within the University’s Blackboard Learning System: https://courses.utexas.edu

Instructor

Dr. Milos Milosavljevic
Office location: RLM 17.220
Phone and voice mail: (512) 471-3397
Email: milos@astro.as.utexas.edu

Teaching Assistants

Sinclaire Manning
Office location: RLM 16.226C
Phone: (512) 232-3958
Email: smanning@astro.as.utexas.edu

TA Help Sessions: Tuesdays 5-6 p.m.
Help Session Location: RLM 15.216b

COURSE OBJECTIVES

The course introduces astronomy, physics, and other science and engineering majors to fundamental astrophysical concepts and their applications. The concepts are developed from first principles, thus linking the elementary physics curriculum (classical and quantum mechanics, electromagnetism, thermodynamics) to a diversity of astrophysical phenomena. The material is introduced both rigorously and with order-of-magnitude and dimensional analysis techniques. The lectures are interactive and are designed to foster proficiency in independent physical reasoning and mathematical modeling. Where possible, connections to current research problems will be highlighted.

This course carries the Quantitative Reasoning flag. Quantitative Reasoning courses are designed to equip you with skills that are necessary for understanding the types of quantitative arguments you will encounter in your adult and professional life. You should therefore expect a substantial portion of your grade to come from your use of quantitative skills to analyze quantitative problems.

TOPICS

  1. Introduction to the course
    1. What this course is, and what it is not
  2. The physics of light
    1. Classical and quantum aspects of electromagnetic radiation
    2. Black body radiation: The Planck law and the Stefan-Boltzmann law (Maoz 2.1)1
    3. The interaction of light with atoms (Maoz 2.2)
    4. Sources of light in the universe
    5. What do astronomical spectra tell us about the astrophysics of the universe?
  3. The equilibrium structure of stars (Maoz 3.1)
    1. Collapse and free fall
    2. Hydrostatic equilibrium
    3. The virial theorem and "negative specific heat"
    4. What else do we need to understand about stars?
  4. Radiative energy transport
    1. Scattering and absorption-emission of photons (Maoz 3.7)
    2. Photoionization in stellar atmospheres
    3. Random walks and the equation of radiative transfer (Maoz 3.3)
    4. Conservation of energy and momentum (Maoz 3.4)
    5. The equations of stellar structure (Maoz 3.5)
    6. Kelvin-Helmholtz timescale (Maoz 3.9)
    7. The Eddington limit (Maoz 4.6)
  5. Thermodynamics of stellar matter: the classical limit
    1. Special theory of relativity
    2. Thermodynamics of ideal gases containing particles and radiation
    3. The equations of state (Maoz 3.6)
    4. The structure of stars containing classical matter and radiation (Maoz 3.8)
    5. The maximum mass of stars
  6. Nuclear energy production in stars
    1. Mass-energy duality
    2. The Coulomb barrier (Maoz 3.9)
    3. Quantum mechanical tunneling and the Gamow energy (Maoz 3.9)
    4. The Maxwell-Boltzmann tail (Maoz 3.10)
    5. The cross section for fusion interaction (Maoz 3.10)
    6. Energy production in fusion (Maoz 3.10)
    7. Stellar thermoregulation
    8. Types of nuclear fusion in stars (Maoz 4.1)
    9. The origin of the elements
  7. Convection (Maoz 3.12)
    1. Stable and unstable buoyancy
    2. The motion of a buoyantly unstable blob
    3. Computer simulations of convection
    4. Convective heat transport
    5. Radiative and convective zones in stars of different masses
  8. Thermodynamics of stellar matter: the quantum limit (Maoz 4.2)
    1. Pauli exclusion principle and the Fermi-Dirac statistics
    2. Statistical mechanics of a fermion gas
    3. Fermi energy and momentum, and degeneracy
    4. The minimum mass of a main sequence star
    5. The white-dwarf mass-radius relation
    6. White dwarf cooling
    7. The Chandrasekhar limit
  9. Stellar evolution and stellar remnants
    1. The main sequence (Maoz 4.1)
    2. Post-main-sequence evolution (Maoz 4.1)
    3. Core collapse and supernovae (Maoz 4.3)
    4. Neutron stars (Maoz 4.3 and 4.4)
    5. General relativity and black holes (Maoz 4.5)
    6. Accretion disks (Maoz 4.6)
  10. Stellar ecology
    1. Star formation (Maoz 5.1)
    2. Planet formation (Maoz 5.1)
    3. Environmental impact of stars (Maoz 5.2)
    4. Stellar habitat in the interstellar medium (Maoz 5.3)
    5. Nucleosynthesis and galactic chemical evolution
  11. What to learn next?
    1. Planets
    2. Galaxies (see also Maoz 6)
    3. Cosmology (see also Maoz 7–9)

1Section numbers in parentheses refer to the course textbook, Astrophysics in a Nutshell, by Dan Maoz, and should serve as a reading guide. Lectures will cover significantly more material than the textbook. Typewritten lecture notes will be provided especially for topics not extensively discussed in the textbook.

PREREQUISITES, LECTURES, HELP SESSIONS, OFFICE HOURS, AND STUDENTS WITH DISABILITIES

Prerequisites

To take Astronomy 353, you should have taken calculus and multivariable calculus, and should have taken calculus-based courses in classical mechanics and in electromagnetism at the level of the standard physics major curriculum. Hands-on experience with ordinary and partial differential equations is also assumed.

Hours and Venue

The class meets in Robert Lee Moore Hall (RLM) 15.216b on Tuesdays and Thursdays at 12:30-1:45 p.m.

Help Sessions

TA study sessions will be provided weekly in Robert Lee Moore Hall (RLM) 15.216b on Tuesdays at 5-6 p.m.

Office Hours

Instructor office hours: Mondays 1-2 p.m. and Thursdays 2-3 p.m., or by appointment, in RLM 17.214.

Students with Disabilities

Students with disabilities may request appropriate academic accommodations from the Division of Diversity and Community Engagement, Services for Students with Disabilities, 471-6259.

TEXTBOOKS

Required Textbooks

Astrophysics in a Nutshell, Dan Maoz (Princeton)

Recommended Reading (On Reserve at Physics, Mathematics, and Astronomy Library)

The Physics of Stars, Second Edition, by A. C. Phillips (Wiley)
An Introduction to Stellar Astrophysics, by Francis LeBlanc (Wiley)

EXAMS AND GRADING

Exams

There will be 2 in-class midterm exams, on February 24 and April 7, and a comprehensive final exam on May 14 at 2 p.m.

The final will count 30% toward the final grade, and each of the midterms will count 15% toward the final grade.

Please bring a calculator to each of the exams! You will need a calculator and we will not be able to provide any.

Homework

There will be weekly homework assignments due on Thursdays, with the exception of the first week and the midterm exam weeks. The cumulative homework assignment grade will count 35% toward the final grade

You are encouraged to collaborate on the homework assignments in groups, but you must write the final answers on your own.

Attendance

Class attendance will count 5% toward the final grade.

Calculation of the grade

Component

Maximum Score

Midterms

2 × 15% = 30%

Weekly homework assignments

35%

Final exam

30%

Attendance

5%

Total

100%

Score Range

Grade

85% ≤ S ≤ 100%

A

70% ≤ S < 85%

B

55% ≤ S < 70%

C