Astronomy 320: Spring 2021

Theoretical Astrophysics

1st galaxies: gas density (Ricotti, Parry & Gnedin 2016)

Modern astronomy has its roots firmly grounded in the fundamental principles of physics (both classical and quantum). Furthermore, many branches of physics as we know them today trace their origins to the search for universal physical laws to explain natural phenomena discovered and analyzed by astronomers.

The goal of theoretical astrophysics is to provide physical and conceptual understanding of the diverse systems that represent our universe. Introductory astronomy courses are often organized by scale (planets, stars, galaxies and the universe as a whole) and observational astronomy courses are often organized by wavelength because of the different technologies. To emphasize the different approach needed for developing a theoretical framework, this course is organized into themes of governing physical principles. For each of the three main themes (gravity, gas physics and quantum physics), we start with fundamental principles and then discuss applications in various astronomical contexts. We will also discuss systems in which several principles interact synergistically and demonstrate how astrophysical theories are developed by successive model refinements and confrontation with data. We will show how application of simple physical laws can explain the observed properties of an astounding range of astronomical objects!

I will assume a basic knowledge of astronomical concepts (up to the ASTR120/ASTR121 level) as well as basic physics (up to the PHYS270/PHYS271/PHYS273 level)

Schedule

    Instructor:  		Massimo Ricotti
    Class:       		Online
    Lectures:    		Tuesday and Thursday from 11:00pm to 12:15pm
    First class: 		Tue Jan 26 
    Last  class: 		Tue May 11 
    TA:		 		Harrison Agrusa 
    Reading session (w/Harrison): Wednesday from 1:00pm to 1:50pm (online)
    First reading session: 	Wed Feb 3

What's New?

Jan 26: First class

Feb 3: Reading session (introduction of Harrison Agrusa)

Contact info and Notes

Office: Physical Sciences Complex (PSC) 1156
E-mail: ricotti "at" astro "dot" umd "dot" edu
Phone: (301) 405 5097
Office hours: TBD
Class web page: http://www.astro.umd.edu/~ricotti/NEWWEB/teaching/ASTR320_21.html
TA: Harrison Agrusa
Office: PSC
E-mail: hagrusa "at" astro "dot" umd "dot" edu
Office hours: TBD

Course Outline

The Syllabus is available on ELMS and here PDF format.

	Date	Lecture

GRAVITY (notes)
#1	Jan 26	Introduction; Recap of Newton’s laws and the conservation of momentum
#2	Jan 28	Newtonian gravity
#3	Feb 2	One body problem - conservation laws and constants of motion
#4	Feb 4	One body problem - solving the equation of motion
#5	Feb 9	One body problem - derivation of Kepler's Laws
#6	Feb 11	One body problem - cont.
#7	Feb 16	Two-body problems and binary systems (notes)
#8	Feb 18	In class execise: LOS velocity and mass function
#9	Feb 23	Two + one (restricted three) body problem - Lagrange points
#10	Feb 25	Two + one (restricted three) body problem - Effective potential
#11	Mar 2	In class exercise: Lagrange L3
#12	Mar 4	N-body dynamics - the virial theorem
#13	Mar 9	N-body dynamics - applications of the virial theorem Pressure and the concept of hydrostatic equilibrium
-	Mar 11	MIDTERM (in class)
-	Mar 16	SPRING BREAK
-	Mar 18	SPRING BREAK
#14	Mar 23	N-body dynamics - two body relaxation
GAS PHYSICS (notes)
#15	Mar 25	Pressure and the concept of hydrostatic equilibrium
#16	Mar 30	Atmospheres in an external gravitational field
#17	Apr 1	Self-gravitating atmospheres
#18	Apr 6	Introduction to thermodynamics and statistical mechanics
#19	Apr 8	Statistical mechanics of ideal gas
#20	Apr 13	Radiation gases
#21	Apr 15	Radiation gases (cont) and applications to Cosmology
#22	Apr 20	Brief introduction to hydrodynamics
QUANTUM PHYSICS (notes)
#23	Apr 22	The Bohr model of the atom
#24	Apr 27	Particle wave duality and particle in a box
#25	Apr 29	Fermions and bosons; Fermi-Dirac and Bose-Einstein statistics
#26	May 4	Degeneracy pressure and while dwarf
#27	May 6	Type-1a supernovae and neutron stars
#28	May 11	Review
-	May 13	Final exam (format and time TBD)

Textbooks

No textbooks are required for this course.
I will use my own class notes that I will hand out and are available for download on ELMS. Since the course is organized by topics, there are no textbooks that follow the structure of this course. You can find some of the topics that will be covered in introductory astrophysics texts. Two of them, on which you may find some useful material are the following:
These books are merely listed for your convenience, but you do not need to buy either of them. In addition a lot of useful material can be found on the web, including Wikipedia. However, keep in mind that some of the derivations or homework you will be exposed to in this class, are meant to introduce you to research in astrophysics and problem solving, so you will not find all the answers on books or on the web.

Class #1	Newton's laws of motion Momentum and conservation of momentum
Class #2	Noether's theorem Gauss's law Newton's shell theorem
Discussion Section #7	Problem related to perturbation theory (Bungee Cord) Note: we skipped perturbation theory in class, hence this topic will NOT be on the Midterm or Final
Class #8	Binary stars
Class #9	Class notes on Lagrange Points Lagrangian points Hill sphere
Class #24 and #25	Chandrasekhar limit Type Ia supernova Core collapse supernova