# Courses

### ASTR 040 - Expanding Ideas of Time and Space

Discussions on astronomy, and the nature of time and space. Topics include the shape and contents of the universe, special and general relativity, dark and light matter, and dark energy. Observations and ideas fundamental to astronomers’ current model of an expanding and accelerating four-dimensional universe.

Enrollment limited to first-year students. Preregistration required; see under First-Year Seminar Program.

### ASTR 110 - Planets and Stars

Astronomy introduction to stars and planetary systems. Topics include the solar system and extrasolar planets, planet and stellar formation, and the evolution of stars from birth to death.

No prerequisite other than a working knowledge of elementary algebra.

### ASTR 155 - Introduction to Astronomical Observing

A hands-on introduction to techniques used in astronomy to observe astronomical objects. Observations of planets, stars, and galaxies using on-campus facilities and remote observing with Yale’s research telescopes. Use of electronic detectors and computer-aided data processing.

Evening laboratory hours required. One previous college-level science laboratory or astronomy course recommended.

### ASTR 180 - Introduction to Relativity and Black Holes

Introduction to the theories of special and general relativity, and to relativistic astronomy and astrophysics. Topics include time dilation and length contraction; mass-energy equivalence; space-time curvature; black holes; wormholes; pulsars; quasars; gravitational waves; Hawking radiation. For students not majoring in the physical sciences; some previous acquaintance with high-school physics and/or calculus may be helpful, but is not required.

### ASTR 210 - Stars and Their Evolution

Foundations of astronomy and astrophysics, focusing on an intensive introduction to stars. Nuclear processes and element production, stellar evolution, stellar deaths and supernova explosions, and stellar remnants including white dwarfs, neutron stars, and black holes. A close look at our nearest star, the sun. How extrasolar planets are studied; the results of such studies.

Prerequisite: a strong background in high school calculus and physics. May not be taken after ASTR 220.

### ASTR 255 - Research Methods in Astrophysics

An introduction to research methods in astronomy and astrophysics. The acquisition and analysis of astrophysical data, including the design and use of ground- and space-based telescopes, computational manipulation of digitized images and spectra, and confrontation of data with theoretical models. Examples taken from current research at Yale and elsewhere. Use of the Python programming language.

Prerequisite: background in high school calculus and physics. No previous programming experience required.

### ASTR 320 - Physical Processes in Astronomy

Introduction to the physics required for understanding current astronomical problems. Topics include basic equations of stellar structure, stellar and cosmic nucleosynthesis, radiative transfer, gas dynamics, and stellar dynamics. Numerical methods for solving these equations.

Prerequisites: MATH 120 and PHYS 201 or equivalents, or permission of instructor. Previous experience with computer programming recommended.

### ASTR 420 - Computational Methods for Astrophysics

The analytic, numerical, and computational tools necessary for effective research in astrophysics and related disciplines. Topics include numerical solutions to differential equations, spectral methods, and Monte Carlo simulations. Applications to common astrophysical problems including fluids and N-body simulations.

Prerequisites: ASTR 320, MATH 120, 222 or 225, and 246.

### ASTR 450 - Stellar Astrophysics

The physics of stellar atmospheres and interiors. Topics include the basic equations of stellar structure, nuclear processes, stellar evolution, white dwarfs, and neutron stars.

Prerequisites: PHYS 201 and MATH 120.

### ASTR 520 - Computational Methods in Astrophysics and Geophysics

The analytic and numerical/computational tools necessary for effective research in astronomy, geophysics, and related disciplines. Topics include numerical solutions to differential equations, spectral methods, and Monte Carlo simulations. Applications are made to common astrophysical and geophysical problems including fluids and N-body simulations.

### ASTR 550 - Stellar Astrophysics

An introduction to the physics of stellar atmospheres and interiors. The basic equations of stellar structure, nuclear processes, stellar evolution, white dwarfs, and neutron stars.

### ASTR 580 - Research

By arrangement with faculty.

### ASTR 600 - Cosmology

A comprehensive introduction to cosmology at the graduate level. The standard paradigm for the formation, growth, and evolution of structure in the universe is covered in detail. Topics include the inflationary origin of density fluctuations; the thermodynamics of the early universe; assembly of structure at late times and current status of observations. The basics of general relativity required to understand essential topics in cosmology are covered.

Advanced undergraduates may register for the course with permission of the instructor.

### ASTR 610 - The Theory of Galaxy Formation

This astronomy course focuses on the physical processes associated with galaxy formation. Topics include Newtonian perturbation theory, the spherical collapse model, formation and structure of dark matter haloes (including Press-Schechter theory), the virial theorem, gravitational interactions, cooling processes, theory of star formation, feedback processes, and numerical simulations. The course also includes a detailed treatment of statistical tools used to describe the large-scale distribution of galaxies and introduces the student to the concepts of galaxy bias and halo occupation modeling. During the final lectures we discuss a number of outstanding issues in galaxy formation.

### ASTR 666 - Statistical Thermodynamics for Astrophysics and Geophysics

Classical thermodynamics is derived from statistical thermodynamics. Using the multi-particle nature of physical systems, we derive ergodicity, the central limit theorem, and the elemental description of the second law of thermodynamics. We then develop kinetics, transport theory, and reciprocity from the linear thermodynamics of irreversible processes. Topics of focus include Onsager reciprocal relations, the Fokker-Planck equation, stability in the sense of Lyapunov, and time invariance symmetry. We explore phenomena that are of direct relevance to astrophysical and geophysical settings. No quantum mechanics is necessary as a prerequisite.

### ASTR 710 - Professional Seminar

A weekly seminar covering science and professional issues in astronomy and ethics.