ASTR 402
Between the Stars: The Interstellar Medium
Last Offered Spring 2018
Division III Quantitative/Formal Reasoning
This course is not offered in the current catalog

The matter between the stars–the interstellar medium–manifests itself in many interesting and unexpected ways, and, as the detritus of stars, its properties and behavior hold clues to the history and future evolution of both stars and the galaxies that contain them. Stars are accompanied by diffuse matter all through their lifetimes, from their birthplaces in dense molecular clouds, to the stellar winds they eject with varying ferocity as they evolve, to their final fates as they shed their outer layers, whether as planetary nebulae or dazzling supernovae. As these processes go on, they enrich the interstellar medium with the products of the stars’ nuclear fusion. The existence of life on Earth is eloquent evidence of this chemical enrichment. In this course we will study the interstellar medium in its various forms. We will learn about many of the physical mechanisms that produce the radiation we observe from diffuse matter, including radiative ionization and recombination, collisional excitation of “forbidden” lines, collisional ionization, and synchrotron radiation. Applying our understanding of these processes, we will analyze the physical conditions and chemical compositions of a variety of nebulae. This course is observing-intensive. Throughout the semester students will work in small groups to design, carry out, analyze, and critique their own observations of the interstellar medium using the equipment on our observing deck.