March Monthly Meeting: “Cepheids”

Location: Zoom + In-Person at First Evangelical Lutheran Church (803 3rd Ave, Longmont, CO 80501)

Summary

In his play Julius Caesar, Shakespeare had Caesar utter the line “I am as constant as the Northern Star.” While poetic, this line isn’t remotely accurate by astronomy standards. Not only does the star that happens to be the “North Star” change over time, the star that is currently the North Star, Polaris, is a Cepheid variable star, a class of variable star that changes in brightness due to the star physically pulsating. Since their discovery in 1784, Cepheids have become one of the most important tools of astronomers, allowing Edwin Hubble to discover that the Universe is expanding, providing important clues about the internal structure of stars, and allowing a way to study the evolution of stars over short time periods. In this talk we will look at what causes Cepheids to pulsate and talk about their important role in modern astronomy.

Bio

Dr. Charles Kuehn is an Associate Professor of Astronomy at the University of Northern Colorado. He earned his B.S. in Astronomy from The Ohio State University and his PhD in Astronomy and Astrophysics from Michigan State University before completing a postdoc at the University of Sydney in Australia. His research focus on the study of variable stars in an effort to understand stellar evolution, the formation of the Milky Way, and to determine the physical properties of stars that host exoplanets. He also engages in astronomy education research aimed to increase the accessibility of astronomy labs at the university level. He is passionate about outreach and runs a quarterly series of physics and astronomy talks at Loveland Aleworks.