Radio Stars: Secrets of Cepheids

For roughly a century, Cepheid variable stars have been used as a yardstick for measuring the scale of the universe. Cepheids undergo steady pulsations, causing their brightness to undergo regular variations. Because the exact period of these brightness fluctuations is tightly linked with the stellar luminosity, measurement of a Cepheid's period and apparent brightness provides a direct way to gauge its distance. But are the lives of Cepheids truly as regular and predictable as they seem?

Learn in this podcast how recent radio and infrared observations have revealed that at least some Cepheids have a "dirty" secret: they are quietly spewing significant amounts of matter into space through stellar winds.