The HI 21-cm Line as a Probe of Stellar Mass Loss and Evolution

This is an observational project to map out the 21-cm emission line of atomic hydrogen in the circumstellar envelopes of nearby Asymptotic Giant Branch (AGB) and Cepheid variable stars in order to better understand stellar mass loss and late stages of stellar evolution. The PI will use data from the Very Large Array (VLA) to provide better estimates of the total mass, extent and chemistry of circumstellar envelopes, new insights into the duration and geometry of mass-loss during the late stages of stellar evolution and new constraints on the occurrence of mass loss on the Cepheid instability strip, as well as better understanding of how evolved stars interact with the surrounding interstellar medium.

Broader impacts include training undergraduate students through the Research Experiences for Undergraduates program, producing an educational podcast on so-called radio stars, making data and data products publicly available, and incorporating research into public lectures.