How Binary Companion Stars Impact Stellar Rotational Evolution

Douglas Stephanie T, New York NY

Investigators

Abstract

Stephanie Douglas is awarded an NSF Astronomy and Astrophysics Fellowship to conduct a program of research and education at the Harvard-Smithsonian Center for Astrophysics. Douglas will observe hundreds of binary stars (stars that orbit each other) to measure their physical properties. This will allow a better understanding of how stars---and their effects on planets---change with time. Alongside this research, Douglas will provide astronomy research experiences to middle school students from socioeconomically disadvantaged backgrounds and to undergraduate students from groups underrepresented in science. Douglas will study the relationship between a star's rotation period and the proximity of a companion. Observations of open clusters show that among stars of a given age, the rapid rotators tend to be binaries. This could be because of tidal effects acting over 0.01 - 10 billion years or interactions between the binary companion and the protoplanetary disk during the first 10 million years. Both effects would cause binary stars to rotate faster than single stars, thus affecting angular momentum evolution in the binary systems. Douglas will combine rotation periods and binary orbital parameters to explain why rapidly rotating stars tend to be binaries. Douglas will use photometry, spectroscopy, and light curves to identify candidate binaries as well as new radial velocity observations to measure orbits. These data will allow her to test how binary companions affect stellar rotation over time. For the educational component of her work, Douglas will develop inquiry-based activities to introduce middle school students to binary and exoplanet research. She will also advise undergraduate students from underrepresented backgrounds on projects related to binary and exoplanet research.