Spin-Orbit Alignment in Binary Stars

Massachusetts Institute Of Technology, Cambridge MA

Investigators

Abstract

This award will support an observational project that will address how close binary stars form and evolve. Various formation scenarios lead to differing expectations about whether the spin axes of the stars are aligned with the orbital axis (for example, the Earth's spin axis is about 23 degrees away from the orbital axis.) The project will perform a statistical analysis on 50 eclipsing binaries discovered in the Kepler survey, and will conduct detailed time-series spectroscopy of a dozen brighter systems. The latter will make use of the Rossiter-McLaughlin effect, which produces changes in the observed spectra of one member of a binary system as the other star passes in front of it. Careful measurement of the effect can determine the projection of the spin-orbit axis misalignment on the sky. The research project is expected to help interpret the recent discoveries of exoplanets on highly tilted orbits. Integrated with this research program are training opportunities for students and a postdoctoral associate, as well as efforts to increase the public understanding of science.