Angular Momentum in Solar-Type Stars

Binary Populations and Stellar Rotation: Angular momentum is one of the key physical outcomes of the star formation process. Indeed one of the challenges of the star formation problem is the decrease in angular momentum from molecular clouds to single stars, a challenge that is likely solved largely by distributing excess angular momentum in binaries and clusters.

Thereafter the life history of a star is marked by angular momentum loss from winds … except in binary stars where angular momentum can be transferred in both directions between orbits and the rotation of stars. One component of our research studies the evolution of stellar angular momentum, both within and outside of binaries, with special emphasis on the evaluation of the powerful Eccentricity – log Period diagrams.

Our binary searches inevitably discover eclipsing binaries, which allow fundamental measurements of masses, radii and distances. Each of these make excellent student projects.

Both our studies of angular momentum and eclipsing binaries have entered a new regime with the advent of the Kepler satellite, and members of our team are co-investigators on several GTO and GO programs with Kepler.

Current student work:

  • K. Milliman, WIYN Observatory – Orbit solutions for binary population of the Kepler cluster NGC 6819.
  • J. Penn, WIYN Observatory – Synthetic spectra analyses of eclipsing binaries
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