There is a long-standing discrepancy regarding the mass distribution of close companions around massive stars. Knowing the companions' masses and orbital characteristics is crucial for understanding massive star formation, evolution, and the progenitor populations of X-ray binaries and gamma-ray bursts. To resolve this discrepancy, the principle investigator will lead a team of graduate students, undergraduate students, school teachers and their students on a 3-year program, ideally suited to the capabilities of Wyoming's 2.3 m telescope, to measure the frequencies, mass ratios and orbital separations of a complete sample of massive stars in the young and populous Cygnus OB2 association. The team will increase the field of view on Wyoming's telescope and perform an optical photometric variability search for eclipsing binaries among the hundreds of massive stars in the association, and continue a radial velocity survey of a complete sample of about 140 massive stars in Cygnus OB2, extending the time base, and beginning to measure their periods and mass ratios. The multi-epoch spectra will be published as an online database available to the community.
Broader Impact. This program will answer fundamental astrophysical questions while involving students and teachers from largely-rural communities and native-American schools in all aspects of astronomy research from optics and data analysis to the presentation of results. This is part of a long-term effort to modernize the basic science & technology infrastructure at the University of Wyoming Physics & Astronomy Department. The Wyoming Space Camp, a modular, long-term education/research enterprise where Wyoming's science teachers, classes, and college students participate in real science will also be initiated. The Space Camp program promotes the National Academy of Sciences standards and the Wyoming Grade 8 Science Content and Performance Standards
