Interacting Binaries: Mass Transfer and Common Envelope Evolution

University Of Rochester, Rochester NY

Investigators

Abstract

More than half of the stars in the night sky come with siblings. Instead of maturing through their birth, middle age and death alone, they live their lives with one or more companion stars. "Binary stars", where two stars progress through their life cycle together, are the most common form of multiple star systems. The investigators seek to understand the final stages of the binary star life cycle, where the smaller star plunges into the atmosphere of the larger one leading to the spectacular phenomena called Common Envelope Evolution (CEE). The CEE stage is one of the most difficult to understand and one of the most important stages of the binary star life cycle. It is important because many of the Universe?s strangest and most exotic phenomena come from the Common Envelope stage. The most famous recent example of a CEE event was the Black Hole-Black Hole merger, which made headlines across the world after being observed via gravitational waves with the NSF funded LIGO project. Modeling CEE requires the most sophisticated supercomputer simulations because the process is so violent and occurs so quickly. The investigators will use a newly developed supercomputer code to reveal new details of CEE and resolve long-standing mysteries about how the binary stars quickly shrink their orbit and drive huge amounts of material into space. Their work will be closely tied to observations via their codes' ability to produce "synthetic observations" that can be directly compared with what is seen on the sky. In addition, the investigators will bring this research to the public through articles written for popular and on-line magazines. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.