Speaker: Professor Jeremy Lim (University of Hong Kong)

Time: 15:00pm, Monday (July 20, 2009)

Place: small conference room, 3rd floor

Abstract:

Most Sun-like stars form as members of binary or multiple systems. Yet, although we have an observationally-supported theoretical framework for how single Sun-like stars form, we lack a commonly accepted framework for how Sun-like stars in binary or multiple systems form. In this presentation, I briefly describe the two most commonly invoked scenarios for how binary/multiple protostellar systems form - fragmentation versus capture. These models make very different predictions for the properties of the resultant protostellar system that can be tested observationally. We compare these model predictions with our very high angular resolution study of the binary protostellar system L1551 IRS5, one of the best studied and closest protostellar system. We show that this system is likely a triple, and that the two main protostellar components have properties consistent with their formation via fragmentation in the inner region of their parent molecular condensation. We also present tentative results for accretion streams feeding the two main protostellar components from their surrounding condensation. We conclude with a brief summary of ongoing work, and plans for future studies with the EVLA and ALMA.