NOAO >   Observing Info >   Approved Programs >   2012B-0130

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Proposal Information for 2012B-0130


PI: Saurav Dhital, Vanderbilt University, saurav.dhital@vanderbilt.edu
Address: Physics Department, 6301 Stevenson Ctr, Nashville, TN 37235, USA

CoI: Nicholas Law, University of Toronto
CoI: Andrew A. West, Boston University
CoI: Keivan G. Stassun, Vanderbilt University
CoI: Adam L. Kraus, University of Hawaii

Title: The Extremely Extreme: Searching for Companions in Wide M-dwarf Binaries

Abstract: We propose to complete a Gemini LGS-AO search for hierarchical close companions in ultra-wide M dwarf binaries. While a large number of such ultra-wide binaries have been identified, formation scenarios generally cannot account for systems that are as wide as most prestellar clouds. The \slowpokes wide binary sample indicates the presence of a bimodal population in physical separation, perhaps delineated by dynamical interactions. Our KECK+Palomar initial followup observations have also revealed that binaries with the largest separations are more likely to harbor a third, close companion. There is tantalizing evidence that the widest systems are formed via a different mechanism, perhaps by dynamical capture during the dissolution of open clusters as has been suggested by recent numerical simulations. Our proposed Gemini observations will double our sample size and push our study to 2\times lower total masses and to systems that are at 5\times larger separations, probing a more extreme population of wide binaries. With a robust measurement of hierarchical multiplicity in wide binaries and their orbital separations, we will constrain the formation scenarios and inform our understanding of star formation.


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