PI: Kevin Gullikson, University of Texas, email@example.com
Address: Astronomy Department, 2515 Speedway, Stop C1400, Austin, TX 78712, USA
CoI: Adam Kraus, University of Texas
Title: A Search for Close, Low-Mass Companions to Nearby A and B stars
Abstract: A stars have become high-priority targets for direct-imaging planet searches following the recent discoveries of planets orbiting e.g. HR 8799 and (beta) Pictoris. Close stellar companions to these stars can affect the formation and orbital evolution of any planets, and so a census of the multiplicity properties of nearby intermediate mass stars is needed. To this end, we propose to observe a sample of southern main sequence A- and B-type stars with high signal-to-noise ratio, high- resolution spectroscopy, in order to search for close low-mass companions. We will cross-correlate the spectra we observe against model spectra for F- to M-type secondary stars; a detected companion will appear as a peak in the cross-correlation function. The cross- correlation method is sensitive to mass-ratios q\equiv M_s/M_p \gtrsim 0.06-0.15, and to orbital separations less then a few tens of AU. We will use the binary population we reveal to measure the mass-ratio distribution for intermediate mass stars, which can help distinguish between companions formed through disk fragmentation and molecular core fragmentation.
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