Poster Abstracts

Name/Affiliation:  Kevin Gullikson (University of Texas)

Title:  A Search for Disk-Born Stellar Companions

Abstract:
Most stars form in binary or multiple systems through either the core fragmentation or circumstellar disk fragmentation mechanisms. While simulations of these processes can not yet follow the systems to a steady state, disk fragmentation tends to generate companions with a lower mass than core fragmentation. Disks around young intermediate-mass stars are massive enough to create low-mass stellar companions, like a scaled-up version of disk-instability planet formation. We will describe a survey of nearby main sequence A and B-type stars in which we specifically look for K/M companions within $\sim 100$ AU. We use high signal-to-noise ratio, high resolution echelle spectra to search directly for the spectral lines of the secondary. This method can detect lower-mass companions than current adaptive optics imaging or radial velocity monitoring for companions from 20-50 AU for most stars in our sample, where we expect a population of disk-born companions may reside. In addition, the high signal-to-noise ratio measurements allow us to constrain the temperature of known single-lined spectroscopic binary companions. We will discuss early results of our survey, which is nearly complete for B stars.