SF-08-0009

Resolving the Unresolved: Using QWSSI and DSSI to Resolve Higher-order Multiples in Low-mass Wide Binaries

Zachary David Hartman, Gerard van Belle, Sebastien Lepine, Catherine Clark, Mark Everett

Wide stellar binaries with separation of thousands of au have long been considered instrumental tools for astronomers. Given their prominent role as metallicity and gyrochronology calibrators, it is surprising how little we understand about the properties of these systems and how these systems are formed. What we do know comes from observations of wide, mainly solar-type field binaries, young star-forming regions, and nearby young moving groups. For the higher-order multiplicity fraction, or how many triples, quadruples, etc. there are compared to true binaries, these observations show that as the separation between the widest components in these systems increases, the higher-order multiplicity fraction increases from 50% to higher than 70-80%. However, there has been very little work on determining this fraction for wide low-mass stellar binaries. To begin to correct this, we present the initial results for two speckle imaging surveys using NESSI on the WIYN telescope and QWSSI/DSSI on the Lowell Discovery Telescope. These surveys targeted a selected sample of low-mass wide binaries from the SUPERWIDE Catalog. We combine these results with previous results from Law et al. 2010 and calculate a higher-order multiplicity of 17.8% without taking into account any biases. We further examine the higher-order multiplicity rate as a function of separation and find that we do not see the increase in the higher-order multiplicity that is seen in solar-type wide binaries. This result could have implications for our understanding of wide binary formation in the solar neighborhood for low-mass wide binaries.