Observing Binary Stars with the Differential Speckle Survey Instrument at Apache Point: A Status Report

Stellar multiplicity surveys play a crucial role in understanding the formation and evolution of binary and multiple star systems. In this study, we present some of the latest results from data obtained using the Differential Speckle Survey Instrument (DSSI), which was moved to the ARC 3.5-m telescope at Apache Point Observatory in New Mexico in 2022 and is currently available as a visitor instrument there. Through our speckle data reduction techniques, we produce diffraction-limited images of our target stars in multiple wavelengths. For binary star observations, systems brighter than V=14 magnitude can be successfully observed, and typical detection limits for companions are ~5 magnitudes fainter than the primary star. We observe a wide range of spectral types, but most target stars are in the spectral range A through M. By analyzing the spatial separation and relative position angles of detected companions, we provide updates on several binaries currently under study, with the aim to eventually characterize the orbital properties of these binary systems with high precision. These results will contribute to the growing body of knowledge on stellar multiplicity and offer insights into the formation processes shaping binary star systems. Additionally, our study underscores the continuing effectiveness of DSSI as a powerful tool for high-resolution imaging and the detection of stellar companions.