# # Program information file # PROGRAM_ID 2023B040 PROGRAM_TITLE Tracing Accretion Flows in Binary Systems PROGRAM_INV1 Benjamin Tofflemire PROGRAM_INV2 Andrea Banzatti PROGRAM_INV3 PROGRAM_INV4 PROGRAM_INV5 PROGRAM_SCICAT stellar PROGRAM_ABSTRACT_BEG The formation of stars and planets are intimately linked. This fact is most directly observable in the interaction between a star and its protoplanetary disk. The star-disk interaction and its impact has been extensively studied in the case of single stars; however, many stars form with close stellar companions that give rise to a completely distinct 'binary-disk' interaction. For close binaries, theory predicts the binary orbit will dynamically clear a central cavity in the disk and that this gap will be periodically bridged by streams of material that are launched during each binary orbit. Evidence for this pulsed-accretion scenario is supported by periodic accretion variability observed in T Tauri binaries. These studies, primarily in the optical, only probed material as it impacts the stellar surfaces. As such, our understanding of the kinematics of the circumbinary disk and its accretion streams remains largely theoretical. In this proposal, we seek to trace the dynamic interaction between a short-period binary and its inner disk using CO ro-vibrational emission lines in the M-band. With iSHELL observations on 8 consecutive nights, we will analyze the velocity structure and variability of emission lines that trace inner-disk material over specific binary orbital phases that comprise the development of accretion streams and their delivery to the stellar surfaces [i.e., apastron to periastron]. These observations will help extend our understanding of star and planet formation into dynamically complex environments that are commonplace in the galaxy. PROGRAM_ABSTRACT_END