Spectroscopic and Adaptive Optics Observations of Protostellar Magnetospheres and Binary Star Evolution
Laos, Stefan Emile
Overall, there has been growing progress in the astrophysical literature towards the characterization of young stellar evolution phenomenon. The use of sensitive, near-infrared observations continues to unravel these mysteries, with this dissertation providing insight into the short, active periods during stellar formation and early binary dynamics. In Chapter 2, we analyze our K-band spectroscopy of Class 0 protostars taken by the Keck I MOSFIRE instrument. This data reveals the properties of their near-stellar environment, finding clear signatures of active disk accretion in the form of CO overtone emission. In particular, we find evidence for the presence of an established magnetosphere in Class 0s (the earliest observable stage of young stellar evolution) from our observed Brackett gamma line profiles. In Chapter 3, we analyze adaptive optics near-infrared imaging data of spectroscopic binaries (SBs) taken by the Robo-AO imaging system at the Kitt Peak National Observatory. With this high-contrast data, we searched for nearby companions in our field of view and find further evidence for the relation originally found by Tokovinin et al. 2006; shorter period SBs are systematically more likely to be in a higher order system than longer period SBs. Collectively, our findings support the mechanisms of angular momentum transfer from three-body interactions during early evolution, ultimately resulting in tight binaries with tertiaries that widen from pre-main-sequence to field ages. We briefly discuss future work and ideas in Chapter 4.