Wisniewski, JohnRich, Evan2019-05-082019-05-082019-05-11https://hdl.handle.net/11244/319609The discovery of new protoplanetary disk structures can help reveal the dynamics of the young planetary systems and potentially point to planet formation within the disk. In my dissertation, I present investigations of three stellar/sub-stellar systems; DoAr 28, VHS J125601.92-125723.9 (VHS 1256), and HD 163296. First, I will discuss the first near-IR scattered light detection of the protoplanetary disk around DoAr 28. I modeled both the observed SED and H-band PI imagery of the system and found that our best fit models have a partially depleted inner gap from the dust sublimation radius out to ~8 au. Second, I present and analyze Subaru/IRCS L' and M' images of the nearby M dwarf VHS 1256, which was recently claimed to have a ~11 Mjup companion (VHS 1256 b). I found that the central star is a binary and conclude that VHS 1256 is most likely a very low mass (VLM) hierarchical triple system. Finally, I present Subaru/HiCIAO H-band imagery, Subaru/SCExAO near-IR imagery, and HST/STIS optical imagery of the protoplanetary disk around HD 163296. I demonstrate that the new Subaru/HiCIAO and HST/STIS imagery exhibits disk illumination variability on timescales < 3 months, possibly due to a non-axisymmetric distribution of dust clouds. show that our SCExAO/CHARIS observations fail to recover the previously identified 6-7 Mjup planetary candidate. Additionally, I did not detect the predicted launch of a new HH-knot nor did I detect any of the previously observed HH-knots, suggesting a potential change in the jet of HD 163296.Attribution-NonCommercial-ShareAlike 4.0 InternationalProtoplanetaryExoplanetYoung Stellar ObjectsHigh Contrast Imaging