Measuring Protoplanetary Disk Alignment in Young Binary Systems Eric Jensen1, Rachel Akeson2, and Aaron Hersch1, 1Swarthmore College, 2Caltech/IPAC, NExSci Acknowledgments We thank Geoﬀ Blake for permission to use the DoAr 24E data in advance of publication. This work makes use of the following ALMA data: ADS/JAO.ALMA#2015.1.00637.S and ADS/JAO.ALMA#2015.1.00168.S. ALMA is a partnership of ESO (representing its member states), NSF (USA) and NINS (Japan), together with NRC (Canada), MOST and ASIAA (Taiwan), and KASI (Republic of Korea), in cooperation with the Republic of Chile. The Joint ALMA Observatory is operated by ESO, AUI/NRAO and NAOJ. The National Radio Astronomy Observatory is a facility of the National Science Foundation operated under cooperative agreement by Associat- ed Universities, Inc. Figure 4: First-moment maps of the primary (GK) and secondary (GI) disks in the binary system GK/GI Tau. Although this system has the largest projected binary separation in our sample at 13.2’’ (1700 AU), its disks show similar position angles. Figure 5: Work in progress: we are exploring the ﬁtting of the ﬁrst-moment maps, along with constraints on the stellar mass, to determine disk inclinations in order to ﬁnd the full three-dimensional orientation diﬀerence in these systems. Above, left to right: data, model, and residuals for a ﬁt to GK Tau using eddy (Teague 2019). Observations and Methods We used ALMA to observe continuum and CO(3-2) emission from 14 young binary systems in Taurus-Auriga, Ophiuchus, and Lupus. The kinematics of the CO emission allows us to deduce the spatial orientation of the disks, even for disks that are near our resolution limit. Six systems had strong enough emission for both components to be detected in CO. We used CASA to image the sources and create velocity maps. We also included in our analysis the previously measured position angles of the disks in V2434 Ori (Williams et al. 2014) and HK Tau (Jensen & Akeson 2014) . Most of the disks are unresolved in the continuum, but the channel-to-channel movement of the CO emission allows us to determine the disk position angle. We measured the CO emission centroid in each channel and ﬁt a straight line to the points to ﬁnd the disk PA. References Bohm, K. H. & Solf, J. A sub-arcsecond-scale spectroscopic study of the complex mass outﬂows in the vicinity of T Tauri. Astrophys. J. 430, 277-290 (1994). Foucart, F., & Lai, D., Evolution of linear warps in accretion discs and applications to protoplanetary discs in binaries. MNRAS 445, 1731-1744 (2014). Jensen, E. L. N. & Akeson, R. Misaligned Protoplanetary Disks in a Young Binary System. Nature, 511, 576 (2014). Jensen, E. L. N., Mathieu, R. D., Donar, A. X. & Dullighan, A. Testing Protoplanetary Disk Alignment in Young Binaries. Astrophys. J. 600, 789-803 (2004). Kurtovic, N. T. et al. DSHARP IV. Characterizing Substructures and Interactions in Disks around Multiple Star Systems Astrophys. J. Lett. 869, L44 (2018). Lubow, S. & Ogilvie, G. On the Tilting of Protostellar Disks by Resonant Tidal Eﬀects, Astrophys. J 538, 326-340 (2000). Monin, J. L., Menard, F. & Duchêne, G. Using polarimetry to check rotation alignment in PMS binary stars. Principles of the method and ﬁrst results. Astron. Astrophys. 339, 113-122 (1998). Ratzka, T. et al. Spatially resolved mid-infrared observations of the triple system T Tauri. Astron. Astrophys. 502, 623-646 (2009). Roccatagliata, V. et al. Multi-wavelength observations of the young binary system Haro 6-10: The case of misaligned discs. Astron. Astrophys. 534, A33 (2011). Salyk, C. et al. ALMA Observations of the T Tauri Binary AS 205: Evidence for Molecular Winds and/or Binary Interactions. Astrophys. J. 792:68 (2014). Skemer, A. J. et al. Evidence for Misaligned Disks in the T Tauri Triple System: 10 μm Superresolution with MMTAO and Markov Chains. Astrophys. J. 676, 1082-1087 (2008). Stapelfeldt, K. R. et al. An Edge-on Circumstellar Disk in the Young Binary System HK Tau