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Abstract:
Context. Transition disks are protoplanetary disks with dust-depleted cavities, possibly indicating substantial clearing of their dust content by a massive companion. For several known transition disks, dark regions interpreted as shadows have been observed in scattered light imaging and are hypothesized to originate from misalignments between distinct regions of the disk.
Aims. We aim to investigate the presence of misalignments in transition disks. We study the inner disk (<1 au) geometries of a sample of 20 well-known transition disks with Very Large Telescope Interferometer (VLTI) GRAVITY observations and use complementary 12CO and 13CO molecular line archival data from the Atacama Large Millimeter/submillimeter Array (ALMA) to derive the orientation of the outer disk regions (>10 au).
Methods. We fit simple parametric models to the visibilities and closure phases of the GRAVITY data to derive the inclination and position angle of the inner disks. The outer disk geometries were derived from Keplerian fits to the ALMA velocity maps and compared to the inner disk constraints. We also predicted the locations of expected shadows for significantly misaligned systems.
Results. Our analysis reveals six disks to exhibit significant misalignments between their inner and outer disk structures. The predicted shadow positions agree well with the scattered light images of HD 100453 and HD 142527, and we find supporting evidence for a shadow in the south of the disk around CQ Tau. In the other three targets for which we infer significantly misaligned disks, V1247 Ori, V1366 Ori, and RY Lup, we do not see any evident sign of shadows in the scattered light images. The scattered light shadows observed in DoAr 44, HD 135344 B, and HD 139614 are consistent with our observations, yet the underlying morphology is likely too complex to be described properly by our models and the accuracy achieved by our observations.
Conclusions. The combination of near infrared and submillimeter interferometric observations allows us to assess the geometries of the innermost disk regions and those of the outer disk. Whereas we can derive precise constraints on the potential shadow positions for well-resolved inner disks around Herbig Ae/Be stars, the large statistical uncertainties for the marginally resolved inner disks around the T Tauri stars of our sample make it difficult to extract conclusive constraints for the presence of shadows in these systems.
