2025MNRAS.541.1600C

The outer regions of the protoplanetary disc surrounding the T Tauri star HD 143006 show rings, dust asymmetries, and shadows. Whilst rings and dust asymmetries can arise from companions and other mechanisms, shadows, and misaligned discs in particular are typically attributed to the presence of misaligned planets or stellar-mass companions. To understand the mechanisms that drive these traits, the innermost regions of discs need to be studied. Using the Michigan Infrared Combiner Exeter (MIRC-X) at the Center for High Angular Resolution Astronomy (CHARA) and the Precision Integrated-Optics Near-infrared Imaging ExpeRiment (PIONIER) at the Very Large Telescope Interferometer (VLTI), we observed the sub-au region of HD 143006. We constrain the orientation of the inner disc of HD 143006 and probe whether a misalignment between the inner and outer disc could be the cause of the shadows. Modelling the visibilities using a geometric model, the inclination and position angle are found to be $i=22^\circ \pm 3^\circ$ and $\mathrm{PA}=158^\circ \pm 8^\circ$ respectively, with an inner dust sublimation radius of ${\sim} 0.04$ au. The inner disc is misaligned by $39^\circ \pm 4^\circ$ with respect to the outer disc, with the far side of the inner disc to the east and the far side of the outer disc to the west. We constrain $h/R$ (scattering surface/radius of scattered light) of the outer disc at 18 au to be about 13 per cent by calculating the offset between the shadow position and the central star. No companion was detected, with a magnitude contrast of 4.4 in the H band and placing an upper mass limit of $0.17\, \mathrm{ M}_\odot$ at separations of $0{\!-\!}8$ au. Therefore, we cannot confirm or rule out that a low-mass star or giant planet is responsible for the misalignment and dust sub-structures.