Protoplanetary disks unveiled by star-hopping: Total intensity, polarimetry, and millimeter imaging modeled in concert

Context. Angular differential imaging (ADI), widely used in ground-based high-contrast imaging, often distorts extended emission such as protoplanetary disks. This hampers efforts to jointly study circumstellar disks and embedded protoplanets, particularly in systems like PDS 70, Lk Ca 15, and HD 163296, where disk substructures and planet formation are closely intertwined.

Aims. Our goal is to recover unbiased photometry and morphology of both disks and planets in these systems, free from self-subtraction artifacts introduced by ADI. This allows for a more accurate study of disk structure, grain properties, and potential dynamical interactions between planets and their natal environments. We also search for additional substellar companions at separations beyond the known planets.

Methods. We analyze SPHERE YJHK-band imaging, polarimetry, and integral field spectroscopy using reference star differential imaging (star-hopping) to preserve extended emission. Submillimeter ALMA data are included to constrain the disk structure and dust distribution. Radiative transfer modeling with RADMC-3D is used to interpret both scattered light and thermal emission, matching the observations in both total and polarized intensity. We also extract spatially resolved spectra of point sources and disk regions for comparative analysis.