The young disk around AB, Aur features a complex assembly of spiral arms, several compact structures, and a protoplanet candidate, AB, Aur, b, suggesting ongoing planet formation in this young system. Because of its brightness and spatial extent, AB, Aur represents a perfect laboratory for investigating the conditions under which planets start to form around intermediate-mass stars. In this paper, we present near-IR polarized images of the AB, Aur disk at three epochs spanning 3. 85 years with SPHERE/IRDIS, as well as ̋a images obtained with SPHERE/ZIMPOL at a single epoch. The purpose of this study is to analyze the dynamics of the entire disk and of the various structures in near-IR polarimetry, and to identify sources of ̋a emission to derive constraints on their mass accretion rate. We developed a method to measure the rotation of the disk as a function of the radius, covering physical separations from as close as ∼25, au up to 400, au. We applied this method to the global structure of the disk as well as to specific features of interest, including both extended or compact sources. For the compact sources, we performed orbital analyses. We also studied the variability of shadows seen as thin radial streaks. For the ̋a data, we extracted photometric measurements of several features and derived estimations of the accretion luminosities and mass accretion rates, assuming three different accretion models. The dynamical study in the near-IR shows that the disk globally follows Keplerian rotation, but we observe a departure from this behavior at radii smaller than sim60, au. At the smallest radius of ∼25, au, we measure a deviation from Keplerian rotation as large as ∼12, , and) suggests that their orbital planes are significantly inclined with respect to the disk plane by several tens of degrees. The variability of the shadows suggests that they are produced by optically thick regions located within ∼60, au. For the photometric analysis in Hmathrmα, we derive a flux of about 8. 22 feature, but only 6. 46 were a point source and the accretion remained constant for 1, Myr, it would correspond to sim5-20 Jupiter masses according to the magnetospheric accretion model or over 3. 85 years, demonstrating sub-Keplerian rotation. The two bright spirals within the millimeter cavity have different dynamic trends, and we discuss their possible link with the identified planet candidates. We also discuss the implications of the non-Keplerian behavior, and we posit that it could be related to interactions with multiple protoplanets orbiting out of the disk plane on elliptical orbits. Furthermore, the orbital analysis of the compact sources (labeled f1 f2 f3 erg/s/cm2 for the entire f1 erg/s/cm² at the location of AB, Aur, b, consistent with non-detection. If f1 Jupiter masses according to the boundary layer accretion model. We further discuss the non-detection of ̋a emission on AB, Aur, b. Finally, we discuss the binarity of the host star, in particular using Gaia measurements. AB, Aur is a rare system in which the morphology and dynamics can be studied at a very high level of detail, contrasting with the generic picture of a young planet-forming disk. The excellent image quality of SPHERE, both in the near-IR and in the visible, allows us to track the disk rotation with unprecedented precision thanks to the stability of the instrument across several years and to study localized ̋a emissions in the disk. Overall, these observations strongly argue for an active and complex phase of planet formation in this system.
Boccaletti et al. (Thu,) studied this question.