A New Planet Candidate Detected in a Dust Gap of the Disk around HD 163296 through Localized Kinematic Signatures: An Observational Validation of the discminer

Abstract

We report the robust detection of coherent, localized deviations from Keplerian rotation possibly associated with the presence of two giant planets embedded in the disk around HD 163296. The analysis is performed using the discminer channel map modeling framework on 12 CO J = 2–1 DSHARP data. Not only orbital radius but also azimuth of the planets are retrieved by our technique. One of the candidate planets, detected at R = 94 ± 6 au, ϕ = 50° ± 3° (P94), is near the center of one of the gaps in dust continuum emission and is consistent with a planet mass of 1 M Jup . The other planet, located at R = 261 ± 4 au, ϕ = 57° ± 1° (P261), is in the region where a velocity kink was previously observed in 12 CO channel maps. Also, we provide a simultaneous description of the height and temperature of the upper and lower emitting surfaces of the disk and propose the line width as a solid observable to track gas substructure. Using azimuthally averaged line width profiles, we detect gas gaps at R = 38, 88, and 136 au, closely matching the location of their dust and kinematical counterparts. Furthermore, we observe strong azimuthal asymmetries in line widths around the gas gap at R = 88 au, possibly linked to turbulent motions driven by the P94 planet. Our results confirm that the discminer is capable of finding localized, otherwise unseen velocity perturbations thanks to its robust statistical framework, but also that it is well suited for studies of the gas properties and vertical structure of protoplanetary disks.