A Localized Kinematic Structure Detected in Atomic Carbon Emission Spatially Coincident with a Proposed Protoplanet in the HD 163296 Disk

Over the past 5 yr, studies of the kinematics in protoplanetary disks have led to the discovery of new protoplanet candidates and several structures linked to possible planet-disk interactions. We detect a localized kinematic bipolar structure in the HD 163296 disk present inside the deepest dust gap at 48 au from atomic carbon line emission. HD 163296's stellar jet and molecular winds have been described in detail in the literature; however, the kinematic anomaly in C i emission is not associated with either of them. Further, the velocity of the kinematic structure points indicates a component fast enough to differentiate it from the Keplerian profile of the disk, and its atomic nature hints at a localized UV source strong enough to dissociate CO and launch a C i outflow or a strong polar flow from the upper layers of the disk. By discarding the stellar jet and previously observed molecular winds, we explore different sources for this kinematic feature in C i emission that could be associated with a protoplanet inflow/outflow or disk winds.