<div>Transition disks (TD) are protoplanetary disks that exhibit inner cavities in dust and gas that could be cleared by massive companions. However, only one TD has so far been confirmed to host planets, namely PDS 70. Fortunately, within recent years, high-resolution observations of gas tracers make it now possible to map the velocity structures of disks, which makes TD prime targets to probe planet-disk interactions. <br></div><div>On the poster, I will present new ALMA observations of the TD around RXJ1604.3?2130A, a system known to feature nearly symmetric shadows in scattered light. The disk hosts a large cavity in the dust continuum enclosed by a thin ring, as well as a smaller cavity in 12CO. By investigating the disk kinematics, we detect a strong localized non-Keplerian feature, on the order of 40% the Keplerian velocity, at the inner edge of the continuum ring. We interpret this feature as tracing a massive planet of about 3.5 Jupiter masses at ~78 au. Possibly connected to the localized feature, a tightly wound spiral arm is detected over 300 deg in azimuth in the outer disk, likely caused by buoyancy resonances driven by planet-disk interaction. However, the planet itself cannot explain the gas-depleted cavity closer in, the low accretion rate and the misaligned inner disk, which suggests the presence of a yet-undetected, more massive companion very close to the star.</div><div>(Stadler, Benisty, Izquierdo, Facchini et al. 2023, A&A Letters)<br></div>
[Poster PDF File]