A 2 au Resolution View by ALMA of the Planet-hosting WISPIT 2 Disk

Abstract We present deep, high-spatial-resolution interferometric observations of 0.88 mm continuum emission from the TYC 5709-354-1 system, hereafter WISPIT 2, obtained with the goal of detecting circumplanetary emission in the vicinity of the newly discovered WISPIT 2b planet. Observations with the most extended baseline configuration offered by the Atacama Large Millimeter/submillimeter Array, achieving an angular resolution of 25 × 17 mas (3.3 × 2.2 au), revealed a single, narrow ring with a deprojected radius of 144.4 au and width of 7.2 au, and no evidence of circumplanetary emission within the cavity. Injection and recovery tests demonstrate that these observations can rule out pointlike emission at the location of WISPIT 2b brighter than ≈ 45 μ Jy at the 3 σ level. While these data can rule out PDS 70 c-like circumplanetary emission, the upper limit is consistent with empirical mass–flux relationships extrapolated from the stellar regime. Visibility modeling of the continuum ring confirms that WISPIT 2b lies significantly interior to the millimeter dust ring, raising doubts about the ability of WISPIT 2b to be the only driver of the dust structure. Possible solutions include either another lower-mass companion, residing between WISPIT 2b and the cavity edge, likely in the gap seen by SPHERE at ∼130 au, or that WISPIT 2b is either substantially more massive than estimates based on IR photometry (∼15 M Jup ) or on a moderately eccentric orbit. The combination of observations sensitive to the gas and dust distributions on larger spatial scales and dedicated hydrodynamical modeling will help differentiate between scenarios.