Gap-opening planets can generate dust-trapping vortices that may explain some of the latest discoveries of high-contrast crescent-shaped dust asymmetries in transition discs .
While planet-induced vortices were previously thought to have concentrated shapes , recent computational work has shown that these features naturally become much more elongated in the gas when simulations account for the relatively long timescale over which planets accrete their mass .
In this work , we conduct two-fluid hydrodynamical simulations of vortices induced by slowly-growing Jupiter-mass planets in discs with very low viscosity ( \alpha = 3 \times 10 ^ { -5 } ) .
We simulate the dust dynamics for four particle sizes spanning 0.3 mm to 1 cm in order to produce synthetic ALMA images .
In our simulations , we find that an elongated vortex still traps dust , but not directly at its center .
With a flatter pressure bump and disruptions from the planet ’ s overlapping spiral density waves , the dust instead circulates around the vortex .
This motion ( 1 ) typically carries the peak off-center , ( 2 ) spreads the dust out over a wider azimuthal extent \geq 180 ^ { \circ } , ( 3 ) skews the azimuthal profile towards the front of the vortex , and ( 4 ) can also create double peaks in newly-formed vortices .
In particular , we expect that the most defining observational signature , a peak offset of more than 30 ^ { \circ } , should be detectable > 30 \% of the time in observations with a beam diameter of at most the planet ’ s separation from its star .