Context
Dust traps are thought to be efficient at blocking the inward flux of icy pebbles, and hence at shaping the composition of the inner disc (towards O-poor and high C/O ratio). However, the impact of dust traps on the inner disc composition has mostly been studied with two-pop-py, a simplified dust framework not suited for trap-hosting discs.
What's been done
We performed a broad parameter study (>300 simulations) with the full dust coagulation code DustPy allowing us to quantify the leakiness of dust traps in different conditions
Our paper in three key results
(1) Dust traps are leakier than previously estimated with two-pop-py, up to 3 orders of magnitude. Efficient planetesimal formation in the dust trap is necessary to make traps highly blocking.
(2) As a result, most dust traps will result in a long-lived oxygen-rich inner disc, consistent with JWST observations (Banzatti et al. 2023, Gasman et al. 2025).
(3) Dust traps strong enough to result in an inner disc with C/O ratio > 1 are extremely challenging to form. To explain the diversity of carbon-rich discs, other processes must be explored.