Type I Migration — Lindblad Torque Simulator

A low-mass protoplanet embedded in its birth gas disk never orbits in peace: the spiral density waves it launches at its inner and outer Lindblad resonances carry away angular momentum unevenly, producing a small net torque that drives slow, steady inward migration — the Type I regime that governs every planet too light to clear a gap in its disk. This simulator computes that torque directly from the Tanaka, Takeuchi & Ward (2002) linear formula, renders the resulting spiral wake in a live particle disk, and integrates the planet's semi-major axis in real time as you vary its mass, the disk's surface-density and temperature profiles, and whether entropy-driven corotation torque is allowed to fight back against — or reverse — the inward drift.