Normalised torques for the different mass ratios associated with planets in low-viscosity discs (α = 10⁻⁴) and with orbital eccentricities e < 0.2. The transition between inward (blue symbols) and outward (red symbols) migration (shaded area) occurs for q between 0.0015 and 0.002 (black dots), depending on the disc’s physical parameters. Symbols and colours are the same as in Figure 3. For cases with near-zero torque, values around 1 × 10⁻⁵ were used for better visibility in the figure.