Ratio of the Kelvin-Helmholtz timescale to the replenishment timescales at the onset of pebble vaporization as a function of time and semi-major axis. The white solid line shows the planets for which the replenishment and the pollution timescales are equal. Planets on the left side have a replenishment timescale shorter than the pollution timescale, meaning that their envelope composition is similar to that of the disk. The replenishment timescale of the planets on the right side is longer than the pollution timescale, and the envelope is highly enriched in heavy elements. The white dotted line shows planets whose envelope enrichment exceeds 0.8, and the white dashed line shows planets whose envelope enrichment exceeds 0.9.