Schematic illustration of how the C/O ratio of host stars regulates the formation, migration, and final orbital periods of giant planets. In the left panel (low stellar C/O case), the solid material is more concentrated in the inner oxygen-rich disk region, and the protoplanet is more likely to form near the water (H₂O) ice line via streaming instability. It subsequently undergoes inward migration by accreting solids and gas, ultimately forming a hot giant planet with a short orbital period. In the right panel (high stellar C/O case), the protoplanet forms at the farther out disk region near the organic carbon and carbon dioxide ice line. After moderate inward disk migration, the planet ends up as a giant planet with a relatively long orbital period.