Oxygen is one of the most discussed biosignature candidates5, 6. This is reasonable because two essential sources for oxygenic photosynthesis—light and liquid water—should by definition be available on habitable exoplanets, and oxygenic phototrophs can significantly change atmospheric compositions, as proven on Earth7. However, recent studies have shown that oxygen can also be a false positive sign of life on habitable exoplanets8,9,10,11. Thus, additional biosignatures will be necessary to determine whether oxygen is produced by phototrophs or abiotic processes. One possible additional biosignature for oxygenic phototrophs is the red-edge, which is a rise in a planet’s surface reflectivity between red absorbance and near-infrared (NIR) reflection due to vegetation12, 13. Although the red-edge position for Earth’s vegetation is fixed at around 700–760 nm, that for exoplanets may not necessarily be the same14,15,16. Thus, it is necessary to predict the red-edge wavelength position in advance in order to use it as an additional biosignature for distant habitable exoplanets.