K2-18 b is a planet with a mass around eight times that of the Earth that lies within the standard habitable zone of its star. Hubble spectra show the presence of an atmosphere around K2-18 b containing significant amounts of water vapour (up to a few tens of per cent, depending on the spectral model), but also a non-negligible amount of H2–He.
- Angelos Tsiaras
- Ingo P. Waldmann
- Sergey N. Yurchenko
