Astronomers from the University of Cambridge, together with a Canadian team, conducted a study on the TOI-270 d exoplanet and obtained interesting results that may indicate the existence of habitable conditions on this planet. During observations using the James Webb Space Telescope (JWST), astronomers from the University of Cambridge together with a Canadian team discovered the presence of water vapor and chemical signatures of methane and carbon dioxide in the atmosphere of the exoplanet TOI-270 d. It is twice the size of the exoplanet, located about 70 light-years from our planet.

Researchers suggest that such a chemical mixture could indicate the existence of a hydrogen-rich atmosphere as well as a deep ocean covering the entire surface of the planet. According to Professor Nikku Madhusudhan, who conducted the analysis, the temperature of the TOI-270 d ocean can reach 100 degrees Celsius and even higher, and at high atmospheric pressure such conditions can still support the liquid form of the ocean. But whether such an ocean would be suitable for life is still an open question.

A team of Canadian scientists who made additional observations expressed doubts about the hypothesis of the existence of an ocean on TOI-270 d. They state that the temperature on the planet can reach up to 4000 °C, which makes the existence of liquid water impossible. Instead, they suggest that TOI-270 d’s surface is composed of rocky material and covered by a dense atmosphere of hydrogen and water vapor.

Initially, evidence for the existence of ocean TOI-270 d was based on the absence of ammonia, which should occur naturally in a hydrogen-rich atmosphere. However, since ammonia dissolves well in water, it will disappear from the atmosphere if the exoplanet has an ocean. Both teams detected carbon disulfide in the atmosphere of TOI-270 d, which may be associated with biological processes but may also have other sources. But they found no evidence of dimethyl sulfide, another biosignature molecule.

TOI-270 d is of particular interest to astronomers: One side of the planet is constantly facing its star, while the other side is immersed in eternal darkness, creating a sharp temperature contrast between the day and night sides. On the day side, the ocean will warm to very high temperatures, while on the night side, more suitable conditions for the emergence of life may arise. However, the high atmospheric pressure, which is tens or hundreds of times higher than the pressure at the Earth’s surface, and the huge amount of water vapor make these conditions extremely extreme.

Professor Bjorn Benneke of the University of Montreal conducted additional research. According to him, the temperature on the exoplanet can reach 4000°C and water is in a supercritical state where the lines between liquid and gas are blurred.

Further studies of TOI-270 d will help clarify and understand what conditions may exist on such exoplanets and which of them may provide optimal conditions for the origin of life.