Is life possible here?
This exoplanet could have an atmosphere after all
December 17, 2024 – 12:38 p.mReading time: 2 min.
The planet Trappist-1b is about 40 light-years away. Until now it was considered barren and atmosphereless. But new data suggests something completely different.
New observations of Trappist-1b show: Contrary to previously assumed, the Earth-sized rocky planet could have a thin atmosphere or even be geologically active. This is what researchers from the Max Planck Institute for Astronomy in Heidelberg announce. What’s special: The findings contradict all previous theories about the planet, according to which it should be barren and without an atmosphere.
Where do the new findings come from? The team of scientists examined the thermal infrared radiation of the exoplanet in the Trappist-1 system and compared it with models for different planetary crusts. The data for this was provided by the James Webb Space Telescope, which observed the planet with its instrument Miri (Mid-Infrared Imager).
“The idea of a rocky planet with a heavily weathered surface without an atmosphere is not compatible with current measurements,” says Jeroen Bouwman from the Max Planck Institute for Astronomy. According to the scientists, the new results suggest that the rock on the planet’s surface could be no more than around 1,000 years old.
How come? Such young surfaces could only be formed by extreme volcanism or plate tectonics – similar to what happens on Earth, according to the scientists. Strong tidal forces acting on Trappist-1b could be responsible for this. The planet is extremely close to its main star and only needs around 36 hours to complete one orbit.
The measured infrared data could also be explained with another theory, according to the researchers. Thomas Henning, director emeritus of the Max Planck Institute for Astronomy, said: “Contrary to previous thinking, there are conditions under which the planet could have a thick atmosphere rich in carbon dioxide.”
Haze from hydrocarbon compounds in the high atmosphere plays an important role in this scenario. This itself could have emitted the infrared radiation that was discovered by the space telescope.
However, scientists are not entirely convinced by this scenario. That’s why the researchers want to observe Trappist-1b’s entire orbit around its star. The change in brightness of the planet could then provide more precise data on the temperature distribution and clarify whether Trappist-1b really has an atmosphere.
However, the new findings about Trappist-1b do not automatically make the planet a new candidate for life. The planet is too close to its star for this, which leads to surface temperatures of over 400 degrees. This rules out the possibility that there could be liquid water there, which, according to current knowledge, is absolutely necessary for the emergence of life.
However, it cannot be ruled out that life could have formed in the Trappist-1 planetary system. Three of the seven rocky planets discovered there so far orbit their star in the habitable zone. This means that there could be temperatures there that allow liquid water to exist on the surface.