KU Leuven researchers discovered that two out of three possible climates on exoplanets are potentially habitable. Credit: KU Leuven – Ludmila Carone
The quest for potentially habitable planets is often interpreted as the search for an Earth twin. And yet, some rocky planets outside our Solar System may in fact be more promising candidates for further research. Scientists have run 165 climate simulations for exoplanets that permanently face their ‘sun’ with the same side. They discovered that 2 of the 3 possible climates are potentially habitable.
Most exoplanets orbit relatively small and cool stars known as red dwarfs. Only exoplanets that orbit close to their 3star can be warm enough for liquid water. What is more, being close to their star also makes these potentially habitable planets relatively easy to detect and observe for research purposes. Many exoplanets that orbit closely to their stars always face that star with the same side ie have permanent day and night sides. And yet, climate on these planets is not necessarily scorching hot on one side and freezing on the other. This is due to efficient ‘air conditioning system’ that keeps surface temperatures within the habitable range.
“On the basis of 3D models, we examined exoplanets with different rotation periods and sizes,” Ludmila Carone explains. “We discovered that these rocky planets have three possible climates, 2 of which are potentially habitable.”
On exoplanets with rotation periods <12d, an eastward wind jet known as superrotation forms in the upper layers of the atmosphere along the equator. This wind jet interferes with atmospheric circulation on the planet, so that its day side becomes too hot to be habitable. A 2nd possible wind system is characterised by 2 weaker westward wind jets at high latitudes. The 3rd climate option combines weak superrotation with 2 high-latitude wind jets. These last 2 wind systems do not interfere with the ‘air conditioning system’, so that the planets remain potentially habitable.
The findings provide valuable input for future space missions. KU Leuven researchers are preparing James Webb Space Telescope mission (2018) and planet-finder mission PLATO (2024). http://www.kuleuven.be/english/news/2015/rocky-planets-may-be-habitable
Recent Comments