Scientists have found traces of water vapor in the atmosphere of a distant exoplanet. However, this hardly makes GJ 486 b suitable for life.
Red dwarfs are the most common stars in the universe, so most existing exoplanets must form around stars of this class. Because of the low temperature of dwarfs, their habitable zone is extremely close to the star, so in order for liquid water to exist on the surface of a planet, it must orbit "close" to its luminary.
Researchers have repeatedly shown that, despite early notions that red dwarfs are suitable for the development of life, these stars are in fact much more unpredictable than our Sun. Their harsh ultraviolet and X-ray radiation can easily destroy a planet's atmosphere. And for a long time astronomers have wondered whether a rocky planet could, in principle, maintain or regenerate an air shell while orbiting a red dwarf.
To answer this question, NASA researchers looked at the exoplanet GJ 486 b, located 26 light-years from Earth, in the constellation Virgo. This planet is too close to its red dwarf, causing its surface temperature to reach 430 degrees Celsius. However, using a near-infrared spectrograph, scientists were able to record traces of the presence of water vapor on it. The study was accepted for publication in The Astrophysical Journal Letters.
If this vapor is in the planet's atmosphere, it means it still has an air shell, despite the sizzling heat and proximity to the star. But the researchers warn that in fact the source of water on GJ 486 b may be... the star itself: as with the Sun, water vapor on GJ 486 can be formed in cold dark spots, and given that this red dwarf is much colder than our luminary, the steam on its surface may form more.
The discovery of water vapor in the atmosphere of a rocky exoplanet would be an astronomical breakthrough, but scientists caution against drawing too bold conclusions. If water vapor is indeed present in the atmosphere of GJ 486 b, it may indicate the volcanic activity of the planet, so that its air shell, being destroyed by the influence of the star, is constantly replenished. Scientists hope that with the help of new tools they will be able to study the "behavior" of the planet and the distribution of heat on its surface in more detail. This will allow them to confirm or deny the presence of its atmosphere.
