James Webb Space Telescope Detects Water Vapor Around Alien Planet

The James Webb Space Telescope (JWST) has detected water vapor around a distant rocky planet located 26 light-years away. “The water vapor could indicate the presence of an atmosphere around the extrasolar planet, or exoplanet, a discovery that could be important for our search for habitable worlds outside the solar system,” reports Space.com. “However, the scientists behind the discovery caution that this water vapor could be coming from the world’s host star rather than the planet itself.” From the report: The exoplanet, designated GJ 486 b, orbits a red dwarf star located 26 light-years away in the Virgo constellation. Although it has three times the mass of Earth, it is less than a third the size of our planet. GJ 486 b takes less than 1.5 Earth days to orbit its star and is probably tidally locked to the red dwarf, meaning it perpetually shows the same face to its star.

Red dwarfs like the parent star of GJ 486 b are the most common form of stars in the cosmos, meaning that statistically speaking, rocky exoplanets are most likely to be found orbiting such a stellar object. Red dwarf stars are also cooler than other types of stars, meaning that a planet must orbit them tightly to remain warm enough to host liquid water, a vital element needed for life. But, red dwarfs also emit violent and powerful ultraviolet and X-ray radiation when they are young that would blast away the atmospheres of planets that are too close, potentially making those exoplanets very inhospitable to life.

That means astronomers are currently keen to discover if a rocky planet in such a harsh environment could manage to both form an atmosphere and then hang on to it long enough for life to take hold, a process that took around a billion years on Earth. […] Even though GJ 486 b’s host star is cooler than the sun, water vapor could still concentrate in starspots. If that is the case, this could create a signal that mimics a planetary atmosphere. If there is an atmosphere around GJ 486 b, then radiation from its red dwarf parent star will constantly erode it, meaning it has to be replenished by steam from the exoplanet’s interior ejected by volcanic activity. The research appears in a paper on arXiv while it awaits publication in the journal Astrophysical Journal Letters. You can read more about it via NASA.