The James Webb Space Telescope, a remarkable astronomical device that is set to fully launch later this year in October, has just made a groundbreaking discovery. Orbiting a distant star located approximately 26 light-years away from Earth, the telescope detected water vapor surrounding a rocky exoplanet.
This incredible finding has sparked a new wave of intrigue and research, as astronomers seek to determine whether this is indicative of the first-known presence of an atmosphere around a rocky exoplanet.
Red dwarf stars, small cool stars that are the most abundant stars in the known universe, often have exoplanets in their “habitable zone,” which is the ideal distance from the star to allow for liquid water on the planet’s surface. These exoplanets usually orbit the red dwarfs very closely since they aren’t as warm as our sun.
The detected exoplanet is called LHS 475 b, and is roughly the same size as Earth. It zooms around its star every two days, making it the fastest orbiting planet known to man. Scientists will be conducting further observations with the James Webb Space Telescope during the summer months in hopes of proving definitively that the planet has an atmosphere. The planet is relatively close to Earth, located just 41 light-years away in the constellation Octans.
The existence of water vapor around this newly discovered exoplanet is truly a groundbreaking event for the world of astronomy. Red dwarf stars are known for emitting harsh ultraviolet and X-ray radiation, which can destroy delicate layers of gas and potentially cause rocky planets in their orbits to lose or struggle to maintain atmospheres.
GJ 486 b, another hot, rocky exoplanet scientists recently observed with the Webb telescope, is about 30% larger than Earth and has stronger surface gravity. It is incredibly close to its host star and completes one full orbit around its star every 1.5 Earth days. This proximity heats the planet up to a surface temperature of 800 degrees Fahrenheit (430 degrees Celsius) and causes one side of the planet to always face the star while the other side is in permanent darkness. Nevertheless, scientists observed hints of water vapor around this exoplanet, which could indicate that it has an atmosphere.
These findings would be truly monumental since, until now, scientists have only detected water vapor on gaseous exoplanets. Finding an atmosphere around a rocky exoplanet would be an enormous milestone for the world of science and would signify a more significant similarity with planets in our own solar system, such as Earth and Mars.
Scientists are being meticulous in their approach to this discovery, however. It’s possible that the water vapor around these exoplanets could stem from their host star rather than the planets themselves. For example, even our own sun has water vapor in sunspot regions, which are cooler than other areas on the sun’s surface. Red dwarf stars, in particular, are known for having even more water vapor in their starspots than our sun. This could lead to a false interpretation of water vapor as a planetary atmosphere surrounding the closely orbiting exoplanet.
As a result, astronomers must be cautious in their interpretation of the data gathered by the James Webb Space Telescope. Future observations and experiments using different instruments will be necessary to determine definitively whether these newly discovered exoplanets have atmospheres.