The James Webb telescope has found an Earth-like planet with possible traces of an atmosphere 26 light-years away
Kyiv • UNN
James Webb detected a signal of water vapor on GJ 486 b. Subsequent data indicated an almost bare surface and possible starspots.
The James Webb Space Telescope detected a signal resembling water vapor as the rocky exoplanet GJ 486 b passed in front of its star; however, follow-up observations showed that the planet likely has little to no atmosphere. SpaceDaily reports, writes UNN.
Details
GJ 486 b is located approximately 26 light-years from Earth in the constellation Virgo. Its radius is about 1.3 times that of Earth, its mass is close to three Earth masses, and it completes an orbit around its red dwarf in 1.47 days.
During the initial observations, the NIRSpec instrument detected a signal in the spectrum corresponding to the absorption of water vapor. This could have indicated a water-rich atmosphere, but a similar signal could have been produced by cooler regions on the star's surface itself.
Follow-up observations
Two observations using MIRI measured the planet's thermal emission as it passed behind its star. The results obtained are inconsistent with a model of a dense atmosphere and are more consistent with an almost bare rocky surface.
GJ 486 b is only a few million kilometers from its star and receives approximately 40 times more radiation than Earth does from the Sun. Its equilibrium temperature is about 700 kelvins, while its dayside is even hotter.
Researchers do not rule out the presence of a thin atmosphere, but for now, an explanation involving cool starspots better fits the data. Observations of GJ 486 b also demonstrate the difficulty of searching for atmospheres on rocky planets orbiting red dwarfs.