Ever since the James Webb Space Telescope (JWST) began its routine science observations, every day there seems to be something new in the world of astronomy. Impressive discoveries ranging from the most distant stars to images of planets outside the solar system. This time, the new telescope has given us confirmation that some planets may have rock clouds.
Using Webb’s NIRSpec and MIRI instruments, astronomers have directly detected silicate clouds in the atmosphere of a brown dwarf. This would be the first time evidence of silicate-rich clouds has been found in a world beyond the solar system.
The brown dwarf in question is named VHS 1256 b and was discovered in 2015. It orbits two small red dwarf stars about 72 light-years from Earth in the constellation Corvus. It is nearly 20 times the mass of Jupiter, and is relatively young, with a reddish-hued atmosphere.
Brown dwarfs are objects that form when a baby star doesn’t accumulate enough mass to kick-start hydrogen fusion in its core. But brown dwarfs can fuse deuterium or heavy hydrogen, that is, hydrogen with one proton and one neutron in the nucleus, instead of just one proton.
This feature allows brown dwarfs, unlike ordinary exoplanets, to emit their own heat and light. This means that it is possible to capture them directly, although it is very difficult because their brightness is extremely low compared to stars. However, the infrared wavelengths and sensitivity that Webb specializes in have provided us with this juicy discovery.
In addition to the strange clouds, astronomers also detected carbon dioxide (CO2). In this case, it would be the second time, since only a few days ago the JWST discovered strong evidence of CO2 on an exoplanet. By using a precise method of subtraction, known as transmission spectroscopy, researchers can measure the content of an exoplanet’s atmosphere.
“In a calm atmosphere, there is an expected ratio of, say, methane and carbon monoxide,” Sasha Hinkley, an astronomer at the University of Exeter in the UK and one of the study’s co-authors, told Forbes. “But in many exoplanet atmospheres we are finding that this ratio is highly skewed, suggesting that there is turbulent vertical mixing in these atmospheres, dredging up carbon dioxide from deep to mix with methane higher up in the atmosphere.”