The exoplanet's atmosphere also contains methane and carbon dioxide.
The James Webb Space Telescope has found a strange alien
world shrouded in clouds of sand-like silicate grains.
The exoplanet discovery, described in a new paper as the
first detection of its kind, was made by the James Webb Space Telescope's
NIRSpec and MIRI instruments. In the data, astronomers spotted evidence of
silicate-rich clouds around a brown dwarf nearly 20 times the size of Jupiter.
The finding confirms some earlier theories about these odd planet-like worlds.
Brown dwarfs are strange objects that are not quite big
enough to ignite into stars but a little too big for ordinary planets. While
brown dwarfs can't burn regular hydrogen, they can produce their own light and
heat by burning deuterium (a less common isotope of hydrogen that contains an
extra neutron).
The brown dwarf in question is called VHS 1256 b and orbits
two small red dwarf stars, some 72 light-years from Earth in the constellation
Corvus, or crow, in the southern sky. Astronomers discovered the strange
exoplanet in 2016 and it has puzzled them ever since due to its reddish glow.
They believed that glow could be caused by some type of atmosphere.
Observations from the James Webb Space Telescope have now confirmed those
theories, revealing that VHS 1256 b must be wrapped in thick clouds full of sand-like
silicate grains, according to Forbes.
Webb also detected water, methane, carbon monoxide, carbon
dioxide, sodium and potassium in the atmosphere of VHS 1256 b.
"We will know more from iterations on the data
reduction," Brittany Miles, an astronomer at the University of California,
Irvine, and lead researcher on the project, told Space.com in an email.
"So far, it looks pretty similar to theoretical expectations."
The Webb data were so detailed they showed that the ratio of
the various gases changes throughout VHS 1256 b's atmosphere, which suggests
the atmosphere is not still, but instead wild and turbulent.
"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 U.K. and one of the study's co-authors, told
Forbes. "But in many exoplanet atmospheres we're finding that this ratio
is very skewed, suggesting that there is turbulent vertical mixing in these
atmospheres, dredging up carbon dioxide from deep down to mix with the methane
higher up in the atmosphere."
VHS 1256 b is small for a brown dwarf, which means that the body is likely young. The exoplanet orbits 360 sun-Earth distances from its two parent stars, following an oval-shaped orbit that takes 17,000 years to complete.