James Webb telescope's 'shocking' discovery may hint at hidden exomoon around 'failed star'

Using the James Webb Space Telescope (JWST), astronomers have made the surprising discovery of methane emissions coming from a brown dwarf, or "failed star."

The find suggests that the brown dwarf features aurorae, and might even be orbited by an undiscovered exomoon, researchers said.

The JWST brown dwarf discovery is surprising, because these cold and isolated worlds are not expected to be warm enough for methane to emit infrared light. 

The findings came about as a result of a JWST program to investigate 12 brown dwarfs. They suggest that these failed stars can generate aurorae similar to Earth's northern lights and southern lights, as well as those seen over Jupiter and Saturn. The lack of a star near this lonely brown dwarf may mean that the polar lights over it are being generated by a hidden active moon. 

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The study team investigated the cold brown dwarf CWISEP J193518.59–154620.3 (W1935), located 47 light-years from Earth. While the mass of W1935 is poorly constrained, ranging from 6 to 35 times that of Jupiter, it is known to have a surface temperature of around 400 degrees Fahrenheit (204 degrees Celsius). That is around the temperature at which you'd bake chocolate chip cookies (failed brownies?).

"Methane gas is expected in giant planets and brown dwarfs, but we usually see it absorbing light, not glowing," Jackie Faherty, team leader and senior Education manager at the American Museum of Natural History, said in a statement. "We were confused about what we were seeing at first, but ultimately, that transformed into pure excitement at the discovery."