The James Webb Space Telescope recently made an unexpected discovery that has puzzled astronomers. The telescope has detected a massive object, larger than Jupiter, emitting methane. This object, known as W1935, is an isolated brown dwarf and unlike gas giants like Jupiter, it doesn’t have a host star to provide the energy for its methane emissions.
Methane emissions are typically associated with gas giants that are heated in their upper atmospheres and display vivid auroras, but W1935 receives no stellar wind to power its methane emissions, making its eerie glow a mystery. Astronomers have put forward several theories to explain this phenomenon, including interstellar plasmas, internal processes, or the presence of an active moon similar to those orbiting Jupiter and Saturn.
The discovery of W1935 was initially made by citizen scientist Dan Caselden, with assistance from NASA’s Wide Field Infrared Survey Explorer. The findings were later confirmed by astronomer Jackie Faherty’s team at the American Museum of Natural History. Computer models have shown that W1935 has a noticeable temperature inversion, meaning it grows warmer with altitude, a phenomenon also observed on gas giants.
The leading theory for temperature inversions involves external heating from the presence of auroras, which may explain similar observations of brown dwarfs in the past. However, W1935 is the first brown dwarf detected beyond our solar system that shows evidence of methane emission, making it a unique observation. Additionally, it is the coolest auroral candidate of its kind.
Further observations with the James Webb Space Telescope may provide more insights into W1935 and help determine if the presence of an active moon could account for its methane emissions. As astronomers continue to unravel this mystery, the discovery of W1935 adds to our understanding of the complex and diverse nature of objects beyond our solar system.