Using the new observations from the James Webb Space Telescope (JWST), astronomers have made a surprising discovery of methane emission on a brown dwarf, which is a cold and isolated world. This finding, published in the journal Nature, suggests that this brown dwarf may generate aurorae similar to those observed on Earth, Jupiter, and Saturn. Brown dwarfs are more massive than planets but lighter than stars and are commonly found in our solar neighborhood, with thousands already identified. One particular brown dwarf, known as W1935, located 47 light years away, was found to emit methane gas, which is a rare observation for objects of this kind. W1935 has a surface temperature of approximately 400° Fahrenheit and a mass estimated to be between 6-35 times that of Jupiter.
After studying a number of brown dwarfs with the JWST, a team led by Jackie Faherty noticed that W1935 had a unique feature of emitting methane, which differs from the typical observations of methane absorbing light on giant planets and brown dwarfs. This discovery sparked excitement among the researchers, leading to further investigation into the phenomenon. Computer modeling revealed that W1935 likely has a temperature inversion, where the atmosphere becomes warmer with increasing altitude. This is a surprising finding since W1935 is an isolated object without an apparent external heat source, raising questions about the origin of the additional upper atmosphere heat.
Further analysis indicated that the methane emission and temperature inversion observed on W1935 could be due to the presence of aurorae on the brown dwarf, similar to those observed on Jupiter and Saturn in our solar system. The team hypothesized that high-energy particles interacting with the brown dwarf’s magnetic field and atmosphere could be responsible for generating the aurorae. However, since W1935 lacks a host star to receive solar winds, the researchers suggested the possibility of an active, yet-to-be-discovered moon orbiting the brown dwarf, similar to the moons of Jupiter and Saturn contributing to their auroral activity.
The study’s findings shed light on the potential for aurorae on a cold and isolated object like W1935, posing new questions and challenges for planetary scientists. The team’s research draws connections between the methane emission, temperature inversion, and auroral activity observed on W1935 and those seen on planets in our solar system, suggesting similarities in the underlying mechanisms driving these phenomena. This groundbreaking discovery highlights the power of new observational tools like the JWST in unveiling hidden aspects of our universe and paves the way for further exploration and understanding of the diverse worlds beyond our own.
