NASA’s James Webb Space Telescope has detected glowing aurorae in the atmosphere of a brown dwarf located over 70 light years from Earth. This marks the first time aurorae have been spotted beyond our solar system, offering an intriguing glimpse into the magnetic properties of these isolated failed stars.
Aurorae Indicate Strong Magnetic Field
The aurorae were spotted emanating from a brown dwarf designated LSR J1835+3259. Brown dwarfs are celestial objects larger than planets but smaller than stars, which never gained enough mass to ignite nuclear fusion in their cores.
Webb detected a bright infrared aura of emissions coming from LSR J1835’s pole. According to researchers, this indicates the presence of powerful aurorae generated by the brown dwarf’s magnetic field interacting with its atmosphere.
“The Webb observations definitely show that strong aurorae can occur even on isolated objects like brown dwarfs,” said Kelle Cruz, an astrophysist at Hunter College in New York and co-author of the research. “The brightness of the aurorae means that magnetic processes are happening on LSR J1835.”
Clues to Brown Dwarf Magnetism
The aurorae provide tantalizing clues to the magnetic properties of cool substellar objects like LSR J1835.
“I think these aurorae give us a window into measurements that are important to understanding magnetism in brown dwarfs,” said Cruz.
Understanding what drives the magnetic fields can in turn reveal insights into the interiors and atmospheres of brown dwarfs.
Table 1: Key Facts on LSR J1835+3259
| Category | Detail |
|---|---|
| Type of Object | L or T brown dwarf |
| Distance from Earth | Over 70 light years |
| Surface Temperature | ~1,300 degrees Fahrenheit |
| Mass | 30-55 times mass of Jupiter |
Unlike stars which generate magnetic fields through the churning nuclear reactions in their core, brown dwarfs would develop magnetism through different mechanisms given their inert interiors. The aurorae spotted by Webb provide evidence that there are indeed vigorous magnetic fields circling this brown dwarf.
Unraveling an Enigma
The discovery of aurorae on LSR J1835 is helping astronomers unravel the enigma of magnetism on brown dwarfs. Models have predicted their chaotic convection and rapid rotation can spawn strong magnetic fields. The Webb observations provide confirmation that these processes are indeed active.
“The radio and optical emission from this object defies easy explanation,” said lead researcher Pavel Evanko from the University of Virginia. “But Webb’s infrared observations uncover new clues – like the aurorae – that can help us disentangle the complex physical processes of this exotic, enigmatic object.”
First Aurora Beyond Solar System
Prior to this, glowing aurorae have only been witnessed in our own solar system – on Earth, Jupiter, Saturn, Uranus, Neptune, and even Mars. Webb’s infrared vision has now spotted the first ever aurorae on an isolated substellar object beyond our neighborhood.
“Finding aurorae beyond the solar system is hugely significant,” said Cruz. “It means magnetic processes we’ve been studying right here at home also shape more exotic substellar objects light years away.”
The aurorae indicate LSR J1835 has a global magnetic field encompassing the entire brown dwarf rather than just localized magnetic fields in certain regions. This is similar to how Earth’s magnetosphere envelops our entire planet and helps shield us from solar winds while also powering the shimmering northern and southern lights.
Next Steps
The team plans to conduct follow up observations using Webb as well as ground-based telescopes like ALMA in Chile. These could reveal tantalizing insights into the interior structure, atmospheric dynamics, and magnetospheric properties of LSR J1835.
“We only have one object displaying this type of activity right now but this finding shows us brown dwarfs have a lot in common with planets in our own solar system,” concluded Cruz. “More detections like this can reveal the magnetic secrets these objects are hiding.”
The auroral discovery underscores the game-changing infrared capabilities of NASA’s $10 billion Webb observatory. Launched in late 2021, Webb is rapidly rewriting astronomy textbooks and uncovering new insights into substellar objects like brown dwarfs as well as exoplanets, black holes, and the earliest galaxies in the high redshift universe over 13 billion light years away.
To err is human, but AI does it too. Whilst factual data is used in the production of these articles, the content is written entirely by AI. Double check any facts you intend to rely on with another source.
