Soon after the first American satellite was launched in 1958, scientists discovered a startling discovery about the planet Earth. Massive amounts of powerful protons and electrons appeared to continuously fly around the rocky globe we call home, producing particle streams that were difficult to explain.
These streams would soon be referred to as the Earth’s radiation belts, and they would develop quite a reputation over time. For instance, radiation belts are known to put astronaut crews in peril and to threaten human technology in orbit. Later, it would be discovered that similar belts were enclosing Jupiter and other nearby planets as well. In fact, only last year a belt was discovered around an object outside of our neighborhood, and not only that but around one of the most puzzling things discovered thus far: a brown dwarf, or “failed star.”
We received important observations of the phenomena from one of the two science teams that independently observed this belt of brown dwarfs on Thursday (August 24), with a resolution that is nearly 50 times greater than that of NASA’s James Webb Space Telescope.
According to Juan Bautista Climent, an astronomer at the Universidad Internacional de Valencia, “this is the first object beyond the solar system where a radiation belt has been detected.” This discovery demonstrates the universality of this structure by demonstrating that radiation belts can occur not only on planets but even on brown dwarfs.
Brown dwarfs are a bit of a mystery to astronomers who study them since they are neither quite huge enough to be a star nor still too heavy to be a planet. The one that Climent and his team analyzed, LSR J1835+3259, sports a traditional space name.
Climent stated that objects like LSR J1835+3259 serve as a link between planets and stars. Their radio emission, as a result, combines certain traits from both.
The team’s discovery that this particular brown dwarf appears to be wearing a radiation belt similar to our planet’s—actually, it’s a little closer to the ones encircling Jupiter—was made possible by those peculiar radio emissions. Later, more on that.
Examining some discovery information: LSR J1835+3259, as Climent remarked, was kind of the ideal target for researchers to explore because it is only 18.5 light-years from us (which is really close, cosmically speaking) and emits enough radio emission data to use a method known as very long baseline interferometry (VLBI).
In a nutshell, VLBI connects numerous telescopes dispersed over Earth to create a massive virtual instrument. Each of those scopes is focused on the same source at once, capturing signals and measuring things like variations in signal arrival times and other things. Overall, it’s like looking into space via a gigantic telescope the size of Earth.
Climent stated that “radio emissions reveal structures and shapes that are frequently hidden in visible light.” “With them, we can map out the sweeping arms of galaxies, trace the paths of high-speed particles around magnetic fields, and even peer through cosmic dust clouds. It’s like getting a new pair of eyes.”
Surprisingly, this was the method used by researchers with the Event Horizon Telescope to obtain the first direct photograph of a black hole.
Climent stated that the radio emission from LSR J1835+3259 has a morphology similar to that of Jupiter’s and Earth’s radiation belts. “We used the European VLBI Network (EVN) to achieve a resolution 50 times better than that of the James Webb Space Telescope,” Climent remarked.
Similar methods were employed by the other team who discovered LSR J1835+3259’s belt, although they did it using a different VLBI network called the High Sensitivity Array.
Climent remarked, “We were, and still are, pushing the limits of what radio measurements can teach us about the universe. We wished to investigate the surroundings of brown dwarfs using this potent method.
Without VLBI, the brown dwarf under study would simply appear as a point of light, similar to a typical star that may be seen in the sky.
Why are brown dwarf radiation belts a big deal?
Putting Earth into perspective