The presence of an aurora could also be a crucial piece in the search for Earth-like exoplanets, two of which were only discovered last month.
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The famed Northern and Southern Lights of Earth, scientifically known as the aurora borealis and aurora australis respectively, are truly one of our planet’s most spectacular natural wonders. With no solar-generated charged particles to ignite the reaction, the team suspects that a planet moved through its magnetosphere to cause the display.
Aurora can be seen at high and low latitudes on Earth. Although brown dwarfs are technically stars, they are much cooler than main sequence stars and behave more like planets.
Brown dwarfs are often referred to as failed stars because they did not gather enough mass to start nuclear fusion at their cores, but they are too large to be classed as planets, estimated to be between 13 and 80 Jupiter masses in size. The dwarf, located just 20 light years away, showed evidence of aurora activity, which is typically more associated with planets than stars.
Using the VLA they detected a bright pulse of radio waves that appeared as the brown dwarf rotated around.
Astronomers have spotted the first aurora ever in an object beyond our Solar System and it’s not coming from a planet, but from a “failed star”.
That set off a long-running chase, with Hallinan and his team spotting LSR J1835+3259, using the Karl G. Unlike our own multi-colored displays, the researchers say these auroras would appear bright red due to an atmoshphere largely made up of hyrdrogen.
Why is it more red than green?
Artist conception of an aurora over the polar region of a brown dwarf. “This suggests that it may be possible to detect this type of activity from extrasolar planets, many of which are significantly more massive than Jupiter”.
“That could be particularly interesting because whether or not a planet has a magnetic field may be an important factor in habitability”, Hallinan said. The reason for this is because LSR J1835+3259 has a magnetic field perhaps 200 times stronger than Jupiter’s, Hallinan added.
Brown dwarfs are not quite stars. Brown dwarfs, though, do not generate large flares and charged-particle emissions in the way that our sun and other stars do, so the radio emissions were surprising.
Scientists theorized that there must be another source of charged particles nearby aside from the Sun or materials are stripped off the surface of the brown dwarf to produce its own electrons. “We know how controversial the situation was with Pluto, where astronomers had to look hard to try to decide if it is fundamentally one of the major planets of the solar system, or the first of the Kuiper Belt objects”. What makes them a remarkable sight is the fact that they are thousands of times brighter than the auroras on our home planet. Finally, they used the Keck telescopes to measure the brightness of the brown dwarf over time.
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Despite its power, the aurora is too faint to be seen with the naked eye. The findings of the astronomers about brown dwarfs can be read in the July 30 issue of Nature.
