Sometimes it's not the perfection of the cosmos that makes it beautiful, but its failures. Scientists have discovered that brown dwarfs - the dim and failed stars of our universe - posses some stunningly planet-like characteristics, including breathtaking aurora displays.
That's at least according to a study recently published in the journal Nature, which details how researchers investigated a brown dwarf some 20 light-years away from Earth using both radio and optical telescopes.
"We're finding that brown dwarfs are not like small stars in terms of their magnetic activity; they're like giant planets with hugely powerful auroras," Gregg Hallinan, a researcher with the California Institute of Technology, explained in a statement. "If you were able to stand on the surface of the brown dwarf we observed -- something you could never do because of its extremely hot temperatures and crushing surface gravity -- you would sometimes be treated to a fantastic light show courtesy of auroras hundreds of thousands of times more powerful than any detected in our solar system." (Scroll to read on....)
Hallinan has long had his eye on brown dwarves , "failed stars" that never gained enough mass and energy to fuse hydrogen in their cores, the way most stars do. His interest was first piques back in 2000, when astronomers began finding radio emissions from brown dwarfs. This was surprising because brown dwarfs cannot not generate large flares and charged-particle emissions the way the sun and other kinds of stars do, leaving experts scratching their heads.
Then, as a graduate student in 2006, Hallinan discovered that these brown dwarf emissions pulse at consistent frequencies.
"We see a similar pulsing phenomenon from planets in our solar system," Hallinan, said "and that radio emission is actually due to auroras."
Traditionally, auroras are caused by a complex interplay between charged solar particles (which come in waves of solar wind), a planet's magnetosphere, and atmospheric gases that glow when heated. Aside from Earth's own stunning aurora borealis, astronomers have confirmed that Saturn and Mars boast their own stunning light shows thanks to the chaotic nature of their magnetic fields.
However, prior to Hallinan's investigation, this phenomenon had never been observed anything other than a planet or moon. (Scroll to read on...)
[Credit: Credit: Stephen Bourke/Caltech ]
To confirm his hunch, Hallinan and his colleagues conducted an extensive observation campaign of a brown dwarf called LSRJ 1835+3259, using the National Radio Astronomy Observatory's Very Large Array (VLA), the most powerful radio telescope in the world (as seen in the above video). Data from the VLA, in conjunction with optical observations from the Palomar's Hale Telescope and the W. M. Keck Observatory's telescopes, allowed the researcher to determine that the brown dwarf's radio pulses were directly linked to periodic spikes in the failed star's brightness (already thousands of times fainter than the Sun) and the emission of excited hydrogen particles.
"As the electrons spiral down toward the atmosphere, they produce radio emissions, and then when they hit the atmosphere, they excite hydrogen in a process that occurs at Earth and other planets, albeit tens of thousands of times more intense," Hallinan explained. "We now know that this kind of auroral behavior is extending all the way from planets up to brown dwarfs."
"This is a whole new manifestation of magnetic activity for that kind of object," Leon Harding, a technologist at NASA's Jet Propulsion Laboratory, Pasadena, California, and co-author on the study, added in a statement.
According to the researchers, the importance of this study doesn't stop at brown dwarves. Magnetic fields have long been considered an important part of planet habitability, so developing a better understanding of how thier strength influence all kinds of celestial bodies could eventually influence the exciting search for Earth-like cousins light-years away.
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