Red Dwarf Star TVLM 513-46546 Generates Extremely Powerful Magnetic Field


Using the Atacama Large Millimeter/submillimeter Array (ALMA) in Chile, astronomers have discovered that a dwarf star located about 35 light-years away from Earth has extremely powerful magnetic field that can rival the most intense magnetic regions of the sun.

The M-class red dwarf dubbed TVLM 513-46546 is so small and cool it is in the dividing line between stars that fuse hydrogen and brown stars but the magnetic field it spews is so powerful that satellites would fail to function if our planet orbits around this star.

The sun is a relatively peaceful star that once in while releases solar flares that threaten to damage satellites and power grids on Earth. Smaller and cooler stars could be expected to be calmer but this particular star shows evidence of having much stronger flares than what the sun produces.

Researchers said that the extraordinary magnetic field observed in this star is possibly linked to the constant flurry of solar flare-like eruptions.

"We argue that the emission is due to the synchrotron process, excluding thermal, free-free, and electron cyclotron maser emission as possible sources," Peter Williams, from the Harvard-Smithsonian Center for Astrophysics, and colleagues reported.

If similar stars are as stormy, potentially habitable planets that orbit them would be much less hospitable than previously believed.

"If we lived around a star like this one, we wouldn't have any satellite communications. In fact, it might be extremely difficult for life to evolve at all in such a stormy environment," said Peter Williams, from the Harvard-Smithsonian Center for Astrophysics.

The star spins very fast making a complete rotation about every 2 hours. In comparison, the sun takes almost a month to make a spin on its axis.

Scientists were baffled by data showing that this dwarf has magnetic field several times more powerful than the sun because the physical processes that produce sun's magnetic field should not apply in such a small object but the star proved to be a magnetic powerhouse.

Observations using ALMA revealed flare-like emissions at a frequency of 95 GHz. It was the first time that astronomers detected such high frequencies from a red dwarf star. The emissions were likewise 10,000 times brighter compared to what the sun produces regardless that the tiny star has less than a tenth of the sun's mass.

"These early results show how ALMA opens a new window for studying the magnetic activity of ultracool dwarfs, particularly shedding light on the particle acceleration mechanism operating in their immediate surroundings," the researchers wrote in their study, which was accepted for publication in the journal Astrophysical Journal.

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