Small red dwarf rivals our own Sun

Observations of a cool, red dwarf star that is producing an intensely powerful magnetic field could have major implications for the search for habitable planets outside our Solar System.

Published: February 20, 2015 at 12:00 pm

Astronomers have discovered a small, cool red dwarf star that seems to be producing a magnetic field powerful enough to rival the most intense magnetic regions of our own Sun.


The physical processes that generate our Sun’s magnetic field should not be occurring in such a small star, which is so tiny and cool that it is sitting on the fence between the category of stars, which fuse hydrogen, and brown dwarfs, which don’t.

It is also emitting such intense solar-like flares that it would barrage any nearby planets with charged particles.

"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," says lead author Peter Williams of the Harvard-Smithsonian Center for Astrophysics (CfA).

The dwarf star, TVLM 513-46546, was detected using the Atacama Large Millimeter/sublimeter Array (ALMA) in Chile.

Credit: NRAO/AUI/NSF; Dana Berry / SkyWorks

It is thought that the star’s strong magnetic field could be associated with the flare eruptions, which create magnetic field lines that act like cosmic particle accelerators.

These emit radio signals that ALMA can detect.

The star is just 10 per cent the mass of our own Sun and spins so rapidly that it completes a full rotation every two hours.

Our Sun takes about 25 days.

These observations mark the first time that emissions at such high frequencies have been detected from a red dwarf star, reaching as much as 10,000 times brighter than our Sun produces.

The astronomers behind the study are suggesting the results could have implications in the search for habitable planets outside the Solar System, as red dwarfs are the most common type of star in the Galaxy.


Any Earth-like planets would have to orbit very close to their host red dwarf star to be warm enough for liquid water to exist, but in the case of the one in this study, such proximity would leave it open to powerful radiation that would destroy any life on its surface.

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