Washington DC: Astronomers have discovered that a dim, cool dwarf star is generating a surprisingly powerful magnetic field, one that rivals the most intense magnetic regions of our own Sun.
The star's extraordinary magnetic field is potentially associated with a constant flurry of solar-flare-like eruptions. As with our Sun, these flares would trace tightly wound magnetic field lines that act like cosmic particle accelerators: warping the path of electrons and causing them to emit telltale radio signals that can be detected with ALMA.
Such intense flare activity, the astronomers note, would barrage 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.
The team used ALMA to study the well-known red dwarf star TVLM 513-46546, which is located about 35 light-years from Earth in the constellation Bootes.
The star is a mere 10 percent the mass of the Sun and is so small and cool that it's right on the dividing line between stars (which fuse hydrogen) and brown dwarfs (which don't). One of the things that make this small star remarkable is that it spins rapidly, completing a full rotation about every two hours. Our Sun takes about 25 days to rotate once at its equator.
The study appears online in The Astrophysical Journal.