Red Dwarf Stars Could Strip Away Planetary Protection

Red dwarf stars are the commonest type of stars, making up about 75% of the stars in our galaxy. They are much smaller and much less massive than our Sun and for that reason a lot dimmer. If planets are found around these stars, then given the number of red dwarfs, life could then be commonplace. But a group of scientists led by Dr. Aline Vidotto of the University of St. Andrews has cast doubt on this idea.

Their work suggests that the magnetic fields of red dwarfs could squash down those found around planets like the Earth, leaving any life vulnerable to radiation from space. Dr. Vidotto presented her work on Tuesday 2 July at the National Astronomy Meeting in St. Andrews, Scotland.

Because of their faintness, even small planets in orbit around red dwarf stars block out a significant amount of light if they pass between the star and the Earth. The low masses of these stars also mean that the gravitational pull of an Earth-sized planet is enough to make its star wobble as the planet moves around it. This motion leads to a back and forth shift in lines in the spectrum of the star that can be detected with telescopes on Earth.