Artist rendering of a red dwarf or M star, with three exoplanets orbiting. About 75 percent of all stars in the sky are the cooler, smaller red dwarfs. (NASA)
It’s tempting to look for habitable planets around red dwarf stars, which put out far less luminosity and so are less blinding. But is it wise?
That question has been near the top of the list for many exoplanet scientists, especially those involved in the search for habitable worlds.
Red dwarfs are plentiful (about three-quarters of all the stars out there) and the planets orbiting them are easier to observe because they are generally close in and because the light from the host star is so reduced compared with a star like our sun. What’s more, they last for much longer than larger, hotter stars — giving habitable planets time to become inhabited.
A potentially rich target, but with some drawbacks that have become better understood in recent years. Not only are most planets orbiting these red dwarf stars tidally locked, with one side always facing the sun and the other in darkness, but the life history of red dwarfs is problematic. They start out with powerful flares that many scientists ...