Could Earth life survive on a red dwarf planet?
Even though exoplanet science has advanced significantly in the last decade or two, we're still in an unfortunate situation. Scientists can only make educated guesses about which exoplanets may be habitable. Even the closest ...
That doesn't stop scientists from trying to piece things together, though.
One of the most consequential questions in exoplanet science and habitability concerns red dwarfs. Red dwarfs are plentiful, and research shows that they host multitudes of planets. While gas giants like Jupiter are comparatively rare around red dwarfs, other planets are not. Observational data shows that about 40% of red dwarfs host super-Earth planets in their habitable zones.
Red dwarfs have a few things going for them when it comes to exoplanet habitability. These low-mass stars have extremely long lifespans, meaning the energy output is stable for long periods of time. As far as we can tell, that's a benefit for potential habitability and the evolution of complex life. Stability gives life a chance to respond to changes and persist in their niches.
One of the most consequential questions in exoplanet science and habitability concerns red dwarfs. Red dwarfs are plentiful, and research shows that they host multitudes of planets. While gas giants like Jupiter are comparatively rare around red dwarfs, other planets are not. Observational data shows that about 40% of red dwarfs host super-Earth planets in their habitable zones.
Red dwarfs have a few things going for them when it comes to exoplanet habitability. These low-mass stars have extremely long lifespans, meaning the energy output is stable for long periods of time. As far as we can tell, that's a benefit for potential habitability and the evolution of complex life. Stability gives life a chance to respond to changes and persist in their niches.
But red dwarfs have a dark side, too: flaring. All stars flare to some degree, even our sun. But the sun's flaring is not even in the same league as red dwarf flaring. Red dwarfs can flare so powerfully that they can double their brightness in a very short period of time. Is there any way life could survive on red dwarf planets?
New research from scientists in Portugal and Germany examines that question. To test the idea of red dwarf exoplanet habitability, the researchers used a common type of mold and subjected it to simulated red dwarf radiation, protected only by a simulated Martian atmosphere.
New research from scientists in Portugal and Germany examines that question. To test the idea of red dwarf exoplanet habitability, the researchers used a common type of mold and subjected it to simulated red dwarf radiation, protected only by a simulated Martian atmosphere.
This artist's illustration shows planets orbiting a red dwarf star. Many red dwarfs have planets in their habitable zones, but red dwarf flaring might mean those zones aren't habitable at all. New research explores the idea. Credit: NASA
This figure from the research shows the Top of Atmosphere UV and X-ray radiation on Proxima Centauri and TRAPPIST-1 exoplanets. Credit: Mota et al, 2024
This figure from the research shows the estimated subsurface X-ray absorbed dose throughout a thin layer of soil (orange) or water (blue). Water has a lower capacity for attenuating these high-energy photons, so a thicker water layer is needed to reduce the same dose compared to soil. The three dashed lines represent the LD90 (Lethal dose for 90% of a population) values for E. coli, A. niger, and D. radiodurans. E. coli is a common bacterium, and D. radiodurans is a radiation-resistant extremophile. Credit: Mota et al, 2024