Violent red dwarf stars could be turning what would be lifeless “mini-Neptunes” into possibly life-bearing “exo-Earths,” a new study has found.
M-type red dwarf stars are typically high-flaring stars that create violent space weather and extreme tides, making life on nearby planets unlikely as the tides would be so strong as to warp the crust of the planet and cause heavy volcanic activity, according to a Discovery News report.
As a result, planets that are an Earth-like distance from the sun would be barren and uninhabitable — but not so for mini-Neptunes much farther away from the host stars, according to the study, which was produced by a team at the University of Washington.
For these mini-Neptunes, ice molecules would join with hydrogen and helium gases to form an icy and rocky core that would be surrounded by a thick, gaseous atmosphere.
These types of planets would be so cold that they would also be inhospitable to life, but they “need not always remain in place,” said Rodrigo Luger, the lead author of the paper that was published in the journal Astrobiology.
The tidal forces can induce what is known as inward planet migration, which would cause the small planet to have its atmosphere blown away after millions of years, and once it enters the star’s habitable zone, a hydrogen-free core would be left behind. This would result in a planet that would have plenty of surface water, because the core was rich in water ice, and now the planet is warm enough for the ice to melt and form oceans.
Still, that’s not enough to make them become habitable, as it would still need a fine balance between atmospheric chemistry and radiation from the host star, but it means that it’s possible that some planets out there have found that happy medium.
The planet would still be subject to the extreme tides of the dwarf star, but it’s possible those tides would be locked in one part of the planet, leaving that part inhospitable but the rest of it perfectly fine. Still, it would result in powerful storms that would ravage the planet, likely resulting in a situation where life would thrive only in very isolated regions of the planet.
Scientists won’t know more until they can use more advanced telescopes to detect atmospheres of worlds that revolve around red dwarf stars.
But, it does provide another possibility for finding life elsewhere in space.