Harsh Space Weather Dooms Life on Exoplanets Near Red Dwarf Stars
How rare is life in our universe? It might just be far less likely than we once thought. Astronomers looking for habitable worlds have found that harsh space weather may doom life on planets near red dwarf stars.
Researchers have been putting a lot of focus on planets around red dwarf stars. These types of stars are actually the most common, comprising about 80 percent of the stars in the universe. Yet now, scientists have found that the space weather coming from these stars may strip the atmosphere of any rocky planet orbiting the star's habitable zone.
Red dwarf stars are actually smaller and cooler than our own sun. This means that in order for life to survive, a planet must be far closer to a red dwarf. Yet because the planet is closer, then it's subjected to severe space weather.
Previous studies have actually looked at the impact of stellar flares from a red dwarf on a nearby planet. Yet this latest work examines the effect of the red dwarf's constantly blowing stellar wind. More specifically, the researchers used a computer model to represent three known red-dwarf planets circling a middle-aged red dwarf.
"A red-dwarf planet faces an extreme environment, in addition to other stresses like tidal locking," said Ofer Cohen, one of the researchers, in a news release.
In this case, the scientists found that even an Earth-like magnetic field couldn't protect a habitable-zone world from the star's space weather.
"If Earth were orbiting a red dwarf, then people in Boston would get to see the Northern Lights every night," said Cohen in a news release. "On the other hand, we'd also be in constant darkness because of tidal locking, and blasted by hurricane-force winds because of the dayside-nightside temperature contrast. I don't think even hardy New Englanders want to face that kind of weather."
The findings reveal that red dwarfs may actually be unable to host planets that are capable of life. This reveals that scientists may want to look elsewhere as they continue their quest to discover life on other planets.
The findings were presented at a meeting of the American Astronomical Society.