Astronomers have analyzed data from the decommissioned GALEX space telescope to study hundreds of thousands of red dwarf stars.
From a study published in the Monthly notices of the Royal Astronomical Societythey identified 182 stellar outbursts on red dwarfs, showing that these radiation emissions could pose a greater threat to potentially habitable planets than previously thought.
Red dwarfs, smaller and cooler than the Sun, make up about 70% of the stars in the Milky Way and have a lifespan of more than 10 billion years.
Because many rocky Earth-sized planets, some slightly larger, have already been discovered around red dwarfs – which are often within their habitable zones – scientists have long speculated that these worlds could support life.
However, red dwarfs have a crucial feature: they produce frequent stellar outbursts, or bursts of radiation and energy, at a much higher rate than the Sun. The new study suggests that these outbursts could be much more dangerous to potentially habitable planets than previously thought.
While most previous studies focused on solar flares in optical wavelengths, the researchers in this study focused on ultraviolet radiation emitted by red dwarf flares.
They found that 98% of the eruptions produced more powerful ultraviolet emissions than previous estimates, indicating that previous research may have significantly underestimated the impact of these events.
While these outbursts may not prevent the emergence of life, astronomers warn that they could threaten its survival. Strong ultraviolet radiation could strip planets of their atmosphere, including vital components such as the ozone layer.
This would make otherwise habitable planets inhospitable, even if they lie in the star’s habitable zone and have surface water.
As a result, the search for extraterrestrial life on planets orbiting red dwarfs may prove more challenging than previously expected.
