As for stars, class M stars, better known as red dwarfs, look like they should be pretty benign. These stars are much cooler than our Sun and, as their name suggests, are relatively small in both mass and surface area. They burn their fuel slowly due to relatively low temperatures, which means they have very long lifespans.

They are also extremely common: About 70 percent of the stars in the Milky Way are M-class. The combination of their stability and abundance, as well as the relatively high probability that rocky planets orbiting red dwarfs will enter the habitable zone, means that these systems are sometimes viewed as promising areas for the search for life.

But red dwarfs have an annoying habit: They produce too many starbursts compared to their larger relatives. Debate has been going on for years about what this might mean for the habitability of planets in these systems, and in bad news for potential extraterrestrial inhabitants of red dwarf systems, a new paper published this month suggests that these outbursts could be much more dangerous than outbursts. we thought.

After analyzing a decade of observations from the now-defunct GALEX space telescope, the paper’s authors examined data from nearly 300,000 stars and focused on 182 flares originating from M-class systems.

Although, as stated in the document, “[попередні] While “large-scale observational studies of star explosions have been conducted mostly at optical wavelengths,” this study focuses on the ultraviolet (UV) radiation emitted by these events. It specifically examines radiation in the near-UV (175-275 nm) and far-UV (135-175 nm) ranges.

While not necessarily harmful to the development of the complex molecules we believe are essential for life, such radiation can have a dramatic impact on the potential habitability of a planet.

The dose makes the poison: The high-energy photons produced by stellar explosions can, in relatively modest amounts, catalyze the formation of such compounds, but in large enough quantities these photons can also destroy the atmospheres of such planets, including their protective ozone layers. .

A new study suggests that previous studies may have significantly underestimated the amount of ultraviolet radiation produced by star explosions. As explained in the paper, common practice has been to model the electromagnetic radiation from flares as a blackbody distribution.

Their temperature is modeled as approximately 8,727 degrees Celsius (15,741 Fahrenheit); this is significantly higher than the surface of their parent star: the coolest red dwarfs have surface temperatures of around 1,727°C (3,140°F), while the hottest can approach 3,227. °C (5,840 °F).

However, this new study shows that the emission from star explosions does not actually follow this distribution. Of the 182 events the researchers examined, 98 percent had UV emissions above what would be expected if they followed the normal blackbody spectrum. As stated in the article, “this indicates that there is a permanent black body of 9000 K [спектрального розподілу енергії] Not enough to explain the levels [дальнього ультрафіолетового] “The radiation we observe”

If stellar explosions caused by red dwarfs produce disproportionate amounts of ultraviolet radiation, planets orbiting these stars could be more hostile to life than we think, even if they meet criteria for being potentially habitable (such as surface temperatures that allow for water). exist in liquid form). The study was published on: Monthly Notices of the Royal Astronomical Society.