Study reveals intense UV flares on red dwarfs, challenging life formation

We still don't have any evidence of extraterrestrial life. Although arguments suggest that its existence is possible, scientists also find reasons why its development could be impossible.

Astronomers from the University of Hawai'i have, in their research, reached conclusions that may revolutionise current beliefs about the possibility of life on exoplanets. Their discoveries suggest that red dwarfs—the most numerous stars in the universe—experience ultraviolet radiation explosions much more intense than previously assumed.

- Few stars have been thought to generate enough UV radiation through flares to impact planet habitability. Our findings show that many more stars may have this capability, according to the study's lead author, Vera Berger. Her work was published in the renowned journal "Monthly Notices of the Royal Astronomical Society".

Berger and her team conducted research based on an analysis of archival data from the GALEX space telescope. This data described explosions that took place on 300,000 stars located at a relatively close distance to Earth.

GALEX is a telescope that is no longer in use, but it has previously observed most of the sky in the ultraviolet wavelength range.

- Combining modern computer power with gigabytes of decades-old observations allowed us to search for flares on thousands and thousands of nearby stars - explains Michael Tucker from Ohio State University, who collaborated with the research team.

Ultraviolet radiation is not exclusively harmful. As scientists explain, UV rays can contribute to forming the chemical components of life. However, they can also destroy a planet's atmosphere. The key here is the dose of radiation. New calculations suggest that the radiation intensity is, on average, three times higher than usual and sometimes even twelve times higher.

- A change of three is the same as the difference in UV in the summer from Anchorage, Alaska to Honolulu, where unprotected skin can get a sunburn in less than 10 minutes - explains Benjamin J. Shappee, one of the astronomers involved in the study.

The reason why the radiation is so strong remains unknown. Researchers speculate that the radiation from flares may be concentrated only at specific wavelengths, including ultraviolet, which could indicate the presence of atoms such as carbon and nitrogen.

- This study has changed the picture of the environments around stars less massive than our Sun, which emit very little UV light outside of flares - says Jason Hinkle, one of the authors of the discovery.