When Red Dwarfs Attack: High-energy UV radiation from stellar emissions can be life-threatening 

Groundbreaking research has revealed that red dwarfs can produce stellar emissions that carry much higher levels of ultraviolet (UV) radiation than previously believed, casting doubt on the ability of planets orbiting them to sustain life.

Red dwarfs can produce stellar emissions with much higher levels of ultraviolet (UV) radiation than previously estimated, which may affect the habitability of surrounding planets.

Groundbreaking research has revealed that red dwarfs can produce stellar emissions that carry much higher levels of ultraviolet (UV) radiation than previously believed. This discovery suggests that the intense UV radiation from these emissions may have a significant impact on whether planets around red dwarfs could be suitable for life. The research, led by current and former astronomers from the Institute for Astronomy at the University of Hawaii (IfA), was recently published in the journal Monthly Notices of the Royal Astronomical Society.

"Few stars have been thought to have the ability to produce enough UV radiation through emissions to affect the habitability of planets. Our findings show that there may be many more stars with this ability," said astronomer Vera Berger, who led the study as part of the Research Experiences for Undergraduates program at the IfA , an initiative supported by the National Science Foundation.

An extrasolar planet orbiting a red dwarf 

Berger and her team used archival data from the GALEX space telescope to search for emissions among 300,000 nearby stars. GALEX was a now-defunct NASA mission that simultaneously observed most of the sky at near- and far-UV wavelengths from 2003 to 2013. Using new computational techniques, the team derived new insights from the data.

"By combining modern computing power with gigabytes of decades-old observations, we were able to search for emissions in thousands of nearby stars," said Michael Tucker, an IfA postdoctoral fellow and current postdoctoral fellow at Ohio State University.

The double side of UV radiation 

According to the researchers, UV radiation from stellar emissions can either erode the atmospheres of planets and thus threaten their potential to support life, or contribute to the creation of RNA building blocks, which are necessary for the creation of life.

This study challenges existing models of stellar emissions and exoplanet habitability, showing that far-UV emissions are on average three times more energetic than commonly thought, and can reach energy levels twelve times higher than expected.

"A three-fold change is like the difference in summer UV radiation between Anchorage, Alaska and Honolulu, where bare skin can burn in less than 10 minutes," said Benjamin J. Sheffey, an IfA fellow astronomer who supervised Berger.

The mysterious nature of increased UV radiation 

The exact reason for this stronger UV radiation is unclear. The team believes that the radiation may be concentrated at certain wavelengths, indicating the presence of atoms such as carbon and nitrogen.

"This research has changed the understanding of the conditions around stars smaller than our Sun, which emit very little UV light," said Jason Hinkle, a doctoral student at the IfA who co-authored the study.

According to Berger, now a Churchill Fellow at the University of Cambridge, more data from space telescopes is needed to study the UV light from the stars, which is crucial to understanding the source of this radiation.

for the scientific article

More on the subject on the science website:

• Weizmann Institute scientists analyzed the composition of the elements emitted from a rare star, just before it exploded
• Strange supernovae reveal the stars' secrets
• Pioneering research: exposure to the sun - increases fertility
• Winter Vision / Anne-Marie Hodge
• Tanning has a biological clock

Topics: astrobiology, astronomy, atmosphere, extrasolar planet, planets, University of Hawaii at Manoa