I find myself returning again to discussing exoplanets: specifically exoplanets that may orbit the closest star to our Sun, Proxima Centauri. In a new study of this star using radio telescopes, astronomers have realized that this red-dwarf star is even more violent than previously thought. This has consequences for the two or more possible planets that orbit in this system. This work was led by Andrew Zic, who was able to link optical flares from Proxima Centauri with radio bursts.

This linkage has been previously seen with our Sun. According to Zic: Our own Sun regularly emits hot clouds of ionized particles during what we call ‘coronal mass ejections’. But given the Sun is much hotter than Proxima Centauri and other red-dwarf stars, our ‘habitable zone’ is far from the Sun’s surface, meaning the Earth is a relatively long way from these events.

Mercury is not someplace you want to be when the Sun acts out, but with Proxima Centauri, even Mercury’s orbit is too big to keep it within the habitable zone. The terrestrial world orbiting Proxima Cen is just 0.05 AU from the star, and its orbit is just 11.2 days long. At this distance, Zic says: This is probably bad news on the space weather front. It seems likely that the galaxy’s most common stars – red dwarfs – won’t be great places to find life as we know it.

So if you are working on some great fiction describing a civilization just 4.2ly away, know that your fiction needs life that is down with being radiated and okay with experiencing all the nasty weather we know comes with being a tidally locked world. While life may find a way, it likely won’t be something we have so far anticipated.

More Information

The University Of Sydney press release 

“A Flare-type IV Burst Event from Proxima Centauri and Implications for Space Weather,” Andrew Zic et al., 2020 December 9, The Astrophysical Journal