The “parent” celestial bodies of planets that Earthlings hope to find life on could potentially be monstrous.
In a study published in the Monthly Notices of the Royal Astronomical Society, a research team led by the Institute for Astronomy at the University of Hawaii (IfA) warns that planets orbiting red dwarf stars may have been stripped of life.
This is because red dwarf stars—the coolest and smallest type of star—are much scarier than they appear.
Exoplanets that are most suitable for life and closest to us, such as Proxima b, may be in danger from their parent star – (Graphic: INSTITUTE FOR ASTRONOMY, UNIVERSITY OF HAWAII).
Previously, it was noted that a few red dwarfs are aggressive, capable of producing ultraviolet flare bursts strong enough to harm planets.
Now, the research team has discovered that this is more common and severe than we thought.
They utilized archival data from the GALEX space telescope to search for outbursts among 300,000 nearby stars.
GALEX was a NASA mission that has since ceased operations, but it managed to observe most of the sky in near and far UV wavelengths from 2003 to 2013.
Using new computational techniques, the research team extracted novel insights from the data.
The UV emission potential of stars can generally erode the atmospheres of the planets orbiting them, threatening the ability of these planets to support life or, conversely, contributing to the formation of RNA building blocks, which are essential for life.
Unlike Earth, the amount of UV that planets around red dwarfs receive is excessively high.
This energy level is 3 to 12 times greater than what life requires, leading to destruction.
The exact cause of this stronger far-ultraviolet emission remains unclear, but the research team suggests it is due to the distinct composition of red dwarfs compared to our Sun.
Thus, despite being much smaller and cooler than our parent star, red dwarfs have become “killers.”
Unfortunately, red dwarfs are the most common type of star in our Milky Way galaxy.
Many exoplanets that astrobiologists are hopeful may harbor life also have “parents” that are red dwarfs.
One example is Proxima b (Proxima Centauri b), which orbits the red dwarf Proxima Centauri, located just 4.2 light-years away, where some research groups have anticipated the existence of marine life.
This would be unfortunate news for astrobiologists, although it provides crucial data that helps us pinpoint more accurately the worlds with the potential to support life.
