Using data from NASA’s Chandra X-ray Observatory and other telescopes, astronomers have discovered a new threat to life on planets like Earth: a stage where intense X-ray radiation from exploding stars can affect planets 100 light-years away. This result has implications for studies of exoplanets and their habitability, as outlined in our latest press release.

This newly discovered threat comes from a supernova blast wave hitting the dense gas surrounding the exploding star, as shown in the upper right corner of our artist’s image. When this effect occurs, it can produce large doses of X-rays that reach the Earth-like planet (shown below left, illuminated by the main star on the right) months or years after the explosion and persist for decades. Such an intense impact could trigger extinction on the planet.

Reporting on this threat, based mostly on X-ray observations of 31 supernovae from NASA’s Chandra X-ray Observatory, Swift and NuSTAR missions, and ESA’s XMM-Newton, and beyond, a new study suggests planets may be exposed. lethal dose of radiation from about 160 light-years away. The four supernovae in the study (SN 1979C, SN 1987A, SN 2010jl and SN 1994I) are shown in composite images containing Chandra data in a complementary image.

Until now, most studies of the effects of supernova explosions have focused on the dangers of two eras: the intense radiation the supernova produces in the days and months after the explosion, and the energetic particles that arrive hundreds or thousands of years later.

If a stream of X-rays passes over a nearby planet, the radiation can drastically change the chemical composition of the planet’s atmosphere. For an Earth-like planet, this process could destroy much of the ozone that ultimately protects life from the host star’s dangerous ultraviolet radiation. In addition, it can lead to extinction by causing the death of a wide variety of organisms, especially sea creatures, at the bottom of the food chain.

After years of exposure to the deadly X-rays from the supernova interaction and the ultraviolet radiation of the Earth-like host star, large amounts of nitrogen dioxide can form as pictured, causing a brown haze in the atmosphere. Land masses “greening” can also occur due to damage to plants.

A separate artist’s impression (panel 1) shows the same Earth-like planet teeming with life during a nearby supernova explosion, years before most X-ray effects are felt (image 2).

Of the four supernovae in the image set, SN 2010jl produced the most X-rays. According to the authors, this sent lethal doses of X-rays to Earth-like planets less than 100 light-years away.

There is compelling evidence that supernovae formed near Earth about 2 to 8 million years ago, including the discovery of radioactive iron in various parts of the world. According to the researchers, these supernovas were located about 65 to 500 light-years from Earth.

While the Earth and Solar System are now in safe space in terms of potential supernova explosions, many other planets in the Milky Way are not. These high-energy events will actually shrink regions of the Milky Way galaxy known as the Galactic Life Zone, which are conducive to life as we know it. Because X-ray observations of supernovae, especially those that interact strongly with their environment, are rare, the authors call for more observations of interacting supernovae in the months and years after the explosion.