“But even if there were magnetic fields, given the stellar proximity of habitable zone planets around M-dwarf stars, this might not be enough to protect them.” Whether exoplanets have magnetic fields or not is still an open question for astronomers. “Further, the Earth has a very powerful planetary magnetic field that shields us from these intense blasts of solar plasma,” says Zic. Some of the dishes of the ASKAP telescope in Western Australia. Stars like our Sun also emit such radiation, but since the Sun is much hotter, Earth sits in the habitable zone much further away. This radiation would severely erode a planet’s atmosphere, leaving it exposed to further dangers such as intense X-rays or UV light. “What our research shows is that this makes the planets very vulnerable to dangerous ionising radiation that could effectively sterilise the planets,” Zic explains. However, the habitable zones of small, cool red dwarfs are tucked in close to the star – much closer than Mercury is to our Sun – which could put planets in the path of the star’s ferocious weather.
One is particularly exciting because it exists in the habitable zone around the star, where it receives enough warmth for liquid water to hypothetically exist. “It seems likely that the galaxy’s most common stars – red dwarfs – won’t be great places to find life as we know it.”Īstronomers previously knew that Proxima Centauri is home to two rocky planets. “This is probably bad news on the space weather front,” says Zic. Lead researcher Andrew Zic, from the University of Sydney, says it’s highly likely similar intense events occur on M-type red dwarfs. The Australian and US team used optical and radio telescopes to observe our closest star – Proxima Centauri, just 4.2 light-years away – as it simultaneously emitted powerful stellar flares and radio bursts, providing the first definitive link between these two events in a star other than our Sun.īut here in our Solar System, these events are linked to coronal mass ejections – massively energetic blasts of ionised plasma and radiation. But this study, published in The Astrophysical Journal, suggests that planets orbiting M-type red dwarf stars will have to contend with violent weather conditions.
Over the past decade, astronomers have discovered more than 4300 planets orbiting distant stars and the list is growing every week. Wild space weather may mean most of the exoplanets in the Milky Way are uninhabitable, according to new research.