Scientists using the LOFAR radio telescope and ESA's XMM-Newton observatory have detected the first confirmed coronal mass ejection from a star other than the Sun. The eruption, from a red dwarf 130 light-years away, traveled at 2400 km per second and could strip atmospheres from nearby planets. This discovery has significant implications for the habitability of exoplanets around such stars.
Astronomers have long suspected that stars beyond our Sun produce coronal mass ejections (CMEs), violent bursts of plasma and charged particles that drive space weather. For decades, evidence remained elusive, but a team led by Joe Callingham of the Netherlands Institute for Radio Astronomy (ASTRON) has now confirmed one using combined observations from the Low Frequency Array (LOFAR) radio telescope and the European Space Agency's (ESA) XMM-Newton X-ray observatory.
The CME originated from a red dwarf star approximately 130 light-years away. This star, cooler and dimmer than the Sun, has about half its mass, rotates 20 times faster, and possesses a magnetic field estimated to be 300 times stronger. Most exoplanets in the Milky Way orbit red dwarfs like this one. The eruption generated a shock wave and a brief, intense radio signal, which LOFAR detected thanks to advanced data-processing techniques developed by co-authors Cyril Tasse and Philippe Zarka at the Observatoire de Paris-PSL.
XMM-Newton provided crucial measurements of the star's temperature, rotation, and X-ray brightness, allowing the team to interpret the radio burst and confirm the CME's nature. 'We needed the sensitivity and frequency of LOFAR to detect the radio waves,' says co-author David Konijn, a PhD student at ASTRON. 'And without XMM-Newton, we wouldn't have been able to determine the CME's motion or put it in a solar context... Neither telescope alone would have been enough—we needed both.'
The CME reached speeds of roughly 2400 km per second, occurring in only about 1 out of every 2000 solar events. Its density and energy suggest it could entirely strip atmospheres from close-orbiting planets, reducing them to bare rock. This poses challenges for habitability in the habitable zones of red dwarfs, where liquid water might otherwise persist.
'Astronomers have wanted to spot a CME on another star for decades,' Callingham notes in the study published in Nature. 'We've now managed to do this for the first time.' Henrik Eklund, an ESA research fellow at ESTEC in Noordwijk, adds, 'This work opens up a new observational frontier for studying... eruptions and space weather around other stars.' The findings highlight how intense space weather may threaten exoplanet atmospheres, informing the search for life beyond the Solar System.