Astronomers have caught the clearest glimpse yet of a giant, violent solar storm blowing away from a star outside our own, an event that left scientists to redefine how they understand space weather throughout the galaxy. The eruption, a coronal mass ejection from a red dwarf about 130 light-years away, was observed not only by its telltale radio signature but in real time, evidence that the charged material had really broken free of the star’s magnetic grasp and raced out into interstellar space.
How the stellar eruption was captured and confirmed
The occurrence was announced about a recent event that took place near the M-dwarf StKM 1-1262 and was spotted through a speedy, two-minute radio-burst capture by the Low Frequency Array — a continent-spanning radio telescope in Europe.
The signal moved from higher to lower frequency, the telltale signature of a shock wave driven by an outward coronal mass ejection. Follow-up observations with the European Space Agency’s XMM-Newton observatory further anchored the flare activity that accompanied the burst, adding strength to claims that the suspected CME was an honest-to-goodness one and not some more localized magnetic hiccup.
Indirect evidence of stellar CMEs — short dimming events or spectral red-shifting in hydrogen lines — has been observed for many years, but unambiguous detections had proven elusive. Radio shock signatures, also known as type II bursts in solar physics, are more difficult to fake: they demand a supersonic front that carves its way through plasma, pushing the emission down in frequency as it expands. In other words, the star did not just sputter; it erupted like a geyser.
Extreme velocity, and a boot camp for space weather
From the radio drift, the team calculates that it would have been about 5.37 million miles per hour — fast enough to travel from Earth to the Sun in less than a day — as it cast off this material. On the Sun, very few CMEs achieve these speeds. Standard solar CMEs fly anywhere between a few hundred to about 2,000 miles per second; the fastest of these outliers go faster than that. This is well into the extreme.
That matters because kinetic energy increases with the square of speed. If one of these CMEs were to hit a close-in planet, it would press its magnetosphere thinner, ramming energy into the upper atmosphere and possibly causing fast atmospheric escape. Earth’s own magnetic field and thick air form strong defenses, but in this case, even we are not immune or invulnerable: severe storms can harm satellites and our power grids too — think of the Quebec blackout and very large radio interruptions during past geomagnetic events. Around a puny, active star where planets orbit at riskily close range, the stakes are higher still.
A blow to exoplanet habitability of red dwarfs
M-dwarfs such as StKM 1-1262 rule the Milky Way and account for many of the rocky worlds we’ve unearthed so far, including systems like TRAPPIST-1 and Proxima Centauri.
Their habitability zones are much closer to the star so flares, charged particles, and CMEs wash over planets with greater regularity. If eruptions that powerful are common, they can methodically peel away atmospheres over time and lay surfaces open to bombardment with harsh radiation, rendering any young oceans sterile.
We have a cautionary tale close at hand: NASA’s MAVEN mission has discovered that Mars lost most of its atmosphere to steady solar wind erosion after the weakening of the Martian magnetic field. Translate that process to a planet orbiting a currently active red dwarf, and the losses might speed up. There’s a reason why a high-priority program with NASA’s James Webb Space Telescope (JWST) is working to find hints of those intact atmospheres around small, temperate M-dwarf planets. This detection is a new input to such models, and now eliminates assumptions in favor of measurements.
Why this case is different from prior stellar CME hints
It all comes down to timing and technique. The sensitivity of LOFAR to low radio frequencies allowed us to follow the swift evolution of the shock, and concurrent X-ray observations established that this shock was associated with underlying flare activity that is known to drive a CME. The analysis, which appears in Nature and involves international collaboration led by researchers at the Netherlands Institute for Radio Astronomy, takes the field beyond hints to a more organized set of characteristics that can be applied routinely for predicting stellar space weather.
Most importantly, the radio data prove that substance really did escape the star’s magnetic stranglehold — it’s a little like noticing the smoke plume clearing the rim of a volcano rather than just recording seismic tremors. It’s that distinction exoplanet scientists care about most: A runaway CME can plunge through a planetary system and sandblast atmospheres again and again.
What comes next for tracking coronal mass ejections
Now that researchers have one bona fide stellar CME in the bag, they can tune surveys to just the right frequencies, durations, and cadence to spot more. LOFAR will be closely followed by the next-generation Square Kilometre Array, as well as space telescopes that are sensitive to X-rays and ultraviolet light, which can map how often these eruptions happen and how powerful they are in different types of stars. Those rates will plug directly into climate and escape models for exoplanets, allowing astronomers to prioritize targets on which atmospheres have a better shot at sticking around.
The find also strengthens the connection between traditional solar physics and the wider exoplanet revolution. No longer is space weather just a local story about auroras or the resilience of the electrical grid; it is an environmental factor that spans our galaxy. With better numbers on stellar CMEs, scientists can go from wondering whether red dwarfs are deadly to life and start calculating by how much — and under what conditions planets like Proxima b might beat the odds.