The challenge in answering this question lies in the brevity of our observational record. The energy released by a solar flare can be measured directly only from outside Earth’s atmosphere, or determined indirectly from data and images gathered by space probes. Both approaches have been available only since the dawn of the space age roughly seventy years ago. In that entire period, the Sun has produced no superflare. Yet seventy years is a vanishingly small sliver of time for a star that has been burning for 4.6 billion years. As Natalie Krivova, an MPS scientist and lead author of the new study, explained, there is some evidence suggesting that the Sun, too, can produce superflares at great intervals, but there is no direct proof. The new research set out to close that evidentiary gap through an ingenious combination of modern solar observation and historical record-keeping stretching back centuries.

One line of evidence comes from the Sun’s stellar peers. Our galaxy contains many thousands of stars that resemble the Sun in key characteristics such as mass, temperature, and rotation rate. In late 2024, MPS researchers demonstrated that these Sun-like stars produce superflares approximately once every hundred years. If our star behaves like its counterparts, and there is good reason to think it might, then superflares should be a recurring, if rare, feature of solar activity. A second line of evidence comes from natural archives of solar history. Tree trunks preserved for millennia and ice cores extracted from the Arctic’s permafrost contain spikes in the concentrations of radioactive isotopes, isolated, short-lived, and exceptionally strong signals that suggest Earth has repeatedly been exposed to intense bombardment by high-energy solar particles in the distant past. These cosmogenic fingerprints are the only long-term traces such events leave behind, because a flare itself, no matter how powerful, leaves no lasting physical record on the Sun or in its immediate surroundings.

The relationship between these extreme particle eruptions and superflares remains an active area of investigation. According to Valeriy Vasilyev, an MPS scientist and lead author of a companion review article also published in Philosophical Transactions of the Royal Society A, the current state of research indicates that extreme particle eruptions and particularly intense flares often, but not always, occur together. This partial overlap means that isotope spikes in tree rings and ice cores are suggestive but not conclusive evidence of past superflares. What was needed was a way to connect the physics of flare production to measurable quantities that humans have been recording for far longer than the space age. The new study led by Krivova provides exactly that bridge, and it does so by exploiting one of the most carefully maintained observational datasets in all of science.

The first step of the analysis relied on modern instrumentation. The team examined observational data collected by NASA’s Solar Dynamics Observatory between 2010 and 2016, a period of intense solar monitoring during which the spacecraft continuously tracked the Sun’s surface, magnetic field, and atmosphere. From this dataset, the researchers identified the 300 strongest flares of the observation window and correlated the amount of energy each flare released with the size of the corresponding active region on the Sun’s visible surface. Active regions are areas where the magnetic field is particularly strong and structurally complex, and they are intimately associated with sunspots, the dark, cooler patches that dot the solar surface when magnetic fields suppress convection. Active regions are widely considered the potential starting points for eruptions, and quantifying the relationship between their size and flare energy is a cornerstone of modern flare forecasting.

Of course, as Krivova noted, the researchers knew that no superflares had occurred during the observation period. The power of the approach lies in the statistical relationship they uncovered: the link between released energy and active region size should hold true for more powerful events as well, extrapolating the physics observed in ordinary flares into the extreme regime that has never been witnessed on the Sun directly. This empirical scaling allowed the team to convert a measurement of active region area into an estimate of maximum possible flare energy, effectively turning the solar surface into a historical archive of eruptive potential.

The second step reached deep into the observational past. Sunspots have been systematically and regularly recorded for about 400 years, beginning with the telescopic observations of the early seventeenth century. As Theodosios Chatzistergos, an MPS scientist and co-author of the new study, explained, these records offer another way to look into the history of our star. Because sunspots are the visible manifestation of the magnetic complexity in active regions, the size of a sunspot group can be used to infer the size of the associated active region, and from there the strength of a possible eruption. The researchers combed through four centuries of sunspot records with particular interest in the rare outliers, the exceptionally large spots that stood apart from the ordinary run of solar activity and represented the most extreme magnetic configurations the Sun has displayed in the modern era.

One such outlier towers over the historical record: the giant sunspot of April 1947. This behemoth covered approximately 0.6 percent of the visible solar disk, and its diameter was about forty times that of Earth. It remains one of the largest sunspots the Sun has displayed since the beginning of systematic solar observations. Remarkably, no superflare erupted from this region during its transit across the solar disk. The Sun, in other words, loaded the barrel but never fired. Yet the new study demonstrates that a sunspot of this size is statistically capable of triggering a superflare in rare cases. The implication is sobering: the machinery for the most extreme bursts of radiation in the stellar repertoire exists on our own star, and it has assembled itself within living memory.

As Krivova put it, our Sun has superflare potential. It can produce massive sunspots that, in principle, can serve as the starting point for the most extreme bursts of radiation. The finding reframes the question from whether the Sun could ever generate a superflare to whether it has done so, and how often. The statistical frequency suggested by Sun-like stars, roughly once per century, means that a superflare could occur within a human lifetime, and that the absence of one during the space age is not evidence of safety but a matter of timing. Whether a superflare has actually erupted on the Sun in the historical period remains one of our star’s open mysteries, but the new work transforms that mystery from speculation into a quantifiable risk that can be studied, modeled, and prepared for.

The practical stakes are considerable. A Carrington-class event alone would stress twenty-first-century technological infrastructure in ways the nineteenth century never experienced, and a superflare, releasing orders of magnitude more energy, would represent a hazard of a different category entirely. Satellites in orbit, astronauts beyond the protection of Earth’s atmosphere, aviation routes over the poles, and continental power distribution networks would all face exposure. By establishing an empirical link between the largest sunspots in the historical record and the energy scales of superflares, the MPS-led team has given space weather researchers a concrete observational benchmark: when the next giant sunspot rounds the eastern limb of the Sun, scientists will be able to assess its eruptive potential with a rigor that was impossible before this study. The Sun’s most violent capabilities, long hidden in the statistics of distant stars and the chemistry of ancient trees, are now written in its own spotted face, waiting to be read.

Subject of Research: Solar superflare potential inferred from historical sunspot records and flare energy statistics

Article Title: Sun: New evidence of superflares

Article References: Sun: New evidence of superflares. (n.d.). Original publication

Image Credits: AI Generated

DOI: Not provided

Keywords: Sun, superflares, solar flares, sunspots, space weather, Solar Dynamics Observatory, Max Planck Institute for Solar System Research, Carrington Event, active regions, solar activity, stellar flares, Philosophical Transactions of the Royal Society A

The stakes of this question extend far beyond stellar physics. Space telescopes such as Kepler and TESS have revealed that magnetically active stars frequently unleash superflares, explosive releases of magnetic energy exceeding 10^33 erg, roughly the energy of the largest solar flares on record and often much greater. On the Sun, large flares are usually accompanied by CMEs, eruptions that carry billions of tons of plasma into interplanetary space and drive the most severe space weather at Earth. If young solar-type stars behave the same way, their planets would be bathed not only in intense X-ray and ultraviolet radiation but also in dense magnetized plasma, shocks, and energetic particles, conditions that could strip atmospheres, alter chemistry, and influence whether a rocky world can ever become habitable.

Yet confirming a CME on another star is extraordinarily difficult. Unlike the Sun, distant stars cannot be spatially resolved, so astronomers must infer eruptions from disk-integrated spectra and light curves. The most productive technique searches for transient Doppler shifts in chromospheric lines, especially H-alpha. Cool filament or prominence material erupting toward the observer produces a blue-shifted absorption or emission feature, exactly as seen in solar eruptions. Other diagnostics include coronal dimming, a temporary fading of X-ray or ultraviolet emission caused by the evacuation of coronal plasma, and radio bursts such as type-II and type-IV events that trace shocks and energetic electrons. Each method has limitations, and a single signature is rarely enough to prove that material actually escaped the star.

The breakthrough came from dedicated monitoring of two nearby young solar-type stars: EK Draconis, a G1.5V star roughly 50 to 125 million years old, and V889 Herculis, a G0V star only about 30 million years old. Using the KOOLS-IFU spectrograph on the 3.8-meter Seimei Telescope in Okayama, Japan, Namekata and collaborators captured a spectacular event on April 5, 2020, when EK Draconis produced a superflare of about 2 x 10^33 erg accompanied by a clear blue-shifted absorption component in H-alpha, reaching velocities up to 510 kilometers per second. The feature decelerated in a way consistent with the star’s surface gravity, indicating that cool material had been ejected from near the stellar surface, the hallmark of a filament eruption.

A second event on April 10, 2022 revealed the complementary geometry. During a superflare of roughly 1.5 x 10^33 erg, the H-alpha line showed a blue-shifted emission component moving at 400 to 690 kilometers per second, interpreted as a prominence erupting above the stellar limb. Because the feature appeared in emission rather than absorption, and because its velocity was too high to be explained by flare-related line broadening, the natural interpretation is cool material rising beyond the edge of the visible disk. Together, the two events demonstrate that both on-disk filament eruptions and off-limb prominence eruptions can be detected in unresolved stellar spectra, mirroring the two ways solar eruptions are observed.

Critical to these interpretations is the solar-stellar connection. By analyzing solar filament eruptions as if the Sun were an unresolved point of light, the so-called Sun-as-a-star approach, researchers have shown that the disk-integrated H-alpha signature of a solar eruption closely resembles the EK Draconis events, including the blue-shifted absorption and a post-flare dimming-like feature. This calibration provides a powerful check against false positives. Data-driven modeling strengthens the case further: pseudo two-dimensional magnetohydrodynamic simulations reproduce the observed H-alpha dynamic spectra, showing that cool erupting material embedded in an expanding magnetic loop can decelerate under gravity while the surrounding structure continues to expand outward and evolve into a CME.

Do these eruptions actually escape? Several lines of evidence say yes, at least sometimes. The observed velocities approach or exceed the escape velocity of EK Draconis, with velocity dispersions suggesting top speeds of 660 to 1080 kilometers per second. On the Sun, the CME front typically propagates several times faster than its filament core, implying stellar CME fronts of several thousand kilometers per second. Moreover, an empirical solar criterion based on the velocity-length-scale relation, which separates CME-associated from confined filament eruptions, places the EK Draconis events well above the threshold. The inferred masses of the cool erupting material, ranging from about 10^17 to 10^20 grams, are vastly larger than typical present-day solar filament masses and broadly consistent with extrapolations of solar mass-flare energy relations.

Not everything fits the simple solar extrapolation, however. The kinetic energies of the stellar events fall below some naive solar scaling relations, a discrepancy that has two competing explanations. Physically, the strong overlying magnetic fields of active stars may suppress or decelerate eruptions, confining even enormous events. Observationally, H-alpha traces only the cool core of an eruption, whose projected velocity is expected to be slower than the surrounding coronal front, so the inferred kinetic energies should be treated as lower limits. Resolving this controversy is one of the central challenges for the coming decade, and it will require multi-wavelength observations that can trace the hotter, faster components of eruptions.

Frequency matters as much as size. A five-year monitoring campaign of EK Draconis and V889 Herculis detected fifteen H-alpha superflares, including four with blue-shifted signatures of eruptions, yielding a lower-limit association rate of about 27 percent and an eruption frequency of roughly 0.21 events per day for EK Draconis. Combining this rate with the estimated masses gives a CME-driven mass-loss rate of order 10^-13 to 10^-12 solar masses per year, comparable to the expected steady wind of a young solar-type star. If confirmed, transient eruptions would be a major player in the spin-down and angular momentum evolution of young stars, not a curiosity.

The implications for planets are profound. CME impacts can compress magnetospheres, disturb ionospheres, and drive atmospheric escape, particularly on weakly magnetized worlds like early Mars and Venus, while energetic particles from CME-driven shocks can both destroy ozone and synthesize greenhouse gases and prebiotic molecules. Modeling of the young solar analog kappa^1 Ceti suggests that CME impact probabilities for early terrestrial planets may be as high as 30 percent. The review points to a future built on coordinated campaigns spanning optical, X-ray, ultraviolet, and radio wavelengths, with missions such as ESCAPE, LAPYUTA, XRISM, NewAthena, and the SKA poised to fill critical gaps. For the first time, astronomers have an empirical foundation for understanding the space weather that young Earths endured, and perhaps that made life possible.

Subject of Research: Observational evidence for coronal mass ejections from young solar-type stars and their impact on planetary space weather

Article Title: Coronal mass ejections from young Suns: an observational view through the solar–stellar connection

Article References: Namekata, K. (2026). Coronal mass ejections from young Suns: an observational view through the solar–stellar connection. Astrophysics and Space Science, 371(9), Article 110. https://doi.org/10.1007/s10509-026-04641-w

Image Credits: AI Generated

DOI: 10.1007/s10509-026-04641-w

Keywords: coronal mass ejections, superflares, young solar-type stars, EK Draconis, stellar activity, space weather, H-alpha spectroscopy, solar-stellar connection, exoplanets, stellar mass loss, filament eruptions, magnetic fields