For years, astronomers have observed the stars and wondered whether violent storms like those shaking the Sun could erupt somewhere in the universe. The star usually sends giant clouds of plasma into space – known as coronal mass ejections – capable of altering space weather, generating dazzling aurora borealis or make you tremble to satellites that orbit the Earth. But besides him, no one had seen another celestial body do the same… until now. An international team of astronomers, combining the careful gaze of the LOFAR radio telescope and the European Space Agency’s (ESA) XMM-Newton space observatory, has managed to detect for the first time a large stellar explosion in a star outside our cosmic neighborhood, the solar system.
The protagonist of this event is a red dwarf called StKM 1-1262located about 40 light years from our planet, indicates the new study published this Wednesday in the journal Nature. The star, smaller and cooler than the Sun, unleashed an eruption that consisted of a burst of radio waves – something like very powerful, short bursts of energy – that shot through space, giving indications that a colossal outpouring of magnetized plasma had erupted on its surface.
“The magnetic explosion occurred in 1883 and the light from that event only arrived in 2016, when we detected it,” Cyril Tasse, researcher at the Paris Observatory (France) and co-author of the discovery, explains to EL PAÍS. The study covered the sky of the Northern Hemisphere and each region was analyzed for eight consecutive hours. When a star’s CME moves from the corona (the outermost layer of its atmosphere) into space, it generates a shock wave. The violence of the explosion was such, the recent survey indicates, that any nearby planet would have been unfortunate enough to lose its atmosphere completely. Tasse recalls that the expulsion lasted about a minute. “The star was in that position, so there wasn’t much discussion. We knew it would be great,” he adds.
The discovery was not a matter of luck. Behind that solitary explosion there are years of meticulous work and technology. It was just the scream of plasma that finally managed to detect LOFAR, the network of antennas spread across Europe that captures the lowest frequencies in the sky. Tasse recalls that the expulsion lasted about a minute. This type of signal, according to scientists, would not exist if matter had not completely abandoned the star’s magnetic bubble.
To estimate the extent of the phenomenon, the researchers applied models similar to those used to study the Sun, but adapted to the conditions of this red dwarf. Therefore, they developed a technique to study, simultaneously, all the stars that fall within the field of view. The expert compares it to throwing a fishing net into the sea, to “try to catch as many fish as possible”. Measurements revealed that the ejected plasma was traveling at a speed of approximately 2,400 kilometers per second. Without this data analysis technique, developed at the Paris Observatory, they would not have been able to detect it.
This speed, unthinkable for most solar flares, is observed only in the most extreme events on the Sun, although such a crash has never occurred. If this happened, humanity would be in grave danger. Although the red dwarf has about half its mass, rotates 20 times faster and has a magnetic field 300 times stronger, in this type of star events can be much more frequent and powerful.
The best-known exoplanets orbit stars like StKM 1-1262, making these discoveries crucial to understanding the galaxy. Benjamín Montesinos, astrophysicist and researcher at the Center for Astrobiology (CSIS), indicates that it was known that red dwarfs have great magnetic activity, especially when they are young. “Until now the flares had been observed in X-rays, ultraviolet and optical rays. The novelty is radio detection, which integrates these observations and allows a direct comparison with solar phenomena”, says the expert who did not participate in the analysis.
A magnetic monster
The discovery raises serious questions about the habitability of worlds orbiting red dwarfs, the most common stars in the Milky Way and the hosts of the best-known exoplanets. A planet constantly hit by powerful coronal mass ejections could lose its entire atmosphere, reducing itself to barren, uninhabitable rock. Cyril Tasse does not hesitate to explain it. “For liquid water to exist on the surface of a planet, an adequate temperature must be maintained, and this depends on the greenhouse effect. This occurs when the atmosphere retains some of the energy coming from the star,” he points out.
But it is not enough to receive the right amount of light, you also need an atmosphere that does not allow the heat to disperse. “Him Holy Grail For researchers, it is now a question of finding planets similar to Earth, but around stars similar to the Sun”, adds Benjamín Montesinos.
The publication also broadens understanding of space weather in general, an area of research that the European Space Agency has followed for decades. XMM-Newton, launched in 1999, has been instrumental in studying the extreme environments of the universe. From galactic nuclei to explosions of radiation coming from distant stars and galaxies. Tasse announced that he and his team have detected other types of signals: “We believe we are seeing the aurora borealis on exoplanets, on the radio, which is quite interesting.”
It’s not just the Sun that throws fire into the void. Other stars do it too. And that discovery, more than a simple astronomical observation, opens a new window towards understanding how life is forged and how it can at the same time vanish into the worlds that surround it.
