Astronomers using the European Space Agency’s XMM-Newton Space Observatory and LOFAR telescope have conclusively detected an explosion of material ejected into space by another star.
According to the ESA report, this is an explosion powerful enough to strip the atmosphere of any unfortunate planet in its path.
This burst is a coronal mass ejection (CME), an eruption typically seen coming from the Sun. During a CME, large amounts of material are ejected from the star and flood the surrounding space. These spectacular eruptions can shape and cause space weather, eroding the atmospheres of nearby planets, like the dazzling auroras seen on Earth.
But while coronal mass ejections (CMEs) are common in the Sun, no convincing ones have been detected so far in other stars.
“For decades, astronomers have been trying to detect coronal mass ejections (CMEs) in other stars,” says Joe Cullingham of the Netherlands Institute for Radio Astronomy (ASTRON), author of the new study published in Nature.
Previous discoveries have suggested or hinted at its existence, but it has not been clearly confirmed what kind of material escaped into space. “Now I’ve achieved it for the first time,” he celebrated.
When a coronal mass ejection (CME) travels through the star’s layers into interplanetary space, it creates a shock wave and a burst of radio waves (a type of light). This short, powerful radio signal was detected by Joe Cullingham and his colleagues and found to originate from a star some 40 light years away (just under 15 times the diameter of our solar system, a considerable distance by cosmic standards).
“This kind of radio signal will not exist unless the material completely escapes from the star’s strong magnetic bubble. In other words, it is caused by EMC,” the astronomer added.
Dangerous to any planet
The star emitting material is a red dwarf, a type of star that is much fainter, cooler, and smaller than the Sun. It is completely different from our star. It has about half the mass, rotates 20 times faster, and has a magnetic field 300 times more powerful. Most of the known planets in the Milky Way galaxy orbit this type of star.
This radio signal was detected with the LOFAR (Low Frequency Array) radio telescope thanks to a new data processing method developed by co-authors Cyril Tasse and Philippe Zarka of the Paris Observatory PSL.
The team then used ESA’s XMM Newton Observatory to measure the star’s temperature, rotation, and brightness in X-rays. This was essential for interpreting radio signals and understanding what was happening.
“We needed the sensitivity and frequency of LOFAR to detect radio waves,” said co-author David Konijn.
Researchers have discovered that coronal mass ejections (CMEs) occur at a dizzying speed of 2,400 kilometers per second. This speed is observed in only one out of every 20 CMEs that occur on the Sun. The ejecta had enough velocity and density to completely remove the atmosphere of a planet orbiting close to the star.
in search of life
The ability of coronal mass ejections (CMEs) to strip planets of their atmospheres is an interesting discovery for the search for life around other stars.
As we know, a planet’s habitability for life is defined by its distance from its parent star. That is, whether the planet is within the star’s “habitable zone” (the region where liquid water can exist on the surface of a planet with a suitable atmosphere).
This is an ideal situation. If it’s too close to a star, it gets too hot, if it’s too far away, it gets cold, and somewhere in between is ideal. But what if the star is particularly active, regularly spewing out dangerous material and causing violent storms?
Planets that regularly experience powerful coronal mass ejections, even if their orbits are suitable, can lose their atmospheres completely, leaving behind barren rock, making the world uninhabitable.
“This study opens up new observational frontiers in the study and understanding of flares and space weather around other stars,” added ESA researcher Henrik Eklund of the European Space Research and Technology Center (ESTEC) in Noordwijk, Netherlands.
The discovery also contributes to the understanding of space weather, a long-standing focus of ESA missions and a topic currently being explored by the SOHO, Prova, Swarm and Solar Orbiter missions.
Meanwhile, XMM Newton is one of the leading explorers of the hot, extreme universe. Launched in 1999, the space telescope has observed the cores of galaxies, studied stars to understand their evolution, explored the surroundings of black holes, and detected intense bursts of energy radiation from distant stars and galaxies.
“XMM-Newton will help us discover how coronal mass ejections (CMEs) vary from star to star. This is not only interesting for the study of stars and the Sun, but also for the search for habitable worlds around other stars,” said Eric Courkers, ESA’s XMM-Newton project scientist.
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