Astronomy: Eruption on a star would have swept away a planet's atmosphere
Solar flares can cause impressive auroras on Earth. Now, one has been confirmed on a star for the first time – and it was much less harmless.
Artist's impression of the eruption
(Image: Olena Shmahalo/Callingham et al.)
(Image:Â SOHO (ESA & NASA), NASA/SDO/AIA, JHelioviewer/D. MĂĽller)
Using several European observatories, it has been possible for the first time to observe a coronal mass ejection on another star. This has now been made public by the European Space Agency ESA now made public, and it is explained that this has been attempted for decades. While there have already been indications that these eruptions, which we know from the Sun, also occur on other stars, definitive proof has now been provided that material was indeed ejected into space during such an event on another star. At the same time, the eruption now observed was much more violent than what we are familiar with: it would have completely stripped a planet orbiting the star of its atmosphere, the research group writes.
Too violent for a planet
The crucial radio signal was found using the European LOFAR telescope network. This could only have been generated if the material ejected from the star had actually left it. Therefore, it was clearly a coronal mass ejection, or, according to the English term, CME. The star responsible for this has about half the mass of our Sun, rotates 20 times faster, and has a magnetic field 300 times stronger than the team writes. It is a red dwarf star; more exoplanets have been found around no other star type.
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The fact that the first CME observed on another star was so violent that a planetary atmosphere would not have survived it is relevant for the search for possible extraterrestrial life. The finding confirms that the habitability of conditions is not solely determined by the distance of an exoplanet to its star. To receive enough energy in orbit around a red dwarf for water to exist in liquid form, exoplanets must come dangerously close to it. Previously, the focus was on radiation. However, the new study now also shows that for understanding other stars, we no longer need to rely solely on our Sun; direct observation is becoming easier. It is presented in Nature.
(mho)
