Close-up of a star from another Galaxy taken

They had been keeping an eye on her for a long time, a decade or so, and it was clear that she was fading little by little, but the reason just wasn't clear.

Then, by having the four large European 8.2 metre aperture telescopes in Chile working in unison, they were able to obtain a sharp, exceptional and unique image of WOH G64, not very poetically named. It is the first image we have of a star outside our Galaxy, the Milky Way.

There is some clarity to be made: it is the first detailed image; in fact, we see billions of stars in our Galaxy, some also in other very nearby galaxies, but they are bright spots, even if we use the most powerful instruments, which is why the observation obtained by the international team of astronomers led by Keiichi Ohnaka, an astrophysicist at the Universidad Andrés Bello in Chile, is important. It shows us a red supergiant star that is probably about to explode as a supernova, one of the most energetic phenomena in the universe. To clarify: a red supergiant, the best known of which is Betelgeuse in the constellation Orion, can be between 500 and 1000 times larger than our small Sun, and the Supernova phenomenon, typical of stars that are at least 10 times more massive than our Sun, emits more energy in a few seconds than our Sun has ever emitted in its entire existence of billions of years. In practice, within seconds the huge star collapses in on itself, as if a huge building could no longer stand. The great mass of gas falling into the core, which is very hot, many millions of degrees, causes a gigantic explosion and the outward ejection of the outermost layers of gas.

WOH G64, which is huge, record-breaking even as a supergiant, is located 160,000 light years away in the Large Magellanic Cloud, a small dwarf galaxy that is in fact a satellite of our much larger Milky Way. The four European telescopes with an aperture of 8.2 metres, the Very Large Telescope, have been made to work together, in a way that is called 'interferometric' and which is rather complex, in the sense that each of these mammoth instruments points in the same direction and acquires the image, which is then put together with the others in real time to form a single one, in practice it is like observing with a telescope with a much higher resolution, i.e. a power of detail.

Instead of the usual bright spot, a central cocoon of gas was seen with a band of dust surrounding it. These outflows of material indicate that WOH G64 is in the final stages of its existence and has begun the process that will lead it to explode as a Supernova.