В небе только что появилась звезда, взрыв которой виден невооружённым глазом!

Imagine, you go out at night, look at the sky and suddenly notice a new star that has never been before. It does not blink, does not move, does not look like a satellite or a fluttering balloon. But still a bright point of light, visible to the naked eye. As if someone lit a match in the far, far corner of space. But this is not an optical illusion and not a delusion. This is an explosion. A real explosion of a star, a thermonuclear disaster of a cosmic scale, which occurred thousands of years ago, but only now has reached the Earth in the form of light. So this summer we witnessed just such an event. In front of you is a star with a formidable name V462 Lupi. The discovery of this new star began on June 12, 2025, when the automatic observation system AllSky recorded a surge of brightness in the constellation Wolf. Of course, this is not uncommon for astronomy. Telescopes record fluctuations in brightness every day. But there was something else here. The luminosity grew too fast. Its brightness later grew to 6.1, which is about 11 times higher than the initial value, and makes it available for observation without optics in a fairly dark sky. But what are we watching? Is this Nova, Supernova, the first or second type? Or maybe this is Kelonova? Well, we can find out. The fact is that a star is essentially a nuclear reactor compressing a substance under the influence of its own gravity. At the center of the star, hydrogen atoms collide, merge, form helium and release energy. This energy pushes out like steam in an Asian kettle. Gravitation pulls the star inside, and nuclear energy pushes it out. While these two forces are in balance, the star is alive. It shines, warms up and burns steadily. This can last for billions of years. However, when the hydrogen reserves run out, and we get a couple of wrinkles, the balance is disrupted. The star begins to shrink. At this point, it all depends on the mass. Light stars, like the Sun, all end relatively peacefully. They inflate into a red giant, drop the shell, and a white dwarf remains. A star core the size of the Earth, compressed to an unimaginable density. It cools for a long time, like a hot stone. But heavy stars are different. If the mass is 2, 3, 10 times more than the Sun, the outcome will be explosive. After hydrogen, helium is burned, then carbon, then oxygen. At each stage, the temperature and pressure rise. The star works to the limit. Until, finally, the fatal limit comes. Iron is formed. But iron is fatal. It cannot be used in thermonuclear reactions with energy release. The entire thermonuclear kitchen freezes. The pressure drops sharply, and in the end, gravity, without resistance, wins. In a matter of seconds, the core of the star shrinks to neutron density, and the outer layers fly away. This is the supernova explosion. The brightness increases by millions of times. For a fraction of a second, the star can shine brighter than the entire galaxy. This light flies through space, and it can be seen from Earth. And even ancient Chinese and Arab astronomers described new stars as the supernova of 1054, which gave birth to a carnivorous nebula. The core remains behind the flash, the neutron star, or, if the mass was huge, then the black hole. Molecular dust scatters in all directions, and new stars can be born from it someday, planets, maybe even life. But not only massive office solos explode. There is another way, through double systems. It won't be difficult. Imagine a white dwarf, the very remnant of a star that survived the end of the world. If it enters a close pair with another star and begins to absorb its substance, it can gain a critical mass. This is about 1.4 times the mass of the Sun. When it exceeds the limit of Chandrasekhar, the dwarf can't stand it and a thermonuclear explosion of the supernova of the first type occurs. This is not a collapse, but a complete destruction. The dwarf explodes entirely, leaving nothing but slippers. These are some of the brightest and most predictable explosions in the Universe. Standard candles, according to which astronomers measure the distance to the galaxies. And here is the supernova of the second type. This is a collapse of the core of a massive star, more than 8 solar masses. Then there is an explosion. It is possible that the remnant is a neutron star or a black hole. Next is Kelonov, a merger of two neutron stars. It is rare, but a powerful source of gravitational waves and heavy elements, especially gold and platinum, keep this in mind. And there are also star flashes, or nova, which look like explosions, but they are not. These are nova, such as the star of Lupi. Here the white dwarf does not explode, but only leaves the first impression, a spark in the eyes. It burns the accumulated hydrogen on the surface, throws out the shell, but remains the same. Such nova can be repeated over and over again, once a century or even more often. As we can see, Lupi is not a real newborn star. This is an old system consisting of a white dwarf and an ordinary companion star. In a tight double system, evil dwarfs literally steal the resources of their neighbors. Everything is like in humans, especially hydrogen, which accumulates on the surface. When the pressure and temperature reach a critical point, an explosion is launched, a thermonuclear reaction that does not destroy the dwarf itself, but throws a huge amount of energy into space. This is a nova flash, not a complete destruction like with a supernova, but a flash. Such a flash can increase the luminosity of the system by a thousand, or even a million times in a few days. The most amazing thing about this phenomenon is not just a flash, but what we see in the past. The light of the formidable Lupi has been coming to us for thousands of years. The distance is estimated at several thousand light years. That is, the event actually happened long before you and I. Perhaps when this thermonuclear fire exploded in the heart of the dwarf system, our distant ancestors were just beginning to think that the Earth is actually not flat. But how long will we be able to observe this phenomenon? Usually, classic novae shine brightly for only a few weeks. Then the shine gradually decreases, and the system returns to its previous dim state. By the end of July this year, the star Lupi will most likely cease to be visible to the naked eye. There will be an opportunity to observe it in a telescope, and then only in archives. Therefore, now is the best time. Astronomers around the world have already directed their telescopes to this star. Spectroscopy, photometry, ultraviolet and infrared research. Everything is in full swing. The goal is to understand how powerful the flash was, how quickly the ejected substance spreads, what chemical elements are contained in it. Such data helps clarify theories about the behavior of white dwarfs, about supernovae and even about what conditions can lead to the complete destruction of a dwarf, including in scenarios where it becomes a supernova of the first type, a standard candle in the universe. If we talk about the location of the star, then Lupi is located in the southern hemisphere of the sky. It belongs to the constellation of Wolves, which is difficult to see in the northern latitudes. But with a certain luck and an open horizon, it can be noticeable both in southern Europe and in the south of Russia. In the southern hemisphere, for example, in South America, Australia or South Africa, it is now like on the palm. You can find it by tracking Phantarus in Scorpio and moving a little south. Any modern map of the starry sky with relevant coordinates will help you. The peculiarity of this new one is that it has outperformed other candidates, from which astronomers have been waiting for flashes. Especially in recent months, attention has been drawn to the star of Battlegeys, the red supergiant in the constellation of Orion. Everything there talks about the approach of a collapse and an explosion, but alas, so far. Keep in mind, if this happens, I will definitely tell you about it. In any case, all this is a cycle of substances in the universe. Explosions of stars enrich the interstellar environment with heavy elements. Water in our bodies, iron in our blood, calcium in the bones. All this was born in the bowels of dying stars. We are the dust of stars. Literally. As we can see, even the glowing spores, with billions of years of life, at some point come to an end. Because gravity and nuclear energy are in an endless struggle. And at some point, one of the sides wins. And we, the observers of the tiny planet, can only look at the sky, wait for the light that has reached the depths of time and freeze in awe of the great fragility of space. Transcription by ESO. Translation by —