Astronomers

Astronomers’ trick to hunt hundreds of nearby exoplanets: look for suspiciously “quiet” stars

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The hunt for exoplanets in the universe has always depended on our ability to observe the invisible. Until now we have mainly noticed the flickering of a star when it passes in front of one of these planets or the subtle gravitational wobble that it causes, but we have never seen them directly. Now a team of astronomers has perfected a much more ingenious method: searching for planets based on the “false” magnetic tranquility of their stars. And now it works. The project known as Dispersed Matter Planet Project (DMPP) has just confirm the discovery of seven new planets spread across five star systems, and its projections indicate that there could be hundreds of rocky worlds hidden in our closest cosmic neighborhood. And we have not been able to ‘see’ all of these with our traditional systems. How it works. The DMPP method is fascinating because it turns the traditional way of observing the universe on its head. Now, instead of looking for active stars, the team selects bright, very nearby stars that have anomalously low calcium emission. In fact, they show levels of magnetic activity below their basal level. But these samples do not indicate that the star is without activity, but rather that it is hidden. Here astronomers have discovered that these systems host planets very close to the star, which due to the intense heat are evaporating. From this gas that is released from these worlds, a kind of ‘shield’ or orbital cloud is formed that absorbs radiation and hides the activity of the stellar chromosphere. That is, the star’s apparent inactivity is the gas “fingerprint” of a disintegrating planet. Its precision. To confirm these suspicions, the team does not stop at observing the gas, since it uses very high precision radial velocity spectrographs such as HARPS-Nwhich are capable of measuring minute variations in the star’s motion. One of the most intriguing case studies of the project is the system DMPP-4located about 25 parsecs away. In this star, candidates for planets with sub-Neptunian masses have already been detected, on the order of between 8 and 12.2 times the mass of the Earth, orbiting at breakneck speeds, with “years” that last only between 2 and 5 days. Where are they? These planets inhabit what astronomers know as the “Neptunian Desert,” a region very close to the star where planets the size of Neptune are rarely found. The leading theory is that these worlds are actually rocky cores of ancient Neptunes that migrated into the system and whose atmospheres were swept away by intense stellar radiation. Many to discover. The implications of this study are massive for modern astrophysics, as data from the DMPP project suggests that between 10% and 20% of these low magnetic activity stars could host compact systems of rocky planets that we have not known about until now. This not only helps explain certain anomalies in the historical catalogs of the Kepler telescope, but gives us a treasure map. As they are star systems so bright and close to Earth, these newly discovered exoplanets become the perfect candidates to be observed by the James Webb Space Telescope (JWST) and the future generation of Extremely Large Telescopes (ELT). Images | NASA Hubble Space Telescope In Xataka | A new “solar system” has just been discovered. There’s just one problem: it shouldn’t exist.

A star 1,540 times larger than the Sun is mutating in real time and it is something that baffles astronomers

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The universe is rarely in a hurry, since stellar processes usually be measured in millions or billions of yearsso witnessing the metamorphosis of a great star in the span of a single human life is practically unheard of. And this is precisely what is happening with WOH G64a true cosmic monster located in the Large Magellanic Cloudabout 163,000 light years from Earth. Big changes. Astronomers have been analyzing this astronomical giant for years, and now the red supergiant is changing radically in front of our telescopes as it heats up rapidly and opens a heated scientific debate. The question that the community is asking itself right now is whether we are facing the transformation towards a very rare yellow hypergiant or if it is simply the fierce interaction of a binary system before collapsing. What we knew. Discovered in the 1970s, WOH G64 has long held the title of one of the largest stars known. The data we know about it is no wonder, since it has a radius 1,540 times greater than that of our Sun, an approximate mass of 28 solar masses and shines 282,000 times brighter than our star. Despite its enormous size, it is an extremely young star, since it is barely 5 million years old. And if we put it into context, in the ruthless world of astrophysics, the largest stars “live fast and die young”, devouring the fuel inside them at great speed. The script twist. Until recently, everything fit the classic profile of an extreme red supergiant, placing its temperature at 3,400 ± 25 degrees Kelvin. But a turning point came in the last decade after the data published in Nature Asia which pointed out that the star suffered a mysterious dimming in 2011, followed by a sudden warming of more than 1,000 ºC and significant chemical alterations in the atmosphere. Now, a new study analyzes the photometry and optical spectroscopy accumulated over more than thirty years of this star. And the conclusion they have reached is that between 2013 and 2014, WOH G64 began to transition from red supergiant to yellow hypergiant. What are they? Yellow hypergiants are an exceptionally rare transition phase of which we barely have data and, above all, it is very ephemeral. In this case, the dramatic thermal evolution could be due to the star having partially ejected its outer envelope or to its stellar companion aggressively stripping away material. The debate is served. As is often the case on the frontier of astrophysics, not everyone agrees that the transition is complete. Rigorous science requires fact-checking constant, and recent research adds nuance to this story. This same year, one study pointed out because the star continues to maintain its classic red supergiant characteristics, questioning whether it has become a rare yellow hypergiant. The most logical explanation they see in this case is that the interaction with its companion star is causing these large temperature changes. This generates a great debate, since it goes completely against the other part of astrophysics that is convinced that we are facing a great twist in the script. A supernova. The big question that everyone is asking is how this titan will end, and some voices suggest that we are seeing the prelude to an imminent supernova. However, in astronomical terms, “imminent” is an elastic concept, since core collapse could occur in a time frame ranging from 100 to a few thousand years. And even if it collapses, even a spectacular explosion is not guaranteed. Although there is also the possibility that it fails in its attempt to explode and, instead, collapses directly in on itself, silently forming a black hole. Likewise, what happens seems to be something that our next generations will see. Images | European Southern Observatory In Xataka | We have analyzed the universe for 20 years looking for ET and all we have are 100 signals that China is now investigating

Some astronomers analyzed the “Big Bang sound.” Now they believe that the Earth is in a vacuum of 2,000 million light years

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Cosmology has a huge problem. It is known as hubble tension and suggests that the nearby universe is expanding faster than the distant and primitive universe He is telling us. Something does not fit. Now, a disturbing study offers a solution. The big problem of cosmology. Hubble tension is One of the biggest headaches of modern physics. On the one hand, we have the measurements of the cosmic microwave background (CMB), the oldest light in the universe. When applying the standard cosmological model (LBDACDM), these observations show a 67.4 km/s/mpc hubble constant. On the other hand, when The expansion of the universe is measured Using nearby objects such as standard candles (a type of supernova), a significantly higher value is obtained: about 73 km/s/mpc. This difference, that the most recent data places in a tension of more than 5Sigma (a level that in particle physics is considered a discovery), refuses to disappear. A disturbing explanation. A new study Prepublished in Arxiv proposes a solution as elegant as depressing. That the discrepancy is not in our measurements, but in our location. According to Indranil Cosmologists Banik and Vasileios Kalaitzidis, we could be living in the center of a gigantic cosmic vacuum, a “bubble” of 2,000 million light years in diameter with a density 20% lower than the universal average. The test, they affirm, It is in the “Big Bang sound”. A local vacuum. The idea of the local vacuum is not new: it is known as the empty KBC (Keenan-Barger-Cowie, in honor of the astronomers who proposed the idea based on the galaxies count). If our galaxy, the Milky Way, were in a region with less matter than normal, the severity of the surrounding, densest areas, would “throw away” out. This effect, added to the general expansion of the universe, would cause nearby galaxies to move away from us faster than normal. “This would give the appearance of a faster local expansion rate,” explains Indranil Banik, of the New Research. The Hubble tension problem would thus become a local phenomenon, without the need to revolutionize the entire cosmological model. The sound of the Big Bang as proof. What the new study of Banik and Kalaitzidis contributes is a much more fundamental test based on barionic acoustic oscillations. Although we call them “the sound of the Big Bang”, they are not sound waves that we can hear. They are the traces that left the pressure waves that spread through the superdense plasma of the primitive universe. These waves were “frozen” about 380,000 years after the Big Bang and created A characteristic pattern in the distribution of matter. This pattern works as a cosmic rule of about 500 million light years in length, which astronomers use to measure the expansion of the universe to different eras. The results. The team analyzed 20 years of measurements and compared them with two scenarios: on the one hand, the homogeneous standard model, without emptiness; and on the other, the model that includes the empty KBC. The results, presented at the National Astronomy Meeting 2025 of the Astronomical Society Royal, are blunt. According to the statistical analysis of the study, the model with a local vacuum conforms to the data in a spectacularly better way. While the standard model has a 3.3sigma voltage with observations, vacuum models reduce it to only 1.1sigma –1.4sigma. Calmly. The researchers consider “demonstrated” that A vacuum model is about 100 million times more likely than a model without emptiness. However, it is a preliminary study, which has not yet gone through the pairs review. Previous studies set very strict limits to the existence of such an influential vacuum, concluding that it is not enough to explain the entire Hubble tension. They also propose early dark energy as a solution. But Banik’s work offers one of the strongest evidence to date that the Earth could be in a very lonely region of the universe. Image | Greg Rakozy (UNSPLASH) In Xataka | The James Webb and Hubble telescope coincide in the expansion of the universe. And physics fails to explain why

Astronomers have been theorizing about “planets kamikaze.” They just found one and is 100 times more violent than it was believed

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We already know A good handful of exoplanetsbut astronomers of the European Space Agency have just added a fascinating category to the catalog of strange worlds. The Kamikaze planets. Using the Cheops space telescope, The first exoplature observatory of EuropeESA researchers have first observed a planet that causes flares in their own star, a suicidal custom that will end up sealing their own destiny. The “Kamikaze planets” are actually a phenomenon of cosmic self -destruction that has been theorizing since the 1990s. But it had never been observed directly, so far. And what astronomers have seen is a hundred times more energy than anyone had imagined. A violent neighborhood. The protagonist of this story is Hip 67522, a solar system located about 490 light years from Earth. Its star is a bit larger and cold than our sun, but it is very different: while the sun exceeds median age with 4.5 billion years, Hip 67522 is a teenage star of just 17 million years. Like any teenager, this star is full of energy, with a very agitated nucleus that does not stop turning, which makes it a very potent magnet. Around this violent cosmic magnet two planets turn. The one that interests us is the closest, Hip 67522 B, a world that completes an orbit in just seven days. The planet that plays with fire. Since they began to discover exoplanets, astronomers wonder if there are worlds orbiting enough close to their star to disturb their magnetic field and, in essence, “prick it” so that great flares are unleashed. Cheops space telescope observations They demonstrated that the planet Hip 67522 B is so close to its star that its own magnetic influence interacts with that of its host. The planet acts as a whip: as the star orbits, energy is accumulated in the form of waves along the lines of the star magnetic field. When these energy waves collide with the surface of the star, they trigger a gigantic solar flare, much more violent than expected. And absolutely destructive for the planet. Up to 15 lashes captured in camera. The Cheops telescope detected a total of 15 flares, almost all produced while the planet was ahead of the star from our perspective. This synchronization is the definitive proof: the fact that the flares occur just when the planet passes between us and the star confirms that it is the planet who is causing them. The tragic part of this story is that the planet is causing these gigantic energy explosions in its own direction. Hip 67522 B is being bombarded with six times more radiation than I would receive if it would simply stay still. The planet is shrinking. According to astronomers, in the next 100 million years it could go from being a gaseous giant of Jupiter’s size to a planet of Neptune size. It is a slow -chanted cosmic suicide. Image | THAT In Xataka | Astronomers have discovered a planet that should not exist: great as a jupiter and light like sugar cotton

Astronomers have seen live the awakening of a giant black hole. They had never detected something so violent

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Good morning, Ansky. SDSS1335+0728 was a black hole so boring that it didn’t even have a nickname. Located 300 million light years, in the constellation of Virgo, he had been asleep from our point of view. But go aroused. The supermassive black hole has aroused in such a violent way that it has left fascinated and somewhat baffled astronomers. Now it is an active galactic nucleus (AGN) dodged affectionately “Ansky”. Years of study. The galaxy where Ansky is began to shine unexpectedly in visible light at the end of 2019. Chilean astronomer Paula Sánchez Sáez, of the Southern European Observatory (ESO), leads the first team that detected activation. “When we saw Ansky illuminate in optical images, we activate monitoring observations with the NASA X -ray space telescope and review archived data of the erosite German telescope,” Paula says in a statement. “But at that time we did not see evidence of X -ray emissions.” The surprise arrived in February 2024. A second team led by Lorena Hernández-García, from the University of Valparaíso (in Chile), saw how Ansky began to emit gusts of incredibly energy and regular X-ray. “It is the first time we observed such an event in a black hole that seems to be waking up,” Lorena explains. Out of the ordinary. He XMM-Newton telescope From the European Space Agency it has allowed to measure the faint x -ray light that comes to us from the explosions, which has been key to measuring how much energy releases Ansky in each “flash”. Known as “quasiperiódicas eruptions” (QPES), X -ray emissions turned out to be ten times longer and ten times luminous than other supermassive black holes. Each eruption of Ansky releases a hundred times more energy than the Qpes observed so far. In addition, it had never seen a time between eruptions so wide, with a cadence of four and a half days. Ansky takes astronomical models to the limit and challenges our current ideas on how these flashes are generated. What causes these explosions? The most accepted theory about the QPES is that they are caused by the interaction of an object (such as a smaller star or hole) with the accretion disc (the hot and bright material that revolves around the black hole before being engulf). They usually occur when the Black hole is eaten a starbut it does not seem to be the case of Ansky. This has led the international astronomer team to consider other possibilities. Perhaps the accretion disk will be formed from gas captured from the galactic environment, and the flares are the result of highly energetic shock waves caused by a smaller object that orbit and disturbed repeatedly the disc. Gravitational waves. Notice Real Time Awakening It is an unprecedented opportunity to check if their energy eruptions could be related to gravitational waves, predicted by Einstein’s relativity and detected for the first time a few years ago. The smooth mission of ESA and NASA will try to observe these disturbances in the space-time fabric from point L1 of Lagrange after its launch in an Ariane 6 rocket planned for 2035. Image | THAT In Xataka | We knew that the supermassive black holes were huge. Thanks to James Webb, now we know we were short

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