Latest news with #IvoSeitenzahl
Yahoo
14-07-2025
- Science
- Yahoo
Astronomers caught a star that blew up not once, but twice when it died
Astronomers have finally caught a dying star in space going out with a bang — and then another bang. The new photographic evidence, captured using the European Southern Observatory's Very Large Telescope in Chile, shows the first proof of a rare kind of stellar death called a double-detonation supernova. This double-blast event, spotted in the supernova remnant known as SNR 0509-67.5, confirms a theory that has divided astrophysicists for decades. The star's remains, about 300 years old, show a distinctive pattern: two separate shells of calcium, one nested inside the other like Russian matryoshka dolls. This could only form if a white dwarf exploded twice. The breakthrough, published in Nature Astronomy, rewrites part of the story behind one of the most important tools in astronomy, the Type Ia supernova. Sometimes dubbed a "cosmic yardstick" by NASA, this special supernova shines brightly for a short time and gives off a predictable, known amount of light. That makes it perfect for measuring distance in space: The farther the supernova, the fainter it appears to us. By collecting light from these blasts, scientists also can figure out how fast the universe has been expanding. "Our results required a large resource commitment with a very advanced instrument on a large telescope," Ivo Seitenzahl, one of the researchers, told Mashable. "Basically, the observations are near the limit of what's currently technically feasible." Understanding how exactly these events work isn't just academic, it's essential for making sense of the universe. These explosions forge the majority of iron in our galaxy — the same stuff found in our blood, buildings, and planet. A white dwarf star — the dense stellar core left behind after a sun-like star runs out of fuel — gradually steals material from a neighboring star. Once it grows massive enough, it ignites in a thermonuclear explosion. But some researchers have suspected there is another way: A thin outer layer of helium could explode first, sending a shockwave inward that then blows up the white dwarf's core. The second blast is the ultimate supernova that tears the star apart. Until now, this two-step concept lived mostly on whiteboards and in computer simulations. Now, astronomers have receipts proving it really happens. The explosions would have occurred in quick succession, Seitenzahl said. The second blast likely followed just two seconds later, "essentially the time it takes the helium detonation to travel from one side of the white dwarf star to the other." Scientists turned the telescope's Multi Unit Spectroscopic Explorer instrument toward the glowing wreckage in the Large Magellanic Cloud, a galaxy neighboring the Milky Way. The calcium detections were the giveaway. Sandwiched in between the blown-off shells was sulfur, with each layer consisting of different densities from the two explosions. "Revealing the inner workings of such a spectacular cosmic explosion is incredibly rewarding," said Priyam Das, lead author of the paper, in a statement, describing the remnant as a "beautifully layered structure." Astronomers can't normally see what happens deep inside a star during its final moments. The explosion itself is too bright, fast, and distant. But hundreds of years later, the drifting shrapnel betrays the secret. Though this discovery doesn't close the case on how all Type Ia supernovas work, it does show at least some stars don't need to hit a critical mass of matter before going boom. It seems a smaller star with the right kind of helium wrapper can self-destruct just fine. For this particular system, there won't be any more explosions, but the hunt continues for variations on this exotic breed. Some models for double detonations indicate the primary star can actually trigger yet another double detonation in the lighter companion star. "This would be a double double detonation," Seitenzahl said. UPDATE: Jul. 2, 2025, 12:50 PM EDT This story has been updated to include additional reporting, including new quotes, from the researchers.
India Today
03-07-2025
- Science
- India Today
Astronomers get first visual of a sun dying by detonating twice
In a first-of-its-kind observation, astronomers have obtained the visual evidence of a star dying by double detonation, when stars are known to disappear by giant European Southern Observatory's Very Large Telescope has studied the centuries-old remains of supernova SNR 0509-67.5 to confirm the patterns of dual back-to-back explosions obliterated a white dwarf that had a mass roughly equal to the sun and was located about 1,60,000 lightyears from Earth in the direction of the constellation Dorado in a galaxy near the Milky Way called the Large Magellanic Cloud. A light-year is the distance light travels in a year, 5.9 trillion miles (9.5 trillion km). This image shows the distribution of calcium in the supernova remnant SNR 0509-67.5. (Photo: ESO) advertisement "The explosions of white dwarfs play a crucial role in astronomy. Yet, despite their importance, the long-standing puzzle of the exact mechanism triggering their explosion remains unsolved," Priyam Das, a PhD student at the University of New South Wales Canberra, who led the study, details of the finding were published in the journal Nature Astronomy. Astronomers had long been suspecting that some stars do meet their end of life with a dual detonation and new images prove their hunch was right: at least some Type Ia supernovae explode through a 'double-detonation' mechanism instead."The time delay between the two detonations is essentially set by the time it takes the helium detonation to travel from one pole of the star all the way around to the other. It's only about two seconds," said astrophysicist and study co-author Ivo Seitenzahl, a visiting scientist at the Australian National University in Canberra. This image marks the position on the sky of the supernova remnant SNR 0509-67.5. (Photo: ESO) advertisementIn the more common type of supernova, a remnant of the massive exploded star is left behind in the form of a dense neutron star or a black hole.'This tangible evidence of a double-detonation not only contributes towards solving a long-standing mystery, but also offers a visual spectacle,' Priyam says, describing the 'beautifully layered structure' that a supernova creates. For him, 'revealing the inner workings of such a spectacular cosmic explosion is incredibly rewarding.'- EndsTrending Reel
GMA Network
02-07-2025
- Science
- GMA Network
Astronomers get picture of aftermath of a star's double detonation
The supernova remnant SNR 0509-67.5 view from the European Southern Observatory's Very Large Telescope, the expanding remains of a star that exploded hundreds of years ago in a double-detonation – the first photographic evidence that stars can die with two blasts, as seen in this undated handout picture obtained by Reuters on July 2, 2025. WASHINGTON —The explosion of a star, called a supernova, is an immensely violent event. It usually involves a star more than eight times the mass of our sun that exhausts its nuclear fuel and undergoes a core collapse, triggering a single powerful explosion. But a rarer kind of supernova involves a different type of star - a stellar ember called a white dwarf - and a double detonation. Researchers have obtained photographic evidence of this type of supernova for the first time, using the European Southern Observatory's Chile-based Very Large Telescope. The back-to-back explosions obliterated a white dwarf that had a mass roughly equal to the sun and was located about 160,000 light?years from Earth in the direction of the constellation Dorado in a galaxy near the Milky Way called the Large Magellanic Cloud. A light-year is the distance light travels in a year, 5.9 trillion miles (9.5 trillion km). The image shows the scene of the explosion roughly 300 years after it occurred, with two concentric shells of the element calcium moving outward. This type of explosion, called a Type Ia supernova, would have involved the interaction between a white dwarf and a closely orbiting companion star - either another white dwarf or an unusual star rich in helium - in what is called a binary system. The primary white dwarf through its gravitational pull would begin to siphon helium from its companion. The helium on the white dwarf's surface at some point would become so hot and dense that it would detonate, producing a shockwave that would compress and ignite the star's underlying core and trigger a second detonation. "Nothing remains. The white dwarf is completely disrupted," said Priyam Das, a doctoral student in astrophysics at the University of New South Wales Canberra in Australia, lead author of the study published on Wednesday in the journal Nature Astronomy. "The time delay between the two detonations is essentially set by the time it takes the helium detonation to travel from one pole of the star all the way around to the other. It's only about two seconds," said astrophysicist and study co-author Ivo Seitenzahl, a visiting scientist at the Australian National University in Canberra. In the more common type of supernova, a remnant of the massive exploded star is left behind in the form of a dense neutron star or a black hole. The researchers used the Very Large Telescope's Multi-Unit Spectroscopic Explorer, or MUSE, instrument to map the distribution of different chemical elements in the supernova aftermath. Calcium is seen in blue in the image - an outer ring caused by the first detonation and an inner ring by the second. These two calcium shells represent "the perfect smoking-gun evidence of the double-detonation mechanism," Das said. "We can call this forensic astronomy - my made-up term - since we are studying the dead remains of stars to understand what caused the death," Das said. Stars with up to eight times the mass of our sun appear destined to become a white dwarf. They eventually burn up all the hydrogen they use as fuel. Gravity then causes them to collapse and blow off their outer layers in a "red giant" stage, eventually leaving behind a compact core - the white dwarf. The vast majority of these do not explode as supernovas. While scientists knew of the existence of Type Ia supernovas, there had been no clear visual evidence of such a double detonation until now. Type Ia supernovas are important in terms of celestial chemistry in that they forge heavier elements such as calcium, sulfur and iron. "This is essential for understanding galactic chemical evolution including the building blocks of planets and life," Das said. A shell of sulfur also was seen in the new observations of the supernova aftermath. Iron is a crucial part of Earth's planetary composition and, of course, a component of human red blood cells. In addition to its scientific importance, the image offers aesthetic value. "It's beautiful," Seitenzahl said. "We are seeing the birth process of elements in the death of a star. The Big Bang only made hydrogen and helium and lithium. Here we see how calcium, sulfur or iron are made and dispersed back into the host galaxy, a cosmic cycle of matter."—Reuters
