Latest news with #supernova
CNA
38 minutes ago
- Science
- CNA
Astronomers get picture of aftermath of a star's double detonation
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."
Yahoo
an hour ago
- Science
- Yahoo
Astronomers capture incredible 1st image of a dead star that exploded twice. How did it happen?
When you buy through links on our articles, Future and its syndication partners may earn a commission. You may only live once, but some stars die twice. Astronomers have now discovered the first visual evidence of such a stellar event, a dead star that underwent a so-called "double-detonation." This could indicate that some stars could go supernova without reaching the so-called Chandrasekhar limit, the minimum mass that a star needs to go supernova. Using the Very Large Telescope (VLT) and its Multi Unit Spectroscopic Explorer (MUSE) instrument, the team zoomed in on the centuries-old remains of supernova SNR 0509-67.5 located 60,000 light-years away in the constellation Dorado. This investigation revealed structures within this explosive wreckage that indicate its progenitor star exploded not once but twice. Said star was a white dwarf, the type of stellar remnant that forms when a star with a mass similar to that of the sun runs out of fuel for nuclear fusion. The types of supernova explosions that white dwarfs undergo, Type Ia supernovas, are important to astronomers because they can be used to measure cosmic distances because their light output is so uniform. Thus, astronomers often refer to them as "standard candles."The first visual evidence of a double detonation white dwarf reveals hidden depths to these important stellar events, scientists say. "The explosions of white dwarfs play a crucial role in astronomy," team leader and University of New South Wales researcher Priyam Das said in a statement. "Yet, despite their importance, the long-standing puzzle of the exact mechanism triggering their explosion remains unsolved." Scientists agree that the genesis of Type Ia supernovas is binary systems of two stars in which one becomes a white dwarf. If this dead star orbits close enough to its living stellar companion, or if that companion swells up, then the white dwarf becomes a stellar vampire, greedily stripping material from its companion or "donor" star. This continues until the piling up stolen material has added so much mass to the white dwarf that the stellar remnant crosses the so-called Chandrasekhar limit, which is about 1.4 times the mass of the sun. Hence, this cosmic vampire white dwarf explodes in a Type Ia supernova. It is believed that in most cases, the eruption completely destroys the white dwarf. But for some time, astronomers have suspected there may be more to the story. Maybe white dwarfs can experience a second explosion. This research confirms that at least some white dwarfs experience double-detonations. The question is: why? Theory behind double-detonations suggests that in these cases, as white dwarfs are stripping material from a donor star, they wrap themselves in a blanket of stolen helium. This envelope becomes unstable and eventually ignites, triggering the first detonation. The initial explosion generates a shockwave that ripples inwards, eventually striking the core of the white dwarf, triggering a second detonation, the actual supernova. The significance of this to our understanding of Type Ia white dwarf supernovas is that it can occur well before a dead star swells beyond the Chandrasekhar limit. Recently, scientists determined that this double-detonation process would imprint a distinctive "fingerprint" with supernova wreckage. This should be present long after the supernova ripped its progenitor star apart. That fingerprint is now visually confirmed as being present in the wreckage of SNR 0509-67.5, supernova wreckage in the Large Magellanic Cloud first detected in 2004 and believed to be around 400 years old as we see it. Related Stories: — 'Vampire stars' explode after eating too much — AI could help reveal why — Supernova explosion's weird leftovers may contain a super-dense star — Peer inside remnants of an 800-year-old supernova and see a 'zombie' star Beyond being an important discovery for our scientific understanding of these events and solving a lingering mystery about the evolution of white dwarfs, the observation of SNR 0509-67.5 has provided astronomy lovers with some stunning eye-candy. "This tangible evidence of a double-detonation not only contributes towards solving a long-standing mystery, but also offers a visual spectacle," Das concluded. The team's research was published on Wednesday (July 2) in the journal Nature Astronomy
Yahoo
7 hours ago
- Science
- Yahoo
Massive ‘double detonation' spotted by astronomers for the first time
Some stars are so primed for greatness that they blow up twice. For the first time, a team of astronomers have found direct visual evidence of a star that met its fiery end by detonating two times. The team using the European Southern Observatory's Very Large Telescope (ESO's VLT) found this double explosion in the centuries-old remains of a supernova designated as SNR 0509-67.5. They found patterns that confirm its star suffered two explosive blasts. The findings are detailed in a study published July 2 in the journal Nature Astronomy and offers a new look at some of the universe's most important explosions. The majority of the universe's supernovae are the explosive deaths of massive stars. One important supernova variety comes from an unassuming source–white dwarfs. These celestial bodies are the small, inactive cores left over after larger stars–similar to our sun–burn out of all their nuclear fuel. White dwarfs can also produce what astronomers call a Type Ia supernova. 'The explosions of white dwarfs play a crucial role in astronomy,' said Priyam Das, a study co-author and PhD student at the University of New South Wales Canberra, Australia. 'Yet, despite their importance, the long-standing puzzle of the exact mechanism triggering their explosion remains unsolved.' A great deal of our knowledge of how the universe expands rests on understanding Type Ia supernovae. These types of supernovae are a primary source of Earth's iron–including the iron pumping around in your blood right now. Type Ia supernovae generally start with a white dwarf that is one star in a pair. If the other star orbits close enough, the dwarf can steal material from its partner. In the most established theory behind Type Ia supernovae, the white dwarf grabs matter from its companion–until it reaches a critical mass. Then, it's time for a single, great, fiery explosion. However, recent studies have hinted some Type Ia supernovae may be better explained by a double explosion that is triggered before the star reaches this critical mass. [ Related: Astronomers find spiraling stars heading towards a rare cosmic explosion. ] The supernova in this new study–SNR 0509-67.5–is roughly 160,000 light-years away from Earth in the constellation Dorado. The astronomers describe a new image they took with data from the ESO's VLT that proves this hunch about double explosions was correct. Some Type Ia supernovae explode through a 'double-detonation' mechanism rather than just one. In this new model, the white dwarf forms a blanket of stolen helium around itself. Helium is a chemical element that can become unstable and ignite. If that happens, the initial explosion generates a shockwave that travels around the white dwarf and inwards. This triggers a second detonation in the core of the star, which ultimately forms the supernova. Previously, there has been no clear, visual evidence of a white dwarf undergoing a double detonation. Astronomers have predicted that this process would create a distinct pattern or fingerprint seen in the supernova's still-glowing remains. They theorized that this clue would be visible long after the initial explosion, partially because the remnants of such a supernova would have two separate shells of calcium. Astronomers have now found this kind of calcium fingerprint in a supernova's remains. According to Ivo Seitenzahl, a study co-author and nuclear astrophysicist from Germany's Heidelberg Institute for Theoretical Studies, these results show 'a clear indication that white dwarfs can explode well before they reach the famous Chandrasekhar mass limit, and that the 'double-detonation' mechanism does indeed occur in nature.' The team detected these calcium layers–shown in blue in the image–by observing supernova remnant SNR 0509-67.5 with the Multi Unit Spectroscopic Explorer (MUSE) on ESO's VLT. The findings provide strong evidence that a Type Ia supernova can feasibly occur before its parent white dwarf reaches a critical mass. Type Ia supernovae are also important for astronomers because they behave in very consistent ways and have predictable brightness–no matter how far away they are. This level of consistency helps astronomers measure distances in space. While using Type Ia supernovae as a cosmic measuring tape, astronomers discovered the accelerating expansion of the universe. The team behind this groundbreaking discovery was awarded the Physics Nobel Prize in 2011. Studying how these supernovae explode will help us understand why they have such a predictable and consistent brightness. 'This tangible evidence of a double-detonation not only contributes towards solving a long-standing mystery, but also offers a visual spectacle,' said Das, describing the 'beautifully layered structure' that a supernova creates. 'Revealing the inner workings of such a spectacular cosmic explosion is incredibly rewarding.'
Forbes
10 hours ago
- Science
- Forbes
First Ever ‘Double Supernova' Found In Night Sky — What To Know
This image, taken with ESO's Very Large Telescope (VLT), shows the supernova remnant SNR 0509-67.5. Astronomers studying the night sky from the Southern Hemisphere have uncovered a supernova — the powerful explosion of a star — that appears to detonated twice. The unique discovery of the double-detonation supernova comes as two smaller nova explosions have caused stars to suddenly become visible to the naked eye. A supernova, according to NASA, is an extremely bright, super-powerful explosion of a star and the biggest explosion that humans have ever seen. Astronomers uncovered the rare double-detonation supernova by studying a 'cosmic bubble' — known as a supernova remnant — called SNR 0509-67.5. It's 23 light-years across and expanding at over 11 million miles per hour. It's previously been imaged by NASA's Hubble Space Telescope. SNR 0509-67.5 is in the Large Magellanic Cloud, a dwarf galaxy that orbits the Milky Way about 160,000 light-years distant in the constellation Dorado. SNR 0509-67.5 is Type Ia supernovae, which are known to produce iron on Earth, including in blood. Understanding these explosions of white dwarf stars is critical to astronomers who use them to measure distances in space. How A Supernova Exploded Twice SNR 0509-67.5 is a Type Ia supernova, the result of two stars orbiting each other. One, a white dwarf star — the dense core of a dead sun-like star — sucks matter onto its surface from the other star until a thermonuclear explosion occurs. The new discovery of a double-detonation supports the theory that, in at least some Type Ia supernovae, the white dwarf can be covered by a bubble of helium that, when it ignites, causes a shockwave that triggers a second detonation in the core of the star. Astronomers predicted that if a double detonation had occurred, the remnant of the supernova would contain two separate shells of calcium. That's exactly what was observed using the European Southern Observatory's Very Large Telescope in Chile. The discovery was published today in Nature Astronomy. Hubble Spots A Supernova Earlier this year, NASA's Hubble Space Telescope imaged a supernova about 600 million light-years away in the constellation Gemini. Visible as a blue dot at the center of the image above, supernova SN 2022aajn is also a Type Ia supernova. Exactly these types of supernovae are useful for astronomers because they all have the same intrinsic luminosity. That means they can be used as beacons to measure the distance to faraway galaxies. Background Although they fall into the category of smaller explosions called a nova, two exploding stars are currently visible in the night sky. V572 Velorum, in the constellation Vela and V462 Lupi, in the constellation Lupus — only visible from the Southern Hemisphere — are currently shining millions of times brighter than usual. Later this year or next year, if predictions are correct, a star in the Northern Hemisphere called T Coronae Borealis (T CrB and 'Blaze Star') in the constellation Corona Borealis will explode and become visible to the naked eye for several nights. This star system, about 3,000 light-years away, is a recurrent nova, meaning it experiences predictable eruptions. The last time T CrB brightened noticeably was in 1946. Wishing you clear skies and wide eyes.
Gizmodo
10 hours ago
- Science
- Gizmodo
Star Meets Stunning End by Exploding Twice
Astronomers have, for the first time, witnessed a star meeting a dramatic end by exploding twice. In a study published in Nature Astronomy, researchers analyzed the centuries-old remains of supernova SNR 0509-67.5 with the European Southern Observatory's Very Large Telescope, finding the first visual evidence of a star's 'double-detonation.' Most supernovae are the explosive result of massive stars collapsing when they exhaust their nuclear fuel. Others, though, come from white dwarfs, the inactive cores left over after smaller stars like our Sun run out of fuel. 'The explosions of white dwarfs play a crucial role in astronomy,' Priyam Das, a PhD student at the University of New South Wales Canberra, Australia, and a study co-author, said in a statement. 'Yet, despite their importance, the long-standing puzzle of the exact mechanism triggering their explosion remains unsolved.' When they share a star system with another star, white dwarfs can produce what astronomers call a Type Ia supernova. These supernovae occur only in binary star systems, when a white dwarf, like a selfish sibling, steals material from its companion star until it grows to a critical mass. At this point, the white dwarf becomes unstable, resulting in a massive explosion. Recent studies have hinted that this might not be the whole story. Astronomers have theorized that at least some Type Ia supernovae could actually be the result of not one but two explosions. In this scenario, the white dwarf blankets itself in helium-rich material stolen from its partner star. That helium becomes unstable and detonates, sending a shockwave through the inactive star. This triggers yet another blast starting in the star's core, ultimately creating a supernova. Astronomers predicted that a double detonation would leave a unique fingerprint in a supernova's remains, visible long after the initial explosion. Until now, astronomers didn't have any visual evidence of this fingerprint. But they were finally able to find some in studying supernova SNR 0509-67.5, by observing it with the Multi Unit Spectroscopic Explorer (MUSE) on the European Southern Observatory's Very Large Telescope. The analysis allowed the researchers to determine the distribution of different chemical elements, displayed in the image as different colors. They clearly saw distinct layers of calcium, arranged in two concentric shells. These two layers provide evidence that the star experienced two blasts. The results were 'a clear indication that white dwarfs can explode well before they reach the famous Chandrasekhar mass limit, and that the 'double-detonation' mechanism does indeed occur in nature,' Ivo Seitenzahl, a researcher at the Heidelberg Institute for Theoretical Studies in Germany, said in a statement. Besides being extremely cool, Type Ia supernovae are also key to studying the universe's expansion and dark energy, as their consistent behavior and predictable brightness can help astronomers measure distances in space. And, as a bonus, it's visually stunning. 'This tangible evidence of a double-detonation not only contributes towards solving a long-standing mystery, but also offers a visual spectacle,' Das said in a statement, describing the 'beautifully layered structure' that a supernova creates.
