Latest news with #AustralianSquareKilometerArrayPathfinder
Yahoo
20-05-2025
- Science
- Yahoo
Astronomers Baffled by a Suspicious, Perfectly Round Sphere in Our Galaxy
Today, in questions you didn't know you needed the answer to: Is there such a thing as a perfect ball? And if there were, would it contain the secrets of the universe? To wit, a spherical object lurking in our galaxy is so perfectly round that astronomers can't explain how it was formed. Dubbed "Teleios" after the Greek word for "perfect," the object is what's known as a supernova remnant (SNR), a glowing cloud of hot gases and other material left behind after a massive star dies in a powerful explosion called a supernova. And it's definitely earned its nickname. According to the astronomers' findings, as reported in a pre-print study accepted for publication in Publications of the Astronomical Society of Australia, this is one of the most circular galactic SNRs ever found. "The shape indicates Teleios has remained relatively untouched by its environment," said lead author Miroslav Filipovic, an astronomer at Western Sydney University, in an essay for The Conversation written with his colleagues earlier this year. "This presents us with an opportunity to make inferences about the initial supernova explosion, providing rare insight into one of the most energetic events in the universe." When a star goes supernova, it blasts all that stellar material into space in a tremendous release of energy bright enough to momentarily outshine even entire galaxies. The astronomers believe that Teleios is the result of a rare type of explosion — we're talking happening only once every 500 years in the Milky Way rare — called a type Ia supernova that occurs in binary star systems. When a smaller but far denser white dwarf siphons enough matter from its companion star whose orbit has crept too close, the stolen stellar material detonates in an epic thermonuclear explosion that obliterates both the stars. For something so symmetrical to emerge out of an event so violent is unusual, to put it mildly. "The supernova remnant will be deformed by its environment over time. If one side of the explosion slams into an interstellar cloud, we'll see a squashed shape," explained Filipovic in the essay. "So, a near-perfect circle in a messy universe is a special find." Teleios was uncovered as part of the Evolutionary Map of the Universe (EMU) survey using the Australian Square Kilometer Array Pathfinder (ASKAP), an enormous radio telescope that's proving to be a powerful tool for finding SNRs that aren't visible in other wavelengths. Teleios, exclusively seen at radio-continuum frequencies, is one of them. Along with its perfect shape, it has one of the lowest surface brightnesses among all known galactic SNRs. The astronomers estimate that Teleios lies at a distance of either 2.2 or 7.7 kiloparsecs away (or approximately 7,100 or 25,100 light years). The uncertainty surrounding its distance means its age and size are hard to pin down, too. It's either on the younger side at less than 1,000 years old, or much older at over 10,000 years old. Likewise, it could be as small as 46 light years across, or as large as 157 light years. In any case, their findings place Teleios at a stage of its evolution called the Sedov-Taylor phase, during which the expansion of the SNR first begins to slow down, as it sweeps up additional mass from the interstellar medium of space. There's a catch, though: this process should produce detectable x-ray emissions, but the astronomers haven't see any. Maybe, the astronomers explored, Teleios is actually the remnant of an even rarer type of Ia supernova: a type Iax, in which the white dwarf partially survives as "zombie star." In that case, Teleios might be much closer at less than 3,200 light years away while being about 10.7 light years across. No hard answer, however, can be made from the data we have now. But this is just the beginning, and the astronomers are optimistic that more detailed observations in the future will one day help put this mystery to bed. More on stars: NASA's James Webb Telescope Just Found Frozen Water Around Another Star
Gizmodo
20-05-2025
- Science
- Gizmodo
This Perfectly Spherical Supernova Is Weirding Us Out
Dubbed Teleios, the unusually symmetrical space object is puzzling astronomers with its near-perfect shape and mysterious origin. The universe is a chaotic place filled with exploding stars, material falling into black holes, and rogue planets wandering off on their own. All that chaos makes astronomers suspicious when they glimpse a hint of perfection in the cosmos, like a bubble of material left over from the death of a star that appears to be in perfectly symmetrical shape. Astronomers recently discovered the remnant of a galactic supernova with a remarkable circular symmetry, making it stand out as one of the most perfectly spherical objects detected in the universe. Perfection is not always a bad problem to have, but it does prompt certain questions regarding how the object came to be this way. The discovery, submitted to the Publications of the Astronomical Society of Australia and made available on the preprint website arXiv, was spotted in images collected by the Australian Square Kilometer Array Pathfinder. The researchers behind the paper identified the object as a galactic supernova remnant—an expanding cloud of debris that forms in the aftermath of the exploding death of a star. The object, located in the Milky Way galaxy, has been dubbed Teleios, the Greek word for perfect. Although it is almost perfectly symmetrical, Teleios is not very bright. It has one of the lowest recorded surface brightness levels among known supernova remnants. Astronomers observing Teleios are also uncertain about its distance to Earth, estimating that it could either be around 7,175 or 25,114 light-years away. That's a huge difference in distance, and the uncertainty is affecting our understanding of how long the object has been there. The two different distances imply different sizes for Teleios, since objects appear smaller the farther away they are. At its closer distance to Earth, the supernova remnant would be about 46 light-years wide. If it were much farther away, it would be a much larger cloud—around 157 light-years across. Based on its size variation, the scientists suggest that this particular cloud of expanding material has either been around for less than 1,000 years at its smaller size, or a much older supernova remnant that formed more than 10,000 years ago and grew to its larger size. Another odd thing about Teleios is that it only appears in radio wavelengths, even though modeling of the object suggests it should have X-ray emissions. The scientists behind the study try to explain the lack of X-ray emissions by suggesting Teleios is a Type Ia supernova, which takes place in a binary star system in which one of the stars is a white dwarf. In that case, a zombie star is often left behind along with the supernova remnant. There is a nearby star that fits the profile, but it would mean that Teleios is much smaller, spanning across a mere 11 light-years in the Milky Way. However, none of the measurements of Teleios' distance correspond to this small size. 'We consider several different scenarios to explain Teleios's unusual properties, all of which have their challenges,' the researchers wrote in the paper. 'While we deem the Type Ia scenario the most likely, we note that no direct evidence is available to definitively confirm any scenario.' The researchers suggest that sensitive and high-resolution observations of this object are needed in order to uncover its mysteriously perfect shape and unusual qualities.
Yahoo
08-03-2025
- Science
- Yahoo
Images Show Entire "Universe" of Circular Structure That Can Only Be Seen as Radio Signals
The vast realm probed by radio astronomers is one invisible to the naked eye, and even most kinds of telescopes. Now, thanks to the latest advances in radio observatories, scientists are uncovering an entire "low surface brightness universe" teeming with circular curiosities, according to a team of researchers from Australia — including an entirely new class of cosmic object. "It's comprised of radio sources so faint they have never been seen before, each with their own unique physical properties," writes Miroslav Filipovic, an astronomer at Western Sydney University, and his colleagues in an essay for The Conversation. "As we study the sky with telescopes that record radio signals rather than light, we end up seeing a lot of circles." Allowing astronomers to delve into this uncharted realm include the Australian Square Kilometer Array Pathfinder (ASKAP), which is made up of 36 powerful antennas, and the South African MeerKAT radio telescope, comprising 64 antennas. Both are continuously involved in performing surveys of the night sky, but ASKAP in particular is leading one called the Evolutionary Map of the Universe (EMU) launched in 2022, which seeks to account for every radio source imaginable in the Southern sky. In their essay, Filopovic and his colleagues document some of the most interesting objects this new generation of radio telescopes have found so far. Two of them are stellar oddities known as a Wolf-Rayet star. Dubbed Kýklos and WR16, these are massive celestial bodies, perhaps 25 times heavier than the Sun, near the end of their relatively brief lifespans. At this moribund stage, Wolf-Rayets rapidly shed mass, forming extremely luminous shells that, at their source, outshine our Sun by millions of times. That light is extremely faint by the time it reaches our planet, however, and since they only stick around for a few million years, spotting them is rare. "In these objects, a previous outflow of material has cleared the space around the star, allowing the current outburst to expand symmetrically in all directions," wrote the astronomers. "This sphere of stellar detritus shows itself as a circle." Radio imagery has also revealed a number of supernova remnants, or the sphere of gases and other material left behind after a massive star burns through its fuel, collapses under its own gravity, and epically explodes. "The supernova remnant will be deformed by its environment over time. If one side of the explosion slams into an interstellar cloud, we'll see a squashed shape," explained Filipovic and company. "So, a near-perfect circle in a messy universe is a special find." Lo and behold, ASKAP managed to spot one: a remnant named Teleios. And it's so perfect that nothing like it has ever been seen, according to the astronomers. "This presents us with an opportunity to make inferences about the initial supernova explosion, providing rare insight into one of the most energetic events in the universe," the scientists wrote. Most mysterious of all is the latest instance (viewable here, on the right) of a new class of cosmic objects called Odd Radio Circles (ORCs), which, as the name suggests, are a phenomenon exclusively visible to the wavelength. ORCs are unfathomably large — large enough that they often imprison entire galaxies at their centers, with some being ten times as wide as the Milky Way. Tantalizingly, this is just the beginning of our exploration of the "low-surface brightness universe," according to Filopovic, because the ASKAP and MeerKAT are just the prelude to the mother of all telescopes: the Square Kilometer Array, which, once completed, will be the biggest radio observatory in history. More on space: James Webb Spots Mysterious Object Crossing Space Between Stars
