Universe Today
NASA’s Webb Telescope Rules Out Two New Dyson Sphere Candidates
Recent searches for the technosignatures of hypothetical Dyson Spheres again turn up empty.
Stars
Stars and stellar evolution
Recent Articles
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Surface Chemistry Shows Which Massive Stars Have Gained Mass from Binary Companions
Most stars, including massive ones, are in binary pairs. Astronomers think that about 70% of them have gained mass from their companions, but there's been no way to determine which ones have done so. Now, researchers have found a way.
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Strange Signals Called Long-period Radio Transits Come From Cataclysmic Variables
Long-period Radio Transients are sources that emit repeating radio and x-ray signals. The signals are polarized and coherent, and are similar to pulsars in some respects. But the type of astrophysical object responsible for them has been vigorously debated. New research says that at least one of them comes from a cataclysmic variable, a binary star where a white dwarf and a red dwarf orbit closely.
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How Gas Filaments and Interfilaments Feed Star Formation in Monoceros R2
Researchers studied gas flows in the Monoceros R2 star forming region to understand how gas is channeled into star forming hubs. By tracing the flow of carbon monoxide, they found that a system of hub-filaments and interfilaments are responsible for feeding gas into star-forming locations. The filaments move most of the gas, but the interfilaments play a role too, especially by feeding more gas into the main filaments.
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The Fastest Star in the Milky Way Will Test Relativity
Astronomers have discovered another S star, the population of stars that orbits the Milky Way's SMBH. This one is the fastest of them all, and also comes closest to the SMBH. It will let astronomers test relativity, especially the Lense-Thirring effect.
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Even Near a Supermassive Black Hole, Stars Enrich the Interstellar Medium
Astronomers know that evolved AGB stars shed their outer layers, contributing to the makeup of the interstellar medium. But new JWST observations show this can happen even near a supermassive black hole, where powerful radiation could obliterate molecules.
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Astronomers Finally See the Twisted Magnetic Fields That Drive Protostar Jets
For decades, scientists have theorized that young protostar jets are shaped and driven by complex, twisted magnetic fields. But they couldn't detect them. Now, thanks to ALMA, they've found them around a young binary protostar.
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MOTHRA Shows Us A Star Being Recycled in the Helix Nebula
Astronomers used new MOTHRA telescope in Chile to image the famous Helix Nebula. They found 22 glowing shock waves where stellar debris from a dying star collided with interstellar gas. After colliding with gas, stellar fragments remain intact for just 10,000 years, the team estimates. The observations show how dying stars are recycled and return material to the interstellar medium to form new stars and planets.
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The Tarantula That Lost Its Fire
A new composite image combining data from Chandra, Hubble, Webb and the retired Spitzer telescope has helped astronomers solve a long standing puzzle in the Tarantula Nebula, a star forming region 160,000 light years away. Young, massive stars there should be heating enough gas to emit X-rays, but observations showed far less X-ray emission than predicted.
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Solar Magnetic Field Braids May Have a Previously Hidden Cause
Scientists using the Daniel K. Inouye Solar Telescope (DKIST) in Hawai'i have found a mechanism occurring on the Sun's surface that they think is heating our star's outer atmosphere. The process, called a Kelvin-Helmholtz Instability (KHI), could well be the root cause of a phenomenon called flux braiding that builds up and moves around on the Sun and heats the coronasphere. This discovery may well also explain the fundamental physics of similar activity at other stars.
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Watching the First Moments in a Star's Death
Astronomers were fortunate when the Einstein Probe detected the difficult-to-observe initial shock break out (SBO) from a supernova. The SBO is the first electromagnetic indication that a star is going to explode, and by observing it and the aftermath, researchers were able to determine what type of progenitor star exploded, and what it's pre-explosion environment was like.
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Ancient Maltese Seafarers Likely Navigated By The Stars
Ancient Maltese seafarers had both a complex cosmology and likely at least rudimentary skills in celestial navigation. It's thought that they used stars in the southern constellation of Crux to make their way around the south-central Mediterranean.
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The Star That Exploded Without Hydrogen
Twenty five years ago a star in the constellation Puppis blew itself apart and then vanished behind a curtain of its own soot. Astronomers knew only that the explosion contained no hydrogen at all, which for the most abundant element in the universe is a very strange absence. Now the dust has finally thinned, and the culprits have stepped into view, a white dwarf quietly stripping a rare helium star of its substance. But the emerging picture came with something nobody expected, clumps of gas tearing outwards at twenty million miles an hour, of a kind never seen in any other nova. Nobody yet knows what fired them.
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It Took a Century, but Astronomers Imaged Betelgeuse's Companion
Most of us are familiar with Betelgeuse (also known as alpha Orionis), the bright shoulder star in the constellation Orion. It's a red supergiant star that lies somewhere between 400 and 550 light-years away from us and is quite bright. Betelgeuse contains about 14 times the mass of the Sun and is a fairly young star compared to ours. It appears to be no more than 10 million years old, which means that it evolved rapidly from a protostar to the red giant we see today. That lifecycle means Betelgeuse will explode as a supernova sometime in the relatively near future — say within the next 100,000 years.
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White Dwarfs Eat More Planetary Debris Than Thought, But Magnetic Fields Hide It
Planetary debris disks around white dwarfs appear to be more plentiful than thought. That's because some white dwarfs are magnetic, and those magnetic fields create patches of metallic debris near the stars' poles, where it's more difficult to detect. This leads to an underestimation of debris, something new research is trying to correct.
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Meet Our Newest Stellar Neighbours That Hid in the Glare of Other Stars
Astronomers have found four new white dwarfs within about 65 light years. Even though the sky has been studied thoroughly, these escaped detection. That's because they're tight binaries with red dwarf partners, and the much brighter red dwarfs hide the white dwarfs. The binaries used to share common envelopes.
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The Case of the Sun's Missing Silver
Astronomers have solved a decades old puzzle about the Sun's missing silver, not by finding something new, but by modelling something old far more accurately. A revised, more realistic model of the Sun's atmosphere reveals it actually contains 55 per cent more silver than previously calculated, finally matching what meteorites have been telling us all along. It's a quiet reminder that some of the biggest revelations in astronomy come not from new data, but from asking familiar questions with sharper tools.
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The Dark Energy Camera's New Image is Reminiscent of van Gogh
The Dark Energy Camera (DECam) has a massive 570 megapixel camera, and its new image is of the Corona Australis Molecular Cloud. Corona Australis is one of the closest star-forming regions to Earth. It's not as well-studied as the Orion Molecular Cloud or Ophiuchus, but as DECam's new iage of Corona Australis shows, it's just as fascinating.
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X-Ray Eyes Reveal the Magnetic Secrets of the Lighthouse Pulsar's Cosmic Wake
Occasionally, when a massive star dies in a supernova, it can leave behind a dense, rapidly spinning core known as a pulsar. These extreme objects are some of the most fascinating in the universe, and are extremely useful for astronomers when measuring distances or navigating the void of space. A new paper from Jack Dinsmore, a graduate student at Stanford, and his co-authors, and published in The Astrophysical Journal, takes a look at some of the features of one of the most famous examples of a pulsar - PSR J1101-6101, commonly known as the Lighthouse pulsar.
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Listening for the Universe's Faintest Whispers, a Billion Supernovae at Once
Buried a kilometre underground in Japan, one of the world's most sensitive detectors may have caught its first faint trace of a sound scientists have been straining to hear for decades, the combined whisper of every supernova that has ever exploded across the universe. It is not yet a confirmed discovery, but if it holds up, it could rewrite how we trace the life and death of stars.