Stars and stellar evolution
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.
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.
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.
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.
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.
When a massive star reaches the end of its life, it explodes as a supernova that can light up the sky for months. But some supernovae stay luminous for much longer, and astrophysicists have wondered what causes their extended brightness. New research points to binary stars, where one star expels material right before the explosion that creates a cocoon of circumstellar medium.
Ptolemy and al-Sufi were keen ancient astronomers, one in Greece and one in Persia, whose observations were separated by almost a thousand years. They both noted that the star Theta Eridani was far brighter than it is today. Now we know why.
When stars like the Sun reach the end of their lives, the textbook story has them puffing up and quietly shedding their outer layers to leave a white dwarf behind. A new model suggests it is far less serene than that. As dying stars eject mass asymmetrically, each burst delivers a tiny recoil, and over hundreds of thousands of years roughly ten thousand of these kicks add up to send the star drifting through space at a respectable speed. The idea neatly explains why wide binary star systems tend to fall apart once one star becomes a white dwarf, and it hints at something more dramatic still waiting to be confirmed
The centre of the Milky Way is one of the most violent places in the Galaxy, a churning storm of gas moving faster than sound, and about the last spot you would expect a star to be born. Yet astronomers mapping that chaos with the ALMA telescope have stumbled on a hidden pocket of calm, where the gas slows, settles and quietly begins gathering itself into the seeds of new stars. The find suggests stars may take their first steps the same way everywhere, even here, and that our own Sun was likely born from just such an island of stillness, billions of years ago.
Star formation is a major driver in galaxy evolution, right up there with the collisions and mergers that shape all galaxies. Researchers led by Ohio State University graduate student Debosmita Pathak, studied 18,000 star-forming regions in nearby spiral galaxies to get a better handle on the influence of starbirth.
Stars form inside molecular clouds where cold gas collapses gravitationally on itself. But there's more to this process than gravity. New research shows how magnetic field lines funnel gas through sub-filaments into star formation sites.
For a long time, astrophysicists thought that the Universe's first stars, called Population III stars, were uniformly massive. It seemed like the conditions they formed in were calm and serene, which favoured massive stars. But new research based on high-resolution simulations show that conditions were more chaotic than thought, and gas cloud turbulence means that Population III stars were not all massive. This affected the metallicity of the next stars to form.
Half the stars in the universe live in pairs and when one of them dies it can feed hungrily off the other in a slow, violent dance. Now a Korean team has caught a couple of stars breaking the rules, locked in an orbit so impossibly fast that our best theories of how stars grow old cannot account for it. So what is this dying star trying to tell us?
A team of 14 researchers from the United States and Chile have found evidence of a subgiant star eating one of its planets. The star, called TOI-5882, was already known to astronomers because of its massive companion, a brown dwarf called TOI-5882 b. The companion may well have helped kick a planet onto a spiraling journey into the star.
Astrophysicists have found what is likely the very first pair of sibling supernova remnants. One is the well-known Jellyfish Nebula, and the other was long thought to be hidden in the bright glare from the Jellyfish. The pair are connected by a bright filament of gas.
Somewhere in the plane of the Milky Way, a dead star is spinning 220 times a second, and it's circling its companion in almost the most perfect orbit astronomers have ever measured. China's giant FAST radio telescope has just found it, and the shape of that orbit is a near flawless record of a billion year relationship between two stars.
When we scan the skies for signs of alien civilisations, where exactly should we be looking and perhaps more importantly, where should we not? A high school student from Ankara has just published a remarkably sophisticated answer to that question, building a filtering system that sifts nearly 1.75 million stars and identifies which ones are genuinely worth our attention. The result is a publicly available catalogue that could transform how the search for extraterrestrial intelligence allocates its most precious resource - time.
New simulations show that interactions with a magnetic field can work to decrease the distance between still forming binary protostars. These results can help explain the characteristics of the binary star systems observed in the Milky Way. These results can also be extrapolated to binary black holes, giving insights into how super massive black holes evolve.
Stephen Hawking predicted that stars can capture primordial black holes (PBH). The PBH find their way to the stellar core, creating a Hawking star. There are two possible outcomes, both deadly for the star. Either it explodes rapidly, or it's slowly consumed by the parasitic PBH.
Scientists using the Euclid space telescope found a red-dwarf brightness “gap” in the population of a globular cluster—an ancient, crowded collection of stars. A similar gap was detected by the Gaia observatory in nearby stellar populations, but it has never before been seen in a globular cluster.
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