Tuesday, April 29, 2025

SPACE/COSMOS

Flares from magnetized stars can forge planets’ worth of gold, other heavy elements

Flatiron Institute researchers calculate that a single flare from a supermagnetized star called a magnetar can produce the mass equivalent of 27 moons’ worth of the universe’s heaviest atoms such as gold, platinum and uranium.

Simons Foundation

Magnetar Flare — image:
In an ejection that would have caused its rotation to slow, a magnetar is depicted losing material into space in this artist’s concept. The magnetar’s strong, twisted magnetic field lines (shown in green) can influence the flow of electrically charged material from the object, which is a type of neutron star.
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Credit: NASA/JPL-Caltech

Astronomers have discovered a previously unknown birthplace of some of the universe’s rarest elements: a giant flare unleashed by a supermagnetized star. The astronomers calculated that such flares could be responsible for forging up to 10 percent of our galaxy’s gold, platinum and other heavy elements.

The discovery also resolves a decades-long mystery concerning a bright flash of light and particles spotted by a space telescope in December 2004. The light came from a magnetar — a type of star wrapped in magnetic fields trillions of times as strong as Earth’s — that had unleashed a giant flare. The powerful blast of radiation only lasted a few seconds, but it released more energy than our sun does in 1 million years. While the flare’s origin was quickly identified, a second, smaller signal from the star, peaking 10 minutes later, confounded scientists at the time. For 20 years, that signal went unexplained.

Now, a new insight by astronomers at the Flatiron Institute’s Center for Computational Astrophysics (CCA) in New York City has revealed that the unexplained smaller signal marked the rare birth of heavy elements such as gold and platinum. In addition to confirming another source of these elements, the astronomers estimated that the 2004 flare alone produced the equivalent of a third of Earth’s mass in heavy metals. They report their discovery in a paper published on April 29 in The Astrophysical Journal Letters.

“This is really just the second time we've ever directly seen proof of where these elements form,” the first being neutron star mergers, says study co-author Brian Metzger, a senior research scientist at the CCA and a professor at Columbia University. “It’s a substantial leap in our understanding of heavy elements production.”

Most of the elements we know and love today weren’t always around. Hydrogen, helium and a dash of lithium were formed in the Big Bang, but almost everything else has been manufactured by stars in their lives, or during their violent deaths. While scientists thoroughly understand where and how the lighter elements are made, the production locations of many of the heaviest neutron-rich elements — those heavier than iron — remain incomplete.

These elements, which include uranium and strontium, are produced in a set of nuclear reactions known as the rapid neutron-capture process, or r-process. This process requires an excess of free neutrons — something that can be found only in extreme environments. Astronomers thus expected that the extreme environments created by supernovae or neutron star mergers were the most promising potential r-process sites.

It wasn’t until 2017 that astronomers were able to confirm an r-process site when they observed the collision of two neutron stars. These stars are the collapsed remnants of former stellar giants and made of a soup of neutrons so dense that a single tablespoon would weigh more than 1 billion tons. The 2017 observations showed that the cataclysmic collision of two of these stars creates the neutron-rich environment needed for the formation of r-process elements.

However, astronomers realized that these rare collisions alone can’t account for all the r-process-produced elements we see today. Some suspected that magnetars, which are highly magnetized neutron stars, could also be a source.

Metzger and colleagues calculated in 2024 that giant flares could eject material from a magnetar’s crust into space, where r-process elements could form.

“It’s pretty incredible to think that some of the heavy elements all around us, like the precious metals in our phones and computers, are produced in these crazy extreme environments,” says Anirudh Patel, a doctoral candidate at Columbia University and lead author on the new study.

The group’s calculations show that these giant flares create unstable, heavy radioactive nuclei, which decay into stable elements such as gold. As the radioactive elements decay, they emit a glow of light, in addition to minting new elements.

The group also calculated in 2024 that the glow from the radioactive decays would be visible as a burst of gamma rays, a form of highly energized light. When they discussed their findings with observational gamma-ray astronomers, the group learned that, in fact, one such signal had been seen decades earlier that had never been explained. Since there’s little overlap between the study of magnetar activity and heavy-element synthesis science, no one had previously proposed element production as a cause of the signal.

“The event had kind of been forgotten over the years,” Metzger says. “But we very quickly realized that our model was a perfect fit for it.”

In the new paper, the astronomers used the observations of the 2004 event to estimate that the flare produced 2 million billion billion kilograms of heavy elements (roughly equivalent to Mars’ mass). From this, they estimate that one to 10 percent of all r-process elements in our galaxy today were created in these giant flares. The remainder could be from neutron star mergers, but with only one magnetar giant flare and one merger ever documented, it’s hard to know exact percentages — or if that’s even the whole story.

“We can't exclude that there could be third or fourth sites out there that we just haven’t seen yet,” Metzger says.

“The interesting thing about these giant flares is that they can occur really early in galactic history,” Patel adds. “Magnetar giant flares could be the solution to a problem we’ve had where there are more heavy elements seen in young galaxies than could be created from neutron star collisions alone.”

To narrow down the percentages, more magnetar giant flares need to be observed. Telescopes like NASA’s Compton Spectrometer and Imager mission, set to launch in 2027, will help better capture these signals. Large magnetar flares seem to occur every few decades in the Milky Way and about once a year across the visible universe — but the trick is to catch it in time.

“Once a gamma-ray burst is detected, you have to point an ultraviolet telescope at the source within 10 to 15 minutes to see the signal's peak and confirm r-process elements are made there,” Metzger says. “It’ll be a fun chase.”

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About the Flatiron Institute

The Flatiron Institute is the research division of the Simons Foundation. The institute's mission is to advance scientific research through computational methods, including data analysis, theory, modeling and simulation. The institute's Center for Computational Astrophysics creates new computational frameworks that allow scientists to analyze big astronomical datasets and to understand complex, multi-scale physics in a cosmological context.

Journal

The Astrophysical Journal Letters

DOI

10.3847/2041-8213/adc9b0

Article Title

Direct evidence for r-process nucleosynthesis in delayed MeV emission from the SGR 1806-20 magnetar giant flare

Article Publication Date

29-Apr-2025

Graphical depiction of how magnetars create heavy elements.

Credit

Lucy Reading-Ikkanda/Simons Foundation

Chip-shop fish among key seabed engineers

University of Exeter

image:
Atlantic cod
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Credit: Alex Mustard

Many of the fish we eat play a key role in maintaining the seabed – and therefore our climate, new research shows.

Convex Seascape Survey scientists assessed the role of fish in bioturbation (churning and reworking sediments) in shallow UK seas.

The Atlantic cod – a staple in chip shops – jointly topped the list of these important “ecosystem engineers” (along with Atlantic hagfish and European eel).

In total, 185 fish species were found to play a role in bioturbation – and 120 of these are targeted by commercial fishing.

“Ocean sediments are the world’s largest reservoir of organic carbon – so what happens on the seabed matters for our climate,” said University of Exeter PhD student Mara Fischer, who led the study.

“Bioturbation is very important for how the seabed takes up and stores organic carbon, so the process is vital to our understanding of how the ocean absorbs greenhouse gases to slow the rate of climate change.

“Bioturbation is also important for seabed and wider ocean ecosystems.

“We have a good understanding of how invertebrates contribute to global bioturbation – but until now, we have been missing half the story.

“Our study is the first to attempt to quantify the bioturbation impact of fish, and it shows they play a significant, widespread role.”

Overfished and overlooked

Co-author Professor Callum Roberts, from the Centre for Ecology and Conservation at Exeter’s Penryn Campus in Cornwall, said: “We also found that species with the highest bioturbation impacts are among the most vulnerable to threats such as commercial fishing.

“Many of the largest and most powerful diggers and disturbers of seabed sediments, like giant skates, halibut and cod, have been so overfished they have all but vanished from our seas.

“These losses translate into big, but still uncertain, changes in the way seabed ecosystems work.”

The researchers examined records for all fish species living on the UK continental shelf, and found more than half have a role in bioturbation – sifting and excavating sediment during foraging, burrowing and/or building nests.

These different ways of reworking the sediments – termed bioturbation modes – alongside the size of the fish and the frequency of bioturbation, were used by the researchers to calculate a bioturbation impact score for each species.

Examples include:

European eel. Bioturbation mode: burrower. Bioturbation score (out of 125): 100. IUCN conservation status: critically endangered. Fished primarily using traps and fyke nets, they are considered a delicacy in many parts of Europe and Asia – commonly prepared as smoked eel or dishes like eel pie and eel soup. Threats include climate change, diseases and parasites, habitat loss, pollutants and fishing.
Atlantic cod. Bioturbation mode: vertical excavator. Bioturbation score: 100. IUCN status: vulnerable. Primarily fished using trawling and longlining, they are consumed in many forms, including fish and chips, fresh fillets, salted cod, and cod liver oil. Threats include overfishing, climate change and habitat degradation. Populations have declined in several parts of its range, particularly the North Sea and West Atlantic.
Common skate. Bioturbation mode: lateral excavator. Bioturbation score: 50. IUCN status: critically endangered. Historically targeted by trawling and longlining, this species is now protected in several regions – but often caught accidentally (bycatch). Numbers have drastically declined due to overfishing. The species is vulnerable due to its large size, slow growth rate, and low reproductive rate – only about 40 eggs are laid every other year, and each generation takes 11 years to reach maturity.
Black seabream. Bioturbation mode: nest builder. Bioturbation score: 36. IUCN status: least concern. Primarily caught using bottom trawling, gillnets, and hook and line. Fishing during the spawning season in April and May can impact population replenishment. Bottom trawling at this time has the potential to remove the fish, nests and eggs.
Red gurnard. Bioturbation mode: sediment sifter. Bioturbation score: 16. IUCN status: least concern. Historically not of major interest to commercial fisheries, the species has been targeted more in recent years (including in Cornwall). It is mainly caught by trawlers. There is currently no management for any gurnard species in the EU: no minimum landing size, no quota, etc – which could lead to unsustainable fishing.

Julie Hawkins, another author of the study, commented: “Anyone who has spent time underwater, whether snorkelling or diving, knows that fish are constantly digging up the seabed.

“It’s hard to believe that such an obvious and important activity has been largely overlooked when it comes to understanding ocean carbon burial.”

The Convex Seascape Survey is a partnership between Blue Marine Foundation, the University of Exeter and Convex Group Limited. The ambitious five-year global research programme is the largest attempt yet to build a greater understanding of the properties and capabilities of the ocean and its continental shelves in the earth’s carbon cycle, in the urgent effort to slow climate change.

The paper, published in the journal Marine Environmental Research, is entitled: “A functional assessment of fish as bioturbators and their vulnerability to local extinction.”