Event Horizon Telescope reveals why M87’s black hole ring is not a perfect circle

This figure compares simulated (left) and observed (right) images of the black hole M87*. In simulations, the actual shadow of a spinning black hole (outlined in blue) appears less than 2% squished due to gravity alone. However, with the current resolution of the EHT, due to turbulent plasma near the black hole the ring can appear 2–20% distorted. The EHT observations (right) reveal the ring is squished by about 8%, with its major axis tilted 50° counterclockwise from north, roughly aligned with the brightest spot. This suggests the observed ellipticity is driven NOT by gravity or spin, but by turbulent matter swirling around the black hole. Credit: Rohan Dahale (IAA-CSIC), Ilje Cho (KASI/Yonsei University

Study co-led by the Instituto de Astrofísica de Andalucía (IAA-CSIC) reveals that the ellipticity of the M87* ring is due to plasma turbulence and not due to its spin.

The results, published in Astronomy & Astrophysics, bring the scientific community closer to isolating the gravitational signature of a black hole and directly measuring its spin.

The galaxy M87, located about 55 million light-years from Earth, hosts at its core the supermassive black hole M87*, whose image whose image went viral around the globe in 2019 thanks to the Event Horizon Telescope (EHT). That historic photograph revealed a luminous ring around M87* with a slightly elongated shape that raised many questions: why is it not perfectly circular? Today, the journal Astronomy & Astrophysics (A&A) publishes a study co-led by the Instituto de Astrofísica de Andalucía (IAA-CSIC) that sheds light on the issue.

“We have demonstrated that the slightly elongated shape of the ring is not caused by gravity or by the black hole’s spin, but by turbulent astrophysical processes in the surrounding plasma,” explains Rohan Dahale, researcher at the IAA-CSIC and co-lead author of the study.

Einstein’s general theory of relativity predicts that the “shadow” of a spinning black hole is slightly flattened, adopting an elliptical shape due to the distortion of spacetime caused by its spin. Quantifying this ellipticity provides a direct path to estimating the black hole’s spin—one of the two parameters, along with mass, that fully define its appearance and physical properties.

Beyond a perfect circle: What the shape of M87*reveals

To refine this measurement, the scientific team added the Greenland Telescope to the EHT network in 2018, increasing both the spatial resolution and the sensitivity of the collaboration, which tripled compared to previous campaigns. Using five independent image reconstruction algorithms based on aperture synthesis techniques, they consistently found that the ring deviates from a perfect circle by about 8%. They also discovered that the ellipse is tilted roughly 50° counterclockwise from North, roughly aligned with the brightest point on the ring.

To determine whether gravity alone could explain the elongated shape, the team compared the real images with a series of computer simulations exploring different physical scenarios, including various spin values for the black hole. Surprisingly, they found no clear relationship between spin and the elliptical shape in the simulated images. Instead, they discovered that the elongation of the ring was associated with what they call “non-ring emission”: a diffuse glow surrounding the main ring, more intense in models with very energetic electrons and a brighter jet.

“These results suggest that the ellipticity of M87* is mainly a footprint of the turbulent plasma swirling around the black hole, rather than a direct reflection of its gravitational strength or spin,” says Ilje Cho (KASI/Yonsei University), co-lead author of the study. “This allows us to better disentangle the role of gravity from that of astrophysical processes in shaping these remarkable images and brings us a step closer to understanding how matter behaves in the most extreme environments in the universe.”

Although measuring the spin of M87* in the presence of such turbulence remains a major challenge, the team proposes moving forward through two complementary approaches: first, by conducting sustained observations over the years to smooth out short-term fluctuations and reveal the subtle gravitational distortions currently obscured; second, by launching space-based telescopes that, through very long baseline interferometry (VLBI), would be capable of directly resolving the “photon ring”—the thin light shell orbiting the black hole that carries a purer gravitational signal, ideal for measuring spin.

“With the upgrades in the next-generation EHT (ngEHT) and space missions, we are getting closer to isolating the true gravitational signature of a black hole,” explains Rohan Dahale (IAA-CSIC). “And thus, the information contained in the images themselves will allow us to directly measure spin,” he concludes.

TCredit: Rohan Dahale (IAA-CSIC), Ilje Cho (KASI/Yonsei University)

Source: Max Planck for Radio Astronomy/Announcements

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About theEvent Horizon Telescope

The Event Horizon Telescope (EHT) is an international collaboration that has created a virtual Earth-sized telescope by computationally linking radio observatories around the globe. It is designed to image black holes and test fundamental physics in extreme gravitational environments.

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Reference:

Origin of the ring ellipticity in the black hole images of M87*
https://www.aanda.org/10.1051/0004-6361/202555235

More info:

Rohan Dahale (Instituto de Astrofísica de Andalucía) - rdahale@iaa.es
Dr. Ilje Cho (Korea Astronomy and Space Science Institute (KASI) / Yonsei University) - icho@kasi.re.kr

Contact:

Instituto de Astrofísica de Andalucía (IAA-CSIC)
Unidad de Divulgación y Comunicación
Amanda López – alm@iaa.es
Emilio García – garcia@iaa.es - 649 407 445 (vía whatssap)
Celia Navas - navas@iaa.es
https://www.iaa.csic.es
https://divulgacion.iaa.csic.es

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NASA's Webb Scratches Beyond Surface of Cat's Paw for 3rd Anniversary

Cat's Paw Nebula (NIRCam Image)
Credits/Image: NASA, ESA, CSA, STScI

Cat's Paw (NIRCam) Compass Image
Credits/Image: NASA, ESA, CSA, STScI

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It’s the cat’s meow! To celebrate its third year of revealing stunning scenes of the cosmos in infrared light, NASA’s James Webb Space Telescope has “clawed” back the thick, dusty layers of a section within the Cat’s Paw Nebula (NGC 6334). Focusing Webb’s NIRCam (Near-Infrared Camera) on a single “toe bean” within this active star-forming region revealed a subset of mini toe beans, which appear to contain young stars shaping the surrounding gas and dust.

Webb’s look at this particular area of the Cat’s Paw Nebula just scratches the surface of the telescope’s three years of groundbreaking science.

“Three years into its mission, Webb continues to deliver on its design – revealing previously hidden aspects of the universe, from the star formation process to some of the earliest galaxies,” said Shawn Domagal-Goldman, acting director of the Astrophysics Division at NASA Headquarters in Washington. “As it repeatedly breaks its own records, Webb is also uncovering unknowns for new generations of flagship missions to tackle. Whether it’s following up on the mysteries of dark matter with NASA’s nearly complete Nancy Grace Roman Space Telescope, or narrowing our search for life to Earth-like planets with the Habitable Worlds Observatory, the questions Webb has raised are just as exciting as the answers it’s giving us.”

Star Formation Flex

The progression from a large molecular cloud to massive stars entails multiple steps, some of which are still not well understood by astronomers. Located approximately 4,000 light-years away in the constellation Scorpius, the Cat’s Paw Nebula offers scientists the opportunity to study the turbulent cloud-to-star process in great detail. Webb’s observation of the nebula in near-infrared light builds upon previous studies by NASA’s Hubble and retired Spitzer Space Telescope in visible- and infrared-light, respectively.

With its sharp resolution, Webb shows never-before-seen structural details and features: Massive young stars are carving away at nearby gas and dust, while their bright starlight is producing a bright nebulous glow represented in blue. It’s a temporary scene where the disruptive young stars, with their relatively short lives and luminosity, have a brief but important role in the region’s larger story. As a consequence of these massive stars’ lively behavior, the local star formation process will eventually come to a stop.

Opera House’s Intricate Structure

Start with the toe bean at top center, which is nicknamed the “Opera House” for its circular, tiered-like structure. The primary drivers for the area’s cloudy blue glow are most likely toward its bottom: either the light from the bright yellowish stars or from a nearby source still hidden behind the dense, dark brown dust.

Just below the orange-brown tiers of dust is a bright yellow star with diffraction spikes. While this massive star has carved away at its immediate surroundings, it has been unable to push the gas and dust away to greater distances, creating a compact shell of surrounding material.

Look closely to notice small patches, like the tuning fork-shaped area to the Opera House’s immediate left, that contain fewer stars. These seemingly vacant zones indicate the presence of dense foreground filaments of dust that are home to still-forming stars and block the light of stars in the background.

Spotlight on Stars

Toward the image’s center are small, fiery red clumps scattered amongst the brown dust. These glowing red sources mark regions where massive star formation is underway, albeit in an obscured manner.

Some massive blue-white stars, like the one in the lower left toe bean, seem to be more sharply resolved than others. This is because any intervening material between the star and the telescope has been dissipated by stellar radiation.

Near the bottom of that toe bean are small, dense filaments of dust. These tiny clumps of dust have managed to remain despite the intense radiation, suggesting that they are dense enough to form protostars. A small section of yellow at the right notes the location of a still-enshrouded massive star that has managed to shine through intervening material.

Across this entire scene are many small yellow stars with diffraction spikes. Bright blue-white stars are in the foreground of this Webb image, but some may be a part of the more expansive Cat’s Paw Nebula area.

One eye-catching aspect of this Webb image is the bright, red-orange oval at top right. Its low count of background stars implies it is a dense area just beginning its star-formation process. A couple of visible and still-veiled stars are scattered throughout this region, which are contributing to the illumination of the material in the middle. Some still-enveloped stars leave hints of their presence, like a bow shock at the bottom left, which indicates an energetic ejection of gas and dust from a bright source.

Further explore this subset of toe beans by embarking on a narrated tour or getting closer to the image. We also invite you to reminisce about Webb’s three years of science observations.

The James Webb Space Telescope is the world’s premier space science observatory. Webb is solving mysteries in our solar system, looking beyond to distant worlds around other stars, and probing the mysterious structures and origins of our universe and our place in it. Webb is an international program led by NASA with its partners, ESA (European Space Agency) and CSA (Canadian Space Agency).

Source: NASA's James Webb Space Telescope/News

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About This Release

Credits:

Media Contact

Abigail Major
Space Telescope Science Institute, Baltimore

Hannah Braun
Space Telescope Science Institute, Baltimore

Permissions: Content Use Policy

Contact us: Direct inquiries to the News Team.

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"Third Wheel" Star Brings Companions Closer Together

This artwork depicts a triple-star system in which two of the stars are locked in a tight gravitational orbit. The bright star in the foreground on the right is a white dwarf, which is stealing mass from its stellar companion. Eventually, this building up of mass on the white dwarf will trigger periodic explosions. Together, the two stars form an object called cataclysmic variable. New Caltech-led research has shown that a third star in triple-star systems (like the star depicted in the background here), can gravitationally influence its neighboring stars. and lead to the formation of cataclysmic variables. Credit: Caltech/R. Hurt (IPAC)

Cheyanne Shariat and Kareem El-Badry
Credit: Lance Hayashida/Caltech

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New findings show that certain explosive star systems may form with help of third star

When white dwarfs—the hot remnants of stars like our Sun—are orbited closely by another star, they sometimes steal mass away from their companion. The stolen matter builds up on the surface of the white dwarf, triggering eruptions called novae.

Theorists have long predicted how these volatile partnerships, called cataclysmic variables (CVs), form, but now a new Caltech-led study reveals a surprising twist: In some cases, a third star, circling farther away from the primary pair, may in fact be the reason the star couple got together in the first place.

"Our results are revealing another formation channel for CVs," says Kareem El-Badry, assistant professor of astronomy at Caltech and a co-author of a new paper appearing in the Publications of the Astronomical Society of the Pacific. "Sometimes, a lurking third star is key," he says. The lead author of the study is Caltech graduate student Cheyanne Shariat.

Before now, scientists believed that CVs formed from a process called common envelope evolution, in which the partner stars are brought closer together via an envelope of gas that cocoons them. An aging star destined to become a white dwarf expands into a red giant that encompasses both stars, creating a shared envelope. The envelope corrals the two stars, causing them to spiral inward. Eventually, the envelope is ejected, leaving a tight pair that have become close enough for the white dwarf to steal its companion's mass.

Although a third star was not mentioned in these descriptions, the team wondered if one could be involved. After all, they reasoned, triple-star dynamics do play a role in other types of star systems.

To further investigate the matter, the researchers turned to data from the European Space Agency's Gaia mission, now retired. Sorting through these observations, they identified 50 CVs in hierarchical triple-star systems, or triples, as the researchers call them. A hierarchical triple is one in which two stars are located fairly close together, while the third is much farther out and orbits the primary pair. The results suggested that at least 10 percent of all known CVs are part of triple systems.

That 10 percent number was higher than what would be expected if triples had no role in CV formation, so the researchers decided to learn more by running computer simulations. They performed so-called three-body simulations on 2,000 hypothetical triples; these simulations sped up the gravitational interactions of the trio of stars, evolving them over time.

In 20 percent of the triple-star simulations, CVs formed without the traditional mechanism of common envelope evolution. In these cases, the researchers say, the third star torqued the main binary.

"The gravity of the third star causes the binary stars to have a super eccentric orbit, and this forces the companion star closer to the white dwarf. Tidal forces dissipate energy and shrink and circularize the orbit," Shariat says. "The star doesn't have to spiral in through the common envelope."

In 60 percent of the simulations, the triple star helped initiate the process of common envelope evolution, bringing the two primary stars close enough to one another to be encased in the same envelope. In the remaining 20 percent of the simulations, the CVs formed via the traditional common envelope evolution route that requires just two stars.

When the researchers accounted for a realistic population of stars in our galaxy, including CVs known to have formed from just two stars, their theoretical models predicted around 40 percent of all CVs form in triple systems. This is higher than the 10 percent they observed using Gaia because, in many cases, the third stars can be either hard to see or have become unbound from the CV.

Finally, the simulation results enabled predictions about the types of triple-star systems that would be more likely to form CVs. Specifically, the triple systems would be expected to start out in wider configurations, such that the tight-knit pair and the third star are separated by more than 100 astronomical units (an astronomical unit, or au, is the distance between the Sun and Earth).

Looking back at the Gaia data, the researchers found agreement: The triples with CVs did exhibit wider separations on average than typical systems.

"For the past 50 years, people were using the spiral-in common-envelope evolution model to explain CV formation," El-Badry says. "Nobody had noticed before that this was largely happening in triples!"

The study titled "Cataclysmic Variables in Triples: Formation Models and New Discoveries" was funded by the Joshua and Beth Friedman Foundation Fund, NASA, the National Science Foundation, and Howard and Astrid Preston. The project was done in collaboration with Smadar Naoz, a researcher at UCLA who specializes in theoretical studies of triples. Other authors include Antonio Rodriguez, a graduate student at Caltech, and Jan van Roestel of the University of Amsterdam.

Written by Whitney Clavin

Source: Caltech/News

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Contact:

Whitney Clavin
(626) 395‑1944
wclavin@caltech.edu

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Galactic Mystery: How “Ice Cubes” Survive in the Milky Way’s Blazing Bubbles

An artist's interpretation of the highest-latitude neutral hydrogen clouds ever detected within the Fermi Bubbles in the center of our Milky Way Galaxy. The cold clouds reside more than 13,000 light-years above the Galactic center, in a region where frigid materials like this were never expected to be discovered. Credit: NSF/AUI/NSF NRAO/P.Vosteen

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Astronomers discover fragile hydrogen clouds surviving inside the superheated Fermi Bubbles, revealing the Milky Way’s most extreme outflows are younger and more complex than ever imagined

clouds of cold, neutral hydrogen gas—akin to “ice cubes”—surviving deep inside the Fermi Bubbles, two enormous lobes of superheated plasma erupting from the center of our Milky Way Galaxy. These cold clouds reside more than 13,000 light-years above the Galactic center, in a region where frigid materials like this were never expected to be discovered.

The Fermi Bubbles are among the most violent environments in our Galaxy, filled with plasma at temperatures over a million degrees Kelvin. In such a harsh setting, cold gas should quickly evaporate or be torn apart—much like ice cubes tossed into an active volcano. Yet, these clouds remain structured, dynamic, and surprisingly long-lived, with lifetimes estimated at several million years. This resilience matches independent estimates of the Fermi Bubbles’ age and challenges existing models, which often predict much longer formation times for the Bubbles themselves.

“These findings change our previous assumptions, showing that cold gas can persist in the hot, turbulent Fermi Bubbles,” explained Rongmon Bordoloi, the lead scientist of this research and an associate professor North Carolina State University, “We didn’t know that cold gas can survive in these extreme outflows. This challenges our understanding of how galaxies recycle and expel matter.”

To find these cold clouds, the research team conducted the deepest-ever 21 cm radio survey of the Fermi Bubbles, using the NSF GBT’s unmatched sensitivity and resolution. They identified eleven cold hydrogen clouds at unprecedented heights, making these the highest-latitude neutral hydrogen clouds ever detected within the Bubbles. The NSF GBT’s unique capabilities were essential for this breakthrough—no other instruments can match its sensitivity and sky coverage for this type of observation.

“We believe that these cold clouds were swept up from the Milky Way’s center and carried aloft by the very hot wind that formed the Fermi bubbles”, said Jay Lockman an astronomer at the Green Bank Observatory and coauthor of the paper. “Just as you can’t see the motion of the wind on Earth unless there are clouds to track it, we can’t see the hot wind from the Milky Way but can detect radio emission from the cold clouds it has entrained.”

These findings also challenge the previously understood age of the Fermi Bubbles, which are now likely believed to have been formed more recently. The survival of these fragile, cold clouds suggests that the Fermi Bubbles may be only a few million years old—pointing to a dramatic outburst from the Milky Way’s central black hole, rather than star formation, as their likely origin. “If the Bubbles were older, these clouds would have long since vanished,” adds Bordoloi.

Scientists wonder how these clouds formed or survived. Did they condense out of the hot plasma, were they swept up from the galaxy’s disk, or are they remnants of pre-existing structures? What physical processes—such as magnetic fields or pressure confinement—are allowing them to resist destruction in such an extreme environment.

“Finding these cold clouds so high up in the Fermi Bubbles was unexpected”, adds co-author Andrew Fox, ESA-AURA Astronomer at the Space Telescope Science Institute in Baltimore, MD. “It challenges our understanding of where they came from and what their ultimate fate will be.”

This discovery pushes the boundaries of what scientists thought possible in our Galaxy’s most extreme environments. It opens new avenues for research into how galaxies evolve, how matter cycles through the cosmos, and what physical mechanisms allow fragile structures to persist amid cosmic violence. Future studies will focus on unraveling the origins and survival mechanisms of these clouds, providing critical tests for models of galactic feedback and outflows.

Source: National Radio Astronomy Observatory (NRAO)/News

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About GBO

The Green Bank Observatory, part of the National Radio Astronomy Observatory, is a facility of the U.S. National Science Foundation, operated under cooperative agreement by Associated Universities, Inc.

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Exo-Saturns and Exo-Jupiters Are Within JWST’s Reach

Illustration of Jupiter and a Jupiter-like exoplanet.
Credit: NASA/JPL-Caltech

A JWST image of the exoplanet Epsilon Indi Ab, one of the coldest exoplanets to be directly imaged. The planet’s temperature is estimated to be just 275K (35℉/2℃). Credit: NASA, ESA, CSA, STScI, Elisabeth Matthews (MPIA)

Of the nearly 6,000 currently known exoplanets, few closely resemble any of the planets in our solar system. New research suggests that JWST is capable of directly imaging exoplanets with temperatures and orbital distances similar to Jupiter and Saturn, placing truly familiar exoplanets within our observational grasp.

Increasingly Cold Discoveries

JWST has already proven itself to be a powerful tool to directly image exoplanet systems. The telescope has imaged increasingly cold planets, but the gas giants in our solar system are substantially colder than the coldest planet imaged by JWST so far. This raises the question of whether JWST is capable of directly imaging Jupiter and Saturn if they orbited another star.

Answering this question requires a deep dive into the abilities of JWST’s instruments. The current go-to method for directly imaging planets with JWST is coronagraphy with its Near-Infrared Camera (NIRCam). In this observing mode, the instrument blocks the light from the star, allowing the fainter thermal glow of the planet to shine through.

But as Rachel Bowens-Rubin (University of Michigan and Eureka Scientific) and collaborators note in a recent research article, this may not be the best way to detect cold giant planets. Models suggest that these planets have cloudy atmospheres, which means that they wouldn’t be bright at NIRCam’s preferred near-infrared wavelengths, and would instead be detected more easily in the mid-infrared, where JWST’s Mid-Infrared Instrument (MIRI) reigns.

Temperatures of coldest detectable planets as a function of separation from the host star for Wolf 350 and EV Lac. Results are shown for MIRI F2100W imaging and NIRCam F444W coronagraphy. Credit: Bowens-Rubin et al. 2025

Combining Data and Models

To examine the capabilities of both of these instruments, Bowens-Rubin’s team analyzed JWST observations from the Cool Kids on the Block program, which targets cold, low-mass giant planets around nearby low-mass stars with NIRCam coronagraphy and MIRI imaging. The team used observations of nearby M-dwarf stars Wolf 359 and EV Lac to construct constrast curves: the level of planet–star flux contrast that is detectable by each instrument as a function of distance from each star. These curves depend on the flux of the star and the planet as well as the limitations of the instrument — the detector noise and background noise.

Bowens-Rubin and coauthors converted the contrast curves into information about the coldest planet each instrument can detect. To do this, the team modeled the atmospheres of planets with temperatures down to 50K and generated thermal emission spectra, which allowed them to relate the temperature of their modeled planets to the level of contrast.

Temperatures of planets detectable to a signal-to-noise ratio of 3 as a function of distance from Earth. Detection limits for MIRI and NIRCam are shown as red and blue lines, respectively. Credit: Bowens-Rubin et al. 2025

NIRCam vs. MIRI

This analysis showed that MIRI is the best choice for directly imaging cold planets around nearby stars (within 65 light-years). MIRI should be able to detect giant planets with temperatures down to 94K around Wolf 359 and 114K around EV Lac — about the temperature of Saturn and slightly colder than Jupiter, respectively. For Wolf 359, sub-100K planets are detectable at orbital distances of at least 4.8 au, meaning these planets could also have similar orbital separations to Jupiter and Saturn.

NIRCam coronagraphy can match MIRI’s performance only for the unlikely case of cloud-free giant planets; for cloudy planets around nearby stars, MIRI can spot planets 90–130K colder than NIRCam can. NIRCam has the advantage for more distant stars — beyond about 200 light-years — but only planets significantly warmer than Jupiter and Saturn are detectable at these distances.

As impressive as these results are already, Bowens-Rubin and coauthors noted that future work, such as developing strategies to mitigate MIRI’s “brighter-fatter effect” that limits sensitivity at small angular separations from the host star, could enhance the search for exo-Saturns and exo-Jupiters even further.

Citation

J“NIRCam Yells at Cloud: JWST MIRI Imaging Can Directly Detect Exoplanets of the Same Temperature, Mass, Age, and Orbital Separation as Saturn and Jupiter,” Rachel Bowens-Rubin et al 2025 ApJL 986 L26. doi:10.3847/2041-8213/addbde

Source: American Astronomical Society/AAS-Nova

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Supernova’s ‘Trapped’ Jet Reveals Source of Fast X-ray Transient

This image shows the cosmic field in which the fast X-ray transient EP 250108a, and the supernova that followed it, were detected by Einstein Probe (EP) in early 2025. Using a combination of telescopes, including the W. M. Keck Observatory, a team of astronomers studied the evolving signal of EP 250108a/SN 2025kg to uncover details about its origin. Their analysis reveals that fast X-ray transients can result from the ‘failed’ explosive death of a massive star. Credit: International Gemini Observatory/NOIRLab/NSF/AURA.

Maunakea, Hawaiʻi – An international team of astrophysicists using W. M. Keck Observatory on Maunakea, Hawaiʻi Island have uncovered a possible origin of fast X-ray transients (FXTs) — mysterious, fleeting bursts of X-rays that have long puzzled astronomers.

Using a combination of telescopes around the globe and in space, the team studied the closest FXT associated with the explosive death of a massive star, or supernova, ever observed. A geyser of high-energy particles, or jet, trapped inside a supernova produced the FXT, the scientists discovered.

When jets burst through a massive star’s onion-like layers, they generate gamma-ray bursts (GRBs), the most powerful and luminous explosions in the universe. When the jets are stifled, however, they emit lower levels of energy, which astronomers can detect only from X-ray signals. The new observations now point to these “failed” jets as a source of the emission, explaining the historically elusive phenomena.

This finding marks a significant step in understanding the diverse landscape of cosmic explosions — bridging the gap among FXTs, GRBs and supernovae.

A pair of studies, led by Northwestern University and the University of Leicester in England, has been accepted by The Astrophysical Journal Letters.

“Since the 1970s, astronomers have detected FXTs — blasts of X-rays from distant galaxies that can last from seconds to hours,” said Northwestern’s Jillian Rastinejad, lead author of one of the studies. “But their origin sources have remained a long-standing mystery. Our work definitively shows that FXTs can originate from the explosive death of a massive star. It also supports a causal link between GRB-supernovae and FXT-supernovae, in which GRBs are produced by successful jets, and FXTs are produced by trapped weak jets.”

The team utilized the various time zones and locations of its members to gather and analyze the data, passing it along to the next time zone to make decisions on the next night of observations.

“The result? A massive and beautiful stream of data collected from facilities large and small, on the ground and in space, chronicling this event’s first month. It takes really special events to motivate such a global effort, and this FXT was one,” said Northwestern’s Wen-fai Fong, a senior author on the study.

This sequence of images shows the fading light of the supernova SN 2025kg, which followed the fast X-ray transient EP 250108a, a powerful blast of X-rays that was detected by Einstein Probe (EP) in early 2025. Using a combination of telescopes, including the W. M. Keck Observatory, a team of astronomers studied the evolving signal of EP 250108a/SN 2025kg to uncover details about its origin. Their analysis reveals that fast X-ray transients can result from the ‘failed’ explosive death of a massive star. Credit: International Gemini Observatory/NOIRLab/NSF/AURA.

Spectroscopy obtained from Keck Observatory’s Low-Resolution Imaging Spectrometer (LRIS) revealed that SN 2025kg is a Type Ic-BL supernova—an especially fast and powerful kind of stellar explosion. By analyzing the light, scientists measured how quickly the star’s material was ejected (nearly 19,000 kilometers per second or about 11,800 miles per second) and gained insight into the immense energy released during the blast.

“The fact that Keck Observatory was able to respond quickly to a transient of interest was pivotal to understanding the composition and speed of the supernova ejecta, and how much material was shed,” said Fong. “Its nimble capabilities were particularly important at later times when the source was fainter and only detectable with the most sensitive ground-based spectrographs.”

“This result highlights the important role Keck Observatory plays with observatories across the globe and in space,” added John O’Meara, chief scientist and deputy director at the observatory. “The international team has really pulled out all the stops to characterize and understand this new type of transient.”

“The fact that Keck Observatory was able to respond quickly to a transient of interest was pivotal to understanding the composition and speed of the supernova ejecta, and how much material was shed,” said Fong. “Its nimble capabilities were particularly important at later times when the source was fainter and only detectable with the most sensitive ground-based spectrographs.”

“This result highlights the important role Keck Observatory plays with observatories across the globe and in space,” added John O’Meara, chief scientist and deputy director at the observatory. “The international team has really pulled out all the stops to characterize and understand this new type of transient.”

An explosive neighbor

Although astronomers have detected FXTs for decades, the limited number of discoveries prevented detailed studies. But now, scientists have a new space-based tool, called the Einstein Probe, which is dedicated to the search. Launched in January 2024 by the Chinese Academy of Sciences in partnership with the European Space Agency and the Max Planck Institute for Extraterrestrial Physics, the Einstein Probe carries two scientific instruments, specially designed to observe X-ray sources.

“FXTs have long fascinated us but their study has relied on a small number of events that were discovered in serendipitous ways,” Fong said. “The Einstein Probe has revolutionized this field by increasing the number of known events by ten-fold in just a year of operations. Thus, it is not only filling in the previously sparse landscape of FXTs, but also making our picture of that landscape crisper, bringing facets of these explosions into focus that we had not imagined before.

Shortly after its launch, the Einstein Probe captured the most nearby FXT, associated with a supernova, to date. Dubbed EP 250108a, the FXT was located 2.8 billion light-years away from Earth, within the river-like constellation Eridanus. Its close proximity to Earth gave astronomers an unprecedented opportunity to observe the event’s evolution.

To track this evolving behavior, the team captured the event’s signal across multiple wavelengths. The Gemini South telescope at the International Gemini Observatory provided near-infrared data, the Gemini North telescope atop Maunakea provided optical data, the MMT Observatory in Arizona provided the infrared images, and the James Webb Space Telescope provided highly sensitive infrared data.

Failed jet, big breakthrough

By analyzing the rapidly evolving signal of EP 250108a, the scientists concluded the object is likely a “failed” GRB. Although EP 250108a is similar to a jet-driven explosion, its jets did not break through the outer layer of the dying star. Instead, the jets remained trapped inside.

“Through decades of scientific study, we know that jets can successfully plow through a dying star’s outer layers, and we view them as GRBs,” Rastinejad said. “In our study, we found this ‘trapped’ jet outcome is more common in massive star explosions than jets that successfully emerge from the star.”

The researchers now plan to use datasets provided by the Vera C. Rubin Observatory that will show how stars and their explosive deaths change over time. These insights could help reveal the inner workings of FXTs and many other exotic cosmic events.

Related Links:

• Science Paper by Rastinejad et. al

Source: W. M. Keck Observatory/News

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The birth of a solar system revealed by planet 'pebbles'

An artist’s impression of dust and tiny grains in a protoplanetary disc surrounding a young star (left) alongside an e-MERLIN map showing the tilted disc structure around the young star DG Tauri (top right) and the HL Tau disc captured by e-MERLIN is shown overlaid on an ALMA image, revealing both the compact emission from the central region of the disc and the larger scale dust rings (bottom right). Credit: NASA/JPL-Caltech/Hesterly, Drabek-Maunder, Greaves, Richards, et al./Greaves, Hesterly, Richards, and et al./ALMA partnership et al.

Licence type: Attribution (CC BY 4.0)

An e-MERLIN map showing the tilted disc structure around the young star DG Tauri where pebble-sized clumps are beginning to form. Its long axis is southeast to northwest (lower left to upper right). Emission from an outflow of material from the central star is also seen in the northeast and southwest directions. Credit: Hesterly, Drabek-Maunder, Greaves, Richards, et al.

Licence type: Attribution (CC BY 4.0)

The HL Tau disc captured by e-MERLIN is shown overlaid on an ALMA image, revealing both the compact emission from the central region of the disc and the larger scale dust rings. Credit: Greaves, Hesterly, Richards, and et al./ALMA partnership et al.

Licence type: Attribution (CC BY 4.0)

An artist’s impression of dust and tiny grains in a protoplanetary disc surrounding a young star. Credit: NASA/JPL-Caltech
Licence type: Attribution (CC BY 4.0)

e‑MERLIN is an interferometer array of seven radio telescopes spanning 217 km (135 miles) across the UK, connected by a superfast optical fibre network to its headquarters at Jodrell Bank. Observatory in Cheshire. Credit: e‑MERLIN

Licence type: Attribution (CC BY 4.0)

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A fascinating glimpse into how a solar system like our own is born has been revealed with the detection of planet-forming 'pebbles' around two young stars.

These seeds to make new worlds are thought to gradually clump together over time, in much the same way Jupiter was first created 4.5 billion years ago, followed by Saturn, Uranus, Neptune, Mercury, Venus, Earth and Mars.
The planet-forming discs, known as protoplanetary discs, were spotted out to at least Neptune-like orbits around the young stars DG Tau and HL Tau, both around 450 light-years from Earth.

The new observations, revealed at the Royal Astronomical Society’s National Astronomy Meeting 2025 in Durham, are helping to fill in a missing piece of the planet formation puzzle.

"These observations show that discs like DG Tau and HL Tau already contain large reservoirs of planet-forming pebbles out to at least Neptune-like orbits," said researcher Dr Katie Hesterly, of the SKA Observatory.

"This is potentially enough to build planetary systems larger than our own solar system."

The latest research is part of the PEBBLeS project (Planet Earth Building-Blocks – a Legacy eMERLIN Survey), led by Professor Jane Greaves, of Cardiff University.

By imaging the rocky belts of many stars, the team are looking for clues to how often planets form, and where, around stars that will evolve into future suns like our own.

The survey uses e‑MERLIN, an interferometer array of seven radio telescopes spanning 217 km (135 miles) across the UK and connected by a superfast optical fibre network to its headquarters at Jodrell Bank Observatory in Cheshire.

It is currently the only radio telescope able to study protoplanetary discs – the cosmic nurseries where planets are formed – at the required resolution and sensitivity for this science.

"Through these observations, we’re now able to investigate where solid material gathers in these discs, providing insight into one of the earliest stages of planet formation," said Professor Greaves.

Since the 1990s, astronomers have found both disks of gas and dust, and nearly 2,000 fully-formed planets, but the intermediate stages of formation are harder to detect. 

"Decades ago, young stars were found to be surrounded by orbiting discs of gas and tiny grains like dust or sand," said Dr Anita Richards, of the Jodrell Bank Centre for Astrophysics at the University of Manchester, who has also been involved in the research.

"Enough grains to make Jupiter could be spread over roughly the same area as the entire orbit of Jupiter, making this easy to detect with optical and infra-red telescopes, or the ALMA submillimeter radio interferometer.

"But as the grains clump together to make planets, the surface area of a given mass gets smaller and harder to see."

For that reason, because centimetre-sized pebbles emit best at wavelengths similar to their size, the UK interferometer e-MERLIN is ideal to look for these because it can observe at around 4 cm wavelength.

In one new e‑MERLIN image of DG Tau’s disc, it reveals that centimetre-sized pebbles have already formed out to Neptune-like orbits, while a similar collection of planetary seeds has also been detected encircling HL Tau.

These discoveries offer an early glimpse of what the Square Kilometre Array (SKA) telescopes in South Africa and Australia will uncover in the coming decade with its improved sensitivity and scale, paving the way to study protoplanetary discs across the galaxy in unprecedented detail.

"e-MERLIN is showing what’s possible, and the SKA telescopes will take it further," said Dr Hesterly.

"When science verification with the SKA-Mid telescope begins in 2031, we’ll be ready to study hundreds of planetary systems to help understand how planets are formed."

Source: Royal Astronomical Society (RAS)/News

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Media contacts:

Sam Tonkin
Royal Astronomical Society
Mob: +44 (0)7802 877 700
press@ras.ac.uk

Dr Robert Massey
Royal Astronomical Society
Mob: +44 (0)7802 877 699
press@ras.ac.uk

Megan Eaves
Royal Astronomical Society
press@ras.ac.uk

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Science contacts:

Dr Katie Hesterly
SKA Observatory
katie.hesterly@skao.int

Professor Jane Greaves
Cardiff University
greavesj1@cardiff.ac.uk

Dr Anita Richards
Jodrell Bank Centre for Astrophysics at the University of Manchester
a.m.s.richards@manchester.ac.uk

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Further information

The talk 'PEBBLeS in Protoplanetary Discs' will take place at NAM at 09:00 BST on Monday 7 July 2025 in room TLC033. Find out more at: https://conference.astro.dur.ac.uk/event/7/contributions/867/

PEBBLES is an ultra-deep continuum survey of the circumstellar disks that are predicted to be the most conducive to planet formation. Imaging the thermal emission from pebble-sized dust grains shows where and when planet-core growth is proceeding, helping to identify actual accreting proto-planets. The survey sample comprises a mass-limited cut from all known northern disks with long-millimetre wavelength dust emission, above a threshold of 2.5 times the minimum-mass Solar-nebula, at the theoretical boundary for forming the Sun's planets.

The survey results will show how planet growth proceeds - where, when, and with what outcomes - for comparison to inferred histories of the Sun and extrasolar planetary systems. The scientific legacy will also include measuring quantities vital to theoretical progress - particle sizes, disk surface densities and radial distributions, for the first time on few-AU scales - and providing a database of proto-planet targets for future followup with EVLA, ALMA and SKA.

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Notes for editors

The NAM 2025 conference is principally sponsored by the Royal Astronomical Society and Durham University.

About the Royal Astronomical Society

The Royal Astronomical Society (RAS), founded in 1820, encourages and promotes the study of astronomy, solar-system science, geophysics and closely related branches of science.

The RAS organises scientific meetings, publishes international research and review journals, recognises outstanding achievements by the award of medals and prizes, maintains an extensive library, supports education through grants and outreach activities and represents UK astronomy nationally and internationally. Its more than 4,000 members (Fellows), a third based overseas, include scientific researchers in universities, observatories and laboratories as well as historians of astronomy and others.

The RAS accepts papers for its journals based on the principle of peer review, in which fellow experts on the editorial boards accept the paper as worth considering. The Society issues press releases based on a similar principle, but the organisations and scientists concerned have overall responsibility for their content.

Keep up with the RAS on Instagram, Bluesky, LinkedIn, Facebook and YouTube.

Download the RAS Supermassive podcast

About the Science and Technology Facilities Council

The Science and Technology Facilities Council (STFC), part of UK Research and Innovation (UKRI), is the UK’s largest public funder of research into astronomy and astrophysics, particle and nuclear physics, and space science. We operate five national laboratories across the UK which, supported by a network of additional research facilities, increase our understanding of the world around us and develop innovative technologies in response to pressing scientific and societal issues. We also facilitate UK involvement in a number of international research activities including the ELT, CERN, the James Webb Space Telescope and the Square Kilometre Array Observatory.

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ukri.org/councils/stfc

About Durham University

Durham University is a globally outstanding centre of teaching and research based in historic Durham City in the UK. 

We are a collegiate university committed to inspiring our people to do outstanding things at Durham and in the world.

We conduct research that improves lives globally and we are ranked as a world top 100 university with an international reputation in research and education (QS World University Rankings 2026).

We are a member of the Russell Group of leading research-intensive UK universities and we are consistently ranked as a top five university in national league tables (Times and Sunday Times Good University Guide and The Complete University Guide).

For more information about Durham University visit: www.durham.ac.uk/about/

Submitted by Sam Tonkin

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Portrait of a galaxy cluster

Abell 209

A cluster of distant, mainly elliptical galaxies. They appear as brightly shining points radiating golden light that each take the shape of a smooth, featureless oval. They crowd around one that is extremely large and bright. A few spiral galaxies of comparable size appear too, bluer in colour and with unique shapes. Of the other, more small and distant galaxies covering the scene, a few are warped into long lines. Credit: ESA/Hubble & NASA, M. Postman, P. Kelly

A massive, spacetime-warping cluster of galaxies is the setting of today’s NASA/ESA Hubble Space Telescope Picture of the Week. The galaxy cluster in question is Abell 209, which is located 2.8 billion light-years away in the constellation Cetus (The Whale).

This Hubble image of Abell 209 shows more than a hundred galaxies, but there’s more to this cluster than even Hubble’s discerning eye can see. Abell 209’s galaxies are separated by millions of light-years, and the seemingly empty space between the galaxies is actually filled with hot, diffuse gas that can be spotted only at X-ray wavelengths. An even more elusive occupant of this galaxy cluster is dark matter: a form of matter that does not interact with light. The Universe is understood to be comprised of 5% normal matter, 25% dark matter, and 70% dark energy

Hubble observations like the ones used to create this image can help astronomers answer fundamental questions about our Universe, including mysteries surrounding dark matter and dark energy. These investigations leverage the immense mass of a galaxy cluster, which can bend the fabric of spacetime itself and create warped and magnified images of background galaxies and stars in a process called gravitational lensing.

While this image lacks the dramatic rings that gravitational lensing can sometimes create, Abell 209 still shows subtle signs of lensing at work, in the form of streaky, slightly curved galaxies within the cluster’s golden glow. By measuring the distortion of these galaxies, astronomers can map the distribution of mass within the cluster, illuminating the underlying cloud of dark matter. This information, which Hubble’s fine resolution and sensitive instruments help to provide, is critical for testing theories of how our Universe has evolved.

Source: ESA/Hubble/potw

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The young stars of Taurus

GN 04.32.8

A long, smoky, greyish-blue cloud in the centre of the image curves in an arc around three bright stars, each with long cross-shaped diffraction spikes. The cloud is lit more brightly on the inner side facing the stars, and fades into the dark background on the outer side. A few other stars and points of light surround the cloud: one small star below it has a dark band crossing its centre. Credit: ESA/Hubble & NASA, G. Duchêne

The subject of this week's Hubble Picture of the Week is a reflection nebula, identified as GN 04.32.8. Reflection nebulae are clouds of dust in space that don't emit their own light, as other nebulae do. Instead, the light from nearby stars hits and scatters off their dust, lighting them up. Because of the way the light scatters, many reflection nebulae tend to appear blue, GN 04.32.8 included.

GN 04.32.8 is a small part of the stellar nursery known as the Taurus Molecular Cloud. At only roughly 480 light-years from Earth in the constellation Taurus, it's one of the best locations for studying newly forming stars. This reflection nebula is illuminated by the system of three bright stars in the centre of this image, mainly the variable star V1025 Tauri in the very centre. One of those stars overlaps with part of the nebula: this is another variable star that is named HP Tauri, but is classified as a T Tauri star, for its similarity to yet another variable star elsewhere in the Taurus Molecular Complex. T Tauri stars are very active, chaotic stars at an early stage of their evolution, so it's no surprise that they appear in a prolific stellar nursery like this one! The three stars are also named HP Tau, HP Tau G2 and HP Tau G3; they’re believed to be gravitationally bound to each other, forming a triple system.

Eagle-eyed viewers might notice the small, squashed, orange spot, just left of centre below the clouds of the nebula, that’s crossed by a dark line. This is a newly-formed protostar, hidden in a protoplanetary disc that obstructs some of its light. Because the disc is edge-on to us, it’s an ideal candidate for study. Astronomers are using Hubble here to examine it closely, seeking to learn about the kinds of exoplanets that might be formed in discs like it.

Link

• Pan: GN 04.32.8

Source: ESA/Hubble/potw

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Citizen Science Born in the Pandemic: The Hubble Image Similarity Project

A handful of images used in the Hubble Image Similarity Project
Adapted from White & Peek 2025

Motivated by a desire to support community members financially during the coronavirus pandemic, researchers employed 30 local citizen scientists in the Hubble Image Similarity Project. This project quantified the similarities between astronomical images, providing a way to test the results of image-search algorithms.

The Eagle Nebula, pictured here in an image from Kitt Peak National Observatory, is a star-forming region in the Milky Way. Credit:  T.A.Rector (NRAO/AUI/NSF and NOIRLab/NSF/AURA) and B.A.Wolpa Credit: NOIRLab/NSF/AURA); CC BY 4.0

Seeking Similarities

Say you have an image of a star-forming region, featuring eye-catching gas clouds, dense and dusty knots, and newborn stars. How would you go about finding other images that resemble yours?

You might start your search with an astronomical image database, using filters for object type or instrument to sift through thousands and thousands of options. But even filtering out everything but star-forming regions might yield vastly different results, given the widely varying shapes, colors, and sizes of these regions.

Or maybe you’ll feed your image into a neural network that has been trained to spot similar images. The results may seem promising, but how can you tell whether the algorithm has found the images that are the most similar? Would another algorithm do better?

An example of individual test images (green squares) extracted from a Hubble Legacy Archive image (red square). Low-contrast areas have been excluded, leaving the galaxy’s spiral arms for analysis. Credit: White & Peek 2025

The Hubble Image Similarity Project

Astronomical image collections rarely contain information about similarities between images in their metadata, and while neural networks appear to excel at gathering similar images, the results of these models are generally unverified. The Hubble Image Similarity Project, led by Richard White (Space Telescope Science Institute) and Josh Peek (Space Telescope Science Institute and Johns Hopkins University), addressed these issues with a team of citizen scientists who generated similarity information for astronomical images, providing a quantitative means to test the results of neural networks.

White and Peek began by amassing a sample of images from the Hubble Legacy Archive. This sample included many different object types, such as galaxies, planetary nebulae, star-forming regions, and star clusters. After trimming and binning the images, converting them to 8-bit grayscale, filtering out low-contrast images, and eliminating satellite trails, image artifacts, and repeated observations of the same patch of sky, 2,098 images of 666 objects remained.

Examples of similar images according to the image similarity matrix. In the lower-right corner is a visualization of the similarity data. The semicircle of data points in the bottom half of this visualization represents galaxies, while star clusters occupy the small arc near the top and nebulae sit in the island in the center of the plot. Credit: Adapted from White & Peek 2025

Citizen Scientists, Assemble

White and Peek recruited 30 members of the community within walking distance of the Space Telescope Science Institute to identify similar astronomical images, and the reviewers were paid for their work. In the three phases of the project, reviewers considered test images one at a time and 1) selected all similar images from a set of 15 comparison images, 2) selected the most similar image from a narrowed-down set of 6 comparison images, and finally 3) selected the most similar image from a set of 3 comparison images.

The citizen science team ultimately compared 5.4 million pairs of images, and White and Peek used these comparisons to produce an image similarity matrix. The matrix describes the metaphorical “distance” between the images, with the most similar images being the smallest distance apart.

Similar images resemble one another in terms of structure, texture, and other factors that White and Peek say are “difficult even to describe in words” — for example, the diffuse glow of a galaxy interrupted by a bright star with diffraction spikes, or a nebula speckled with stars and dense dusty clumps. The similarity data from this study are available online and can be used to test the performance of image-search algorithms. In future work, the authors plan to carry out a similar project using images of the Martian landscape.

By Kerry Hensley

Citation

“The Hubble Image Similarity Project,” Richard L. White and J. E. G. Peek 2025 AJ 169 306. doi:10.3847/1538-3881/adcb43

Source: American Astronomical Society/ASS-Nova

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Double detonation: new image shows remains of star destroyed by pair of explosions

PR Image eso2511a
VLT image of a double-detonation supernova

PR Image eso2511b
Distribution of calcium around the supernova remnant SNR 0509-67.5

PR Image eso2511c
Artist’s impression of a double-detonation supernova

PR Image eso2511d
Location of the supernova remnant SNR 0509-67.5

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Videos


PR Video eso2511a
First visual proof of a star destroyed by pair of explosions | ESO News


PR Video eso2511b
Zooming into a star that detonated twice


PR Video eso2511c
Animation of a double-detonation supernova

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For the first time, astronomers have obtained visual evidence that a star met its end by detonating twice. By studying the centuries-old remains of supernova SNR 0509-67.5 with the European Southern Observatory’s Very Large Telescope (ESO’s VLT), they have found patterns that confirm its star suffered a pair of explosive blasts. Published today, this discovery shows some of the most important explosions in the Universe in a new light.

Most supernovae are the explosive deaths of massive stars, but one important variety comes from an unassuming source. White dwarfs, the small, inactive cores left over after stars like our Sun burn out their nuclear fuel, can produce what astronomers call a Type Ia supernova.

"The explosions of white dwarfs play a crucial role in astronomy,” says Priyam Das, a PhD student at the University of New South Wales Canberra, Australia, who led the study on SNR 0509-67.5 published today in Nature Astronomy. Much of our knowledge of how the Universe expands rests on Type Ia supernovae, and they are also the primary source of iron on our planet, including the iron in our blood. “Yet, despite their importance, the long-standing puzzle of the exact mechanism triggering their explosion remains unsolved," he adds.

All models that explain Type Ia supernovae begin with a white dwarf in a pair of stars. If it orbits close enough to the other star in this pair, the dwarf can steal material from its partner. In the most established theory behind Type Ia supernovae, the white dwarf accumulates matter from its companion until it reaches a critical mass, at which point it undergoes a single explosion. However, recent studies have hinted that at least some Type Ia supernovae could be better explained by a double explosion triggered before the star reached this critical mass.

Now, astronomers have captured a new image that proves their hunch was right: at least some Type Ia supernovae explode through a ‘double-detonation’ mechanism instead. In this alternative model, the white dwarf forms a blanket of stolen helium around itself, which can become unstable and ignite. This first explosion generates a shockwave that travels around the white dwarf and inwards, triggering a second detonation in the core of the star — ultimately creating the supernova.

Until now, there had been no clear, visual evidence of a white dwarf undergoing a double detonation. Recently, astronomers have predicted that this process would create a distinctive pattern or fingerprint in the supernova’s still-glowing remains, visible long after the initial explosion. Research suggests that remnants of such a supernova would contain two separate shells of calcium.

Astronomers have now found this fingerprint in a supernova’s remains. Ivo Seitenzahl, who led the observations and was at Germany’s Heidelberg Institute for Theoretical Studies when the study was conducted, says 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 were able to detect these calcium layers (in blue in the image) in the supernova remnant SNR 0509-67.5 by observing it with the Multi Unit Spectroscopic Explorer (MUSE) on ESO’s VLT. This provides strong evidence that a Type Ia supernova can occur before its parent white dwarf reaches a critical mass.

Type Ia supernovae are key to our understanding of the Universe. They behave in very consistent ways, and their predictable brightness — no matter how far away they are — helps astronomers to measure distances in space. Using them as a cosmic measuring tape, astronomers discovered the accelerating expansion of the Universe, a discovery that won the Physics Nobel Prize in 2011. Studying how they explode helps us to understand why they have such a predictable brightness.

Das also has another motivation to study these explosions. “This tangible evidence of a double-detonation not only contributes towards solving a long-standing mystery, but also offers a visual spectacle,” he says, describing the “beautifully layered structure” that a supernova creates. For him, “revealing the inner workings of such a spectacular cosmic explosion is incredibly rewarding.”

Source: ESO/News

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More information

This research was presented in a paper titled “Calcium in a supernova remnant shows the fingerprint of a sub-Chandrasekhar mass explosion” to appear in Nature Astronomy at https://www.nature.com/articles/s41550-025-02589-5 (doi: 10.1038/s41550-025-02589-5).

The team is composed of P. Das (University of New South Wales, Australia [UNSW] & Heidelberger Institut für Theoretische Studien, Heidelberg, Germany [HITS]), I. R. Seitenzahl (HITS), A. J. Ruiter (UNSW & HITS & OzGrav: The ARC Centre of Excellence for Gravitational Wave Discovery, Hawthorn, Australia & ARC Centre of Excellence for All-Sky Astrophysics in 3 Dimensions), F. K. Röpke (HITS & Institut für Theoretische Astrophysik, Heidelberg, Germany & Astronomisches Recheninstitut, Heidelberg, Germany), R. Pakmor (Max-Planck-Institut für Astrophysik, Garching, Germany [MPA]), F. P. A. Vogt (Federal Office of Meteorology and Climatology – MeteoSwiss, Payerne, Switzerland), C. E. Collins (The University of Dublin, Dublin, Ireland & GSI Helmholtzzentrum für Schwerionenforschung, Darmstadt, Germany), P. Ghavamian (Towson University, Towson, USA), S. A. Sim (Queen’s University Belfast, Belfast, UK), B. J. Williams (X-ray Astrophysics Laboratory NASA/GSFC, Greenbelt, USA), S. Taubenberger (MPA & Technical University Munich, Garching, Germany), J. M. Laming (Naval Research Laboratory, Washington, USA), J. Suherli (University of Manitoba, Winnipeg, Canada), R. Sutherland (Australian National University, Weston Creek, Australia), and N. Rodríguez-Segovia (UNSW).
The European Southern Observatory (ESO) enables scientists worldwide to discover the secrets of the Universe for the benefit of all. We design, build and operate world-class observatories on the ground — which astronomers use to tackle exciting questions and spread the fascination of astronomy — and promote international collaboration for astronomy. Established as an intergovernmental organisation in 1962, today ESO is supported by 16 Member States (Austria, Belgium, Czechia, Denmark, France, Finland, Germany, Ireland, Italy, the Netherlands, Poland, Portugal, Spain, Sweden, Switzerland and the United Kingdom), along with the host state of Chile and with Australia as a Strategic Partner. ESO’s headquarters and its visitor centre and planetarium, the ESO Supernova, are located close to Munich in Germany, while the Chilean Atacama Desert, a marvellous place with unique conditions to observe the sky, hosts our telescopes. ESO operates three observing sites: La Silla, Paranal and Chajnantor. At Paranal, ESO operates the Very Large Telescope and its Very Large Telescope Interferometer, as well as survey telescopes such as VISTA. Also at Paranal ESO will host and operate the Cherenkov Telescope Array South, the world’s largest and most sensitive gamma-ray observatory. Together with international partners, ESO operates ALMA on Chajnantor, a facility that observes the skies in the millimetre and submillimetre range. At Cerro Armazones, near Paranal, we are building “the world’s biggest eye on the sky” — ESO’s Extremely Large Telescope. From our offices in Santiago, Chile we support our operations in the country and engage with Chilean partners and society.

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Links

• Research paper
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Contacts:

Priyam Das
School of Science (Astrophysics), University of New South Wales at the Australian Defence Force Academy
Canberra, Australia
Email: priyam.das@unsw.edu.au

Ashley Ruiter
School of Science (Astrophysics), University of New South Wales at the Australian Defence Force Academy
Canberra, Australia
Email: ashley.ruiter@unsw.edu.au

Ivo Seitenzahl
Heidelberg Institute for Theoretical Studies
Heidelberg, Germany (currently in Canberra, Australia)
Email: ivoseitenzahl@gmail.com

Friedrich Röpke
Heidelberg Institute for Theoretical Studies
Heidelberg, Germany
Email: friedrich.roepke@h-its.org
Bárbara Ferreira
ESO Media Manager
Garching bei München, Germany
Tel: +49 89 3200 6670
Cell: +49 151 241 664 00
Email: press@eso.org

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