Showing posts with label Royal Astronomical Society (RAS). Show all posts
Showing posts with label Royal Astronomical Society (RAS). Show all posts

Thursday, August 28, 2025

Cosmic butterfly reveals clues to Earth's creation

This image, which combines infrared data from the James Webb Space Telescope with submillimetre observations from the Atacama Large Millimetre/submillimetre Array (ALMA), shows the doughnut-shaped torus and interconnected bubbles of dusty gas that surround the Butterfly Nebula’s central star. The torus is oriented vertically and nearly edge-on from our perspective, and it intersects with bubbles of gas enclosing the star. The bubbles appear bright red in this image, illuminated by the light from helium and neon gas. Outside the bubbles, jets traced by emission from ionised iron shoot off in opposite directions. vCredit ESA/Webb, NASA & CSA, M. Matsuura, ALMA (ESO/NAOJ/NRAO), N. Hirano, M. Zamani (ESA/Webb)
Licence type: Attribution (CC BY 4.0)

Clues about how worlds like Earth may have formed have been found buried at the heart of a spectacular 'cosmic butterfly'.

With the help of the James Webb Space Telescope, researchers say they have made a big leap forward in our understanding of how the raw material of rocky planets comes together.

This cosmic dust – tiny particles of minerals and organic material which include ingredients linked to the origins of life – was studied at the core of the Butterfly Nebula, NGC 6302, which is located about 3,400 light-years away in the constellation Scorpius.

From the dense, dusty torus that surrounds the star hidden at the centre of the nebula to its outflowing jets, the Webb observations reveal many new discoveries that paint a never-before-seen portrait of a dynamic and structured planetary nebula.

They have been published today in Monthly Notices of the Royal Astronomical Society.

Most cosmic dust has an amorphous, or randomly oriented-atomic structure, like soot. But some of it forms beautiful, crystalline shapes, more like tiny gemstones.

"For years, scientists have debated how cosmic dust forms in space. But now, with the help of the powerful James Webb Space Telescope, we may finally have a clearer picture," said lead researcher Dr Mikako Matsuura, of Cardiff University.

"We were able to see both cool gemstones formed in calm, long-lasting zones and fiery grime created in violent, fast-moving parts of space, all within a single object.

"This discovery is a big step forward in understanding how the basic materials of planets, come together."

This image set showcases three views of the Butterfly Nebula, featuring an optical and near-infrared view from Hubble (left and middle) and the latest Webb/ALMA image. Credit: ESA/Webb, NASA & CSA, M. Matsuura, J. Kastner, K. Noll, ALMA (ESO/NAOJ/NRAO), N. Hirano, J. Kastner, M. Zamani (ESA/Webb)
Licence type: Attribution (CC BY 4.0)

The Butterfly Nebula's central star is one of the hottest known central stars in a planetary nebula in our galaxy, with a temperature of 220,000 Kelvin.

This blazing stellar engine is responsible for the nebula's gorgeous glow, but its full power may be channelled by the dense band of dusty gas that surrounds it: the torus.

The new Webb data show that the torus is composed of crystalline silicates like quartz as well as irregularly shaped dust grains. The dust grains have sizes on the order of a millionth of a metre — large, as far as cosmic dust is considered — indicating that they have been growing for a long time.

Outside the torus, the emission from different atoms and molecules takes on a multilayered structure. The ions that require the largest amount of energy to form are concentrated close to the centre, while those that require less energy are found farther from the central star.

Iron and nickel are particularly interesting, tracing a pair of jets that blast outward from the star in opposite directions.

Intriguingly, the team also spotted light emitted by carbon-based molecules known as polycyclic aromatic hydrocarbons, or PAHs. They form flat, ring-like structures, much like the honeycomb shapes found in beehives.

On Earth, we often find PAHs in smoke from campfires, car exhaust, or burnt toast.

Given the location of the PAHs, the research team suspects that these molecules form when a 'bubble' of wind from the central star bursts into the gas that surrounds it.

This may be the first-ever evidence of PAHs forming in a oxygen-rich planetary nebula, providing an important glimpse into the details of how these molecules form.

This annotated image takes the viewer on a deep dive into the heart of the Butterfly Nebula, NGC 6302, as seen by the James Webb Space Telescope. Credit: ESA/Webb, NASA & CSA, M. Matsuura, ALMA (ESO/NAOJ/NRAO), N. Hirano, M. Zamani (ESA/Webb)
Licence type: Attribution (CC BY 4.0)

NGC 6302 is one of the best-studied planetary nebulae in our galaxy and was previously imaged by the Hubble Space Telescope.

Planetary nebulae are among the most beautiful and most elusive creatures in the cosmic zoo. These nebulae form when stars with masses between about 0.8 and 8 times the mass of the Sun shed most of their mass at the end of their lives. The planetary nebula phase is fleeting, lasting only about 20,000 years.

Contrary to the name, planetary nebulae have nothing to do with planets: the naming confusion began several hundred years ago, when astronomers reported that these nebulae appeared round, like planets.

The name stuck, even though many planetary nebulae aren't round at all — and the Butterfly Nebula is a prime example of the fantastic shapes that these nebulae can take.

The Butterfly Nebula is a bipolar nebula, meaning that it has two lobes that spread in opposite directions, forming the 'wings' of the butterfly. A dark band of dusty gas poses as the butterfly's 'body'.

This band is actually a doughnut-shaped torus that's being viewed from the side, hiding the nebula's central star — the ancient core of a Sun-like star that energises the nebula and causes it to glow. The dusty doughnut may be responsible for the nebula's insectoid shape by preventing gas from flowing outward from the star equally in all directions.

The new Webb image zooms in on the centre of the Butterfly Nebula and its dusty torus, providing an unprecedented view of its complex structure. The image uses data from Webb's Mid-InfraRed Instrument (MIRI) working in integral field unit mode.

This mode combines a camera and a spectrograph to take images at many different wavelengths simultaneously, revealing how an object’s appearance changes with wavelength. The research team supplemented the Webb observations with data from the Atacama Large Millimetre/submillimetre Array, a powerful network of radio dishes.

Researchers analysing these Webb data identified nearly 200 spectral lines, each of which holds information about the atoms and molecules in the nebula. These lines reveal nested and interconnected structures traced by different chemical species.

The research team were able to pinpoint the location of the Butterfly Nebula's central star, which heats a previously undetected dust cloud around it, making the latter shine brightly at the mid-infrared wavelengths that MIRI is sensitive to.

The location of the nebula's central star has remained elusive until now, because this enshrouding dust renders it invisible at optical wavelengths. Previous searches for the star lacked the combination of infrared sensitivity and resolution necessary to spot its obscuring warm dust cloud.




Media contacts

Sam Tonkin
Royal Astronomical Society
Mob: +44 (0)7802 877 700

press@ras.ac.uk

Science contacts:

Dr Mikako Matsuura
Cardiff University

matsuuram@cardiff.ac.uk



Further information

The paper 'The JWST/MIRI view of the planetary nebula NGC 6302 I.: a UV irradiated torus and a hot bubble triggering PAH formation' by Mikako Matsuura et al. has been published in Monthly Notices of the Royal Astronomical Society. DOI: 10.1093/mnras/staf1194.

About the James Webb Space Telescope

Webb is the largest, most powerful telescope ever launched into space. Under an international collaboration agreement, ESA provided the telescope’s launch service, using the Ariane 5 launch vehicle. Working with partners, ESA was responsible for the development and qualification of Ariane 5 adaptations for the Webb mission and for the procurement of the launch service by Arianespace. ESA also provided the workhorse spectrograph NIRSpec and 50% of the mid-infrared instrument MIRI, which was designed and built by a consortium of nationally funded European Institutes (The MIRI European Consortium) in partnership with JPL and the University of Arizona.

Webb is an international partnership between NASA, ESA and the Canadian Space Agency (CSA).




Notes for editors

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.

Submitted by Sam Tonkin


Fresh twist to mystery of Jupiter's core

A high-resolution simulation of a planet colliding with Jupiter, used to study whether this process could be responsible for forming the planet's dilute core. The impact generates striking shock waves and stirs material in Jupiter's interior through turbulent mixing. However, the core material rapidly re-settles, and no dilute core is produced in the simulations. Credit: Jacob Kegerries/Thomas Sandnes

The mystery at Jupiter's heart has taken a fresh twist – as new research suggests a giant impact may not have been responsible for the formation of its core.

It had been thought that a colossal collision with an early planet containing half of Jupiter's core material could have mixed up the central region of the gas giant, enough to explain its interior today.

But a new study published in Monthly Notices of the Royal Astronomical Society suggests its make-up is actually down to how the growing planet absorbed heavy and light materials as it formed and evolved.

Unlike what scientists once expected, the core of the largest planet in our solar system doesn't have a sharp boundary but instead gradually blends into the surrounding layers of mostly hydrogen – a structure known as a dilute core.

How this dilute core formed has been a key question among scientists and astronomers ever since NASA's Juno spacecraft first revealed its existence.

Tn impacting planet collides with Jupiter's core in the simulations, triggering shock waves and turbulent mixing. Credit: Thomas Sandnes/Durham University
Licence type: Attribution (CC BY 4.0)

Using cutting-edge supercomputer simulations of planetary impacts, with a new method to improve the simulation's treatment of mixing between materials, researchers from Durham University, in collaboration with scientists from NASA, SETI, and CENSSS, University of Oslo, tested whether a massive collision could have created Jupiter's dilute core.

The simulations were run on the DiRAC COSMA supercomputer hosted at Durham University using the state-of-the-art SWIFT open-source software.

The study found that a stable dilute core structure was not produced in any of the simulations conducted, even in those involving impacts under extreme conditions.

Instead, the simulations demonstrate that the dense rock and ice core material displaced by an impact would quickly re-settle, leaving a distinct boundary with the outer layers of hydrogen and helium, rather than forming a smooth transition zone between the two regions.

Reflecting on the findings, lead author of the study Dr Thomas Sandnes, of Durham University, said: "It's fascinating to explore how a giant planet like Jupiter would respond to one of the most violent events a growing planet can experience.

"We see in our simulations that this kind of impact literally shakes the planet to its core – just not in the right way to explain the interior of Jupiter that we see today

This image from the simulations shows how the collision of the impactor with Jupiter's core produces striking patterns of fluid instabilities as materials mix. Credit: Jacob Kegerreis/Thomas Sandnes/Durham University
Licence type: Attribution (CC BY 4.0)

The core material rapidly re-settles in the simulations to form a core with a sharp boundary. Credit: Jacob Kegerreis/Thomas Sandnes/Durham University
Licence type: Attribution (CC BY 4.0)

Jupiter isn't the only planet with a dilute core, as scientists have recently found evidence that Saturn has one too.

Dr Luis Teodoro, of the University of Oslo, said: "The fact that Saturn also has a dilute core strengthens the idea that these structures are not the result of rare, extremely high-energy impacts but instead form gradually during the long process of planetary growth and evolution."

The findings of this study could also help inform scientists' understanding and interpretation of the many Jupiter- and Saturn-sized exoplanets that have been observed around distant stars. If dilute cores aren't made by rare and extreme impacts, then perhaps most or all of these planets have comparably complex interiors.

Co-author of the study Dr Jacob Kegerreis said: "Giant impacts are a key part of many planets' histories, but they can't explain everything!

"This project also accelerated another step in our development of new ways to simulate these cataclysmic events in ever greater detail, helping us to continue narrowing down how the amazing diversity of worlds we see in the Solar System and beyond came to be."




Media contacts:

Sam Tonkin
Royal Astronomical Society
Mob: +44 (0)7802 877 700

press@ras.ac.uk

Science contacts:

Dr Thomas Sandnes
Durham University

thomas.d.sandnes@durham.ac.uk



Further information

The paper ‘No dilute core produced in simulations of giant impacts on to Jupiter’ by T. D. Sandnes, V. R. Eke, J. A. Kegerreis, R. J. Massey and L. F. A. Teodoro, has been published in Monthly Notices of the Royal Astronomical Society. DOI: 10.1093/mnras/staf1105.



Notes for editors

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.

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 overwritten to this Rankings 2025).

We are a member of the Russell Group of leading research-intensive UK universities and we are consistently ranked as a top 10 university in national league tables (Times and Sunday Times Good University Guide, Guardian University Guide and The Complete University Guide).

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

Submitted by Sam Tonkin


Wednesday, August 20, 2025

Rare quadruple star system could unlock mystery of brown dwarfs

An artist's impression of the UPM J1040−3551 system against the backdrop of the Milky Way as observed by Gaia. On the left, UPM J1040−3551 Aa & Ab appears as a distant bright orange dot, with an inset revealing these two M-type stars in orbit. On the right, in the foreground, a pair of cold brown dwarfs – UPM J1040−3551 Ba & Bb – orbit each other for a period of decades while collectively circling UPM J1040−3551 Aab in a vast orbit that takes over 100,000 years to complete. Credit: Jiaxin Zhong/Zenghua Zhang
Licence type: Attribution (CC BY 4.0)

The "exciting" discovery of an extremely rare quadruple star system could significantly advance our understanding of brown dwarfs, astronomers say.

These mysterious objects are too big to be considered a planet but also too small to be a star because they lack the mass to keep fusing atoms and blossom into fully-fledged suns.

In a new breakthrough published in the Monthly Notices of the Royal Astronomical Society (MNRAS), astronomers have now identified an extremely rare hierarchical quadruple star system consisting of a pair of cold brown dwarfs orbiting a pair of young red dwarf stars, located 82 light-years from Earth in the constellation Antlia.

The system, named UPM J1040−3551 AabBab, was identified by an international research team led by Professor Zenghua Zhang, of Nanjing University.

The researchers made their discovery using common angular velocity measured by the European Space Agency’s Gaia astrometric satellite and NASA\s Wide-field Infrared Survey Explorer (WISE), followed by comprehensive spectroscopic observations and analysis.

That’s because this wide binary pair need more than 100,000 years to complete one orbit around each other, so their orbital motion cannot be seen in years. Researchers therefore had to analyse how they are moving towards the same direction with the same angular velocity.

In this system, Aab refers to the brighter stellar pair Aa and Ab, while Bab refers to the fainter substellar pair Ba and Bb.

"What makes this discovery particularly exciting is the hierarchical nature of the system, which is required for its orbit to remain stable over a long time period," said Professor Zhang.

"These two pairs of objects are orbiting each other separately for periods of decades, while the pairs are also orbiting a common centre of mass over a period of more than 100,000 years."

The two pairs are separated by 1,656 astronomical units (au), where 1 au equals the Earth-Sun distance. The brighter pair, UPM J1040−3551 Aab, consists of two nearly equal-mass red dwarf stars, which appear orange in colour when observed in visible wavelengths.

With a visual magnitude of 14.6, this pair is approximately 100,000 times fainter than Polaris (the North Star) in visible wavelengths. In fact, no red dwarf star is bright enough to be seen with the naked eye – not even Proxima Centauri, our closest stellar neighbour at 4.2 light-years away. To make UPM J1040−3551 Aab visible without optical aid, this binary pair would need to be brought to within 1.5 light-years of Earth, placing it closer than any star in our current cosmic neighbourhood.

The fainter pair, UPM J1040−3551 Bab, comprises two much cooler brown dwarfs that emit virtually no visible light and appear roughly 1,000 times dimmer than the Aab pair when observed in near-infrared wavelengths, where they are most easily detected.

The close binary nature of UPM J1040−3551 Aab was initially suspected due to its wobbling photocentre during Gaia's observations and confirmed by its unusual brightness – approximately 0.7 magnitude brighter than a single star with the same temperature at the same distance, as the combined light from the nearly equal-mass pair effectively doubles the output.

Similarly, UPM J1040−3551 Bab was identified as another close binary through its abnormally bright infrared measurements compared to typical brown dwarfs of its spectral type. Spectral fitting analysis strongly supported this conclusion, with binary templates providing a significantly better match than single-object templates.

Dr Felipe Navarete, of the Brazilian National Astrophysics Laboratory, led the critical spectroscopic observations that helped characterise the system components.

Using the Goodman spectrograph on the Southern Astrophysical Research (SOAR) Telescope at Cerro Tololo Inter-American Observatory in Chile, a Program of NSF NOIRLab, Dr Navarete obtained optical spectra of the brighter pair, while also capturing near-infrared spectra of the fainter pair with SOAR's TripleSpec instrument.

"These observations were challenging due to the faintness of the brown dwarfs," said Dr Navarete, "but the capabilities of SOAR allowed us to collect the crucial spectroscopic data needed to understand the nature of these objects."

Their analysis revealed that both components of the brighter pair are M-type red dwarfs with temperatures of approximately 3,200 Kelvin (about 2,900°C) and masses of about 17 per cent that of the Sun.

The fainter pair are more exotic objects: two T-type brown dwarfs with temperatures of 820 Kelvin (550°C) and 690 Kelvin (420°C), respectively.

Brown dwarfs are small and dense low-mass objects, with the brown dwarfs in this system having sizes similar to the planet Jupiter but masses estimated to be 10-30 times greater. Indeed, at the low end of this range these objects could be considered "planetary mass" objects.

"This is the first quadruple system ever discovered with a pair of T-type brown dwarfs orbiting two stars," said Dr MariCruz Gálvez-Ortiz of the Center for Astrobiology in Spain, a co-author of the research paper.

"The discovery provides a unique cosmic laboratory for studying these mysterious objects."

Unlike stars, brown dwarfs continuously cool throughout their lifetime, which changes their observable properties such as temperature, luminosity, and spectral features.

This cooling process creates a fundamental challenge in brown dwarf research known as the "age-mass degeneracy problem".

An isolated brown dwarf with a certain temperature could be a younger, less massive object or an older, more massive one – astronomers cannot distinguish between these possibilities without additional information.

"Brown dwarfs with wide stellar companions whose ages can be determined independently are invaluable at breaking this degeneracy as age benchmarks," explained Professor Hugh Jones, of the University of Hertfordshire, a co-author of the research paper.

"UPM J1040−3551 is particularly valuable because H-alpha emission from the brighter pair indicates the system is relatively young, between 300 million and 2 billion years old."

The team believes the brown dwarf pair (UPM J1040−3551 Bab) could potentially be resolved with high-resolution imaging techniques in the future, enabling precise measurements of their orbital motion and dynamical masses.

"This system offers a dual benefit for brown dwarf science," said co-researcher Professor Adam Burgasser, of the University of California San Diego.

"It can serve as an age benchmark to calibrate low-temperature atmosphere models, and as a mass benchmark to test evolutionary models if we can resolve the brown dwarf binary and track its orbit."

The discovery of the UPM J1040−3551 system represents a significant advancement in he understanding of these elusive objects and the diverse formation paths for stellar systems in the neighbourhood of the Sun.




Media contacts:

Sam Tonkin (Submitted by)
Royal Astronomical Society
Mob: +44 (0)7802 877 700

press@ras.ac.uk

Science contacts:

Professor Zenghua Zhang
Nanjing University

zz@nju.edu.cn



Further information

The paper ‘Benchmark brown dwarfs – I. A blue M2 + T5 wide binary and a probable young M4 + [T7 + T8] hierarchical triple’ by Zenghua, Zhang et al. has been published in Monthly Notices of the Royal Astronomical Society. DOI:10.1093/mnras/staf895.



Notes for editors

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.

'Most massive black hole ever discovered' is detected

The Cosmic Horseshoe gravitational lens. The newly discovered ultramassive blackhole lies at the centre of the orange galaxy. Far behind it is a blue galaxy that is being warped into the horseshoe shaped ring by distortions in spacetime created by the immense mass of the foreground orange galaxy. Credit:NASA/ESA
Licence type: Attribution (CC BY 4.0)

Astronomers have discovered potentially the most massive black hole ever detected.

The cosmic behemoth is close to the theoretical upper limit of what is possible in the universe and is 10,000 times heavier than the black hole at the centre of our own Milky Way galaxy.

It exists in one of the most massive galaxies ever observed – the Cosmic Horseshoe – which is so big it distorts spacetime and warps the passing light of a background galaxy into a giant horseshoe-shaped Einstein ring.

Such is the enormousness of the ultramassive black hole, it equates to 36 billion solar masses, according to a new paper published today in Monthly Notices of the Royal Astronomical Society.

It is thought that every galaxy in the universe has a supermassive black hole at its centre and that bigger galaxies host bigger ones, known as ultramassive black holes.

“This is amongst the top 10 most massive black holes ever discovered, and quite possibly the most massive,” said researcher Professor Thomas Collett, of the University of Portsmouth.

“Most of the other black hole mass measurements are indirect and have quite large uncertainties, so we really don't know for sure which is biggest. However, we’ve got much more certainty about the mass of this black hole thanks to our new method.”

Researchers detected the Cosmic Horseshoe black hole using a combination of gravitational lensing and stellar kinematics (the study of the motion of stars within galaxies and the speed and way they move around black holes).

The latter is seen as the gold standard for measuring black hole masses, but doesn't really work outside of the very nearby universe because galaxies appear too small on the sky to resolve the region where a supermassive or ultramassive black hole lies.

Adding in gravitational lensing helped the team “push much further out into the universe”, Professor Collett said.

“We detected the effect of the black hole in two ways – it is altering the path that light takes as it travels past the black hole and it is causing the stars in the inner regions of its host galaxy to move extremely quickly (almost 400 km/s).

“By combining these two measurements we can be completely confident that the black hole is real.”

Lead researcher, PhD candidate Carlos Melo, of the Universidade Federal do Rio Grande do Sul (UFRGS) in Brazil, added: “This discovery was made for a 'dormant' black hole – one that isn’t actively accreting material at the time of observation.

“Its detection relied purely on its immense gravitational pull and the effect it has on its surroundings.

“What is particularly exciting is that this method allows us to detect and measure the mass of these hidden ultramassive black holes across the universe, even when they are completely silent.”

Another image of the Cosmic Horseshoe, but with the pair of images of a second background source highlighted. The faint central image forms close to the black hole, which is what made the new discovery possible. Credit: NASA/ESA/Tian Li(University of Portsmouth)
Licence type: Attribution (CC BY 4.0)

The Cosmic Horseshoe black hole is located a long way away from Earth, at a distance of some 5 billion light-years.

“Typically, for such remote systems, black hole mass measurements are only possible when the black hole is active,” Melo said. “But those accretion-based estimates often come with significant uncertainties.

“Our approach, combining strong lensing with stellar dynamics, offers a more direct and robust measurement, even for these distant systems.”

The discovery is significant because it will help astronomers understand the connection between supermassive black holes and their host galaxies.

“We think the size of both is intimately linked,” Professor Collett added, “because when galaxies grow they can funnel matter down onto the central black hole.

“Some of this matter grows the black hole but lots of it shines away in an incredibly bright source called a quasar. These quasars dump huge amounts of energy into their host galaxies, which stops gas clouds condensing into new stars.”

Our own galaxy, the Milky Way, hosts a 4 million solar mass black hole. Currently it's not growing fast enough to blast out energy as a quasar but we know it has done in the past, and it may will do again in the future.

The Andromeda Galaxy and our Milky Way are moving together and are expected to merge in about 4.5 billion years, which is the most likely time for our supermassive black hole to become a quasar once again, the researchers say.

An interesting feature of the Cosmic Horseshoe system is that the host galaxy is a so-called fossil group.

Fossil groups are the end state of the most massive gravitationally bound structures in the universe, arising when they have collapsed down to a single extremely massive galaxy, with no bright companions.

“It is likely that all of the supermassive black holes that were originally in the companion galaxies have also now merged to form the ultramassive black hole that we have detected,” said Professor Collett.

“So we're seeing the end state of galaxy formation and the end state of black hole formation.”

The discovery of the Cosmic Horseshoe black hole was somewhat of a serendipitou discovery. It came about as the researchers were studying the galaxy’s dark matter distribution in an attempt to learn more about the mysterious hypothetical substance.

Now that they’ve realised their new method works for black holes, they hope to use data from the European Space Agency’s Euclid space telescope to detect more supermassive black holes and their hosts to help understand how black holes stop galaxies forming stars.
highlights


Media contacts:

Sam Tonkin (Submitted by)
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

Science contacts:

Carlos Melo
UFRGS

crmc.melo@gmail.com

Professor Thomas Collett
University of Portsmouth

thomas.collett@port.ac.uk



Further information

The paper ‘Unveiling a 36 Billion Solar Mass Black Hole at the Centre of the Cosmic Horseshoe Gravitational Lens’ by Carlos Roberto and Thomas Collett et al. has been published in Monthly Notices of the Royal Astronomical Society. DOI: 10.1093/mnras/staf1036.



Notes for editors

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.


Tuesday, August 05, 2025

The Milky Way could be teeming with more satellite galaxies than previously thought

The dark matter distribution of a Milky Way mass halo in a Lambda-cold dark matter (LCDM) cosmological simulation. This is the highest resolution simulation of a MW-mass dark matter halo ever performed, called Aquarius-A-L1. The MW halo (in the centre) is surrounded by myriad substructures, a key prediction of the "cold dark matter” model. Some of these subhalos host a satellite galaxy within them that could be observable. Credit: The Aquarius simulation, the Virgo Consortium/Dr Mark Lovell
Licence type: Attribution (CC BY 4.0)

The Milky Way could have many more satellite galaxies than scientists have previously been able to predict or observe, according to new research.

Cosmologists at Durham University used a new technique combining the highest-resolution supercomputer simulations that exist, alongside novel mathematical modelling, predicting the existence of missing "orphan" galaxies.

Their findings suggest that there should be 80 or perhaps up to 100 more satellite galaxies surrounding our home galaxy, orbiting at close distances.

If these galaxies are seen by telescopes then it could provide strong support for the Lambda Cold Dark Matter (LCDM) theory which explains the large-scale structure of the universe and how galaxies form.

This ongoing research is being presented today (Friday 11 July) at the Royal Astronomical Society's National Astronomy Meeting at Durham University.

The research is based on the LCDM model where ordinary matter in the form of atoms represents only 5 per cent of the universe’s total content, 25 per cent is cold dark matter (CDM), and the remaining 70 per cent is dark energy.

In this model, galaxies form in the centre of gigantic clumps of dark matter called halos. Most galaxies in the universe are low-mass dwarf galaxies, the majority of which are satellites orbiting around a more massive galaxy, such as our Milky Way.

The existence of these enigmatic objects has long posed challenges to LCDM – otherwise known as the standard model of cosmology. According to LCDM theory, many more Milky Way companion galaxies should exist than cosmological simulations have so far produced, or astronomers have been able to see.

An artist’s concept of the Milky Way galaxy.
NASA/JPL-Caltech
Licence type: Attribution (CC BY 4.0)

This included the Aquarius simulation, produced by the Virgo Consortium. Aquarius is the highest resolution simulation of a Milky Way dark matter halo ever created and is used to understand the fine-scale structure predicted around the Milky Way.

It also included the GALFORM model, a cutting-edge code developed at Durham over the past two decades which follows the detailed physical processes that are responsible for the formation and evolution of galaxies.

Their results showed that halos of dark matter, which may host a satellite galaxy, have been orbiting around the central Milky Way halo for most of the age of the universe, leading to the stripping of their dark matter and stellar mass, and rendering them extremely small and faint.

As a result, the research predicts that the total number of satellite galaxies – of any brightness – likely to exist around the Milky Way is around 80 or potentially up to 100 more than currently known.

The research puts particular emphasis on the approximately 30 newly discovered tiny Milky Way satellite candidates that are extremely faint and small.

Scientists are unclear if these are dwarf galaxies embedded in a dark matter halo, or globular clusters, collections of self-gravitating stars.

The Durham researchers argue that these objects could be a subset of the faint population of satellite galaxies they predict should exist.

Co-researcher Professor Carlos Frenk, of the Institute for Computational Cosmology, Department of Physics, Durham University said: "If the population of very faint satellites that we are predicting is discovered with new data, it would be a remarkable success of the LCDM theory of galaxy formation.

"It would also provide a clear illustration of the power of physics and mathematics. Using the laws of physics, solved using a large supercomputer, and mathematical modelling we can make precise predictions that astronomers, equipped with new, powerful telescopes, can test. It doesn't get much better than this."

The research is funded by the European Research Council through an Advanced Investigator grant to Professor Frenk, and by the Science and Technology Facilities Council (STFC). The calculations were performed on the Cosmology Machine (COSMA), a supercomputer supported by the STFC's Distributed Infrastructure for Research using Advanced Computing (DiRAC) project, and hosted by Durham University. The new research shows that the Milky Way's missing satellites are extremely faint galaxies stripped almost entirely of their parent dark matter halos by the gravity of the Milky Way’s halo. These so-called "orphan" galaxies are lost in most simulations, but should have survived in the real universe.

Using their new technique, the Durham researchers were able to track the abundance, distribution, and properties of these Milky Way orphan galaxies – showing that many more Milky Way satellites should exist and be observable today. It is hoped that new advances in telescopes and instruments like the Rubin Observatory LSST camera (which recently saw its first light), will give astronomers the ability to detect these very faint objects, bringing them into our view for the first time.

The dark matter distribution of a Milky Way mass halo in a Lambda-cold dark matter (LCDM) cosmological simulation. This is the highest resolution simulation of a MW-mass dark matter halo ever performed, called Aquarius-A-L1. The MW halo (in the centre) is surrounded by myriad substructures, a key prediction of the "cold dark matter” model. Some of these subhalos host a satellite galaxy within them that could be observable. The new predicted Milky Way “orphan satellite” galaxies are marked with an 'x' symbol. The Aquarius simulation, the Virgo Consortium/Dr Mark Lovell
Licence type: Attribution CC BY 4.0)

Lead researcher Dr Isabel Santos-Santos, in the Institute for Computational Cosmology, Department of Physics, Durham University, said: "We know the Milky Way has some 60 confirmed companion satellite galaxies, but we think there should be dozens more of these faint galaxies orbiting around the Milky Way at close distances.

"If our predictions are right, it adds more weight to the Lambda Cold Dark Matter theory of the formation and evolution of structure in the universe.

"Observational astronomers are using our predictions as a benchmark with which to compare the new data they are obtaining.

"One day soon we may be able to see these 'missing' galaxies, which would be hugely exciting and could tell us more about how the universe came to be as we see it today."

The concept of LCDM is the cornerstone of our understanding of the universe. It has led to the Standard Model of Cosmology and is the most widely accepted model for describing the universe's evolution and structure on large scales.

The model has passed multiple tests but has recently been challenged by puzzling observational data on dwarf galaxies.

The Durham researchers say that even the best existing cosmological simulations (which include gas and star formation, in addition to dark matter) do not have the resolution needed to study galaxies as faint as those astronomers are starting to discover close to the Milky Way.

These simulations also lack the precision required to follow the evolution of the small dark matter halos that host the dwarf galaxies as they orbit around the Milky Way over billions of years.

This leads to the artificial disruption of some halos, leaving galaxies "orphaned". Although the simulations lose the halos of "orphan" galaxies, such galaxies should survive in the real universe.

An artist’s concept of the Milky Way galaxy. Credit: NASA/JPL-Caltech
Licence type: Attribution (CC BY 4.0)

The Durham researchers combined cosmological supercomputer simulations with analytical models to overcome these numerical issues.

This included the Aquarius simulation, produced by the Virgo Consortium. Aquarius is the highest resolution simulation of a Milky Way dark matter halo ever created and is used to understand the fine-scale structure predicted around the Milky Way.

It also included the GALFORM model, a cutting-edge code developed at Durham over the past two decades which follows the detailed physical processes that are responsible for the formation and evolution of galaxies.

Their results showed that halos of dark matter, which may host a satellite galaxy, have been orbiting around the central Milky Way halo for most of the age of the universe, leading to the stripping of their dark matter and stellar mass, and rendering them extremely small and faint.

As a result, the research predicts that the total number of satellite galaxies – of any brightness – likely to exist around the Milky Way is around 80 or potentially up to 100 more than currently known.

The research puts particular emphasis on the approximately 30 newly discovered tiny Milky Way satellite candidates that are extremely faint and small.

Scientists are unclear if these are dwarf galaxies embedded in a dark matter halo, or globular clusters, collections of self-gravitating stars.

The Durham researchers argue that these objects could be a subset of the faint population of satellite galaxies they predict should exist.

Co-researcher Professor Carlos Frenk, of the Institute for Computational Cosmology, Department of Physics, Durham University said: "If the population of very faint satellites that we are predicting is discovered with new data, it would be a remarkable success of the LCDM theory of galaxy formation.

"It would also provide a clear illustration of the power of physics and mathematics. Using the laws of physics, solved using a large supercomputer, and mathematical modelling we can make precise predictions that astronomers, equipped with new, powerful telescopes, can test. It doesn't get much better than this."

The research is funded by the European Research Council through an Advanced Investigator grant to Professor Frenk, and by the Science and Technology Facilities Council (STFC).

The calculations were performed on the Cosmology Machine (COSMA), a supercomputer supported by the STFC's Distributed Infrastructure for Research using Advanced Computing (DiRAC) project, and hosted by Durham University.
 
Submitted by Sam Tonkin




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



Science contacts:

Dr Isabel Santos
Durham University

isabel.santos@durham.ac.uk



Further information

The talk ‘The contribution of "orphan" galaxies to the ultrafaint population of MW satellites’ will take place at NAM at 10:15 BST on Friday 11 July 2025 in room TLC106. Find out more at: https://conference.astro.dur.ac.uk/event/7/contributions/515/

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.

linkedin.com/company/stfc

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/


Monday, July 21, 2025

Newly discovered interstellar object 'may be oldest comet ever seen'

Top view of the Milky Way galaxy showing the estimated orbits of both our Sun and the 3I/ATLAS comet. 3I/ATLAS is shown in red dashed lines, and the Sun is shown in yellow dotted lines. The large extent of 3I’s orbit into the outer thick disk is clear, while the Sun stays nearer the core of the galaxy.  Credit: M. Hopkins/Ōtautahi-Oxford team. Base map: ESA/Gaia/DPAC, Stefan Payne-Wardenaar, CC-BY-SA 4.0

The same as Figure 1 with text labels showing the various arms of the galaxy, and the current meeting of our solar system and 3I/ATLAS in the Orion Arm towards the bottom. Credit: M. Hopkins/Ōtautahi-Oxford team. Base map: ESA/Gaia/DPAC, Stefan Payne-Wardenaar, CC-BY-SA 4.0

A zoomed-in version of Figure 1, the unlabelled orbits. Credit: M. Hopkins/Ōtautahi-Oxford team. Base map: ESA/Gaia/DPAC, Stefan Payne-Wardenaar, CC-BY-SA 4.0

A zoomed-in version of Figure 2, with text labels. Credit: M. Hopkins/Ōtautahi-Oxford team. Base map: ESA/Gaia/DPAC, Stefan Payne-Wardenaar, CC-BY-SA 4.0

A side-on view of the Milky Way, showing the estimated orbits of both our Sun and the 3I/ATLAS comet. 3I/ATLAS is shown in red dashed lines, and the Sun is shown in yellow dotted lines. The large extent of 3I’s orbit vertically into the outer thick disk is clear, while the Sun stays nearer the plane of the galaxy. Credit: M. Hopkins/Ōtautahi-Oxford team. Base map: ESA/Gaia/DPAC, Stefan Payne-Wardenaar, CC-BY-SA 4.0

A zoomed-in version of Figure 5. Credit: M. Hopkins/Ōtautahi-Oxford team. Base map: ESA/Gaia/DPAC, Stefan Payne-Wardenaar, CC-BY-SA 4.0

In this Very Large Telescope (VLT) timelapse, 3I/ATLAS is seen moving to the right over the course of about 13 minutes. These data were obtained with the FORS2 instrument on the VLT on the night of 3 July 2025, just two days after the comet was first discovered. Credit: ESO/O. Hainaut



A mystery interstellar object discovered last week is likely to be the oldest comet ever seen – possibly predating our solar system by more than three billion years, researchers say.

The "water ice-rich" visitor, named 3I/ATLAS, is only the third known object from beyond our solar system ever spotted in our cosmic neighbourhood and the first to reach us from a completely different region of our Milky Way galaxy.

It could be more than seven billion years old, according to University of Oxford astronomer Matthew Hopkins – who is discussing his findings at the Royal Astronomical Society's National Astronomy Meeting 2025 in Durham – and may be the most remarkable interstellar visitor yet.

Unlike the previous two objects to enter our solar system from elsewhere in the cosmos, 3I/ATLAS appears to be travelling on a steep path through the galaxy, with a trajectory that suggests it originated from the Milky Way's 'thick disk' – a population of ancient stars orbiting above and below the thin plane where the Sun and most stars reside.

"All non-interstellar comets such as Halley's comet formed with our solar system, so are up to 4.5 billion years old," Hopkins said.

"But interstellar visitors have the potential to be far older, and of those known about so far our statistical method suggests that 3I/ATLAS is very likely to be the oldest comet we have ever seen."

The object was first spotted on 1 July 2025 by the ATLAS survey telescope in Chile, when it was about 670 million km from the Sun.

Hopkins' research predicts that, because 3I/ATLAS likely formed around an old, thick-disk star, it should be rich in water ice.

"This is an object from a part of the galaxy we've never seen up close before," said Professor Chris Lintott, co-author of the study and presenter of the BBC’s The Sky at Night.

"We think there's a two-thirds chance this comet is older than the solar system, and that it's been drifting through interstellar space ever since."

As it approaches the Sun, sunlight will heat 3I/ATLAS's surface and trigger cometary activity, or the outgassing of vapour and dust that creates a glowing coma and tail.

Early observations already suggest the comet is active, and possibly larger than either of its interstellar predecessors, 1I/'Oumuamua (spotted in 2017) and 2I/Borisov (2019).

If confirmed, this could have implications for how many similar objects future telescopes, such as the new Vera C. Rubin Observatory, are likely to detect. It may also provide clues about the role that ancient interstellar comets play in seeding star and planet formation across the galaxy.

"We're in an exciting time: 3I is already showing signs of activity. The gases that may be seen in the future as 3I is heated by the Sun will test our model," said co-author Dr Michele Bannister, of the University of Canterbury in New Zealand.

"Some of the biggest telescopes in the world are already observing this new interstellar object – one of them may be able to find out!"

The discovery of 3I caught the team by the surprise. It happened as they were gearing up for the beginning of survey operations with the Vera C. Rubin Observatory, which their model predicts will discover between 5 and 50 interstellar objects.

"The solar system science community was already excited about the potential discoveries Rubin will make in the next 10 years, including an unprecedented number of interstellar objects," said co-researcher Dr Rosemary Dorsey, of the University of Helsinki.

"The discovery of 3I suggests that prospects for Rubin may now be more optimistic; we may find about 50 objects, of which some would be similar in size to 3I. This week's news, especially just after the Rubin First Look images, makes the upcoming start of observations all the more exciting."

The team's findings come from applying a model developed during Hopkins' doctoral research, which simulates the properties of interstellar objects based on their orbits and likely stellar origins.

Just a week before the comet's discovery, Hopkins had defended his thesis, and when 3I/ATLAS was announced, he was set to go on holiday. Instead, he found himself comparing real-time data to his predictions.

"Rather than the quiet Wednesday I had planned, I woke up to messages like '3I!!!!!!!!!!'," said Hopkins. "It's a fantastic opportunity to test our model on something brand new and possibly ancient."

Hopkins and his co-authors have published their a nalysis as a preprint on arXiv. Their model, dubbed the Ōtautahi–Oxford Model, marks the first real-time application of predictive modelling to an interstellar comet.

For those keen to catch a glimpse of 3I/ATLAS, it should be visible through a reasonably-sized amateur telescope in late 2025 and early 2026.




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

Science contacts:

Matthew Hopkins
University of Oxford

matthew.hopkins@physics.ox.ac.uk

Professor Chris Lintott
University of Oxford

chris.lintott@physics.ox.ac.uk


Tuesday, July 08, 2025

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)



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."




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



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



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.



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, LinkedInFacebook 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.

linkedin.com/company/stfc

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