Tuesday, January 20, 2026

ALMA and the NSF VLA Use a Cosmic Lens to Reveal a Hyperactive Cradle of a Future Galaxy Cluster

The galaxy cluster lens J0846 in optical light (bottom right), the ALMA view of dust-enshrouded, star-forming galaxies strongly lensed into bright arcs (top right), and a composite view (left) revealing at least 11 dusty galaxies in a compact protocluster core more than 11 billion light-years away, magnified by the foreground cluster’s gravity. Credit: NSF/AUI/NSF NRAO/B. Saxton; NSF/NOIRLab


ALMA observations, together with NSF VLA, uncover the first strongly lensed protocluster core, revealing an intense burst of galaxy growth in the early universe

Astronomers using the Atacama Large Millimeter/submillimeter Array (ALMA), together with the U.S. National Science Foundation Very Large Array (NSF VLA), have uncovered a rare, extraordinarily active region of the early universe where a future galaxy cluster is rapidly forming. By exploiting a powerful natural phenomenon known as gravitational lensing, ALMA revealed a compact, dust-enshrouded swarm of young galaxies forming stars at an exceptional rate more than 11 billion years ago.

The discovery marks the first strongly lensed protocluster core ever identified, providing an unprecedented, magnified view of one of the universe’s earliest large-scale structures in formation. Complementary observations with the NSF VLA helped characterize both the distant galaxies and the massive foreground cluster responsible for the lensing effect.

Galaxy clusters are the largest gravitationally bound structures in the universe. Their ancestors, known as protoclusters, are regions where galaxies are still assembling, rapidly converting gas into stars and growing in mass. Studying these systems allows astronomers to trace how today’s massive clusters emerged from much smaller, denser environments in the early cosmos.

ALMA’s high-resolution observations revealed that what initially appeared as a single bright source in all-sky survey data is actually a tightly packed group of at least 11 dusty, star-forming galaxies. These galaxies are confined to a region only a few hundred thousand light-years across — remarkably compact on cosmic scales — and are experiencing intense bursts of star formation.

Because these galaxies are heavily shrouded in dust, most of their visible light is absorbed and re-emitted at millimeter and submillimeter wavelengths. ALMA’s sensitivity to this cold dust and molecular gas allowed astronomers to detect the raw material fueling star formation and to measure the dynamics of the system with exceptional clarity.

The protocluster lies behind a massive foreground galaxy cluster whose gravity acts as a cosmic magnifying glass, bending and amplifying the light from the more distant system. This gravitational lensing effect dramatically boosts ALMA and the NSF VLA’s ability to resolve individual galaxies and study their properties in detail, effectively turning the universe itself into a telescope.

ALMA detected carbon monoxide (CO) emission, a key tracer of molecular gas, helping confirm that the galaxies share a common distance and form a physically connected structure. These observations show that the protocluster core contains enormous gas reservoirs capable of sustaining vigorous star formation and driving the rapid buildup of stellar mass.

Complementary observations with the NSF VLA provided radio-frequency data that helped map the foreground cluster and identify radio emission associated with both star formation and energetic processes within the system, strengthening the interpretation of the lensing configuration and the nature of the galaxies involved.

“Galaxy clusters are akin to a sprawling modern metropolis that was built upon an ancient civilization from the past. For example, if an archaeologist digs deeper into the ground, then they uncover an earlier civilization. Similarly, when astronomers observe objects farther away, they can look further back in time. In this way, the study of this distant protocluster gives us a glimpse into how one of the earliest ‘settlements’ of galaxies grew and evolved into the mature structures such as that foreground galaxy cluster that we observe today,” said Nicholas Foo, a graduate student at Arizona State University.

Protoclusters like this one represent the earliest construction phases of galaxy clusters seen in the present-day universe. By combining ALMA’s detailed view of cold gas and dust with complementary radio observations from the NSF VLA, astronomers can investigate how galaxies grow, interact, and evolve in the densest environments of the early cosmos.

This rare alignment of a young protocluster and a massive foreground lens provides an exceptional opportunity to test theories of galaxy and cluster formation. Future ALMA observations will further explore how these compact, dust-rich systems evolve and how their extreme environments shape the galaxies that will eventually populate massive clusters billions of years later.



Additional Information
The results of this research appear as "PASSAGES: The Discovery of a Strongly Lensed Protocluster Core Candidate at Cosmic Noon" in the Astrophysical Journal by N. foo et al.

The original press release was published by the National Radio Astronomy Observatory of the United States, an ALMA partner, on behalf of North America.

The Atacama Large Millimeter/submillimeter Array (ALMA), an international astronomy facility, is a partnership of the European Southern Observatory (ESO), the U.S. National Science Foundation (NSF), and the National Institutes of Natural Sciences (NINS) of Japan in cooperation with the Republic of Chile. ALMA is funded by ESO on behalf of its Member States, by NSF in cooperation with the National Research Council of Canada (NRC) and the National Science and Technology Council (NSTC) in Taiwan, and by NINS in cooperation with the Academia Sinica (AS) in Taiwan and the Korea Astronomy and Space Science Institute (KASI).

>ALMA construction and operations are led by ESO on behalf of its Member States; by the National Radio Astronomy Observatory (NRAO), managed by Associated Universities, Inc. (AUI), on behalf of North America; and by the National Astronomical Observatory of Japan (NAOJ) on behalf of East Asia. The Joint ALMA Observatory (JAO) provides the unified leadership and management of ALMA's construction, commissioning, and operation.


Contacts:

Nicolás Lira
Education and Public Outreach Officer
Joint ALMA Observatory, Santiago - Chile
Phone: +56 2 2467 6519
Email: nicolas.lira@alma.cl

Jill Malusky
Public Information Officer
NRAO
Phone: +1 304-456-2236
Email:jmalusky@nrao.edu

Bárbara Ferreira
ESO Media Manager
Garching bei München, Germany
Phone: +49 89 3200 6670
Email: press@eso.org

Yuichi Matsuda
Education and Public Outreach Officer
NAOJ
Email: yuichi.matsuda@nao.ac.jp

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Monday, January 19, 2026

'Reborn' black hole spotted 'erupting like cosmic volcano'

This LOFAR DR2 image of J1007+3540 superimposed over an optical image by Pan-STARRS shows a compact, bright inner jet, indicating the reawakening of what had been a ‘sleeping’ supermassive black hole at the heart of the gigantic radio galaxy. Credit: LOFAR/Pan-STARRS/S. Kumari et al.
 Licence type: Attribution (CC BY 4.0)

One of the most vivid portraits of “reborn” black hole activity – likened to the eruption of a “cosmic volcano” spreading almost one million light-years across space – has been captured in a gigantic radio galaxy.

The dramatic scene was uncovered when astronomers spotted the supermassive black hole at the heart of J1007+3540 restarting its jet emission after nearly 100 million years of silence.

Radio images revealed the galaxy locked in a messy, chaotic struggle between the black hole's newly ignited jets and the crushing pressure of the massive galaxy cluster in which it resides.

They have been published today in Monthly Notices of the Royal Astronomical Society after being obtained using highly sensitive radio interferometers – the Low Frequency Array (LOFAR) in the Netherlands and India’s upgraded Giant Metrewave Radio Telescope (uGMRT).

Most galaxies host a supermassive black hole, but only a few produce vast jets of radio-emitting magnetised plasma. J1007+3540 is unique, the international team of researchers behind the new study say, because it shows clear evidence of multiple eruptions – proof that its central engine has turned on, shut down, and restarted after long periods of quiet.

The radio images show a compact, bright inner jet, which lead researcher Shobha Kumari, of Midnapore City College in India, said was the unmistakable sign of the black hole’s recent awakening. Just outside it lies a cocoon of older, faded plasma – leftover debris from the black hole’s past eruptions, distorted and squeezed by the hostile environment around it.

“It’s like watching a cosmic volcano erupt again after ages of calm – except this one is big enough to carve out structures stretching nearly a million light-years across space”, Kumari added.

“This dramatic layering of young jets inside older, exhausted lobes is the signature of an episodic AGN – a galaxy whose central engine keeps turning on and off over cosmic timescales.”

The research was carried out by Kumari and co-authors Dr Sabyasachi Pal, of Midnapore City College, Dr Surajit Paul, associate professor at the Manipal Centre for Natural Sciences in India, and Dr Marek Jamrozy, of Jagiellonian University in Poland.

“J1007+3540 is one of the clearest and most spectacular examples of episodic AGN with jet-cluster interaction, where the surrounding hot gas bends, compresses, and distorts the jets,” Dr Pal said.

The same images with labels showing the compressed northern lobe, curved backflow signature of plasma and the inner jet of the black hole. Credit: LOFAR/Pan-STARRS/S. Kumari et al.
 Licence type: Attribution (CC BY 4.0)

J1007+3540 lives inside a massive galaxy cluster filled with extremely hot gas. This environment creates enormous external pressure – far higher than what most radio galaxies experience. As the revived jets push outward, they are bent, squeezed, and distorted by the interaction with the dense medium.

The LOFAR image reveals that the northern lobe is compressed and dramatically distorted, the authors say, showing a curved backflow signature of plasma that seems to be shoved sideways by the surrounding gas.

The uGMRT image also shows that this compressed region has an ultra-steep radio spectrum, meaning the particles there are extremely old and have lost much of their energy – another sign of the cluster’s harsh influence.

The long, faint tail of diffuse emission stretching to the southwest tells an equally dramatic story, the researchers say. It shows that magnetised plasma is being dragged in a large extension through the cluster environment, leaving behind a wispy trail millions of years old. This, they add, suggests the galaxy is not just producing jets, it is also being shaped and sculpted by the powerful environment around it.

Systems such as J1007+3540 are extremely valuable to astronomers. They reveal how black holes turn on and off, how jets evolve over millions of years, and how cluster environments can reshape the entire morphological structure of a radio galaxy.

The combination of restarted activity, giant scale, and strong environmental pressure makes J1007+3540 a useful example of galaxy evolution in action. The authors say it shows that the growth of galaxies is not peaceful or gradual but rather a battle between the explosive power of black holes and the crushing pressure of the environments they live in.

By studying this galaxy, astronomers are gaining rare insight into:

  • How often black holes switch between active and quiet phases

  • How old radio plasma interacts with hot cluster gas

  • How repeated eruptions can transform a galaxy’s surroundings over cosmic time

The research team now plans to use more sensitive, high-resolution observations to zoom even deeper into the core of J1007+3540 and track how the restarted jets propagate through this turbulent environment.

Understanding systems like J1007+3540 helps scientists piece together how galaxies grow, shut down, and awaken again, and how huge cosmic environments can shape, bend, distort, and even suffocate the jets that try to escape from their central engine.



Media contacts:

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

Science contacts:

Shobha Kumari
Midnapore City College in India
shobhakumari@mcconline.org.in


Further information

The paper ‘Probing AGN duty cycle and cluster-driven morphology in a giant episodic radio galaxy’ by S. Kumari et al. has been published in Monthly Notices of the Royal Astronomical Society. DOI: 10.1093/mnras/staf2038.


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.

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Submitted by Sam Tonkin on Thu, 15/01/2026 - 10:42

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Sunday, January 18, 2026

When Winds Collide: Predicting the Effects of Stream Interaction Regions

Illustration of the solar wind interacting with Earth's magnetic field.
Credit: NASA's Goddard Space Flight Center

The Solar Heliospheric Observatory (SOHO) took this coronagraphic image of a coronal mass ejection on 20 April 1998.
Credit: SOHO (ESA & NASA)

What happens when pileups of solar wind plasma collide with Earth’s protective magnetosphere? New work uses machine learning to examine how strongly these events affect our planet’s magnetic field.

Plasma Pileups

Geomagnetic storms driven by solar activity paint night skies with glowing aurorae, but they also threaten spacecraft electronics with showers of high-energy particles. While immense eruptions of solar plasma and magnetic fields called coronal mass ejections are the most infamous example of solar activity, a team led by Yudong Ye (Sun Yat-Sen University) recently focused on another, less destructive form of activity: stream interaction regions.

Stream interaction regions arise when slow-moving solar wind is struck from behind by faster-moving solar wind emitted later. The collision of the two solar wind streams creates a tangle of compressed plasma and strong magnetic fields capable of peeling back Earth’s protective magnetosphere and dumping in high-energy charged particles, with beautiful yet harmful results.

Illustration of the authors’ support vector machine framework. The optimal hyperplane is the boundary that best divides the data by maximizing the distance between the boundary and the data points nearest to it; these points are called support vectors. Square and triangle symbols represent two classes of data. Click to enlarge. Credit: Ye et al. 2025

Machine Learning Method

Though stream interaction regions are less disruptive than coronal mass ejections, they’re far more common; they frequently needle Earth’s magnetosphere, especially during the calmer years of the Sun’s activity cycle. Predicting how strongly a stream interaction region will influence Earth’s magnetosphere — in other words, how geoeffective it is — is challenging, however. When two streams of solar wind collide, their properties combine in complex and nonlinear ways that traditional statistical investigations have struggled to pin down.

Now, Ye and collaborators have used machine learning to study the properties and impact of stream interaction regions in a physically meaningful way. They performed their study on a sample of 879 stream interaction events for which there is abundant information, such as temperature, magnetic field strength and direction, and solar wind conditions before and after the event.

Ye’s team based their framework on a support vector machine classifier: a classical machine learning algorithm that draws a mathematical boundary between groups of data while maximizing the distance between the boundary and the data points nearest to the dividing line. The support vector machine algorithm is well-suited to the task of modeling the geoeffectiveness of stream interaction regions because it doesn’t require a particularly vast dataset, can tolerate misclassified events, and allows for a physical interpretation of the results.



Illustration of how the interplanetary magnetic field (IMF) interacts with Earth’s magnetosphere. When the IMF points southward, as it does in this diagram, the impact on Earth’s magnetosphere is increased, with magnetic reconnection occurring in the red areas. Credit: NASA

A Physical Interpretation

The team first reined in the model’s complexity by identifying the most important features in the dataset. They then determined which features or combination of features had the largest contribution to the output — in other words, which physical parameters most strongly determined the geoeffectiveness of the event.

Ye and collaborators found that the strongest determinants of an event’s geoeffectiveness were how long the solar wind was directed southward, the strength of the solar wind electric field, and the average and minimum strengths of the southward-pointing solar wind magnetic field. These results align with the current understanding of how energy is transferred from the solar wind to Earth’s magnetosphere through magnetic reconnection, a release of magnetic energy driven by rearrangement of magnetic fields. This shows how classical machine learning methods can enhance our ability to predict the outcome of oncoming space weather while simultaneously examining the physical drivers of the event.

Citation
“Assessing the Geoeffectiveness of Stream Interaction Regions Through Physically Interpretable Machine Learning,” Yudong Ye et al 2025 ApJ 993 10. doi:10.3847/1538-4357/ae0454


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Saturday, January 17, 2026

Do Even Low-mass Dwarf Galaxies Merge? New Clues from the Outer Stars of a Milky Way Satellite

Figure 1: Image of the Ursa Minor dwarf spheroidal galaxy (UMi dSph) observed with Hyper Suprime-Cam, covering three fields of view. The red dashed ellipse indicates the central region of the UMi dSph. Although the galaxy is extremely faint and difficult to identify visually, its member stars extend across the entire image. (Credit: NAOJ)
Figure 2: Spatial distribution of member main-sequence stars of the UMi dSph (central panel), and stellar number density profiles along the major and minor axes (left and right panels, respectively). The color map and contours in the central panel both represent the stellar surface density. The white dashed lines indicate the directions of the major and minor axes of the UMi dSph. The black curves in the side panels show the predicted number density profiles assuming no extended stellar structure. The observed number densities (blue and green points) exceed these predictions along both the major and minor axes, indicating the presence of an extended stellar structure in the outskirts. (Credit: NAOJ)


Using the Subaru Telescope’s wide-field camera, astronomers have discovered a previously unknown structure surrounding a tiny satellite galaxy of the Milky Way. The newly discovered structure exhibits features resembling the remnants of past galaxy mergers. This result provides compelling evidence that even extremely low-mass dwarf galaxies may have experienced mergers in their past.

Numerous small satellite galaxies have long been gravitationally bound to the Milky Way, orbiting around it. These dwarf galaxies are often regarded as "fossil galaxies" formed in the early Universe, and their structures provide valuable clues to understanding how galaxies formed and evolved.

Traditionally, dwarf galaxies have been thought to form through relatively simple processes, such as gas inflow and outflow and internal star formation, meaning that galaxy–galaxy interactions or mergers were considered rare in such low-mass systems. However, recent observations by the European Space Agency’s Gaia mission have revealed that in some dwarf galaxies, stars are distributed beyond their expected outer boundary, known as the tidal radius. Because Gaia observations are limited to relatively bright stars, primarily red giant branch (RGB) stars, it has been difficult to investigate the detailed distribution using numerous faint stars in the outer regions. As a result, it has remained unclear whether these extended structures are the result of tidal interactions with the Milky Way or are intrinsic features formed through past galaxy mergers.

An international research team, led by the National Astronomical Observatory of Japan (NAOJ) and including SOKENDAI (The Graduate University for Advanced Studies), Hosei University, and Tohoku University, observed the Ursa Minor dwarf spheroidal galaxy (UMi dSph), a satellite galaxy of the Milky Way, using Hyper Suprime-Cam (HSC) on the Subaru Telescope. By combining one of the world’s widest fields of view, equivalent to nine full moons, with the powerful light-gathering capability of the 8.2-meter telescope, HSC enabled the team to investigate the faint stellar populations of the galaxy out to its outskirts beyond the nominal tidal radius. As a result, the team detected many faint main-sequence stars that were invisible to Gaia and successfully mapped the stellar distribution extending into the outskirts of the UMi dSph with unprecedented precision.

Their analysis reveals that the stellar distribution extends not only along the major axis, as previously known, but also along the minor axis (Figure 2). The structure along the minor axis shows properties distinct from the elongation along the major axis, which is commonly attributed to tidal forces from the Milky Way. This suggests that the minor-axis structure may have a different origin.

The minor-axis structure discovered around the UMi dSph may have been formed through a merger between dwarf galaxies. These findings suggests that galaxy interactions and mergers may have played a role in the formation and evolution of even extremely low-mass dwarf galaxies, with masses as small as one ten-thousandth that of the Milky Way.

Kyosuke Sato, the lead author of this study and a graduate student at SOKENDAI, says, "We have rarely found evidence of galaxy mergers in the Milky Way’s dwarf galaxies. This discovery offers a new way of thinking about how dwarf galaxies formed."

This study has revealed a previously hidden stellar structure in the outskirts of the UMi dSph, representing an important step toward understanding the formation and evolutionary history of dwarf galaxies. However, to determine whether this structure was formed by tidal interactions with the Milky Way or represents a remnant of a past merger, detailed studies of stellar kinematics and chemical abundances are required. Future observations with the Subaru Telescope’s new spectrograph, ʻŌnohiʻula PFS, are expected to reveal the origin of this structure.

This research has been published in The Astrophysical Journal Letters on October 23, 2025 (Sato et al., "The Extended Stellar Distribution in the Outskirts of the Ursa Minor Dwarf Spheroidal Galaxy").

This work was supported by JSPS KAKENHI (Grant Nos. JP18H05875, JP20K04031, JP20H05855, JP25K01047, and JP24K00669) and by JST SPRING, Japan (Grant No. JPMJSP2104). Part of this work was also supported by Oversea Travel Fund (2025) for students of the Astronomical Science Program, The Graduate University for Advanced Studies, SOKENDAI.



About the Subaru Telescope
The Subaru Telescope is a large optical-infrared telescope operated by the National Astronomical Observatory of Japan, National Institutes of Natural Sciences with the support of the MEXT Project to Promote Large Scientific Frontiers. We are honored and grateful for the opportunity of observing the Universe from Maunakea, which has cultural, historical, and natural significance in Hawai`i.

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Friday, January 16, 2026

NASA’s Webb Delivers Unprecedented Look Into Heart of Circinus Galaxy

This artist’s concept depicts the central engine of the Circinus galaxy, visualizing the supermassive black hole fed by a thick, dusty torus that glows in infrared light. Credit Artwork: NASA, ESA, CSA, Ralf Crawford (STScI)

This image from NASA’s Hubble Space Telescope shows the Circinus galaxy. A close-up of its core from NASA’s James Webb Space Telescope shows the inner face of the hole of the donut-shaped disk of gas disk glowing in infrared light. The outer ring appears as dark spots. Credit Image: NASA, ESA, CSA, Enrique Lopez-Rodriguez (University of South Carolina), Deepashri Thatte (STScI); Image Processing: Alyssa Pagan (STScI); Acknowledgment: NSF's NOIRLab, CTIO

This image shows two views of the Circinus galaxy, one captured by the Hubble Space Telescope and the other by the James Webb Space Telescope’s NIRISS (Near-Infrared Imager and Slitless Spectrograph. It shows compass arrows, scale bar, and color key for reference. Credit Image: NASA, ESA, CSA, Enrique Lopez-Rodriguez (University of South Carolina), Deepashri Thatte (STScI); Image Processing: Alyssa Pagan (STScI); Acknowledgment: NSF's NOIRLab, CTIO

This zoom-in video shows the location of the Circinus galaxy on the sky. It begins with a ground-based photo of the constellation Circinus by the late astrophotographer Akira Fujii. The video closes in on the Circinus galaxy, using views from the Digitized Sky Survey and the Dark. Credit Video: NASA, ESA, CSA, Alyssa Pagan (STScI); Acknowledgment: CTIO, NSF's NOIRLab, DSS, Akira Fujii


The Circinus Galaxy, a galaxy about 13 million light-years away, contains an active supermassive black hole that continues to influence its evolution. The largest source of infrared light from the region closest to the black hole itself was thought to be outflows, or streams of superheated matter that fire outward.

Now, new observations by NASA’s James Webb Space Telescope, seen here with a new image from NASA’s Hubble Space Telescope, provide evidence that reverses this thinking, suggesting that most of the hot, dusty material is actually feeding the central black hole. The technique used to gather this data also has the potential to analyze the outflow and accretion components for other nearby black holes.

The research, which includes the sharpest image of a black hole’s surroundings ever taken by Webb, published Tuesday in Nature.

Outflow question

Supermassive black holes like those in Circinus remain active by consuming surrounding matter. Infalling gas and dust accumulates into a donut-shaped ring around the black hole, known as a torus. As supermassive black holes gather matter from the torus’ inner walls, they form an accretion disk, similar to a whirlpool of water swirling around a drain. This disk grows hotter through friction, eventually becoming hot enough to emit light.

This glowing matter can become so bright that resolving details within the galaxy’s center with ground-based telescopes is difficult. It’s made even harder due to the bright, concealing starlight within Circinus. Further, since the torus is incredibly dense, the inner region of the infalling material, heated by the black hole, is obscured from our point of view. For decades, astronomers contended with these difficulties, designing and improving models of Circinus with as much data as they could gather.

“In order to study the supermassive black hole, despite being unable to resolve it, they had to obtain the total intensity of the inner region of the galaxy over a large wavelength range and then feed that data into models,” said lead author Enrique Lopez-Rodriguez of the University of South Carolina.

Early models would fit the spectra from specific regions, such as the emissions from the torus, those of the accretion disk closest to the black hole, or those from the outflows, each detected at certain wavelengths of light. However, since the region could not be resolved in its entirety, these models left questions at several wavelengths. For example, some telescopes could detect an excess of infrared light, but lacked the resolution to determine where exactly it was coming from.

“Since the ‘90s, it has not been possible to explain excess infrared emissions that come from hot dust at the cores of active galaxies, meaning the models only take into account either the torus or the outflows, but cannot explain that excess,” said Lopez-Rodriguez.

Such models found that most of the emission (and, therefore, mass) close to the center came from outflows. To test this theory, then, astronomers needed two things: the ability to filter the starlight that previously prevented a deeper analysis, and the ability to distinguish the infrared emissions of the torus from those of the outflows. Webb, sensitive and technologically sophisticated enough to meet both challenges, was necessary to advance our understanding.

Webb’s innovative technique

To look into the center of Circinus, Webb needed the Aperture Masking Interferometer tool on its NIRISS (Near-Infrared Imager and Slitless Spectrograph) instrument.

On Earth, interferometers usually take the form of telescope arrays: mirrors or antennae that work together as if they were a single telescope. An interferometer does this by gathering and combining the light from whichever source it is pointed toward, causing the electromagnetic waves that make up light to “interfere” with each other (hence, “interfere-ometer”) and creating interference patterns. These patterns can be analyzed by astronomers to reconstruct the size, shape, and features of distant objects with much greater detail than non-interferometric techniques.

The Aperture Masking Interferometer allows Webb to become an array of smaller telescopes working together as an interferometer, creating these interference patterns by itself. It does this by utilizing a special aperture made of seven small, hexagonal holes, which, like in photography, controls the amount and direction of light that enters the telescope’s detectors.

“These holes in the mask are transformed into small collectors of light that guide the light toward the detector of the camera and create an interference pattern,” said Joel Sanchez-Bermudez, co-author based at the National University of Mexico.

With new data in hand, the research team was able to construct an image from the central region's interference patterns. To do so, they referenced data from previous observations to ensure their data from Webb was free of any artifacts. This resulted in the first extragalactic observation from an infrared interferometer in space.

"By using an advanced imaging mode of the camera, we can effectively double its resolution over a smaller area of the sky," Sanchez-Bermudez said. "This allows us to see images twice as sharp. Instead of Webb’s 6.5-meter diameter, it’s like we are observing this region with a 13-meter space telescope."

The data showed that contrary to the models predicting that the infrared excess comes from the outflows, around 87% of the infrared emissions from hot dust in Circinus come from the areas closest to the black hole, while less than 1% of emissions come from hot dusty outflows. The remaining 12% comes from distances farther away that could not previously be told apart.

“It is the first time a high-contrast mode of Webb has been used to look at an extragalactic source,” said Julien Girard, paper co-author and senior research scientist at the Space Telescope Science Institute. “We hope our work inspires other astronomers to use the Aperture Masking Interferometer mode to study faint, but relatively small, dusty structures in the vicinity of any bright object.”

Universe of black holes

While the mystery of Circinus’ excess emissions has been solved, there are billions of black holes in our universe. Those of different luminosities, the team notes, may have an influence on whether most of the emissions come from a black hole’s torus or their outflows.

“The intrinsic brightness of Circinus’ accretion disk is very moderate,” Lopez-Rodriguez said. “So it makes sense that the emissions are dominated by the torus. But maybe, for brighter black holes, the emissions are dominated by the outflow.”

With this research, astronomers now have a tested technique to investigate whichever black holes they want, so long as they are bright enough for the Aperture Masking Interferometer to be useful. Studying additional targets will be essential to building a catalog of emission data to figure out if Circinus’ results were unique or characteristic of a pattern.

“We need a statistical sample of black holes, perhaps a dozen or two dozen, to understand how mass in their accretion disks and their outflows relate to their power,” Lopez-Rodriguez said.

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).



 Related Links

 Read more: The Modes of Webb’s NIRISS

Explore more: Black Hole Resources from NASA’s Universe of Learning

Read more: Webb’s Scientific Instruments

Video: NASA Animation Sizes Up the Universe’s Biggest Black Holes

More Webb News

More Webb Images

Webb Science Themes

Webb Mission Page


Location: NASA Goddard Space Flight Center

Contact:

 Media

Laura Betz
NASA’s Goddard Space Flight Center
Greenbelt, Maryland
laura.e.betz@nasa.gov

Matthew Brown
Space Telescope Science Institute
Baltimore, Maryland

Hannah Braun
Space Telescope Science Institute
Baltimore, Maryland


Related Links and Documents
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Thursday, January 15, 2026

Astronomers surprised by mysterious shock wave around dead star

 
 

PR Image eso2601a
VLT image of a dead star creating a shock wave as it moves through space

PR Image eso2601b
VLT image of a dead star creating a shock wave as it moves through space

PR Image eso2601c
Wide-field view (DSS) of the area of the sky around the star RXJ0528+2838

PR Image eso2601d
Wide-field view (PanSTARRS) of the area of the sky around the star RXJ0528+2838


Videos

An unexpected shock wave | ESO News
PR Video eso2601a
An unexpected shock wave | ESO News

Zooming on a dead star with a strange shock wave around it
PR Video eso2601b
Zooming on a dead star with a strange shock wave around it

The star RXJ0528+2838 moving through space
PR Video eso2601c
The star RXJ0528+2838 moving through space


Gas and dust flowing from stars can, under the right conditions, clash with a star’s surroundings and create a shock wave. Now, astronomers using the European Southern Observatory’s Very Large Telescope (ESO’s VLT) have imaged a beautiful shock wave around a dead star — a discovery that has left them puzzled. According to all known mechanisms, the small, dead star RXJ0528+2838 should not have such structure around it. This discovery, as enigmatic as it’s stunning, challenges our understanding of how dead stars interact with their surroundings.

“We found something never seen before and, more importantly, entirely unexpected,” says Simone Scaringi, associate professor at Durham University, UK and co-lead author of the study published today in Nature Astronomy. “Our observations reveal a powerful outflow that, according to our current understanding, shouldn’t be there,” says Krystian Iłkiewicz, a postdoctoral researcher at the Nicolaus Copernicus AstronomicalCenter in Warsaw, Poland and study co-lead. ‘Outflow’ is the term used by astronomers to describe the material that is ejected from celestial objects.

The star RXJ0528+2838 islocated 730 light-years away and, like the Sun and other stars, it rotates around our galaxy’s centre. As it moves, it interacts with the gas that permeates the space between stars, creating a type of shock wave called a bow shock, “a curved arc of material, similar to the wave that builds up in front of a ship,” explains Noel Castro Segura, research fellow at the University of Warwick in the UK and collaborator in this study. These bow shocks are usually created by material outflowing from the central star, but in the case of RXJ0528+2838, none of the known mechanisms can fully explain the observations

RXJ0528+2838 is a white dwarf — the left-over core of a dying low-mass star — and has a Sun-like companion orbiting it. In such binary systems, the material from the companion star is transferred to the white dwarf, often forming a disc around it. While the disc fuels the dead star, some of the material also gets ejected into space, creating powerful outflows. But RXJ0528+2838 shows no signs of a disc, making the origin of the outflow and resulting nebula around the star a mystery.

The surprise that supposedly quiet, discless system could drive such a spectacular nebula was one of those rare ‘wow’ moments,” says Scaringi.

The team first spotted a strange nebulosity around RXJ0528+2838 on images from the Isaac Newton Telescope in Spain. Noticing its unusual shape, they observed ;it in more detail with the MUSE instrument on ESO’s VLT. “Observations with the ESO MUSE instrument allowed us to map the bow shock in detail and analyse its composition. This was crucial to confirm that the structure really originates from the binary system and not from an unrelated nebula or interstellar cloud,”Iłkiewic explains.

The shape and size of the bow shock imply that the white dwarf has been expelling a powerful outflow for at least 1000 years. Scientists don’t know exactly how a dead star without a disc can power such a long-lasting outflow — but they do have a uess.

This white dwarf is known to host a strong magnetic field, which has been confirmed by the MUSE data. This field channels the material stolen from the companion star directly onto the white dwarf, without forming a disc around it. “Our finding shows that even without a disc, these systems can drive powerful outflows, revealing a mechanism we do not yet understand. This discovery challenges the standard picture of how matter moves and interacts in these extreme binary systems,” Iłkiewicz explains.

The results hint at a hidden energy source, likely the strong magnetic field, but this ‘mystery engine’, as Scaringi puts it, still needs to be investigated. The data show that the current magnetic field is only strong enough to power a bow shock lasting for a few hundred years, so it only partly explains what the astronomers are seeing.

To better understand the nature of such discless outflows, many more binary systems need to be studied. ESO’s upcoming Extremely Large Telescope (ELT) will help astronomers“to map more of these systems as well as fainter ones and detect similar systems in detail, ultimately helping in understanding the mysterious energy source that remains une/xplained,” as Scaringi foresees.

Source: ESO/News


More information
This research was presented in a paper titled “A persistent bow shock in a diskless magnetised accreting white dwarf” to appear in Nature Astronomy (doi: 10.1038/s41550-025-02748-8).

The team is composed of Krystian Iłkiewicz (Nicolaus Copernicus Astronomical Center, Polish Academy of Sciences, Warsaw, Poland and Centre for Extragalactic Astronomy, Department of Physics, Durham University, Durham, UK [CEA Durham]), Simone Scaringi (CEA Durham and INAF-Osservatorio Astronomico di Capodimonte, Naples, Italy [Capodimonte]), Domitilla de Martino (Capodimonte), Christian Knigge (Department of Physics & Astronomy, University of Southampton, Southampton, UK), Sara E. Motta (Istituto Nazionale di Astrofisica, Osservatorio Astronomico di Brera, Merate, Italy and University of Oxford, Department of Physics, Oxford, UK [Oxford]), Nanda Rea (Institute of Space Sciences (ICE, CSIC), Barcelona, Spain and Institut d’Estudis Espacials de Catalunya (IEEC), Castelldefels, Spain), David Buckley (South African Astronomical Observatory, South Africa [SAAO] and Department of Astronomy & IDIA, University of Cape Town, Rondebosh, South Africa [Cape Town] and Department of Physics, University of the Free State, Bloemfontein, South Africa), Noel Castro Segura (Department of Physics, University of Warwick, Coventry, UK), Paul J. Groot (SAAO and Cape Town and Department of Astrophysics/IMAPP, Radboud University, Nijmegen, The Netherlands), Anna F. McLeod (CEA Durham and Institute for Computational Cosmology, Department of Physics, University of Durham, Durham UK), Luke T. Parker (Oxford), and Martina Veresvarska (CEA Durham).

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 south array of the Cherenkov Telescope Array Observatory, 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.


Links

Contacts:

Krystian Iłkiewicz
Nicolaus Copernicus Astronomical Center
Warsaw, Poland
Tel: +48 223296134
Email: ilkiewicz@camk.edu.pl

Simone Scaringi
Centre for Extragalactic Astronomy, Department of Physics, Durham University
Durham, UK
Cell: +44 7737 980235
Email: simone.scaringi@durham.ac.uk

Noel Castro Segura
Department of Physics, University of Warwick
Coventry, UK
Tel: +44 7859 761377
Email: noel.castro-segura@warwick.ac.uk

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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Wednesday, January 14, 2026

Cotton Candy Worlds Evolve into Rock Candy Worlds

Artist’s conception of the four planets around a young star observed in this research. The puffy planets may be losing their atmospheres due to the intense radiation from the star. (Credit: Astrobiology Center) - Download image (1.9MB)


Using data spanning a decade taken by telescopes around the world and in space, including NAOJ’s 188-cm telescope in Okayama, astronomers have been able to weigh a quartet of baby planets. Even though the planets are currently large and puffy, like cotton candy, as they mature they will evolve into smaller, denser rocky worlds like Earth or small gaseous ‘sub-Neptune’ worlds.

One of the biggest recent surprises in astronomy is the discovery that most stars like the Sun harbor a planet between the size of Earth and Neptune at a distance from the star closer than Mercury’s orbit around the Sun. These ‘super-Earths’ and ‘sub-Neptunes’ are the most common type of planets known in the Galaxy. However, their formation has been shrouded in mystery. Now, an international team of astronomers has found a crucial missing link in the formation process. By weighing four newborn planets in the V1298 Tau system, the team captured a rare snapshot of the development of compact, multi-planet systems.

The study focused on V1298 Tau, a star located 352 light-years away in the direction of the constellation Taurus. V1298 Tau is only about 20 million years old, compared to our 4.5-billion-year-old Sun. Around this young, active star, four giant planets, all between the sizes of Neptune and Jupiter, have been observed in a fleeting and turbulent phase of rapid evolution. This system appears to be a progenitor of the type of compact, multi-planet systems found throughout the Galaxy.

The team used data taken over a decade by an arsenal of ground- and space-based telescopes to precisely measure when each planet passed in front of the star, an event known as a transit. By timing these transits, astronomers detected small variations in the planets' orbits. Their orbital configuration and gravity cause them to tug on each other, slightly speeding up or slowing down the timing of the transit. These tiny shifts in timing allowed the team to robustly measure the planets' masses for the first time. The planets, despite being 5 to 10 times the radius of Earth, were found to have masses of only 5 to 15 times that of our own world. This makes them incredibly low-density—more like planetary-sized cotton candy than Earth-like rock candy worlds.

This puffiness helps solve a long-standing puzzle in planet formation. A planet that simply forms and cools down over time would be much more compact. The puffiness indicates that these planets have already undergone a dramatic transformation, rapidly losing much of their original atmospheres and cooling. Now the planets are predicted to continue evolving, losing their atmospheres and shrinking significantly, transforming into the kinds of super-Earths and sub-Neptunes which are often observed.

The V1298 Tau system now serves as a crucial laboratory for understanding the origins of the most abundant planetary systems in the Milky Way, giving scientists an unprecedented glimpse into the turbulent and transformative lives of young worlds. Understanding systems like V1298 Tau may also help explain why our own Solar System lacks the super-Earths and sub-Neptunes that are so abundant elsewhere in the Galaxy.



Detailed Article(s)

Astronomers Find Missing Link to Galaxy’s Most Common Planets

Astrobiology Center


Release Information

 Researcher(s) Involved in this Release

John H. Livingston (Astrobiology Center/National Astronomical Observatory of Japan)
Norio Narita (Graduate School of Arts and Sciences, The University of Tokyo/Astrobiology Center)
Mayuko Mori (Astrobiology Center/National Astronomical Observatory of Japan)

 Coordinated Release Organization(s)

Astrobiology Center, NINS
National Astronomical Observatory of Japan, NINS
Graduate School of Arts and Sciences, The University of Tokyo

 Paper(s)
John H. Livingston et al. “A young progenitor for the most common planetary systems in the Galaxy”, in Nature, DOI: 10.1038/s41586-025-09840-z


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Tuesday, January 13, 2026

Supernova Remnant Video From NASA's Chandra Is Decades in Making


Kepler's Supernova Remnant
Credit: X-ray: NASA/CXC/SAO; Optical: Pan-STARRS

JPEG (226.7 kb)-Large JPEG (4.3 MB) - Tiff (109 MB) - More Images

A Tour of MSH 15-52 - More Videos


A new video shows changes in Kepler’s Supernova Remnant using data from NASA’s Chandra X-ray Observatory captured over more than two and a half decades with observations taken in 2000, 2004, 2006, 2014, and 2025. In this video, which is the longest-spanning one ever released by Chandra, X-rays (blue) from the telescope have been combined with an optical image (red, green, and blue) from Pan-STARRS.

Kepler’s Supernova Remnant, named after the German astronomer Johannes Kepler, was first spotted in the night sky in 1604. Today, astronomers know that a white dwarf star exploded when it exceeded a critical mass, after pulling material from a companion star, or merging with another white dwarf. This kind of supernova is known as a Type Ia and scientists use it to measure the expansion of the Universe.

Supernova remnants, the debris fields left behind after a stellar explosion, often glow strongly in X-ray light because the material has been heated to millions of degrees from the blast. Kepler’s Supernova Remnant is located in the Milky Way galaxy about 17,000 light-years from Earth. Although this is relatively close in cosmic terms, only Chandra, with its sharp X-ray images and longevity, can see changes like those seen here.

The video allows astronomers to watch as the remains from this shattered star expand and crash into material already thrown out into space. The researchers found that the fastest parts of the remnant are traveling at about 13.8 million miles per hour — or about 2% of the speed of light — moving towards the bottom of the image. Meanwhile, the slowest parts are traveling towards the top at about 4 million miles per hour. This is a large difference in speed, and astronomers think it comes from the fact that the gas that the remnant is plowing into towards the top of the image is denser than the gas towards the bottom. This gives scientists information about the environments into which this star exploded.

Supernova explosions and the elements they hurl into space are the lifeblood of new stars and planets. Understanding exactly how they behave is crucial to knowing our cosmic history.

Jessye Gassel (George Mason University) presented the new Chandra video and the associated research at the 247th meeting of the American Astronomical Society (AAS) meeting in Phoenix, AZ. Quotes from Gassel and co-author Brian Williams from NASA’s Goddard Space Flight Center are provided in our press release.

NASA's Marshall Space Flight Center in Huntsville, Alabama, manages the Chandra program. The Smithsonian Astrophysical Observatory's Chandra X-ray Center controls science operations from Cambridge, Massachusetts, and flight operations from Burlington, Massachusetts




Visual Description:
This release features a ten second silent video of Kepler's expanding Supernova Remnant, located in our own galaxy, about 17,000 light-years from Earth. The video was created using X-ray data gathered in 2000, 2004, 2006, 2014, and 2025. Those distinct datasets were turned into highly-detailed visuals, creating a 25-year timelapse-style video of the growing remnant.

Kepler's Supernova Remnant was once a white dwarf star that exploded when it exceeded its critical mass. Here, in X-ray light, the remnant resembles a cloudy neon blue ring with a diagonal cross line stretching from our upper right down to our lower left. The ring appears thinner and wispier at the bottom, with a band of white arching across the top.

As the video plays, cycling through the 5 datasets, the ring subtly, but clearly, expands, like a slowly inflating balloon. In the video, this sequence is replayed several times with dates included at our lower right, to give sighted learners time to absorb the visual information. Upon close inspection, researchers have determined that the bottom of the remnant is expanding fastest; about 13.8 million miles per hour, or 2% of the speed of light. The top of the ring appears to be expanding the slowest; about 4 million miles per hour, or 0.5% of the speed of light. The large difference in speed is because the gas that the remnant is plowing into towards the top of the image is denser than the gas towards the bottom.

Collecting and interpreting this data over decades has provided information about the environment into which the white dwarf star exploded, and has helped scientists understand how remnants change with time.


 Fast Facts for Kepler's Supernova Remnant:

 Release Date: January 6, 2026
 Scale: Image is about 7.2 arcmin (36 light-years) across.
 Category: Supernovas & Supernova Remnants
Coordinates (J2000): RA 17h 30m 40.80s | Dec -21° 29´ 11.00"
 Constellation: Ophiuchus
Observation Dates: 18 pointings between June 2000 and July 2025
 Observation Time: 298 hours 21.5 minutes (12 days 10 hours 21.5 minutes)
 Obs. ID: 116,4650,6714-6718, 7366, 16004, 16614, 29846, 30138, 30140, 30950-30951, 30969-30970, 30986
 Instrument: ACIS
Also Known As: SN 1604, G004.5+06.8, V 843 Ophiuchi
 References: J. Gassel et al., 2026, 247th AAS meeting
 Color Code: X-ray: blue; Optical: red, green, and blue
 Distance Estimate: About 17,000 light-years from Earth

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NuSTAR helps to identify the source of mysterious massive explosions



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Community observing program Shadow the Scientists took the public on a second tour of the famous interstellar visitor with live observations from the Gemini North telescope control room in Hawai‘i

Gemini North captured new images of Comet 3I/ATLAS after it reemerged from behind the Sun on its path out of the Solar System. The data were collected during a Shadow the Scientists session — a unique outreach initiative that invites students around the world to join researchers as they observe the Universe on the world’s most advanced telescopes.

On 26 November 2025, scientists used the Gemini Multi-Object Spectrograph (GMOS) on Gemini North at Maunakea in Hawai‘i to obtain images of the third-ever detected interstellar object, Comet 3I/ATLAS. The new observations reveal how the comet has changed after making its closest approach to the Sun. Gemini North is one half of the International Gemini Observatory, partly funded by the U.S. National Science Foundation (NSF) and operated by NSF NOIRLab.

After emerging from behind the Sun, 3I/ATLAS reappeared in the sky close to Zaniah, a triple-star system located in the constellation Virgo. These observations were taken as part of a public outreach initiative organized by NSF NOIRLab in collaboration with Shadow the Scientists, an initiative created to connect the public with scientists to engage in authentic scientific experiments, such as astronomy observing experiences on world-class telescopes. The scientific program was led by Bryce Bolin, a research scientist from Eureka Scientific.

This image is composed of exposures taken through four filters — blue, green, orange, and red. As exposures are taken, the comet remains fixed in the center of the telescope’s field of view. However, the positions of the background stars change relative to the comet, causing them to appear as colorful streaks in the final image.

In earlier images of the comet, captured during a Shadow the Scientists session hosted at Gemini South in Chile, it appears to have a red hue. However, in the new image released today, it appears to have a faint greenish glow. This is due to light emitted by gases in the comet’s coma that are evaporating as the comet heats up, including diatomic carbon (C2), a highly reactive molecule of two carbon atoms that emits light at green wavelengths.

What remains unknown is how the comet will behave as it leaves the Sun's vicinity and cools down. Many comets have a delayed reaction in experiencing the Sun's heat due to the lag in time that it takes for heat to make its way through the interior of the comet. A delay can activate the evaporation of new chemicals or trigger a comet outburst. Gemini will continue to monitor the comet as it leaves the Solar System and detect changes in its gas composition and outburst behavior.

This collaboration with Shadow the Scientists builds on NOIRLab’s tradition of combining cutting-edge science with public engagement, ensuring that remarkable cosmic events are shared as widely as possible. By involving learners directly in observing sessions and data collection, programs like this one not only advance knowledge but also inspire the next generation of explorers.

“Sharing an observing experience in some of the best conditions available gives the public a truly front-row view of our interstellar visitor,” says Bolin. “Allowing the public to see what we do as astronomers and how we do it also helps demystify the scientific and data collection process, adding transparency to our study of this fascinating object.”




More Information
NSF NOIRLab, the U.S. National Science Foundation center for ground-based optical-infrared astronomy, operates the International Gemini Observatory (a facility of NSF, NRC–Canada, ANID–Chile, MCTIC–Brazil, MINCyT–Argentina, and KASI–Republic of Korea), NSF Kitt Peak National Observatory (KPNO), NSF Cerro Tololo Inter-American Observatory (CTIO), the Community Science and Data Center (CSDC), and NSF–DOE Vera C. Rubin Observatory (in cooperation with DOE’s SLAC National Accelerator Laboratory). It is managed by the Association of Universities for Research in Astronomy (AURA) under a cooperative agreement with NSF and is headquartered in Tucson, Arizona.

The scientific community is honored to have the opportunity to conduct astronomical research on I’oligam Du’ag (K dge the very significant cultural role and reverence of I’oligam Du’ag to the Tohono O’odham Nation, and Maunakea to the Kanaka Maoli (Native Hawaiians) community.


Links


Contacts:
Bryce Bolin
bolin.astro@gmail.com
Research Scientist
Eureka Scientific, Inc
Josie Fenske
josie.fenske@noirlab.edu
Public Information Officer
NSF NOIRLab

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Monday, January 12, 2026

NSF–DOE Vera C. Rubin Observatory Spots Record-Breaking Asteroid in Pre-Survey Observations

PR Image noirlab2601a
Artist’s illustration of asteroid 2025 MN45

PR Image noirlab2601b
Asteroid 2025 MN45 lightcurve

PR Image noirlab2601c
The Cosmic Treasure Chest

PR Image noirlab2601d
Portion of Virgo Cluster (with asteroids)




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A Swarm of New Asteroids
PR Video noirlab2601a
A Swarm of New Asteroids


First peer-reviewed paper using LSST Camera data identifies an asteroid, nearly the size of eight football fields, rotating every two minutes

Astronomers analyzing data from NSF–DOE Vera C. Rubin Observatory, jointly funded by the U.S. National Science Foundation and the U.S. Department of Energy's Office of Science, have discovered the fastest-ever spinning asteroid with a diameter over half a kilometer — a feat uniquely enabled by Rubin. The study provides crucial information about asteroid composition and evolution, and demonstrates how Rubin is pushing the boundaries of what we can discover within our own Solar System.

As part of the NSF–DOE Vera C. Rubin Observatory First Look event in June 2025, Rubin announced that it had observed thousands of asteroids cruising about our Solar System, about 1900 of which have been confirmed as never-before-seen [1]. Within the flurry, a team of astronomers has discovered 19 super- and ultra-fast-rotating asteroids. One of these is the fastest-spinning asteroid larger than 500 meters (0.3 miles) ever found.

The study was led by Sarah Greenstreet, NSF NOIRLab assistant astronomer and lead of Rubin Observatory’s Solar System Science Collaboration’s Near-Earth Objects and Interstellar Objects working group. The team presents their results in a paper appearing in The Astrophysical Journal Letters, as well as at a press conference at the 247th meeting of the American Astronomical Society (AAS) in Phoenix, Arizona.

Rubin Observatory is a joint program of NSF NOIRLab and DOE’s SLAC National Accelerator Laboratory, who cooperatively operate Rubin. NOIRLab is managed by the Association of Universities for Research in Astronomy (AURA).

“NSF–DOE Rubin Observatory will find things that no one even knew to look for,” says Luca Rizzi, an NSF program director for research infrastructure. “When Rubin's Legacy Survey of Space and Time begins, this huge spinning asteroid will be joined by an avalanche of new information about our Universe, captured nightly.”

The Legacy Survey of Space and Time (LSST) is Rubin’s mission to repeatedly scan the Southern Hemisphere night sky for ten years to create an ultra-wide, ultra-high-definition time-lapse record of the Universe. LSST is expected to start in the coming months

The study discussed here uses data collected over the course of about ten hours across seven nights in April/May 2025, during Rubin Observatory's early commissioning phase. This is the first published peer-reviewed scientific paper that uses data from the LSST Camera — the largest digital camera in the world.

“The Department of Energy's investment in Rubin Observatory's cutting-edge technology, particularly the LSST Camera, is proving invaluable,” said Regina Rameika, the DOE Associate Director for High Energy Physics. “Discoveries like this exceptionally fast-rotating asteroid are a direct result of the observatory's unique capability to provide high-resolution, time-domain astronomical data, pushing the boundaries of what was previously observable.”

“We have known for years that Rubin would act as a discovery machine for the Universe, and we are already seeing the unique power of combining the LSST Camera with Rubin’s incredible speed. Together, Rubin can take an image every 40 seconds,” said Aaron Roodman, Deputy Head of LSST and professor of Particle Physics and Astrophysics at SLAC. “The ability to find thousands of new asteroids in such a short period of time, and learn so much about them, is a window into what will be uncovered during the 10-year survey.”

As asteroids orbit the Sun, they also rotate at a wide range of speeds. These spin rates not only offer clues about the conditions of their formation billions of years ago, but also tell us about their internal composition and evolution over their lifetimes. In particular, an asteroid spinning quickly may have been sped up by a past collision with another asteroid, suggesting that it could be a fragment of an originally larger object.

Fast rotation also requires an asteroid to have enough internal strength to not fly apart into many smaller pieces, called fragmentation. Most asteroids are ‘rubble piles’, which means they are made of many smaller pieces of rock held together by gravity, and thus have limits based on their densities as to how fast they can spin without breaking apart. For objects in the main asteroid belt, the fast-rotation limit to avoid being fragmented is 2.2 hours; asteroids spinning faster than this must be structurally strong to remain intact. The faster an asteroid spins above this limit, and the larger its size, the stronger the material it must be made from.

The study presents 76 asteroids with reliable rotation periods. This includes 16 super-fast rotators with rotation periods between roughly 13 minutes and 2.2 hours, and three ultra-fast rotators that complete a full spin in less than five minutes.

All 19 newly identified fast-rotators are longer than the length of an American football field (100 yards or about 90 meters). The fastest-spinning main-belt asteroid identified, named 2025 MN45, is 710 meters (0.4 miles) in diameter and it completes a full rotation every 1.88 minutes. This combination makes it the fastest-spinning asteroid with a diameter over 500 meters that astronomers have found.

“Clearly, this asteroid must be made of material that has very high strength in order to keep it in one piece as it spins so rapidly,” says Greenstreet. “We calculate that it would need a cohesive strength similar to that of solid rock. This is somewhat surprising since most asteroids are believed to be what we call ‘rubble pile’ asteroids, which means they are made of many, many small pieces of rock and debris that coalesced under gravity during Solar System formation or subsequent collisions.”

Most fast-rotators discovered so far orbit the Sun just beyond Earth, known as near-Earth objects (NEOs). Scientists find fewer fast-rotating main-belt asteroids (MBAs), which orbit the Sun between Mars and Jupiter. This is mainly because of the main-belt asteroids’ greater distance from Earth, which makes their light fainter and more difficult to see.

All but one of the newly identified fast-rotators live in the main asteroid belt, some even just beyond its outer edge, with the lone exception being an NEO. This shows that scientists are now finding these extremely rapidly rotating asteroids at farther distances than ever before, an achievement made possible by Rubin’s enormous light-collecting power and precise measurement capabilities.

In addition to 2025 MN45, other notable asteroid discoveries made by the team include 2025 MJ71 (1.9-minute rotation period), 2025 MK41 (3.8-minute rotation period), 2025 MV71 (13-minute rotation period), and 2025 MG56 (16-minute rotation period). These five super- to ultra-fast rotators are all several hundred meters in diameter and join a couple of NEOs as the fastest spinning sub-kilometer asteroids known.

“As this study demonstrates, even in early commissioning, Rubin is successfully allowing us to study a population of relatively small, very-rapidly-rotating main-belt asteroids that hadn’t been reachable before,” says Greenstreet.

Scientists expect to find more fast rotators once Rubin begins its 10-year Legacy Survey of Space and Time (LSST). Unlike the dense, rapid First Look observations that enabled this quick burst of discoveries, LSST’s regular, sparser observations will instead uncover fast rotators gradually as the survey accumulates data, providing pivotal information about the strengths, compositions, and collisional histories of these primitive bodies.



Notes
[1] These data were submitted to the IAU Minor Planet Center, making them the first publicly available data from Rubin First Look.


More information
This research was presented in a paper titled “Lightcurves, rotation periods, and colors for Vera C. Rubin Observatory’s first asteroid discoveries,” appearing in The Astrophysical Journal Letters. DOI: 10.3847/2041-8213/ae2a30

The team is composed of Sarah Greenstreet (NSF–DOE Vera C. Rubin Observatory/NSF NOIRLab, University of Washington), Zhuofu (Chester) Li (University of Washington), Dmitrii E. Vavilov (University of Washington), et al.

NSF–DOE Vera C. Rubin Observatory, funded by the U.S. National Science Foundation and the U.S. Department of Energy’s Office of Science, is a groundbreaking new astronomy and astrophysics observatory on Cerro Pachón in Chile. It is named after astronomer Vera Rubin, who provided the first convincing evidence for the existence of dark matter. Using the largest camera ever built, Rubin will repeatedly scan the sky for 10 years to create an ultra-wide, ultra-high-definition, time-lapse record of our Universe.

NSF–DOE Vera C. Rubin Observatory is a joint initiative of the U.S. National Science Foundation (NSF) and the U.S. Department of Energy’s Office of Science (DOE/SC). Its primary mission is to carry out the Legacy Survey of Space and Time, providing an unprecedented data set for scientific research supported by both agencies. Rubin is operated jointly by NSF NOIRLab and SLAC National Accelerator Laboratory. NSF NOIRLab is managed by the Association of Universities for Research in Astronomy (AURA), and SLAC is operated by Stanford University for the DOE. France provides key support to the construction and operations of Rubin Observatory through contributions from CNRS/IN2P3. Rubin Observatory is privileged to conduct research in Chile and gratefully acknowledges additional contributions from more than 40 international organizations and teams.

The U.S. National Science Foundation (NSF) is an independent federal agency created by Congress in 1950 to promote the progress of science. NSF supports basic research and people to create knowledge that transforms the future.

The DOE’s Office of Science is the single largest supporter of basic research in the physical sciences in the United States and is working to address some of the most pressing challenges of our time.

 NSF NOIRLab, the U.S. National Science Foundation center for ground-based optical-infrared astronomy, operates the International Gemini Observatory (a facility of NSF, NRC–Canada, ANID–Chile, MCTIC–Brazil, MINCyT–Argentina, and KASI–Republic of Korea), NSF Kitt Peak National Observatory (KPNO), NSF Cerro Tololo Inter-American Observatory (CTIO), the Community Science and Data Center (CSDC), and NSF–DOE Vera C. Rubin Observatory (in cooperation with DOE’s SLAC National Accelerator Laboratory). It is managed by the Association of Universities for Research in Astronomy (AURA) under a cooperative agreement with NSF and is headquartered in Tucson, Arizona.

The scientific community is honored to have the opportunity to conduct astronomical research on I’oligam Du’ag (Kitt Peak) in Arizona, on Maunakea in Hawai‘i, and on Cerro Tololo and Cerro Pachón in Chile. We recognize and acknowledge the very significant cultural role and reverence of I’oligam Du’ag (Kitt Peak) to the Tohono O’odham Nation, and Maunakea to the Kanaka Maoli (Native Hawaiians) community.

 SLAC National Accelerator Laboratory explores how the Universe works at the biggest, smallest, and fastest scales and invents powerful tools used by researchers around the globe. As world leaders in ultrafast science and bold explorers of the physics of the Universe, we forge new ground in understanding our origins and building a healthier and more sustainable future. Our discovery and innovation help develop new materials and chemical processes and open unprecedented views of the cosmos and life’s most delicate machinery. Building on more than 60 years of visionary research, we help shape the future by advancing areas such as quantum technology, scientific computing, and the development of next-generation accelerators. SLAC is operated by Stanford University for the U.S. Department of Energy’s Office of Science.


Links


Contacts:

Sarah Greenstreet
Assistant Astronomer
NSF–DOE Vera C. Rubin Observatory/NSF NOIRLab
Email: sarah.greenstreet@noirlab.edu

Josie Fenske
Public Information Officer
NSF NOIRLab
Email: josie.fenske@noirlab.edu

Aaron Groff
Media Relations Lead
SLAC National Accelerator Laboratory
Email: agroff@slac.stanford.edu

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