Astronomers from the Université de Montréal led an international team in the new research, reported in a recent paper in The Astrophysical Journal, which presents the clearest images ever recorded of gaseous filaments connecting a galaxy’s atmosphere to the rotating disk that the supermassive black hole feeds on.
The team’s analysis of the data paves the way toward understanding how black holes consume matter, a mystery that has stumped astronomers for decades.
Strange Black Hole Feeding
“JWST observations are offering us thousands of new facts and measurements, and I can report it’s a lot to absorb,” said co-author Megan Donahue, MSU University Distinguished Professor of physics and astronomy. “We are all working together to solve the astrophysics questions about how these black holes get their fuel and how they interact with their host galaxy.”
Supermassive black holes anchor most galaxies in the universe, with masses ranging from millions to billions of times that of the Sun. In active galactic nuclei (AGN), these central black holes both consume enormous amounts of surrounding material and unleash powerful jets that shape the galaxies around them.
This activity presents a longstanding puzzle. Because an AGN’s jets heat the surrounding gas, they should effectively cut off the black hole’s fuel supply, leaving astronomers to wonder how it continues to accrete matter.
Testing a Hypothesis
To investigate, the researchers tested the leading explanation: that heated gas eventually cools, condenses into long filaments, and falls back toward the galactic center, replenishing the black hole’s supply of material.
They turned JWST toward one of the best natural laboratories for studying AGN: the galaxy NGC 4696, located at the heart of the Centaurus Cluster, roughly 145 million light-years from Earth.
Using JWST’s NIRSpec instrument, the team collected eight hours of observations, mapping the motion of gas deep within the galaxy—where the black hole’s gravitational influence dominates—at a resolution of about 30 light-years.
Their observations revealed an 800-light-year-wide disk of gas orbiting the supermassive black hole at roughly 600 kilometers per second. Connected to this rapidly rotating disk was a large infalling filament, funneling gas inward to feed the AGN.
Feeding Cycle of the Black Hole
The discovery fills in a crucial missing piece of the puzzle surrounding how supermassive black holes sustain themselves. The researchers propose that after the black hole injects energy into the surrounding gas, heating it, that material eventually cools and collapses into thin filaments stretching hundreds of thousands of light-years. Guided by magnetic fields, these filaments then fall toward the galaxy’s center, where they accumulate in the rotating accretion disk.
The team also ran a series of computer simulations based on this model and found that the predicted behavior closely matched what JWST observed. While additional observations will be needed to confirm the results, the findings provide strong support for the filament-feeding hypothesis.
“It’s been really exciting to participate in this project,” co-author Mark Voit, an MSU Physics and Astronomy Professor, said in a statement.
“Calculations done by our Michigan State group predict that magnetic fields should help feed the universe’s biggest black holes by channeling cool gas toward them, and it’s amazing to see that happening in these JWST images,” he added.
Ryan Whalen covers science and technology for The Debrief. He holds an MA in History and a Master of Library and Information Science with a certificate in Data Science. He can be contacted at ryan@thedebrief.org, and follow him on Twitter @mdntwvlf.
NASA’s James Webb Space Telescope (JWST) is celebrating four years of unexpectedly strong performance by providing a deep new view into one of the universe’s most familiar galaxies: Centaurus A.
Typically, Centaurus A’s thick dust obscures astronomers’ attempts to peer into it, yet the JWST’s near- and mid-infrared sensitivity allows scientists to see more of the galaxy than ever before.
In new images released by NASA to celebrate JWST’s four years of impressive discoveries, the most powerful telescope ever constructed reveals the dense collection of stars that make up the ever-changing Centaurus A galaxy.
Inside Centaurus A
Due to two crucial factors, Centaurus A is an extremely interesting galaxy for astronomers. It is highly active, offering an important opportunity to monitor galaxy and black hole growth while being relatively close by, at just 11 million light-years away—a highly unusual combination.
The history of imaging Centaurus A is marked by questions, which JWST has now begun to answer. Webb’s predecessor, Hubble, could only view visible light in its examinations, leaving the galaxy’s central regions obscured by dust. Additionally, the Spitzer Space Telescope lacked sufficient resolution to resolve individual stars in infrared, although the data it collected provided new discoveries of massive dust structures.
Powerful events are on display in Centaurus A, the aftermath of a collision with another galaxy and a supermassive black hole’s active feeding. As the black hole releases powerful jets and gushes energy, it shapes the surrounding galaxy, which still retains an unusual shape left by its two-billion-year-old merger.
“No single telescope tells the whole story,” said Shawn Domagal-Goldman, division director, Astrophysics, NASA Headquarters in Washington. “Discoveries build over time, and new observatories expand on the foundations laid by earlier missions. Webb represents the most powerful step forward yet, opening a window into wavelengths and details never before accessible. This allows astronomers to examine structures and processes that other telescopes could not see.”
MIRI image of Centaurus A. Credit: NASA, ESA, CSA, STScI; Image Processing: Alyssa Pagan (STScI), Joseph DePasquale (STScI), Macarena Garcia Marin (ESA Office at STScI)
JWST Reveals Amazing Structures
Thanks to JWST’s mid-infrared capabilities, astronomers captured detailed images of Centaurus A’s dust structures and were surprised and confused by the glowing shapes revealed. One unusual feature is a band cutting across the galactic center, shaped like a warped parallelogram, with wispy tendrils stretching out of it.
Another feature, shaped like the letter “S,” also confounds astronomers, leaving many questions about the influence of both the central black hole and the galactic merger on its shape and evolution.
A large portion of the red glowing dots in the image above represent dusty areas, either dust-rich stars or stellar nurseries, both important sources of dust for star formation, and therefore, the continuance of the galaxy.
Single Stars and JWST
The JWST’s incredible resolution is allowing astronomers to study the galaxy star by star for the first time. Combining images from the MIRI (Mid-Infrared Instrument) and the NIRCam (Near-Infrared Camera) revealed tightly packed individual stars.
This view of individual stars is essential for what some astronomers call “galactic archaeology,” by providing important clues that help scientists reconstruct the galaxy’s formation and evolution. This galactic timeline is made up of many important pieces revealed by individual stars, such as when the oldest stars formed, when star formation slowed, when the merger reignited a powerful burst of star formation, and how that collision stirred the galaxy’s gases, further accelerating star formation.
Capturing these details requires spectroscopy, a technique where light is broken down to reveal detailed information about distant stars. Also using this technique, researchers can gain important information about the central black hole, identifying that it can both compress gas to accelerate star formation and push gas away to limit it.
On its fourth anniversary, the unprecedented details now revealed about one of our most interesting galactic neighbors continue to underscore the JWST’s incredible promise as NASA’s premier space observatory.
Ryan Whalen covers science and technology for The Debrief. He holds an MA in History and a Master of Library and Information Science with a certificate in Data Science. He can be contacted at ryan@thedebrief.org, and follow him on Twitter @mdntwvlf.
James Webb Space Telescope (JWST) observations have revealed that the fate of planets after the death of their host star may be surprisingly warm, according to new research from the University of St Andrews.
The JWST observations offer a possible glimpse into what our solar system will be like billions of years from now, particularly for gas giants like Jupiter. In a recent paper published in Nature, the St Andrew researchers describe JWST observations of WD 1856 b, a Jupiter-sized exoplanet much warmer than would be expected for orbiting a dead white dwarf star.
Webb Observes WD 1856 b
A collaboration between NASA, the European Space Agency, and the Canadian Space Agency, the JWST has provided an unprecedented view of the distant edges of the universe, revealing many unexpected finds. Among these surprises was WD 1856 b, whose mass, temperature, and atmosphere readings reveal a surprisingly intact planet after the death of its star.
Our own Sun is projected to exhaust its supply of hydrogen in roughly five billion years, after which it will expand into a red giant star about 100 times larger than it is today, before shedding mass in its final transformation into a white dwarf star.
In the distant future, the Sun’s transformations will likely someday obliterate Mercury, Venus, and even Earth, yet scientists have remained uncertain about how more distant planets will fare. Only by observing real-world examples of planets orbiting dead stars can scientists gather more data on how these scenarios play out for the remaining planets, as with JWST’s observations of WD 1856 b.
A Strange System
Discovered in 2020 by the TESS survey and the Spitzer space telescope, WD 1856 b orbits the white dwarf star WD 1856+534 at a distance of around 80 light-years from Earth.
“The planet is quite the oddball. It’s about the size of Jupiter, but the white dwarf it orbits is the size of Earth, so the planet is seven times larger than its star,” said lead author Dr. Ryan MacDonald from the University of St Andrews.
Perhaps the most confounding element of this system is how close the exoplanet is to its host star. At a distance of 50 times closer than the Earth is to the Sun, the planet is at a distance at which the star’s red giant phase should have destroyed it. How the planet managed to escape the destruction while ultimately ending up so close to its star intrigued the St. Andrews team.
James Webb Space Telescope Data
As WD 1856 b performed a grazing transit, where just its top edge passed in front of the host star, JWST observations allowed the researchers to crucially measure mass and temperature data, allowing them to estimate its mass at between four and eleven times that of Jupiter.
“We’re used to looking back in time when we use telescopes, but this is the first time we have been able to look forward to what might happen to the outer planets around the remnant of a Sun-like star,” MacDonald said, adding that “it’s like using a time machine to peer into the distant future of our Solar System.”
Infrared light emitted by the planet’s own heat showed a surprising temperature of 126°C, which is 240°C hotter than it would be from the white dwarf’s heat alone.
JWST Tells The Future
As the team worked on the problem, the temperature mystery proved to be the answer to the distance issue.
“The big question is how WD 1856 b ended up where it is today, and there are two theories. One is that the planet was swallowed by the host star as it was dying, and managed to survive on the inside,” said Dr. Christopher O’Connor of Northwestern University. “The other is that the migration took place due to the gravitational effect of other objects in the system. The white dwarf is part of a triple star system, and the outer companion stars could have influenced WD 1856 b’s orbit.”
Since no present source of energy should be capable of generating this much heat on the exoplanet, the researchers suggest that it represents heat left over from being engulfed by the red giant or possibly through an inward migration. Cooling models the team analyzed indicated that the planet likely first captured heat about 3 to 3.5 billion years ago, then cooled to its present temperature and migrated closer to its host star.
“This is just the beginning of our exploration of planets orbiting dead stars with Webb, and the search for further planets orbiting white dwarfs is ongoing,” Dr. MacDonald concluded. “Our results show that stellar death is not the end – some planets experience a vibrant and lively future after the death of their star.”
Ryan Whalen covers science and technology for The Debrief. He holds an MA in History and a Master of Library and Information Science with a certificate in Data Science. He can be contacted at ryan@thedebrief.org, and follow him on Twitter @mdntwvlf.
A bright, dense cluster of hot, massive stars in a galaxy that existed 1.4 billion years after the big bang has been found helping to end the early universe's foggy days during which neutral hydrogen gas was draped across the cosmos, obscuring ultraviolet light from luminous objects.
The cluster was found emitting ultraviolet light in a small but quickly growing galaxy by the Hubble Space Telescope. The presence of this ultraviolet light, and the star-forming history of the cluster producing it, suggests that bursts of star formation contributed to waves of ionizing radiation that gradually cleared out the opaque neutral hydrogen.
In the aftermath of the big bang, the universe was filled with neutral hydrogen gas that is opaque at short wavelengths of light, such as ultraviolet. However, this ultraviolet light was the neutral hydrogen's worst enemy, gradually ionizing the gas across the universe. Once ionized, hydrogen gas cannot absorb ultraviolet light — and so, the cosmos became transparent at those wavelengths.
Because of this, the first billion or so years are called the Epoch of Reionization. It is referred to as "reionization" rather than ionization because, technically, the gas had already been ionized once before during the first 379,000 years after the Big Bang.
While investigating what brought about this epoch, astronomers had identified two chief suspects that could have produced sufficient amounts of ultraviolet light to ionize the neutral hydrogen. One is active supermassive black holes and the other is the first generations of hot, massive stars. The problem is, given that neutral hydrogen is adept at absorbing the ultraviolet light, astronomers have had difficulty tracing that ultraviolet back to its source and identifying which of the two suspects are the main culprit.
In 2023 the James Webb Space Telescope (JWST) made a major breakthrough, finding a galaxy that existed just 900 million years after the Big Bang that was producing enough energy to ionize the neutral gas surrounding it.
Now the Hubble Space Telescope has gone further, detecting ultraviolet light from a galaxy called MXDFz4.4. This ultraviolet light should only be visible if the surrounding gas had already been ionized.
"Observing a galaxy like this was thought to be impossible," said Ilias Goovaerts of the Space Telescope Science Institute (STScI) in Baltimore, who led the discovery, in a statement. "Researchers expected the 'fog' of neutral hydrogen that filled the early universe would be too thick and obscure our view of its ionizing light. Hubble not only spotted that light, but it also helped reveal incredible details about the galaxy's characteristics."
The full Hubble Space Telescope's view of MXDFz4.4 and its surroundings from our vantage point. (Image credit: NASA/ESA/CSA/STScI/Ilias Goovaerts and Anton Koekemoer (STScI)/Marc Rafelski (STScI, JHU)/ Image Processing: Alyssa Pagan (STScI))
MXDFz4.4 was first identified in the MUSE eXtremely Deep Field (MXDF), with MUSE being the Multi Unit Spectroscopic Explorer on the European Southern Observatory's Very Large Telescope in Chile. The "z4.4" part of its name tells us that the galaxy exists at a redshift of 4.4, meaning that it existed 12.37 billion years ago. As the universe has expanded in the time since then, the ultraviolet light has been redshifted into visible wavelengths that were detected by Hubble.
"Astronomers have found many galaxies that existed at this point in the history of the universe, but we haven't detected ionizing photons from any of them, making MXDFz4.4 one of a kind," said Marc Rafelski, who is the Hubble Deputy Mission Head at STScI.
MXDFz4.4 is 100 times smaller than our Milky Way galaxy but is forming stars ten times faster than our galaxy is. Many of those stars are being born in the tight, luminous cluster producing the ionizing ultraviolet.
An artist's impression of the young, distant galaxy MXDFz4.4 and its dense cluster of luminous stars. (Image credit: NASA/ESA/Leah Hustak (STScI))
The cluster contains "A lot of young, hot, massive stars in a small space [that] do a better job of blasting through opaque gas," said Goovaerts.
Furthermore, by comparing Hubble's observations of MXDFz.4.4 with those of the JWST, which probed for cooler, older stars in the galaxy, Goovaerts and Rafelski's team discovered that the stars in the cluster had formed in bursts, each burst producing fresh quantities of ionizing ultraviolet radiation that helped to clear out more and more of the neutral gas over time. We now see the galaxy about 250 million years after it finished reionizing the surrounding gas. These hot, massive stars in the cluster end their lives after a few million years as supernova explosions, the blast waves and radiation from which can create bubbles in the gas light years across, creating further pathways for ultraviolet light to escape and be detected by Hubble.
The observations seem to nail down the theory that clusters of hot, massive, luminous stars in young galaxies in the early universe played a dominant role in ionizing the universe's neutral gas.
"Hubble's observations of MXDFz4.4 let us test our hypotheses much closer to the Era of Reionization than ever before," said Rafelski. "Finding more galaxies, especially at slightly later cosmic times where larger samples are within reach, would let us refine these measurements and figure out what cleared our view as that era was ending."
Researchers have identified the most distant dormant black hole known, dating back to the universe’s early history. Astronomers have long relied on brilliant quasars, supermassive black holes actively feeding on surrounding matter, to study the early universe. Yet these luminous objects reveal only part of the story. Now, researchers have detected the most distant dormant [...]
Following its trip around the Sun late last year, 3I/ATLAS had been significantly warmed, causing a large amount of its icy exterior to be converted into a cloudy coma. This not only made the comet more visible but also provided Webb an ideal opportunity to collect spectrographic data that could offer important information about its chemical composition.
The Webb data, which was detailed in a recent study, indicates chemical ratios of carbon and deuterium emanating from the object that are very unlike those of comets found within our solar system.
The compelling new findings, according to NASA officials, “surprised researchers.” Here’s why.
A Rare Look at an Ancient Space Object
Fundamentally, the recent Webb observations provided astronomers with one of their best opportunities to observe information about the comet’s possible origins throughout the duration of its visit to our Solar System last year.
Martin Cordiner, an astro-chemist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, called the observations “a unique opportunity to study an ancient object from the distant galaxy, probably pre-dating our Sun and solar system.”
Above: Researchers used Webb’s NIRSpec instrument to map specific chemical contents of comet 3I/ATLAS as it exited our Solar System (Image Credit: NASA, ESA, CSA, STScI, Martin Cordiner (CUA, NASA-GSFC); Image Processing: Alyssa Pagan (STScI).
Cordiner, who was also the lead author of the recent Nature study, said that the data he and his co-authors were able to obtain helped to provide “direct insight into that distant time and place” from which 3I/ATLAS originates, while also providing new insights into “how unusual our own solar system may be.”
Understandably, the Webb telescope is in high demand, and Cordiner and his team had to interrupt the space observatory’s planned schedule to turn its powerful eye toward 3I/ATLAS as it made its exit.
A Deuterium-Rich Space Object
Cordiner and the research team joined astronomers from many sub-disciplines in taking the opportunity to get a look at 3I/ATLAS on its journey through the solar system, which relied primarily on Webb’s NIRSpec (Near-Infrared Spectrograph) instrument.
As previously reported by The Debrief, the telescope’s NIRSpec instrument revealed “exceptionally high” levels of deuterium—also known as “heavy hydrogen”—amounting to nearly 30 times the amount normally seen in comets within our solar system.
One thing this probably indicates is that early in its lifetime, 3I/ATLAS was likely exposed to large amounts of radiation, which gave rise to the deuterium-rich ice in its composition. However, after drifting through space for eons without coming into proximity to a star like our Sun, there were no opportunities for this “heavy water” to be converted back into the typical kind of H20 water common on our planet.
Clues from Carbon Traces
Another primary finding Cordiner and the team made is that NIRSpec data revealed only small amounts of carbon-13, as opposed to its lighter counterpart, carbon-12. Since carbon-13 enrichment is known to occur within stellar systems over time, the team interprets this as evidence for the extreme age of 3I/ATLAS, which could have origins going as far back as an astonishing 12 billion years ago.
This would place the interstellar object’s birth within the period astronomers identify as “cosmic noon,” during which our universe was undergoing its peak period in star formation. Additionally, separate observations involving the European Southern Observatory’s Very Large Telescope help to affirm the recent Webb findings, along with complementary insights into the ancient comet’s carbon content, as well as nitrogen present in the form of cyanide, revealed from recent spectrographic analysis.
“For us as scientists, finding these rare isotopes is fascinating, but the bigger picture here is looking at the possibilities of prebiotic chemistry elsewhere in the galaxy,” said Stefanie Milam, one of the recent study’s co-authors, and also a researcher at NASA Goddard, in a recent statement.
Fundamentally, what the latest data on 3I/ATLAS conveys is more than just a rare look at a cosmic voyager who briefly entered our Solar System—it is a potential glimpse at how the very building blocks of life could have made their way into our planetary neighborhood long ago, eventually arriving here on Earth.
“So far, we know of only one place in the vast cosmos where chemical ingredients led to life – our solar system, our Earth,” Milam recently said.
“Analysis of these interstellar objects is a major step towards learning how common, or uncommon, the conditions for the evolution of life are in the universe,” Milam added.
The team’s recent study, “Isotopic evidence for a cold and distant origin of 3I/ATLAS,” appeared in the journal Nature on June 22, 2026.
Micah Hanks is the Editor-in-Chief and Co-Founder of The Debrief. A longtime reporter on science, defense, and technology with a focus on space and astronomy, he can be reached atmicah@thedebrief.org. Follow him on X @MicahHanks, and at micahhanks.com.
The James Webb Space Telescope Picture of the Month shows the giant molecular cloud Orion A, an area of the sky replete with star-forming clouds. (Image credit: ESA/Webb, NASA & CSA, T. Megeath, M. Zamani (ESA/Webb) Acknowledgement: M. H. Özsaraç)
The image of the day for Monday (June 22) shows the star-forming clouds of Orion A in stunning detail.
Released as the James Webb Space Telescope (JWST) Picture of the Month, the image further demonstrates the impact the $10 billion space telescope has had on our view of the cosmos since it began operations in July 2022.
What is Orion A?
Located around 1,300 light-years from Earth and situated to the south of Orion's Beltin the night sky,Orion A is one of the largest and closest molecular clouds to our planet. Shaped like a filament, this structure of gas and dust is around 290 light-years long.
Part of the Orion molecular cloud complex, Orion A is a packed stellar nursery. Over the last few million years alone, it is estimated that Orion A has given birth to around 3,000 stellar objects.
The molecular cloud is also host to many young protostars surrounded by platters of gas and dust called protoplanetary disks, which, as the name suggests, will form planets. Thus, studying regions like Orion A could be key to understanding how the solar system came to be around 4.6 billion years ago.
James Webb Space Telescope (JWST) observations have revealed the colorful secret of the Pink Planet, the coldest object of its type ever directly observed.
A team of astronomers led by Northwestern University has revealed their findings in a recent paper published in The Astronomical Journal, finally describing the rose-colored haze covering the planetary-mass companion GJ504b, thanks to JWST data.
For over a decade, researchers have speculated that atmospheric salt clouds may create the pink planet’s strange hue, but this is the first concrete evidence for the hypothesis.
The Pink Planet
Since its discovery in 2013, GJ504b, commonly known as “The Pink Planet,” has been a bit of an astronomical mystery. Even the object’s description is imprecise: a “planetary-mass companion,” a nebulous category teetering between the size of a large planet and a brown dwarf, at roughly 25 times Jupiter’s mass. Residing 57 light-years from Earth, the object’s host star is similar to our Sun.
Faint due to extremely cold temperatures, astronomers cannot obtain clear enough observations with ground-based telescopes to perform spectroscopic analysis. However, from its vantage point beyond our atmosphere, the JWST’s advanced instruments have finally provided the necessary data to make sense of the object’s strange pink atmosphere.
The exoplanets most clearly observed are much hotter than our world, with temperatures between 1,000 and 2,000°F, creating a brilliance which can be seen across the gulf of space and through Earth’s atmosphere.
This giant planet is a mere 550°F, still hot by Earth standards, but far cooler than is normal for its type. According to the new study, GJ504b is an ancient world, some 2.5 to 4billion years old, with a slow cooling over time accounting for its decreased temperature.
Challenging JWST Observation
In addition to providing the first evidence for The Pink Planet’s elusive salt clouds, the team’s research has broader implications for studying cold objects, laying the groundwork for future JWST observations of such faint glows, too dim for ground-based telescopes.
“The Pink Planet is the coldest companion ever discovered using ground-based instruments,” according to Aneesh Baburaj, the study’s lead author. “Many teams all around the world performed follow-up observations to study its light, but it was too faint for ground-based instruments. That made it a perfect target for JWST. When we finally obtained its spectrum, it immediately looked interesting. But once we started digging deeper into the data, we realized it was not like anything we have analyzed before.”
To accurately analyze the light, Baburaj’s team used an advanced data-processing technique to remove considerable glare from the Pink Planet’s host star, improving the quality of the JWST data. Breaking light into separate colors through spectroscopic analysis allows scientists to determine the elemental composition of exoplanet atmospheres using JWST data.
“In the past, other astronomers observed the companion for an entire night with some of the biggest telescopes in the world to obtain a spectrum,” Baburaj said. “And they could not see the object. With JWST, our entire observation took around two hours, and we were successful.”
Analyzing the JWST Data
The team discovered water vapor, methane, carbon dioxide, ammonia, and other molecules in the object’s atmosphere, but these results conflicted with existing atmospheric models, which only made sense if the object had an extremely unlikely combination of physical features. However, once the team added clouds to the model, the effect of their salty formations on the light made the JWST data much easier to explain.
“We ran simulations with clouds, and the results aligned with what we know about cold planets,” Baburaj said. “We tried three different types of clouds, and salt clouds fit best. When we accounted for salt clouds, it subdued the signature of molecules hidden deeper in the companion’s atmosphere. Then, the results became physically possible.”
In addition to the salty clues, the researchers discovered an abundance of heavy metals. These may have something to do with The Pink Planet’s origins, as it may have originally formed as a star instead of a planet, but astronomers remain uncertain. In any case, the work process developed here will be essential to future JWST investigation of cold objects.
“This is the first time we’ve found that salt clouds are critical to explaining the spectrum of an object,” Baburaj concluded. “It’s a good reminder to account for clouds in our models.”
Ryan Whalen covers science and technology for The Debrief. He holds an MA in History and a Master of Library and Information Science with a certificate in Data Science. He can be contacted at ryan@thedebrief.org, and follow him on Twitter @mdntwvlf.
This NASA Hubble Space Telescope image features a swarm of galaxies in the galaxy cluster called CL0016+1609 or MACS J0018.5+1626.
NASA, ESA, H. Ebeling (University of Hawaii), D. Coe (STScI, ESA, JWST); Image Processing: G. Kober (NASA/Catholic University of America)
This NASA Hubble Space Telescope image features a galaxy cluster, called CL0016+1609 or MACS J0018.5+1626, that is very bright at X-ray wavelengths and is one of the most extensively studied clusters at X-ray and radio wavelengths. The X-ray observations of this cluster revealed that it is two clusters merging along our line of sight.
Researchers requested time to observe CL0016+1609 with Hubble’s Advanced Camera for Surveys because that data would help them accurately measure the cluster’s dark-matter distribution, which helps them study the merger and the role of CL0016+1609 in the large-scale structure of the universe. Hubble can’t directly see dark matter, but its infrared and visible light observations can detect dark matter’s gravitational lensing effects on the normal matter Hubble observes.
The data in this image also includes observations with Hubble’s Wide Field Camera 3 taken as part of an observing program that obtained the first Hubble infrared images of 46 massive galaxy clusters and looked for distant galaxies gravitationally lensed by these clusters. Called RELICS (Reionization Lensing Cluster Survey), this survey found some 300 high-redshift candidate galaxies lensed by these clusters.
You can see the faint vertical arc of one of these distant galaxies in the image above. Look for it just to the left of the large elliptical galaxies in the center of the image. Another brighter, though shorter arc is visible just above and to the right of the large elliptical galaxies in the center of the image.
NASA’s Fermi Mission Uncovers Possible Sibling Supernova Remnants
A new study of two supernova remnants, the debris left behind after stars explode, suggests the explosions came from stellar siblings that once orbited each other. The first star’s detonation sent its binary companion hurtling through space, and then, after traveling for thousands of years, the surviving star blew up too.
This multiwavelength scene shows the Jellyfish Nebula supernova remnant (right), the interstellar cloud it’s interacting with, and a distinctive curving filament to its upper left. The filament, which is shown here both in optical and ultraviolet (UV) light, is the visible part of an overlapping supernova remnant, G189.6+3.3, that is more prominent in radio and X-rays. Visible light is shown in yellow, UV from NASA’s Neil Gehrels Swift Observatory is shown in violet, and infrared light from NASA’s retired WISE (Wide-field Infrared Survey Explorer) mission appears in cyan, red, and orange. Both remnants are located about 6,000 light-years away in the constellation Gemini. The brilliant star at far right is Propus, also known as Eta Geminorum.
NASA Goddard Space Flight Center and M. Michailidis et al. 2026; optical: DSS; infrared: NASA/WISE/JPL-Caltech/UCLA; ultraviolet: NASA/Swift
“Using 16 years of data from NASA’s Fermi Gamma-ray Space Telescope, our analysis uncovered gamma rays associated with a supernova remnant that was hidden in the glare of its neighbor, the Jellyfish Nebula, one of the brightest gamma-ray-emitting supernova remnants known,” said Miltiadis Michailidis, a postdoctoral fellow in the physics department at Stanford University in California. “There are so many striking connections between the two remnants that we conclude they’re likely related, giving us the first known example of a binary system where both stars have undergone supernova explosions.”
Michailidis presented the findings Wednesday at the 248th meeting of the American Astronomical Society in Pasadena, California. A paper describing the results will appear in a future edition of Nature Communications.
The study focused on a faint supernova remnant called G189.6+3.3, which is mainly visible in X-rays. It is upstaged by its brighter and better-known neighbor, the Jellyfish Nebula (IC 443). The two star wrecks, both located in the constellation Gemini, appear to partially overlap as seen in X-rays. Recent X-ray evidence suggests that hot plasma likely associated with G189.6+3.3 may extend across the entire region, a hint that the overlap may be nearly total.
A massive star explodes when its energy-producing core runs out of fuel and collapses under its own weight, triggering an explosion that blows the star apart. The explosion’s shock wave encloses a hot cloud of debris that rapidly expands into space. So far, astronomers have cataloged about 300 supernova remnants in our galaxy.
The Fermi mission is part of NASA’s fleet of observatories monitoring the changing cosmos to help humanity better understand how the universe works. More than a decade ago, observations from Fermi’s LAT (Large Area Telescope) showed that the shock waves of supernova remnants accelerated particles to within a fraction of the speed of light, a process first proposed by physicist Enrico Fermi — the mission’s namesake — in 1949.
These high-speed particles, called cosmic rays, interact with interstellar gas to produce gamma rays, the highest-energy form of light. Protons make up 99% of cosmic ray particles. To prove that accelerated protons are responsible for the glow, astronomers search for a specific gamma-ray feature. When cosmic-ray protons smash into interstellar gas, they produce a short-lived particle called a neutral pion, which almost immediately decays into a pair of gamma rays. This emission occurs within a specific band of energies associated with the neutral pion’s mass and lies within the range detected by Fermi’s LAT instrument.
In 2013, Fermi observations proved that the Jellyfish Nebula, which is interacting with part of a glowing cloud of hydrogen gas known as Sharpless 249, produced gamma rays through this mechanism. Its neighbor, G189.6+3.3, was discovered in 1994 as part of an X-ray survey by the German-led ROSAT (Roentgen Satellite) mission.
A bright filament of gas lies between the overlapping remnants. New observations of this feature reveal that the shock wave from G189.6+3.3 slammed into dense interstellar gas there and dramatically slowed, key evidence that both remnants are interacting with the same cloud system.
The well-known supernova remnant IC 443 (right) has an older, fainter neighbor (shown here in blue-green and magenta) called G189.6+3.3. A filament of gas between them, glowing in visible and ultraviolet light (violet arc at center), traces the neighbor’s shock wave and shows that both remnants are interacting with the same molecular cloud, shown in red, orange, brown for infrared and radio data and yellow for visible light. Blue-green shows X-rays from the fainter remnant, while magenta shows gamma rays with energies greater than 10 billion electron volts; for comparison, visible light has energies between about 2 and 3 electron volts. In this view, high-energy light from the much brighter IC 443 has been removed for clarity. Gamma-ray emission near the filament stems from protons accelerated in the supernova’s shock wave as it expands into the cloud.
NASA Goddard Space Flight Center and M. Michailidis et al. 2026; radio, MWISP and ESA/Planck; infrared: NASA/WISE/JPL-Caltech/UCLA; optical: DSS; ultraviolet: NASA/Swift; X-ray: SRG/eROSITA; gamma ray: NASA/DOE/Fermi LAT Collaboration
Astronomers think the Jellyfish Nebula is also a candidate PeVatron, a cosmic particle accelerator capable of boosting protons to energies so high they could nearly escape our galaxy. Such particles can produce gamma rays with trillions of times more energy than visible light. Finding a second particle accelerator near the Jellyfish Nebula could offer scientists new clues for how supernova remnants develop into PeVatrons.
“The overlapping remnants, a connecting gas filament, and the availability of data from Fermi and other facilities motivated us to delve into this complex but little-studied region,” said co-author Marianne Lemoine-Goumard, an astrophysicist at the French National Centre for Scientific Research (CNRS) based at the University of Bordeaux. “With Fermi’s LAT instrument, we found gamma-ray emission associated with accelerated protons in the northern part of the fainter remnant. If both remnants are interacting with the same structure, then they must share a common distance from us.”
The team concludes the remnants lie about 6,000 light-years away, their explosion centers are separated by roughly 40 light-years projected onto the plane of the sky, and the original stars may have been 20 or more times the Sun’s mass.
Estimates of the remnants’ ages vary widely, but the team concludes that the age of the Jellyfish Nebula is 8,000 to 9,000 years, while G189.6+3.3 is between 20,000 to 110,000 years old. This means the delay between the explosions could have extended for up to 100,000 years.
In addition, the team conducted computer simulations of a million massive binary systems. They show that systems where the stars orbit close enough to exchange matter and interact during their lives can readily produce dual supernova explosions with similar separations and time delays as those found for the remnants. The team also estimated that the chance of randomly encountering this combination of observed spatial alignment and compatible distances to be less than 1%, strongly supporting a physical association.
“The evidence we’ve compiled — including observations across the spectrum, the chemical and physical properties of the remnants, simulations, and more — paints a compelling picture of a dual supernova event,” said Michailidis.
This study identifies a unique possible example of a binary system where both stars exploded as supernovae and left behind separate, detectable supernova remnants. Astronomers think that most massive stars form in binary or multiple-star systems. The Jellyfish Nebula/G189.6+3.3 complex offers astronomers a rare opportunity to study how massive binary stars evolve, exchange matter, explode, and experience velocity changes — called kicks — induced by the supernova blast. It also provides a powerful new laboratory for understanding how coupled supernova remnants behave, including how they accelerate particles, generate gamma rays, and shape their surrounding environments.
“Fermi’s gamma-ray observations of supernova remnants continue to reveal the dynamic lives of stars,” said Elizabeth Hays, the Fermi project scientist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “We can now connect the glowing remains of two massive stars to a powerful pair that evolved together over thousands of years.”
This NASA Hubble Space Telescope image features a swarm of galaxies in the galaxy cluster called CL0016+1609 or MACS J0018.5+1626.
NASA, ESA, H. Ebeling (University of Hawaii), D. Coe (STScI, ESA, JWST); Image Processing: G. Kober (NASA/Catholic University of America)
This NASA Hubble Space Telescope image features a galaxy cluster, called CL0016+1609 or MACS J0018.5+1626, that is very bright at X-ray wavelengths and is one of the most extensively studied clusters at X-ray and radio wavelengths. The X-ray observations of this cluster revealed that it is two clusters merging along our line of sight.
Researchers requested time to observe CL0016+1609 with Hubble’s Advanced Camera for Surveys because that data would help them accurately measure the cluster’s dark-matter distribution, which helps them study the merger and the role of CL0016+1609 in the large-scale structure of the universe. Hubble can’t directly see dark matter, but its infrared and visible light observations can detect dark matter’s gravitational lensing effects on the normal matter Hubble observes.
The data in this image also includes observations with Hubble’s Wide Field Camera 3 taken as part of an observing program that obtained the first Hubble infrared images of 46 massive galaxy clusters and looked for distant galaxies gravitationally lensed by these clusters. Called RELICS (Reionization Lensing Cluster Survey), this survey found some 300 high-redshift candidate galaxies lensed by these clusters.
You can see the faint vertical arc of one of these distant galaxies in the image above. Look for it just to the left of the large elliptical galaxies in the center of the image. Another brighter, though shorter arc is visible just above and to the right of the large elliptical galaxies in the center of the image.
NASA’s Fermi Mission Uncovers Possible Sibling Supernova Remnants
A new study of two supernova remnants, the debris left behind after stars explode, suggests the explosions came from stellar siblings that once orbited each other. The first star’s detonation sent its binary companion hurtling through space, and then, after traveling for thousands of years, the surviving star blew up too.
This multiwavelength scene shows the Jellyfish Nebula supernova remnant (right), the interstellar cloud it’s interacting with, and a distinctive curving filament to its upper left. The filament, which is shown here both in optical and ultraviolet (UV) light, is the visible part of an overlapping supernova remnant, G189.6+3.3, that is more prominent in radio and X-rays. Visible light is shown in yellow, UV from NASA’s Neil Gehrels Swift Observatory is shown in violet, and infrared light from NASA’s retired WISE (Wide-field Infrared Survey Explorer) mission appears in cyan, red, and orange. Both remnants are located about 6,000 light-years away in the constellation Gemini. The brilliant star at far right is Propus, also known as Eta Geminorum.
NASA Goddard Space Flight Center and M. Michailidis et al. 2026; optical: DSS; infrared: NASA/WISE/JPL-Caltech/UCLA; ultraviolet: NASA/Swift
“Using 16 years of data from NASA’s Fermi Gamma-ray Space Telescope, our analysis uncovered gamma rays associated with a supernova remnant that was hidden in the glare of its neighbor, the Jellyfish Nebula, one of the brightest gamma-ray-emitting supernova remnants known,” said Miltiadis Michailidis, a postdoctoral fellow in the physics department at Stanford University in California. “There are so many striking connections between the two remnants that we conclude they’re likely related, giving us the first known example of a binary system where both stars have undergone supernova explosions.”
Michailidis presented the findings Wednesday at the 248th meeting of the American Astronomical Society in Pasadena, California. A paper describing the results will appear in a future edition of Nature Communications.
The study focused on a faint supernova remnant called G189.6+3.3, which is mainly visible in X-rays. It is upstaged by its brighter and better-known neighbor, the Jellyfish Nebula (IC 443). The two star wrecks, both located in the constellation Gemini, appear to partially overlap as seen in X-rays. Recent X-ray evidence suggests that hot plasma likely associated with G189.6+3.3 may extend across the entire region, a hint that the overlap may be nearly total.
A massive star explodes when its energy-producing core runs out of fuel and collapses under its own weight, triggering an explosion that blows the star apart. The explosion’s shock wave encloses a hot cloud of debris that rapidly expands into space. So far, astronomers have cataloged about 300 supernova remnants in our galaxy.
The Fermi mission is part of NASA’s fleet of observatories monitoring the changing cosmos to help humanity better understand how the universe works. More than a decade ago, observations from Fermi’s LAT (Large Area Telescope) showed that the shock waves of supernova remnants accelerated particles to within a fraction of the speed of light, a process first proposed by physicist Enrico Fermi — the mission’s namesake — in 1949.
These high-speed particles, called cosmic rays, interact with interstellar gas to produce gamma rays, the highest-energy form of light. Protons make up 99% of cosmic ray particles. To prove that accelerated protons are responsible for the glow, astronomers search for a specific gamma-ray feature. When cosmic-ray protons smash into interstellar gas, they produce a short-lived particle called a neutral pion, which almost immediately decays into a pair of gamma rays. This emission occurs within a specific band of energies associated with the neutral pion’s mass and lies within the range detected by Fermi’s LAT instrument.
In 2013, Fermi observations proved that the Jellyfish Nebula, which is interacting with part of a glowing cloud of hydrogen gas known as Sharpless 249, produced gamma rays through this mechanism. Its neighbor, G189.6+3.3, was discovered in 1994 as part of an X-ray survey by the German-led ROSAT (Roentgen Satellite) mission.
A bright filament of gas lies between the overlapping remnants. New observations of this feature reveal that the shock wave from G189.6+3.3 slammed into dense interstellar gas there and dramatically slowed, key evidence that both remnants are interacting with the same cloud system.
The well-known supernova remnant IC 443 (right) has an older, fainter neighbor (shown here in blue-green and magenta) called G189.6+3.3. A filament of gas between them, glowing in visible and ultraviolet light (violet arc at center), traces the neighbor’s shock wave and shows that both remnants are interacting with the same molecular cloud, shown in red, orange, brown for infrared and radio data and yellow for visible light. Blue-green shows X-rays from the fainter remnant, while magenta shows gamma rays with energies greater than 10 billion electron volts; for comparison, visible light has energies between about 2 and 3 electron volts. In this view, high-energy light from the much brighter IC 443 has been removed for clarity. Gamma-ray emission near the filament stems from protons accelerated in the supernova’s shock wave as it expands into the cloud.
NASA Goddard Space Flight Center and M. Michailidis et al. 2026; radio, MWISP and ESA/Planck; infrared: NASA/WISE/JPL-Caltech/UCLA; optical: DSS; ultraviolet: NASA/Swift; X-ray: SRG/eROSITA; gamma ray: NASA/DOE/Fermi LAT Collaboration
Astronomers think the Jellyfish Nebula is also a candidate PeVatron, a cosmic particle accelerator capable of boosting protons to energies so high they could nearly escape our galaxy. Such particles can produce gamma rays with trillions of times more energy than visible light. Finding a second particle accelerator near the Jellyfish Nebula could offer scientists new clues for how supernova remnants develop into PeVatrons.
“The overlapping remnants, a connecting gas filament, and the availability of data from Fermi and other facilities motivated us to delve into this complex but little-studied region,” said co-author Marianne Lemoine-Goumard, an astrophysicist at the French National Centre for Scientific Research (CNRS) based at the University of Bordeaux. “With Fermi’s LAT instrument, we found gamma-ray emission associated with accelerated protons in the northern part of the fainter remnant. If both remnants are interacting with the same structure, then they must share a common distance from us.”
The team concludes the remnants lie about 6,000 light-years away, their explosion centers are separated by roughly 40 light-years projected onto the plane of the sky, and the original stars may have been 20 or more times the Sun’s mass.
Estimates of the remnants’ ages vary widely, but the team concludes that the age of the Jellyfish Nebula is 8,000 to 9,000 years, while G189.6+3.3 is between 20,000 to 110,000 years old. This means the delay between the explosions could have extended for up to 100,000 years.
In addition, the team conducted computer simulations of a million massive binary systems. They show that systems where the stars orbit close enough to exchange matter and interact during their lives can readily produce dual supernova explosions with similar separations and time delays as those found for the remnants. The team also estimated that the chance of randomly encountering this combination of observed spatial alignment and compatible distances to be less than 1%, strongly supporting a physical association.
“The evidence we’ve compiled — including observations across the spectrum, the chemical and physical properties of the remnants, simulations, and more — paints a compelling picture of a dual supernova event,” said Michailidis.
This study identifies a unique possible example of a binary system where both stars exploded as supernovae and left behind separate, detectable supernova remnants. Astronomers think that most massive stars form in binary or multiple-star systems. The Jellyfish Nebula/G189.6+3.3 complex offers astronomers a rare opportunity to study how massive binary stars evolve, exchange matter, explode, and experience velocity changes — called kicks — induced by the supernova blast. It also provides a powerful new laboratory for understanding how coupled supernova remnants behave, including how they accelerate particles, generate gamma rays, and shape their surrounding environments.
“Fermi’s gamma-ray observations of supernova remnants continue to reveal the dynamic lives of stars,” said Elizabeth Hays, the Fermi project scientist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “We can now connect the glowing remains of two massive stars to a powerful pair that evolved together over thousands of years.”
NASA Webb, Hubble Reveal History of Relic of Milky Way’s Formation
New observations from Webb combined with multiple observations from Hubble prove that Terzan 5 is a self-contained, self-enriching stellar system that contains up to four distinct star populations. It orbits within our Milky Way galaxy’s central bulge.
Credits: Image: NASA, ESA, CSA, STScI, Giorgia Zullo (University of Bologna), Francesco Ferraro (University of Bologna); Image Processing: Alyssa Pagan (STScI)
Researchers using two of humanity’s most powerful observatories — NASA’s James Webb and Hubble Space Telescopes — have definitively shown that Terzan 5 is not a globular star cluster as it was once classified, offering new insight into how galaxies like our own form and evolve over time. A globular star cluster typically has only one ancient star population. New data not only confirms the existence of two distinct populations of stars in Terzan 5, but also provides evidence for two more recent rounds of star formation. Although located within the crowded bulge of our Milky Way, our galaxy’s central, spherical region of older stars, Terzan 5 was massive enough to maintain its separate identity while lighter weight systems spread out and mixed to form the bulge billions of years ago. It’s like a lump in an otherwise well-mixed cake batter.
“Webb’s new near-infrared observations, cross-referenced with Hubble’s archival observations, have given us a much clearer picture of the history of Terzan 5,” said Giorgia Zullo, who led the research and is a PhD student at the University of Bologna in Italy.
These results were presented at a press conference Tuesday at the 248th meeting of the American Astronomical Society in Pasadena, and were published in Astronomy & Astrophysics.
Image: Bulge Fossil Fragment Terzan 5 (Webb and Hubble Image)
New observations from Webb combined with multiple observations from Hubble prove that Terzan 5 is a self-contained, self-enriching stellar system that contains up to four distinct star populations. It orbits within our Milky Way galaxy’s central bulge.
Image: NASA, ESA, CSA, STScI, Giorgia Zullo (University of Bologna), Francesco Ferraro (University of Bologna); Image Processing: Alyssa Pagan (STScI)
Four generations of stars
Discovered in 1968 by astronomer Azop Terzan, Terzan 5 resembles a globular cluster in many ways. However, in 2009 this system was discovered to harbor two distinct populations of stars. In 2016 Hubble provided the first estimate of their ages, showing that one formed roughly 12 billion years ago — as the Milky Way itself was assembling — and the other about 5 billion years ago, just before Earth started forming. This pointed to a more complex history than a typical globular cluster.
Studying Terzan 5 is complicated by its location in a region of our galaxy crowded with stars and heavily obscured by dust. This is where Webb stepped in. Its infrared view allowed the research team to peer through the dust and catalog many more stars, and fainter stars, than previous work. By measuring star colors and brightnesses, astronomers can classify them into populations of different ages and chemistries.
Webb was able to measure these key properties for every star within the field of view in the sky — both stars within Terzan 5 and unrelated foreground stars. To isolate the stars of Terzan 5, the team relied on the power and longevity of Hubble. The 12-year separation allowed the team to measure very small movements of individual stars, known as proper motions, to determine which stars belong to Terzan 5 and which are part of the Milky Way bulge.
By combining data from both Webb and Hubble, the researchers found strong evidence for two more stellar populations, one that formed 3.8 billion years ago and another only 2.5 billion years ago. They also were able to determine the ages of the previously known stellar populations with unprecedented precision, finding that they formed 12.5 billion and 4.7 billion years ago.
With the previously known two generations of stars, astronomers could not rule out the possibility that Terzan 5 interacted with another object, like a globular cluster or a giant molecular cloud, becoming enriched with new gas and dust that set off a second round of star formation. With four stellar generations, those explanations are ruled out.
Measurements of the stellar composition of Terzan 5 populations made at the W. M. Keck Observatory and European Southern Observatory’s Very Large Telescope also point toward very distinct populations. “Along with the ages of these populations, the cluster preserves a fossil record of progressive enrichment of heavy elements by supernovae,” said co-author R. Michael Rich, a research astronomer at the University of California, Los Angeles.
Terzan 5 formed multiple generations of stars because it was able to retain the necessary raw materials. There is evidence of powerful supernova explosions in Terzan 5 that forged heavier elements that were swept up by subsequent generations of stars. In lighter weight systems, the force of the explosions themselves could have ejected the resulting elements as well as sweeping out leftover gas and dust. The progenitor of Terzan 5 had enough mass to retain those stars’ ejections, allowing new generations of stars to form over billions of years.
‘Bulge fossil fragment’
The results show that Terzan 5 is most likely the remnant of a much more massive stellar system that initially formed 12.5 billion years ago. Terzan 5 is extraordinary because it survived — and never merged or fully “mixed in” with the Milky Way’s bulge. “For some reason, this peculiar clump of stars formed separately from the bulge and was not destroyed as the bulge itself formed,” said Francesco R. Ferraro, a professor at the University of Bologna and principal investigator of the Webb observations. “Terzan 5 is what we now call a bulge fossil fragment because it resembles the primordial clumps that contributed to the formation of the bulge.”
To date, there’s one other known cosmic object like Terzan 5. Liller 1 was the second to be reclassified from a globular star cluster to a bulge fossil fragment. It also contains multiple generations of stars. There may be more objects like it. Between 40 to 50 additional globular clusters that orbit within the bulge will be examined by Ferraro’s team to determine if their stellar populations are all the same, like globular clusters, or have several generations, like bulge fossil fragments.
Video: Zoom to See Terzan 5 Near Our Milky Way Galaxy’s Bulge
Zoom in to Terzan 5, a star cluster that lies within the crowded central region of our Milky Way galaxy known as the bulge. The scene starts with a ground-based image of our Milky Way bulge and zooms in on and circles Terzan 5, ending with the composite image of the star system from the James Webb and Hubble Space Telescopes.
Potential parallels for galaxy formation near, far
Ultimately, this research may improve what we know about how the central bulges of galaxies form over hundreds of millions of years. “Based on observations and in-depth simulations, we think that galaxies in the early universe had huge disks of gas that fragmented into clumps and formed stars. These clumps migrated to the center of the galaxies, and many merged to form their bulges,” said Barbara Lanzoni, a co-author and associate professor at the University of Bologna. For example, Webb has turned up several examples of “clumpy” galaxies that were actively forming when the universe was only a few hundred million years old, like the clumps in the Firefly Sparkle galaxy. “Terzan 5 may provide direct evidence that can help explain how bulges formed in galaxies throughout the universe,” Lanzoni 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).
The Hubble Space Telescope has been operating for over three decades and continues to make ground-breaking discoveries that shape our fundamental understanding of the universe. Hubble is a project of international cooperation between NASA and ESA (European Space Agency). NASA’s Goddard Space Flight Center in Greenbelt, Maryland, manages the telescope and mission operations. Lockheed Martin Space, based in Denver, also supports mission operations at Goddard. The Space Telescope Science Institute in Baltimore, which is operated by the Association of Universities for Research in Astronomy, conducts Hubble science operations for NASA.
The following sections contain links to download this article’s images and videos in all available resolutions followed by related information links, media contacts, and if available, research paper and Spanish translation links.
Related Images & Videos
Bulge Fossil Fragment Terzan 5 (Webb and Hubble Image)
New observations from Webb combined with multiple observations from Hubble prove that Terzan 5 is a self-contained, self-enriching stellar system that contains up to four distinct star populations. It orbits within our Milky Way galaxy’s central bulge.
Terzan 5 (Webb and Hubble Compass Image)
This image of bulge fossil fragment Terzan 5 was captured by the James Webb and Hubble space telescopes. Webb’s data are from its NIRCam (Near-Infrared Camera) and Hubble’s from its Advanced Camera for Surveys (ACS). The image shows a scale bar, compass arrows, and co…
Zoom to See Terzan 5 Near Our Milky Way Galaxy’s Bulge
Zoom in to Terzan 5, a star cluster that lies within the crowded central region of our Milky Way galaxy known as the bulge. The scene starts with a ground-based image of our Milky Way bulge and zooms in on and circles Terzan 5, ending with the composite image of the star system f…
NASA Webb, Hubble Reveal History of Relic of Milky Way’s Formation
New observations from Webb combined with multiple observations from Hubble prove that Terzan 5 is a self-contained, self-enriching stellar system that contains up to four distinct star populations. It orbits within our Milky Way galaxy’s central bulge.
Credits: Image: NASA, ESA, CSA, STScI, Giorgia Zullo (University of Bologna), Francesco Ferraro (University of Bologna); Image Processing: Alyssa Pagan (STScI)
Researchers using two of humanity’s most powerful observatories — NASA’s James Webb and Hubble Space Telescopes — have definitively shown that Terzan 5 is not a globular star cluster as it was once classified, offering new insight into how galaxies like our own form and evolve over time. A globular star cluster typically has only one ancient star population. New data not only confirms the existence of two distinct populations of stars in Terzan 5, but also provides evidence for two more recent rounds of star formation. Although located within the crowded bulge of our Milky Way, our galaxy’s central, spherical region of older stars, Terzan 5 was massive enough to maintain its separate identity while lighter weight systems spread out and mixed to form the bulge billions of years ago. It’s like a lump in an otherwise well-mixed cake batter.
“Webb’s new near-infrared observations, cross-referenced with Hubble’s archival observations, have given us a much clearer picture of the history of Terzan 5,” said Giorgia Zullo, who led the research and is a PhD student at the University of Bologna in Italy.
These results were presented at a press conference Tuesday at the 248th meeting of the American Astronomical Society in Pasadena, and were published in Astronomy & Astrophysics.
Image: Bulge Fossil Fragment Terzan 5 (Webb and Hubble Image)
New observations from Webb combined with multiple observations from Hubble prove that Terzan 5 is a self-contained, self-enriching stellar system that contains up to four distinct star populations. It orbits within our Milky Way galaxy’s central bulge.
Image: NASA, ESA, CSA, STScI, Giorgia Zullo (University of Bologna), Francesco Ferraro (University of Bologna); Image Processing: Alyssa Pagan (STScI)
Four generations of stars
Discovered in 1968 by astronomer Azop Terzan, Terzan 5 resembles a globular cluster in many ways. However, in 2009 this system was discovered to harbor two distinct populations of stars. In 2016 Hubble provided the first estimate of their ages, showing that one formed roughly 12 billion years ago — as the Milky Way itself was assembling — and the other about 5 billion years ago, just before Earth started forming. This pointed to a more complex history than a typical globular cluster.
Studying Terzan 5 is complicated by its location in a region of our galaxy crowded with stars and heavily obscured by dust. This is where Webb stepped in. Its infrared view allowed the research team to peer through the dust and catalog many more stars, and fainter stars, than previous work. By measuring star colors and brightnesses, astronomers can classify them into populations of different ages and chemistries.
Webb was able to measure these key properties for every star within the field of view in the sky — both stars within Terzan 5 and unrelated foreground stars. To isolate the stars of Terzan 5, the team relied on the power and longevity of Hubble. The 12-year separation allowed the team to measure very small movements of individual stars, known as proper motions, to determine which stars belong to Terzan 5 and which are part of the Milky Way bulge.
By combining data from both Webb and Hubble, the researchers found strong evidence for two more stellar populations, one that formed 3.8 billion years ago and another only 2.5 billion years ago. They also were able to determine the ages of the previously known stellar populations with unprecedented precision, finding that they formed 12.5 billion and 4.7 billion years ago.
With the previously known two generations of stars, astronomers could not rule out the possibility that Terzan 5 interacted with another object, like a globular cluster or a giant molecular cloud, becoming enriched with new gas and dust that set off a second round of star formation. With four stellar generations, those explanations are ruled out.
Measurements of the stellar composition of Terzan 5 populations made at the W. M. Keck Observatory and European Southern Observatory’s Very Large Telescope also point toward very distinct populations. “Along with the ages of these populations, the cluster preserves a fossil record of progressive enrichment of heavy elements by supernovae,” said co-author R. Michael Rich, a research astronomer at the University of California, Los Angeles.
Terzan 5 formed multiple generations of stars because it was able to retain the necessary raw materials. There is evidence of powerful supernova explosions in Terzan 5 that forged heavier elements that were swept up by subsequent generations of stars. In lighter weight systems, the force of the explosions themselves could have ejected the resulting elements as well as sweeping out leftover gas and dust. The progenitor of Terzan 5 had enough mass to retain those stars’ ejections, allowing new generations of stars to form over billions of years.
‘Bulge fossil fragment’
The results show that Terzan 5 is most likely the remnant of a much more massive stellar system that initially formed 12.5 billion years ago. Terzan 5 is extraordinary because it survived — and never merged or fully “mixed in” with the Milky Way’s bulge. “For some reason, this peculiar clump of stars formed separately from the bulge and was not destroyed as the bulge itself formed,” said Francesco R. Ferraro, a professor at the University of Bologna and principal investigator of the Webb observations. “Terzan 5 is what we now call a bulge fossil fragment because it resembles the primordial clumps that contributed to the formation of the bulge.”
To date, there’s one other known cosmic object like Terzan 5. Liller 1 was the second to be reclassified from a globular star cluster to a bulge fossil fragment. It also contains multiple generations of stars. There may be more objects like it. Between 40 to 50 additional globular clusters that orbit within the bulge will be examined by Ferraro’s team to determine if their stellar populations are all the same, like globular clusters, or have several generations, like bulge fossil fragments.
Video: Zoom to See Terzan 5 Near Our Milky Way Galaxy’s Bulge
Zoom in to Terzan 5, a star cluster that lies within the crowded central region of our Milky Way galaxy known as the bulge. The scene starts with a ground-based image of our Milky Way bulge and zooms in on and circles Terzan 5, ending with the composite image of the star system from the James Webb and Hubble Space Telescopes.
Potential parallels for galaxy formation near, far
Ultimately, this research may improve what we know about how the central bulges of galaxies form over hundreds of millions of years. “Based on observations and in-depth simulations, we think that galaxies in the early universe had huge disks of gas that fragmented into clumps and formed stars. These clumps migrated to the center of the galaxies, and many merged to form their bulges,” said Barbara Lanzoni, a co-author and associate professor at the University of Bologna. For example, Webb has turned up several examples of “clumpy” galaxies that were actively forming when the universe was only a few hundred million years old, like the clumps in the Firefly Sparkle galaxy. “Terzan 5 may provide direct evidence that can help explain how bulges formed in galaxies throughout the universe,” Lanzoni 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).
The Hubble Space Telescope has been operating for over three decades and continues to make ground-breaking discoveries that shape our fundamental understanding of the universe. Hubble is a project of international cooperation between NASA and ESA (European Space Agency). NASA’s Goddard Space Flight Center in Greenbelt, Maryland, manages the telescope and mission operations. Lockheed Martin Space, based in Denver, also supports mission operations at Goddard. The Space Telescope Science Institute in Baltimore, which is operated by the Association of Universities for Research in Astronomy, conducts Hubble science operations for NASA.
The following sections contain links to download this article’s images and videos in all available resolutions followed by related information links, media contacts, and if available, research paper and Spanish translation links.
Related Images & Videos
Bulge Fossil Fragment Terzan 5 (Webb and Hubble Image)
New observations from Webb combined with multiple observations from Hubble prove that Terzan 5 is a self-contained, self-enriching stellar system that contains up to four distinct star populations. It orbits within our Milky Way galaxy’s central bulge.
Terzan 5 (Webb and Hubble Compass Image)
This image of bulge fossil fragment Terzan 5 was captured by the James Webb and Hubble space telescopes. Webb’s data are from its NIRCam (Near-Infrared Camera) and Hubble’s from its Advanced Camera for Surveys (ACS). The image shows a scale bar, compass arrows, and co…
Zoom to See Terzan 5 Near Our Milky Way Galaxy’s Bulge
Zoom in to Terzan 5, a star cluster that lies within the crowded central region of our Milky Way galaxy known as the bulge. The scene starts with a ground-based image of our Milky Way bulge and zooms in on and circles Terzan 5, ending with the composite image of the star system f…
For the first time, astronomers have distinguished between the morning and evening atmospheres of a single planet, revealing two remarkably different environments at its edges. WASP-121 b is a gas giant that orbits extremely close to its star, resulting in one hemisphere exposed to temperatures approaching 2,500 degrees Celsius while the opposite side remains in constant darkness.
WASP-121 b is part of a group of gas giants known as hot Jupiters. These massive planets orbit their stars in just a few days and eventually become locked in place by gravity. Tidal forces keep one side facing the star at all times, while the other side never sees daylight.
“WASP-121 b is particularly extreme,” said co-author Tom Evans-Soma of the University of Newcastle, Australia. “Average temperatures on the dayside hemisphere are around 2,770 Kelvin, while those on the nightside are closer to about 1,000 Kelvin.”
The difference in temperature between the two hemispheres, which is about 1,775 degrees Celsius, makes WASP-121 b one of the most thermally extreme exoplanets known. The regions at the boundary between day and night, called terminators, are where the planet experiences constant morning or evening conditions. Scientists expected these areas to have different atmospheric properties, but only with the precision of JWST could these differences be directly observed.
Mapping the Atmosphere
The researchers used a method based on the planet’s transit across its star to study these differences. As WASP-121 b passes in front of its star, it rotates by about 30 degrees, which means that different parts of its atmosphere can be observed during each transit. By tracking how infrared starlight filters through the atmosphere over time, the team reconstructed how temperature and chemical composition change across different longitudes.
“By measuring how starlight absorption changes as WASP-121 b rotates, we probe its atmosphere longitude by longitude,” said lead author Cyril Gapp of MPIA. The observations not only confirmed what models had predicted, but also showed that the differences between the two terminators are even greater than expected.
Two Different Skies
The evening side of the planet’s terminator absorbs more starlight than the morning side. Powerful eastward winds sweep heat from the scorching dayside toward the nightside, with the evening region getting the first blast of this warmth. This extra heat causes the atmosphere there to puff up, allowing it to absorb even more starlight, as the observations showed.
Chemical measurements backed up these findings. Carbon monoxide absorption increased as the hotter regions of the evening came into view near the end of the transit. Water showed a different pattern. Rather than simply decreasing with higher temperatures, the researchers interpret the result as evidence that water molecules in the upper atmosphere are breaking apart, likely due to the intense heat at the evening terminator. This points to a real chemical change, not just a shift in molecular location.
The Cloud Problem
The morning side shows a different environment. Although models predicted a difference between the two terminators, they did not fully explain why the morning side appears cooler and more opaque. The most likely explanation involves clouds that are unlike those on Earth.
At the morning terminator, air comes in from the cold nightside. Temperatures may be low enough for silicate and mineral compounds to turn into tiny particles, forming clouds that block infrared radiation from below. This makes the atmosphere appear cooler than it really is underneath.
When the team adjusted their models to account for these clouds, the results more closely aligned with their observations. Still, confirming exactly how these clouds form and behave will require more advanced modeling, as cloud formation and evaporation in such extreme environments remain a major puzzle in exoplanet science.
A Method Ready to Scale
WASP-121 b has been the subject of previous studies, but JWST now enables astronomers to examine its atmosphere in detail, section by section. This approach is now also available for use with other exoplanets.
The team has already found other ultra-hot gas giants with the right temperatures and orbits for similar analysis. Using this method on other planets will help astronomers compare atmospheric conditions and deepen our understanding of extreme planetary environments.
Austin Burgess is a writer and researcher with a background in sales, marketing, and data analytics. He holds an MBA, a Bachelor of Science in Business Administration, and a data analytics certification. His work focuses on breaking scientific developments, with an emphasis on emerging biology, cognitive neuroscience, and archaeological discoveries.
James Webb has revealed that the sunrise and sunset sides of WASP-121 b have surprisingly different atmospheres. Astronomers using the James Webb Space Telescope (JWST) have discovered striking differences between the morning and evening sides of the atmosphere of WASP-121 b, an ultra-hot gas giant located far beyond our solar system. The findings provide the [...]
NASA’s Chandra Finds Unexpected Fireworks in Aftermath of Stellar Explosions
A composite image of the nearby galaxy Messier 83, and short timelapse videos of two curious supernova remnants hidden inside.
X-ray: NASA/CXC/SAO; Optical: NASA/ESA/AURA/STScI, Hubble Heritage Team, W. Blair (STScI/Johns Hopkins University) and R. O’Connell (University of Virginia); Image Processing: NASA/CXC/SAO/A. Jubett, L. Frattare and P. Edmonds
The aftermath of a supernova, a stellar explosion, is usually a slowly fading cloud of hot gas. So when astronomers pointed NASA’s Chandra X-ray Observatory at the nearby galaxy Messier 83 (M83), they did not expect to find a population of supernova remnants, or the debris from these explosions, showing dramatic changes in their brightness. The new results were presented at the American Astronomical Society meeting in Pasadena, California, and published in The Astrophysical Journal.
The galaxy M83, located about 15 million light-years from Earth, is forming stars at a high rate. Researchers analyzed 14 years of Chandra data of the galaxy, spanning 2000 to 2014.
Using this extensive set of data, the researchers caught surprising variations in the X-ray brightness of sources previously identified as supernova remnants. The researchers expected supernova remnants older than a century or so to fade gradually in X-rays, but not change dramatically in brightness.
The team found that roughly half of the 22 X-ray sources associated with supernova remnants in their sample showed changes in X-ray brightness over the 14-year span of observations — a result that was completely unexpected.
“We knew that individual X-ray sources could vary dramatically,” said Andrea Prestwich, of the Catholic University of America who led the study. “But finding that so many supernova remnants were behaving this way was a real surprise. Something unusual is going on in these objects. Pinpointing the cause remains a challenge, as M83’s distance limits the detail we can observe.”
One of the 22 variable supernova remnants has a straightforward explanation: SN 1957D, the debris from a supernova first observed nearly 70 years ago, is ramming into material surrounding the explosion site, producing the observed X-ray flares. But this cannot explain the rest of the sample. There is no evidence to suggest that all 22 remnants were formed within the last century. Something else must be driving the variability.
The most likely explanation is that the team has uncovered a population of stellar survivors stars that lived through their partner’s destruction in a supernova explosion. In this scenario, each variable X-ray source began as a pair of massive stars orbiting each other. The more massive star collapsed and exploded as a supernova, leaving behind a black hole or ultra-dense neutron star. Its companion survived.
Galaxy M83 in X-ray and Optical Light.
X-ray: NASA/CXC/SAO; Optical: NASA/ESA/AURA/STScI, Hubble Heritage Team, W. Blair (STScI/Johns Hopkins University) and R. O’Connell (University of Virginia); Image Processing: NASA/CXC/SAO/A. Jubett, L. Frattare and P. Edmonds
“It may be that this galaxy contains a collection of supernova remnants where one massive star survives the supernova and becomes locked into an orbit with a black hole or neutron star,” said co-author Michael McCollough of the Center for Astrophysics | Harvard & Smithsonian (CfA). “The neutron star or black hole can then start pulling material from the massive star’s surface.”
That infalling material is superheated by the intense gravitational pull, producing the X-rays Chandra detects. These types of systems, known as high-mass X-ray binaries (HMXBs), are among the most variable X-ray sources in the universe. Researchers say they may be the cause of the variations seen in M83’s supernova remnants.
Astronomers have known about HMXBs for decades, but the difference with this group in M83 is their connection to supernova remnants. Previously, only a handful of supernova remnants associated with HMXBs had been identified across observations of all galaxies. It is unprecedented to find more than 20 strong candidates in just one galaxy.
The authors found that the variable supernova remnants are in regions with higher concentrations of massive stars than in other parts of the galaxy, increasing the chances of a link between the remnants and HMXBs.
There is another possible explanation: Instead of pulling in material from a companion star, the black hole or neutron star may be recapturing some of the material blasted outward by the original explosion.
“This could be an example of cosmic recycling, where debris from the explosion falls back onto the very object the supernova created,” said co-author Roy Kilgard of Wesleyan University. “And it’s quite possible that both explanations are at play — different sources in our sample may have different origins.”
These results are not unique to M83. A follow-up study of the nearby star-forming galaxy M51 by Zoe Hoiland of Vassar College and Kilgard has uncovered a similar population of variable X-ray sources associated with supernova remnants, suggesting that such systems may be a feature of galaxies undergoing vigorous star formation.
This is a composite image of the galaxy M51 combining data from NASA’s Chandra X-ray Observatory (purple) with optical data (red, green and blue) taken with ground-based telescopes by a team of astrophotographers. A surprisingly high number of X-ray sources associated with supernova remnants in M51 show large changes in brightness, similar to the behavior seen in M83.
Chandra X-ray Data: NASA/CXC/SAO; Astrobin/Optical Groundbased: C.Björk, T.Bähnck, S.Donoso, J.Gentillon, A. and D.Grelin, S.Guberski, R. Hall, T.Heuberger, J.Jacks, P.Kent, Br.Meyers, W.Ostling, N.Puig, T.Schaeffer, F.Schöfbänker, M.Vasilev
The Chandra data for M83 began with single observations in 2000 and 2001, followed by 10 observations from 2010 to 2011 and another observation in 2014.
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 composite image of the nearby galaxy Messier 83, and short timelapse videos of two curious supernova remnants hidden inside.
In the composite image, Messier 83, or M83, is shown to have a spiral structure, viewed straight on. At the center is a brilliant white and yellow pool of light. From that light, spiral arms of hot pink cloud corkscrew out in wide, sweeping arches. The galaxy is covered in a faint grey haze, and flecked with red, green, blue, white, and yellow dots.
In an annotated version of the composite image, two tiny dots to our lower right of center are highlighted by white circles. These are two of the supernova remnants being considered by researchers. Each is examined further in a separate timelapse video.
Over a 14-year period from 2000 to 2014, astronomers pointed NASA’s X-ray observatory at the M83 galaxy. They discovered that about half of the X-ray sources believed to be supernova remnants, the aftermath of stellar explosions, were exhibiting dramatic changes in brightness. This result was entirely unexpected.
Those changes in brightness are highlighted in the timelapse videos. In each video, a series of static images flashes by, focused on one of the two X-ray sources once believed to be supernova remnants. In the videos, the X-ray sources appear as bright blue blobs with glowing cores. But in each image, taken months or years apart, the shapes change, as does the intensity of the blue color, and the brightness of the core. By presenting the substantively different images of the same objects one after another in quick succession, short timelapse videos are created.
The most likely explanation for the changes in brightness is that the team has uncovered a population of stellar survivors, stars that lived through an orbiting partner’s destruction in a supernova explosion. Material is being pulled from the surviving star onto the black hole or neutron star that formed in the supernova, a process known to cause rapid changes in X-ray brightness.