The Red Spider Nebula, caught by Webb

NGC 6537/Red Spider Nebula
Credit: ESA/Webb, NASA & CSA, J. H. Kastner (Rochester Institute of Technology)

---

This new NASA/ESA/CSA James Webb Space Telescope Picture of the Month features a cosmic creepy-crawly called NGC 6537 — the Red Spider Nebula. Using its Near-InfraRed Camera (NIRCam), Webb has revealed never-before-seen details in this picturesque planetary nebula with a rich backdrop of thousands of stars.

Planetary nebulae like the Red Spider Nebula form when ordinary stars like the Sun reach the end of their lives. After ballooning into cool red giants, these stars shed their outer layers and cast them into space, exposing their white-hot cores. Ultraviolet light from the central star ionises the cast-off material, causing it to glow. The planetary nebula phase of a star’s life is as fleeting as it is beautiful, lasting only a few tens of thousands of years.

The central star of the Red Spider Nebula is visible in this image, glowing just brighter than the webs of dusty gas that surround it. The surprising nature of the nebula’s tremendously hot and luminous central star has been revealed by Webb’s NIRCam. In optical-wavelength images, such as from the NASA/ESA Hubble Space Telescope, the star appears faint and blue. But in the NIRCam images, it shows up as red: thanks to its sensitive near-infrared capabilities, Webb has revealed a shroud of hot dust surrounding the central star. This hot dust likely orbits the central star, in a disc structure.

Though only a single star is visible in the Red Spider’s heart, a hidden companion star may lurk there as well. A stellar companion could explain the nebula’s shape, including its characteristic narrow waist and wide outflows. This hourglass shape is seen in other planetary nebulae such as the Butterfly Nebula, which Webb also recently observed.

Webb’s new view of the Red Spider Nebula reveals for the first time the full extent of the nebula’s outstretched lobes, which form the ‘legs’ of the spider. These lobes, shown in blue, are traced by light emitted from H2 molecules, which contain two hydrogen atoms bonded together. Stretching over the entirety of NIRCam’s field of view, these lobes are shown to be closed, bubble-like structures that each extend about 3 light-years. Outflowing gas from the centre of the nebula has inflated these massive bubbles over thousands of years.

Gas is also actively jetting out from the nebula’s centre, as these new Webb observations show. An elongated purple ‘S’ shape centred on the heart of the nebula follows the light from ionised iron atoms. This feature marks where a fast-moving jet has emerged from near the nebula’s central star and collided with material that was previously cast away by the star, sculpting the rippling structure of the nebula seen today.

The observations used to create this image come from Webb GO programme #4571 (PI: J. Kastner) as part of a joint Chandra-JWST observing programme, which aims to understand how bipolar planetary nebulae like the Red Spider Nebula are shaped by the outflows and jets that emerge from the stars at their cores.

Source: ESA/Webb/potm

---

Links

• Science paper
• Annotated image
• Slider tool: Hubble and Webb's views of NGC 6537
• Image on ESA website
• Pan video
• Transition Video: Hubble and Webb's views of NGC 6537
• Space Sparks Episode

---

A new, expansive view of the Milky Way reveals our Galaxy in unprecedented radio colour

Milky Way
Credit: International Centre for Radio Astronomy Research (ICRAR)

Astronomers from the International Centre of Radio Astronomy Research (ICRAR) have created the largest low-frequency radio colour image of the Milky Way ever assembled.

This spectacular new image captures the Southern Hemisphere view of our Milky Way galaxy, revealing it across a wide range of radio wavelengths, or ‘colours’ of radio light.

It provides astronomers with new ways to explore the birth, evolution, and death of stars in our Galaxy.

Astronomers reveal an incredible new radio view of our galaxy.
Credit: ICRAR (Video here)

Silvia Mantovanini, a PhD student at the Curtin University node of ICRAR, dedicated 18 months and and approximately 1M CPU hours to construct the image by using the supercomputers at the Pawsey Supercomputing Research Centre to process and compile the data from two extensive surveys.

The MWA telescope consists of 4,096 spider-like antennas, located at Inyarrimanha Ilgari Bundara, the CSIRO Murchison Radio-astronomy Observatory, on Wajarri Country in Western Australia

The surveys were conducted using the Murchison Widefield Array (MWA) telescope located at Inyarrimanha Ilgari Bundara, the CSIRO Murchison Radio-Astronomy Observatory on Wajarri Yamaji Country in Western Australia.

These were the GaLactic and Extragalactic All-sky MWA (GLEAM) and GLEAM-X (GLEAM eXtended) surveys, respectively conducted over 28 nights in 2013 and 2014, and 113 nights from 2018 to 2020.

The new image, which focuses on our own Galaxy, offers twice the resolution, ten times the sensitivity, and covers twice the area compared to the previous GLEAM image released in 2019. 

Top: The GLEAM/GLEAM-X view of the Milky Way galaxy. Credit: S. Mantovanini & the GLEAM-X team
Bottom: The same area of the Milky Way in visible light. Credit: Axel Mellinger, milkywaysky.com.(Click to enlarge)

Silvia Mantovanini, with the galactic core in the background

The new image, which focuses on our own Galaxy, offers twice the resolution, ten times the This significant improvement in resolution, sensitivity and sky coverage allows for a more detailed and comprehensive study of the Milky Way, providing astronomers with a wealth of new data and insights.

“This vibrant image delivers an unparalleled perspective of our Galaxy at low radio frequencies,” Ms Mantovanini said.

“It provides valuable insights into the evolution of stars, including their formation in various regions of the Galaxy, how they interact with other celestial objects, and ultimately their demise.”

Ms Mantovanini’s research focuses on supernova remnants, the expanding clouds of gas and energy left behind when a star explodes at the end of its life. Although hundreds of these remnants have been discovered so far, astronomers suspect that thousands more are waiting to be found.

The image allows them to distinguish between the gas surrounding new stars and that left behind by dead ones, revealing clearer patterns in the cosmic landscape.

“You can clearly identify remnants of exploded stars, represented by large red circles. The smaller blue regions indicate stellar nurseries where new stars are actively forming,” Ms Mantovanini said.

The image may also help unravel the mysteries surrounding pulsars in our Galaxy. By measuring the brightness of pulsars at different GLEAM-X frequencies, astronomers hope to gain a deeper understanding of how these enigmatic objects emit radio waves and where they exist within our Galaxy.

Associate Professor Natasha Hurley-Walker from the same ICRAR team, who is the principal investigator of the GLEAM-X survey, emphasised how this is a big step forward in studying the Milky Way’s structure.

“This low-frequency image allows us to unveil large astrophysical structures in our Galaxy that are difficult to image at higher frequencies,”

Professor Hurley-Walker, pictured in front of the GLEAM-X survey.

“No low-frequency radio image of the entire Southern Galactic Plane has been published before, making this an exciting milestone in astronomy.”

“Only the world’s largest radio telescope, the SKA Observatory’s SKA-Low telescope, set to be completed in the next decade on Wajarri Yamaji Country in Western Australia, will have the capacity to surpass this image in terms of sensitivity and resolution,” concluded Associate Professor Hurley-Walker.

The surveys involved hundreds of hours of data collection using the MWA radio telescope located at Inyarrimanha Ilgari Bundara, the CSIRO Murchison Radio-astronomy Observatory. The ICRAR researchers catalogued an impressive 98,000 radio sources across the Galactic Plane visible from the southern hemisphere, showcasing a diverse mix of pulsars, planetary nebulae, compact HII regions – which are dense, ionised gas clouds in space – and distant galaxies unrelated to the Milky Way.

Source: Milky Way,International Center for Radio Astronomy Research (ICRAR)/News

---

Publication

The paper “GaLactic and Extragalactic All-sky Murchison Widefield Array survey eXtended (GLEAM-X) III: Galactic Plane” was published overnight in Publications of the Astronomical Society of Australia (PASA).

Multimedia:   Download or access via Google Drive

Media Support

Charlene D’Monte
ICRAR Media Contact | charlene.dmonte@icrar.org | +61 468 579 311 | +61 8 6488 7758

Interviews

Ms Silvia Mantovanini
silvia.mantovanini@postgrad.curtin.edu.au

Associate Professor Natasha Hurley-Walker
Natasha.Hurley-Walker@curtin.edu.au

---

Young Star Cooks Surroundings with Different Temperatures

An artist’s impression of a mass ejection event from EK Draconis. Hot, fast plasma is shown in blu,bre, and cooler, slower gas is shown in red.Credit: NAOJ. Download image (2.2MB)

---

Astronomers have used simultaneous ground-based and space-based observations to measure the temperature and velocity of gas ejected from a young Sun-like star. The result showed a two-component ejection consisting of a hot fast component followed by a slower cooler component. This result is important for understanding how young stars affect their surrounding environment where planets and life may first be forming, and by extension provides insights into the early days of the Solar System, Earth, and life on Earth.

The Sun frequently ejects huge masses of hot ionized gas called plasma, associated with solar flares. These events are known as Coronal Mass Ejections (CMEs). Young Sun-like stars have been observed to emit frequent stellar flares, and some of them are known to be associated with large CMEs, dwarfing any observed from the modern Sun. CMEs on the Sun contain components at different temperatures, ranging from 10,000 Kelvin to 1,000,000 Kelvin, but so far data for CMEs on other stars have been limited to a single temperature component, especially low temperature plasma.

To get a more complete understanding of young stars’ CME events, an international team of researchers led by Kosuke Namekata at Kyoto University arranged for ultraviolet observations by the Hubble Space Telescope, and optical observations by ground-based telescopes in Japan and Korea to simultaneously measure different temperature components of a stellar CME event. Their target was the young Sun-like Star EK Draconis, located 111 light-years away in the direction of the constellation Draco.

The team succeeded in observing different temperature components of a CME event. First, hot plasma of 100,000 Kelvin was ejected at 300 to 550 kilometers per second, followed about ten minutes later by a cooler gas of about 10,000 Kelvin ejected at 70 kilometers per second. This indicates that the hotter components of stellar CMEs possess higher kinetic energies than the cooler ones, and thus can affect exoplanetary atmospheres more severely than previously inferred from measurements limited to cool plasma alone.

Because the young Sun was presumably similar to EK Draconis, this provides insights in to the conditions in the early Solar System, which was likely disturbed by huge and fast CMEs. Theoretical and experimental studies suggest that fast CMEs play a role in initiating biomolecules and greenhouse gases, which are essential for the emergence and maintenance of life on an early planet. Therefore, this discovery has major implications for understanding planetary habitability and the conditions under which life emerged on Earth, and possibly elsewhere.

The team plans to continue their research with new observations using X-rays, radio waves, and next-generation UV space telescopes to better understand the conditions around young stars where planets, and possibly living things, form. In particular, this study highlights the importance of UV astronomy, which will be further explored by JAXA’s upcoming LAPYUTA mission.

Source: National Astronomical Observatory of Japan (NAOJ)/Science

---

Release Information

Researcher(s) Involved in this Release

• Kosuke Namekata (Kyoto University/NASA Goddard Space Flight Center)
• Kazunari Shibata (Kyoto University/Doshisha University)
• Hiroyuki Maehara (NAOJ)
• Satoshi Honda (Nishi-Harima Astronomical Observatory, University of Hyogo)
• Yuta Notsu (University of Colorado Boulder)
• Kevin France (University of Colorado Boulder)
• Jongchul Chae (Seoul National University)
• Vladimir S. Airapetian (NASA Goddard Space Flight Center)

Coordinated Release Organization(s)

• Kyoto University
• National Institutes of Natural Sciences, National Astronomical Observatory of Japan
• Nishi-Harima Astronomical Observatory, University of Hyogo
• NASA Goddard Space Flight Center
• University of Colorado Boulder
• Seoul National University

Paper(s)

• Kosuke Namekata et al. “Discovery of multi-temperature coronal mass ejection signatures from a young solar analogue”, in Nature Astronomy, DOI: 10.1038/s41550-025-02691-8
• Kosuke Namekata et al. “Do Young Suns Produce Frequent, Massive CMEs? Results from Five-Year Dedicated Optical Ob.servations of EK Draconis and V889 Hercules”, in The Astrophysi,brcal Journal, DOI: 10.3847/1538-4357/adfe70

---

Spiral Galaxy NGC 5301

NGC 5301
Detail: Low Res. (226 KB) / Mid. Res. (1.0 MB) / High Res. (9.1 MB)

NGC 5301 is a spiral galaxy located in the constellation Canes Venatici. This edge-on galaxy features prominent dust lanes that stretch across its entire galactic disk. The striking contrast between the reddish central region and the bluish spiral arms enhances its beauty. Compared to NGC 5211 , a face-on spiral galaxy, this image illustrates how the inclination of a galactic disk can significantly change a galaxy's appearance. Since we can only observe a single galaxy from one angle, observing and comparing multiple galaxies with different inclinations is essential for understanding galactic structure. (Credit: NAOJ; Image provided by Masayuki Tanaka)

Distance from Earth: 70 million light-years
Instrument: Hyper Suprime-Cam (HSC)

Source: Subaru Telescope

---

Spiralling star factory

NGC 4571

A spiral galaxy, seen face-on, fills the view. Swirling, patchy and broken spiral arms surround a softly glowing centre. The arms are filled with blue, speckled patches showing star clusters, shining pink and red dots where young stars are lighting up gas clouds, and a web of thin, dark red dust lanes. The glow of the galaxy’s arms extends out into the dark background. Individual tiny stars appear throughout. Credit: ESA/Hubble & NASA, F. Belfiore, J. Lee and the PHANGS-HST Team

A star-studded spiral galaxy shines in this NASA/ESA Hubble Space Telescope Picture of the Week. This galaxy is called NGC 4571, and it’s situated about 60 million light-years away in the constellation Coma Berenices. NGC 4571 dominates the scene with its feathery spiral structure and sparkling star clusters.

The galaxy’s dusty spiral arms are dotted with brilliant pink nebulae that contain massive young stars. Though the star-forming clouds that are seen here are heated to roughly 10 000 degrees by searing ultraviolet light from the young stars at their cores, stars get their start in much chillier environments. The sites of star birth are giant molecular clouds tens to hundreds of light-years across, in which the temperature hovers just a few tens of degrees above absolute zero.

The dramatic transformation from freezing gas cloud to fiery young star happens thanks to the immense pull of gravity, which collects gas into dense clumps within a star-forming cloud. As these clumps yield to gravity’s pull and collapse inward, they eventually become hot and dense enough to spark nuclear fusion in their centres and begin to shine. The glowing clouds in this image surround particularly massive stars that are hot enough to ionise the gas of their birthplaces.

A Hubble image of NGC 4571 was previously released in 2022, using data from an observing programme the combines data from leading observatories like Hubble, the NASA/ESA/CSA James Webb Space Telescope, and the Atacama Large Millimeter/submillimeter Array to study star formation in nearby spiral galaxies like NGC 4571. The new image released today adds data from a programme that seeks to understand how dust affects our observations of young stars deeply embedded within their natal clouds.

Source: ESA/Hubble/potw

---

Astronomers Share Largest Molecular Survey To-date: GOTHAM Legacy Data Goes Public

The NSF Green Bank Telescope.
Credit: NSF/AUI/NSF NRAO/J.Hellerman

---

After 1,400+ hours on the NSF Green Bank Telescope, scientists unveil the largest, most sensitive dataset of molecules from deep space’s TMC-1 cloud

A groundbreaking new dataset from the U.S. National Science Foundation Green Bank Telescope (NSF GBT) is now publicly available, opening the door for scientists worldwide to make discoveries in one of the richest molecular clouds in our galaxy, TMC-1. After 1,438 hours of observations and years of data processing pipeline development, astronomers in the “GBT Observations of TMC-1: Hunting Aromatic Molecules” research survey, known as GOTHAM, have released a spectral line survey with largest amount of telescope time ever conducted, charting more than 100 molecular species—including many with complex and aromatic structures—only found in deep space.

TMC-1 is a region within the Taurus Molecular Cloud known for its incredible diversity of interstellar molecules, the perfect “cosmic laboratory” for astrochemistry. Using the GOTHAM survey, researchers identified ten individual aromatic molecules and nearly a hundred other chemical species, helping decode how molecules form and evolve before stars are born. Unlike regions closer to newborn stars, TMC-1’s chemistry is dominated by large hydrocarbons and nitrogen-rich compounds, providing tantalizing clues about the building blocks of planets and organic matter in the universe.

Until now, most telescope data remained inaccessible or too cumbersome for outside researchers to analyze, limiting discoveries to the original teams that collected the data. By releasing a fully-reduced and calibrated dataset, the GOTHAM project invites the global scientific community to pursue new questions, develop advanced chemical models, and potentially uncover phenomena no one expected. For the first time, astronomers everywhere can explore the deepest secrets of TMC-1 without needing advanced computing or data-cleaning skills.

“Sharing GOTHAM’s research in this way allows us to democratize access to big data in astronomy,” shares Brett McGuire, Associate Professor, Department of Chemistry, Massachusetts Institute of Technology (MIT), and an Adjunct Assistant Astronomer with the NSF National Radio Astronomy Observatory (NSF NRAO.) Data sharing efforts have been a mission of collaborative teams producing large datasets using NSF NRAO instruments for nearly two decades.

“It’s a lot of hard work to prepare and package this data for access. We’re really excited to see what the scientific community does next with this, we want to spread word far and wide that it’s available,” adds Ci (Ceci) Xue, co-PI of GOTHAM and lead author of the paper that shares the process behind the automated pipeline her team developed for data reduction and calibration. Xue, formerly a post doc with MIT’s Department of Chemistry, is now a post doc fellow at the NSF-Simons AI Institute for Cosmic Origins, of which the NSF NRAO is a partner.

The GOTHAM dataset is the largest and most comprehensive survey of its kind, setting a new benchmark for astronomical legacy data. Astronomers at MIT, the NSF NRAO, University of British Columbia, and partners are excited for new opportunities for collaboration and cross-disciplinary breakthroughs. The dataset includes calibrated spectra, detailed molecular abundances, and the cutting-edge software used for analysis, all publicly accessible for scientific exploration and innovation.

The release of this GOTHAM dataset is the product of a diverse collaboration spanning multiple institutions and specialties, led by McGuire, and featuring support from the NSF NRAO, NASA Goddard, and the U.S. National Science Foundation. As new molecule discoveries continue to be made in TMC-1, astronomers anticipate more groundbreaking advances in our understanding of how cosmic chemistry shapes our universe.

Source: National Radio Astronomy Observatory (NRAO)/News

---

About NRAO

The National Radio Astronomy Observatory and Green Bank Observatory are major facilities of the U.S. National Science Foundation, operated under cooperative agreement by Associated Universities, Inc.

---

Aging White Dwarf Still Consuming Its Planetary System

Polluted White Dwarf Illustration

This artist’s illustration shows a 3-billion-year-old white dwarf star accreting material from the remnants of its former planetary system. Gravitational instabilities caused a surviving planet to spiral inward and disintegrate under intense tidal forces, forming a debris disk. Spectroscopic analysis of the white dwarf’s atmosphere revealed the presence of this planetary debris. Credits/Artwork: NASA, ESA, Joseph Olmsted (STScI)

---

Astronomers have identified a rare, ancient planetary system still being actively consumed by its central white dwarf star, LSPM J0207+3331, which is located 145 light-years from Earth. This system hosts the oldest and most metal-rich debris disk ever observed around a hydrogen-rich white dwarf, raising new questions about the long-term stability of planetary systems billions of years after stellar death.

“This discovery challenges our understanding of planetary system evolution,” said lead author Érika Le Bourdais of the Trottier Institute for Research on Exoplanets at Université de Montréal. “Ongoing accretion at this stage suggests white dwarfs may also retain planetary remnants still undergoing dynamical changes.”

Spectroscopic data from the W. M. Keck Observatory on Maunakea in Hawaiʻi revealed the white dwarf’s atmosphere is polluted with 13 chemical elements, an evidence of a rocky body at least 120 miles (200 kilometers) wide that was torn apart by the star’s gravity. “The amount of rocky material is unusually high for a white dwarf of this age,” noted co-author Patrick Dufour, also of Université de Montréal.

Hydrogen-rich atmospheres around white dwarfs typically mask such elemental signatures, making this detection especially significant. “Something clearly disturbed this system long after the star’s death,” said co-investigator John Debes of the Space Telescope Science Institute in Baltimore, Maryland. “There’s still a reservoir of material capable of polluting the white dwarf, even after billions of years.”

Delayed planetary instability

Nearly half of all polluted white dwarfs show signs of accreting heavy elements, indicating their planetary systems have been dynamically disturbed. In the case of LSPM J0207+3331, a recent perturbation— within the last few million years—probably sent a rocky planet spiraling inward. “This suggests tidal disruption and accretion mechanisms remain active long after the main-sequence phase of a star’s life,” said Debes. “Mass loss during stellar evolution can destabilize orbits, affecting planets, comets, and asteroids.”

The system may exemplify delayed instability, where multi-planet interactions gradually destabilize orbits over billions of years. “This could point to long-term dynamical processes we don’t yet fully understand,” Debes added.

Searching for Outer Planets

Astronomers are now investigating what may have triggered the disruption. Surviving Jupiter-sized planets could be responsible but are difficult to detect due to their separation from the white dwarf and low temperatures. Data from ESA’s Gaia space telescope may be sensitive enough to detect such planets through their gravitational influence on the white dwarf.

NASA’s James Webb Space Telescope could also provide insights by taking infrared observations of the system for signs of outer planets. “Future observations may help distinguish between a planetary shakeup or the gravitational effect of a stellar close encounter with the white dwarf,” said Debes.

These results published today in The Astrophysical Journal Letters.

The Space Telescope Science Institute is expanding the frontiers of space astronomy by hosting the science operations center of the Hubble Space Telescope, the science and mission operations centers for the James Webb Space Telescope, and the science operations center for the Nancy Grace Roman Space Telescope. STScI also houses the Barbara A. Mikulski Archive for Space Telescopes (MAST) which is a NASA-funded project to support and provide to the astronomical community a variety of astronomical data archives, and is the data repository for the Hubble, Webb, Roman, Kepler, K2, TESS missions and more. STScI is operated by the Association of Universities for Research in Astronomy in Washington, D.C.

Source: Space Telescope Science Institute (STScI)/Press Releases

---

About This Release

Credits

Media Contact:

Ray Villard
Space Telescope Science Institute, Baltimore

Permissions: Content Use Policy

Related Links and Documents

• The science paper by E. Le Bourdais et al.

---

Hubble sees white dwarf eating piece of Pluto-like objec

Illustration of a cataclysmic variable system, in which a star donates mass to a closely orbiting white-dwarf.
Credit: M.Weiss/Center for Astrophysics | Harvard & Smithsonian

Astronomers have discovered the most compact cataclysmic variable system containing a strongly magnetized white dwarf. The extreme closeness of the system suggests that the companion may be a metal-poor star — the first time such a star has been paired with a strongly magnetized white dwarf.

Meet the Cataclysmic Variable

Cataclysmic variables are binary star systems that contain a white dwarf and a companion star in uncomfortably close quarters. In these systems, the companion star transfers gas to the white dwarf, resulting in sudden, irregular, and often repeated outbursts as the stolen gas ignites on the scorching surface of the white dwarf.

These bound-together stars typically orbit one another on orbits ranging from about 80 minutes to 10 hours. Though theorists place the minimum orbital period around 76 minutes, a handful of cataclysmic variable systems have cropped up with periods below this limit. The systems that have limboed under the limit are thought to have stellar companions that are more compact than typical main-sequence stars, allowing the white dwarf to nestle in closer.

Phase-folded light curves for Gaia19bxc from the Caltech HIgh-speed Multi-colour camERA (CHIMERA) on the Hale Telescope. The double-peaked light curve is evidence for cyclotron beaming, which occurs in strongly magnetized white dwarfs. Adapted from Galiullin et al. 2025

Exploring Below the Limit

Discovered in 2019 by the Gaia spacecraft, Gaia19bxc is a cataclysmic variable that fluctuates with a period of 64.42 minutes. If this variability is linked to the orbital period of the system, that would place it well below the theoretical minimum period. Adding to the intrigue, early observations also hinted that Gaia19bxc’s white dwarf is strongly magnetic, making the system what’s called a polar. In polar systems, the white dwarf’s magnetic field diverts the accreted matter toward the white dwarf’s poles as it is collected, rather than into a disk around the white dwarf’s equator.

Now, Ilkham Galiullin (Kazan Federal University) and collaborators have analyzed photometry and spectra of Gaia19bxc from the Zwicky Transient Facility, the Hale Telescope, and the Keck I telescope to investigate the nature of this unusual system.

The team’s analysis confirmed that the stars of Gaia19bxc orbit one another every 64.42 minutes, cementing the system’s place below the period minimum for typical cataclysmic variables. The system’s double-peaked light curves and evidence for an accretion stream — rather than an accretion disk — confirm the system’s polar nature, implying a magnetic field strength greater than 10 million Gauss. This makes Gaia19bxc the most closely orbiting system to contain a strongly magnetized white dwarf.

Gaia19bxc’s orbital period compared to known polar cataclysmic variables (gray) as well as the theorized minimum periods for systems containing a metal-poor (Pop II) companion (cyan) and an evolved companion (blue). Credit: Galiullin et al. 2025

A Sign of Discoveries to Come

These observations illuminate the nature of the white dwarf — but what about the companion star?

Galiullin and coauthors saw no evidence for metal lines in Gaia19bxc’s spectrum, nor did they see spectral features arising from a hot companion star. These findings suggest that the companion is an old, cool, compact, metal-poor star, which would make Gaia19bxc the first known polar to contain a metal-poor star. It’s also one of only a handful of cataclysmic variables to contain a metal-poor star and be below the theoretical period minimum.

Though Gaia19bxc is currently in a class of its own, it may not be for long; with the start of the Vera C. Rubin Observatory’s Legacy Survey of Space and Time rapidly approaching, many more cataclysmic variable systems as faint as or fainter than Gaia19bxc may soon be discovered.

By Kerry Hensley

Citation

“Optical Spectroscopy of the Most Compact Accreting Binary Harboring a Magnetic White Dwarf and a Hydrogen-Rich Donor,” Ilkham Galiullin et al 2025 ApJL 990 L57. doi:10.3847/2041-8213/adff82

Source: American Astronomical Society/AAS-Nova

---

Are we ready for the next gravitational-wave observing runs?

Fig. 1: The illustration shows the distribution of galaxies in the sky that could host gravitational-wave sources and the measured sky location for three future gravitational-wave observatories – shown using contours – if inaccurate models are used. All three observatories miss the true host galaxy—shown in yellow—which is important for an accurate estimation of the universe's expansion rate and age. © A. Dhani (Max Planck Institute for Gravitational Physics)

---

A study by AEI researchers reveals how even the most advanced waveform models can introduce systematic errors when used to measure key properties of black holes.

To the point:

• Researchers use state-of-the-art waveform models to infer the masses, spins, and location of black holes from simulated gravitational-wave events in order to prepare for future observations.


• The models often misestimate these values, particularly when one or both black holes are processing similar to a spinning top, or when their masses differ significantly.


• These inaccuracies can mislead our understanding of how black hole systems form and evolve, and they may affect measurements used to estimate the expansion rate of the Universe.

Gravitational waves from binary black hole coalescences can help answer important astrophysical, cosmological, and fundamental physics questions. How are black holes born, and how do they evolve? How fast is our Universe expanding? Is Einstein’s theory of general relativity still valid in the strong gravity regime?

When analyzing data from these coalescences, researchers employ the most advanced waveform models to simulate the complex dynamics of these systems and match them to observational data. But how do scientists know their waveform models are accurate and which parameters influence the models’ accuracy? As detectors become more sensitive, researchers have to rely more than ever on the high accuracy of their waveform templates to correctly interpret the data. As they prepare for future observing runs of facilities such as LIGO, Virgo, KAGRA and the upcoming Cosmic Explorer and Einstein Telescope, the reliability of these models becomes increasingly important.

In a new study, researchers from the Max Planck Institute for Gravitational Physics (Albert Einstein Institute, AEI) in the Potsdam Science Park found that state-of-the art approximate gravitational waveform models used to infer the properties of coalescing black holes and neutron stars can introduce systematic errors that significantly skew estimates of key astrophysical parameters. These parameters include the masses, spins, and distances of merging objects, as well as the inferred value of the Hubble constant, which is a fundamental measure of how fast the Universe is expanding. The study shows that, although the cutting-edge waveform models are trying to capture the complexity of real astrophysical systems, they still don’t provide an accurate enough description for the very precise observations we expect to make in the future.

“Even the most advanced models are not sufficiently accurate for upcoming observing runs,” says Arnab Dhani, a postdoctoral scientist in the Astrophysical and Cosmological Relativity department at the AEI and the lead author of the study. “Biased estimates of black hole properties occur, in particular, when the component masses in a binary are highly unequal and one or both black holes are rapidly spinning. Such biases can mislead our understanding of how black hole systems form and evolve,” he adds. "Reliably predicting these biases across state-of-the-art waveform models required crucial improvements to existing data analysis techniques,"says Sebastian Völkel, also a postdoctoral scientist from the same department and co-author of the study.

Impact on cosmology

The biases also can have profound implications for the so-called “Hubble tension” – the growing discrepancy between different, independent measurements of the Hubble constant. Some methods based on the cosmic microwave background suggest a slower expansion rate than methods using supernovae. Observations of gravitational-wave standard sirens provide a third independent measurement, enticing the possibility of resolving the conflict. However, it requires accurate measurements of the distance and the location of the event in the sky to identify the galaxy hosting the event. The researchers demonstrate, using an example, how current waveform models can lead to inaccurate localization of the event impacting our measurement (see figure 1).

These results imply that errors in gravitational-wave modeling could significantly contribute to the Hubble tension, which could undermine the credibility of the standard siren method. “The standard siren method in gravitational-wave astronomy holds immense promise for cosmology, but its success depends on the accuracy of our waveform models,” explains Alessandra Buonanno, co-author of the publication and director of the Astrophysical and Cosmological Relativity department. “If we don’t account for spin, tidal deformations, or asymmetric mass ratios, we’re not just making small errors – we’re potentially misreading the expansion history of the Universe.”

Neutron stars or black holes?

Biased gravitational-wave observation may also impact nuclear physics. Neutron star mergers are the only astrophysical phenomena in which scientists have observed the formation of heavy elements such as gold and uranium. An accurate measurement of the maximum neutron star mass would expand our understanding of nuclear matter at densities that cannot be attained in human experiments on Earth. The researchers found that inaccurate measurements of masses can lead to black holes being identified as neutron stars, thereby misleading our understanding of nuclear matter.

Testing Einstein’s theory

Binary black hole mergers provide one of the most extreme conditions in which to test Einstein’s theory of general relativity. The theory precisely predicts the amount of energy released in such collisions, as well as the mass of the remaining black hole. However, the researchers found that model inaccuracies can lead to incorrect predictions of these quantities, resulting in apparent inconsistencies with the observed data. Quantifying the relevance of systematic effects is crucial for assessing whether possible future tests claiming deviations from general relativity are really due to new physics beyond Einstein’s theory, which would be revolutionary.

More accurate waveform models for future observing runs

Future observing runs at current facilities, such as LIGO, Virgo, and KAGRA are expected to detect thousands of binary black hole mergers. Next-generation observatories, such as the Cosmic Explorer and Einstein Telescope, will detect almost all stellar-origin binary black hole merger in the Universe, totaling millions. Accurately estimating black hole properties is essential to achieve the promising scientific goals of gravitational-wave astronomy. By identifying the most problematic regions in black hole parameter space, the researchers provide a roadmap for improving waveform accuracy in the future. The ERC Synergy Grant “Making Sense of the Unexpected in the Gravitational-Wave Sky” aims to address this accuracy challenge, making it possible to infer properties of gravitational-wave sources limited only by measurement uncertainty.

Source: Max Planck Institute for Gravitational Physics/News

---

Media contact:

Dr. Elke Müller
Press Officer AEI Potsdam, Scientific Coordinator
Tel: +49 331 567-7303
elke.mueller@aei.mpg.de

Science contacts:

Prof. Dr. Alessandra Buonanno
Director
Tel: +49 331 567-7220
Fax: +49 331 567-7298
alessandra.buonanno@aei.mpg.de

Dr. Arnab Dhani
Junior Scientist/Postdoc
Tel: +49 331 567-7236
arnab.dhani@aei.mpg.de

Dr. Héctor Estellés
Research Scientist
hestelles@ice.csic.es
Institute of Space Sciences, Barcelona

Dr. Jonathan Gair
Group Leader
Tel: +49 331 567-7306
Fax: +49 331 567-7298
jonathan.gair@aei.mpg.de

Prof. Harald Pfeiffer
Group Leader
Tel: +49 331 567-7328
Fax: +49 331 567-7298
harald.pfeiffer@aei.mpg.de

Dr. Lorenzo Pompili
Research Fellow
Lorenzo.Pompili@nottingham.ac.uk
University of Nottingham, School of Mathematical Sciences

Dr. Alexandre Toubiana
Assistant Professor
alexandre.toubiana@unimib.it
University of Milano-Biccoca

Dr. Sebastian Völkel
Senior Scientist/Leibniz Fellow
Tel: +49 331 567-7199
sebastian.voelkel@aei.mpg.de

---

Publication:

Arnab Dhani, Sebastian H. Völkel, Alessandra Buonanno, Hector Estelles, Jonathan Gair, Harald P. Pfeiffer, Lorenzo Pompili, and Alexandre Toubiana

Systematic Biases in Estimating the Properties of Black Holes Due to Inaccurate Gravitational-Wave Models
Phys. Rev. X 15, 031036 (2025)

Source | DOI

Further information:

Homepage of the “Astrophysical and Cosmological Relativity” department GWSky

GWSky is an ERC Synergy Grant project led by Enrico Barausse (SISSA), Zvi Bern (University of California, Los Angeles (UCLA), Alessandra Buonanno (AEI), and Maarten van de Meent (NBI).

---

4MOST Begins its Journey of Cosmic Discovery

The sky around the Sculptor Galaxy NGC 253 and the globular cluster NGC 288 was the target of the first observations with 4MOST. The blue frame shows the boundary of 4MOST's field of view. Each circle symbolises one of the more than 2400 fibres. The embedded images show the spectrum of a star (right) and the spectrum of a globular cluster in the Sculptor Galaxy (left). © AIP/R. de Jong, Centre de Recherche Astrophysique de Lyon/J.-K. Krogager, Background: Harshwardhan Pathak/Telescope Live

ESO’s astronomical facilities in Chile are hives of activity — or oases! — in the otherwise barren and arid landscape of the Atacama Desert. This hostile and hard-to-reach location may seem like an odd choice for construction, but the Atacama is one of the best sites in the world for astronomy. It has practically no cloud cover, a distinct lack of light pollution, and is the driest non-polar location in the world, receiving under two centimetres of rainfall every year! Chile has hosted ESO’s telescopes since the 1960s, in observatories based at La Silla, Paranal, and Chajnantor Plateau. Shown here is the Visible and Infrared Survey Telescope for Astronomy (VISTA), situated at the Paranal Observatory. Perched atop a mountain adjacent to Cerro Paranal, the home of the flagship Very Large Telescope (VLT), VISTA is the largest telescope in the world designed to survey the sky in near-infrared light (just beyond that visible to humans). The spectacular sights of the cosmos — including the notable streak of our home galaxy, the Milky Way, stretching across the top of the frame here — are more than enough to keep VISTA and its telescopic siblings busy. © ESO/B. Tafreshi (twanight.org)

 

The components of the 4MOST instrument at the VISTA telescope.
© 4MOST Consortium

,

© AIP/R. de Jong, AIP/K. Riebe, AIP/A. Saviauk, CRAL/J.-K. Krogager
Video MP4 (235 mb)

---

First light marks the start of an ambitious mission to decode the physical and chemical fingerprints of thousands of celestial objects at once.

On October 18, the 4-metre Multi-Object Spectroscopic Telescope (4MOST) facility, installed on the VISTA telescope at the European Southern Observatory’s (ESO) Paranal Observatory in Chile, obtained its first light. This milestone is a crucial step in the life of any telescope marking the moment the instrument is deemed ready to begin its scientific journey. 4MOST does not simply take images of the sky; it records spectra, capturing the light of each object in every individual colour. With this capability, it can unravel the light of 2,400 celestial objects simultaneously into 18,000 colour components, allowing astronomers to study their detailed chemical composition and physical properties. And scientists from the Max Planck Institute for Extraterrestrial Physics (MPE) play a key role in this project.

MPE was part of the 4MOST Consortium since the very beginning, and contributed both resources towards the construction of the spectrographs as well as leadership in the development of the Operations System, the complex software system that ensures efficient planning and execution of the 4MOST observations. The planning of observations is done remotely from MPE. The main scientific focus for MPE scientists is the ability of 4MOST to provide spectra and distance measurements (redshifts) for millions of X-ray sources detected by the eROSITA all-sky survey.

Andrea Merloni, PI of one of the 4MOST surveys devoted to the study of growing Supermassive Black Holes, and Local Project Manager of the Operations System team at MPE, remarks: “With the start of 4MOST Operations, a long-term vision of our team gets a step closer to reality. Finally, we will be able to connect the X-ray emission from supermassive black holes and clusters of galaxies detected by eROSITA with the three-dimensional distribution of the Large-Scale Structure, probed by the 4MOST spectroscopic measurements. The combination of these datasets will have a long-lasting legacy impact on extra-galactic astrophysics and Cosmology.”

Jake Laas, who has been involved in the development of the Operations System software over the last five years, adds: “It’s exciting that all the hard work we’ve put in toward automating such a complex survey will soon be put to the true test. The operational concepts which have been designed and implemented for 4MOST as a joint effort between the Consortium and ESO resulted in many unique solutions.”

The 4MOST science team consists of more than 700 investigators from universities and research institutes around the world. The Leibniz-Institut für Astrophysik Potsdam (AIP) is the lead institute of the 4MOST Consortium that has built and will scientifically operate the facility. Next to overall management, AIP has been involved in many aspects of the facility, like its wide field camera with six lenses that are up to 90 cm in diameter, its guiding and focussing system, and its fibre system that contain more than 2500 glass fibres, each with a diameter of a human hair. AIP is also strongly involved in determining 4MOST’s operations scheme, including observing planning and data archiving.

The Principal Investigator for 4MOST, Roelof de Jong from the AIP, remarks: “It is incredible to see the first spectra from our new instrument. The data looks fantastic from the start and bodes well for all the different science projects we want to execute. That we can catch the light that has travelled sometimes for billions of light years into a glass fibre the size of a hair is mindboggling.”

4MOST_First-Observation

From ESO's VISTA telescope in Chile to the First Light sky region. Here, 4MOST used its 2400 fibres to capture the light of many different objects for further spectral analysis, including the centre of the Sculptor Galaxy, stars in the globular cluster NGC288 and the active core of a distant galaxy.

Once fully operational, 4MOST will investigate the formation and evolution processes of stars and planets, the Milky Way and other galaxies, black holes and other exotic objects, and of the Universe as a whole. By analysing the detailed rainbow-like colours of thousands of objects every 10–20 minutes, 4MOST will build a catalogue of distances, temperatures, chemical compositions, velocities and many more physical parameters of tens of millions of objects spread across the entire Southern sky.

The First Light observations exemplify the unique capabilities of 4MOST: its ability to observe a very large field of view and its capability to investigate a large number of very different objects and science cases simultaneously in great detail. One of the objects dominating the First Light observation of 4MOST is the elongated galaxy NGC253, also called the Sculptor or Silver Coin galaxy, which was discovered by Caroline Herschel in 1783 and is at a distance of about 11.5 million lightyears.

The other large object seen in the field is the Globular Cluster NGC288, a very dense group of about 100,000 very old stars in the outskirts of the Milky Way. It formed about 13.5 billion years ago in the very earliest phases of the formation of the Milky Way. Its stars contain very small amounts of most chemical elements heavier than hydrogen and helium, reflecting it’s pristine composition.

Source: Max Planck Institute for Extraterrestrial Physics/News

---

About 4MOST

4MOST is the largest multi-object spectroscopic survey facility in the southern hemisphere and is unique in its combination of large field of view, number of simultaneous observed objects, and number of spectral colours simultaneously registered. Development started in 2010 and the facility has been designed to operate for at least the next 15 years.

The 4MOST Consortium

The 4MOST facility is designed, built, and scientifically operated by a Consortium of 30 universities and research institutes in Europe and Australia under leadership of the Leibniz Institute for Astrophysics Potsdam (AIP). The main institutes involved in building and operating of the facility are:

• Leibniz Institute for Astrophysics Potsdam (AIP): consortium lead, telescope corrector and guiding system, metrology, control software, fibre system, and archive system,


• Macquarie University / Australian Astronomical Optics (AAO): fibre positioner,


• Centre de Recherche Astrophysique de Lyon (CRAL): low-resolution spectrographs,


• European Southern Observatory (ESO): detector systems


• Max Planck Institute for Astronomy (MPIA): instrument control hardware


• Max Planck Institute for Extraterrestrial Physics (MPE): observation planning and remote operations,


• Nederlandse Onderzoekschool Voor Astronomie (NOVA): calibration system,


• University of Cambridge, Institute of Astronomy (IoA): data management,


• Universität Hamburg (UHH), Hamburger Sternwarte: archive and user management,


• Universität Heidelberg, Zentrum für Astronomie (ZAH): high-resolution spectrograph and instrument control software.

---

Contacts:

Dr. Andrea Merloni
Senior Scientist Highenergy Group; PI eROSITA
Tel: +49 89 30000-3893
Email: am@mpe.mpg.de
Max Planck Institute for Extraterrestrial Physics

Dr. Jake Laas
Tel: +49 89 30000-3812
Email: jclaas@mpe.mpg.de
Max Planck Institute for Extraterrestrial Physics

---

Further Information:

4MOST Project website

4MOST to follow up on eROSITA sources

On 6 March, a series of White Papers was published to introduce the 4MOST survey program to the scientific community. The 4-metre Multi-Object Spectroscopic Telescope 4MOST will be the largest spectroscopic survey facility of its kind in the Southern hemisphere and will address today’s most pressing astronomical questions in the fields of Galactic archaeology, high-energy astrophysics, galaxy evolu­tion and cosmology, starting its public survey program in 2022. MPE has contributed two of the White Papers with the aim of using 4MOST to the followup of eROSITA sources in two major surveys dedicated to Active Galactic Nuclei and Clusters of Galaxies, respectively.

more

The X-ray sky opens to the world

January 31, 2024

First eROSITA sky-survey data release makes public the largest ever catalogue of high-energy cosmic sources 

 

 more

 

  eROSITA relaxes cosmological tension

February 14, 2024

Results from the first X-ray sky survey resolve the previous inconsistency between competing measurements of the structure of the Universe

more

Unveiling the 'Ghost' Baryonic Matter

November 19, 2024

A team of scientists from the Max Planck Institute for Extraterrestrial Physics (MPE) has shed light on one of the most elusive components of the universe: the warm-hot intergalactic medium (WHIM).

more

Cosmic dance of the ‘Space Clover’

April 30, 2024

A group led by MPE has, for the first time, detected X-ray gas at the location of the cloverleaf ORC, an odd radio circle (ORC). The origin of ORCs is unknown; in the case of the cloverleaf ORC, the combined data from different wavelengths indicate that the emission is due to a merger of two small galaxy groups.

more

---

Astronomers Spot Magnetically-Guided Streamer Funneling Star-Building Material into Newborn System in Perseus

Credit: NSF/AUI/NSF NRAO/P.Vosteen
Scientific Paper

---

New ALMA observations reveal spiral-shaped gas streamer guided by magnetic fields in a star-forming nursery

A team of astronomers led by Paulo Cortes, a scientist with the U.S. National Science Foundation National Radio Astronomy Observatory and the Joint ALMA Observatory, have made a groundbreaking discovery about how young star systems grow. Using the powerful Atacama Large Millimeter/submillimeter Array (ALMA), their team observed— for the first time ever— a narrow, spiral-shaped streamer of gas guided by magnetic fields, channeling matter from the surrounding cloud of a star-forming region in Perseus, directly onto a newborn binary star system.

Stars are born from clouds of gas and dust, but recent observations show star birth is far more dynamic than previously thought. The team’s data captured both the dust and molecules swirling around the newborn binary star system, known as SVS13A, revealing that magnetic fields don’t just thread through these stellar nurseries— they actively steer the flow of material, providing a preferred route for gas to travel onto the disk where new stars and planets form.

Imagine a garden hose, but instead of water it’s smoothly delivering star-building material through a winding path carved by invisible forces. That’s the picture emerging from the ALMA observations: a channel of gas, dubbed a “sub-Alfvénic streamer,” regulated by spiral magnetic field lines. “This new data gives us a new window into star formation,” shares Cortes, “This streamer shows how magnetic fields can regulate star formation by shaping the infall of material, like a dedicated highway for the cars to move along.”

The ALMA images and data reveal two spiral arms of dust encircling the stars, with a streamer of gas that closely follows the same path. This remarkable alignment suggests gas in the streamer moves slowly compared to what was previously believed, supporting the idea of a magnetized channel rather than a turbulently collapsing cloud. The fact that such a streamer exists and connects the cloud to the disk— feeding material in a controlled way— means that gravity and magnetism both play crucial roles in building stars and shaping the planets that may eventually form around them.

This pioneering result, accepted for publication in Astrophysical Journal Letters, marks the first time astronomers have directly mapped both the streamer and its guided magnetic field in a single observation.

Source: National Radio Astronomy Observatory (NRAO)/News

---

About NRAO

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

About ALMA

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 the construction, commissioning and operation of ALMA.

---

Distant galaxy A1689-zD1 found to have unusually low dust-to-gas ratio

False-color JWST/NIRCam RGB image cutout (blue: F150W; green: F277W; red: F444W), overlaid with [C ii]-158µm emission contours showing 3, 5, 7, 10σ (white solid lines). A scalebar is shown in the image plane. Credit: arXiv (2025). DOI: 10.48550/arxiv.2510.07936

Using the James Webb Space Telescope (JWST) and the Atacama Large Millimeter/sub-millimeter Array (ALMA), an international team of astronomers has carried out comprehensive multiwavelength observations of a distant massive galaxy known as A1689-zD1.

The new observations, detailed in a paper published October 9 on the pre-print server arXiv, yield important insights into the properties of the galaxy, especially regarding dust production in this system.

A1689-zD1 is a bright highly-lensed massive galaxy at a redshift of approximately 7.13. It has a diameter of about 3,000 light years and its stellar mass is estimated to be some 2.6 billion solar masses.

Previous observations of A1689-zD1 have found that it has a metallicity close to the solar value and that it contains a substantial amount of dust—with an estimated mass of 15 million solar masses. Due to this, A1689-zD1 is an excellent place to study the existence of interstellar dust at early cosmic epochs.

That is why a group of astronomers led by Kasper E. Heintz of the University of Copenhagen, Denmark, decided to explore the dust content with JWST and ALMA.

"We revisited this galaxy to gauge the baryonic matter components in the ISM [interstellar medium], with particular focus on constraining the build up of cosmic dust," the researchers explained.

Hintz's team performed the rest-frame ultraviolet to far-infrared modeling of the spectral energy distribution (SED) of A1689-zD1 to determine its stellar mass, dust mass, visual attenuation, and star-formation rate. The ALMA observations were also used to constrain the total dynamical mass of the source, and infer the gas mass using common gas tracers but bounded by the overall dynamics of the system.

The study found that although A1689-zD1 has a substantial dust mass, its dust-to-gas (DTG) and dust-to-metal (DTM) mass ratios are remarkably low—at a level of 0.00051 and 0.061, respectively. The astronomers note that this is due to the high metallicity of A1689-zD1 and its substantial gas mass, which was calculated to be 28 billion solar masses.

Therefore, the DTG and DTM mass ratios for A1689-zD1 are an order of magnitude lower than that found in the Milky Way and the Large Magellanic Cloud (LMC) or the Small Magellanic Cloud (SMC). These ratios also suggest that the bulk neutral atomic hydrogen (HI) gas in the line-of-sight to A1689-zD1 is relatively dust-poor compared to its chemical enrichment.

The authors of the paper conclude that the obtained results point to a potential change in the relative dust abundance or composition of early galaxies.

"We find that this deviation in the DTG and DTM mass ratios appears to be ubiquitous in other metal-rich galaxies at similar redshifts, z ≳ 6. This suggests that the processes that form and destroy dust at later times, or the dust emissivity itself, are drastically different for galaxies in the early universe," the scientists conclude.

by Tomasz Nowakowski, Phys.org
edited by Sadie Harley, reviewed by Robert Egan

Source: Phys.org/News

---

Written for you by our author Tomasz Nowakowski, edited by Sadie Harley, and fact-checked and reviewed by Robert Egan—this article is the result of careful human work. We rely on readers like you to keep independent science journalism alive. If this reporting matters to you, please consider a donation (especially monthly). You'll get an ad-free account as a thank-you.

---

More information: Kasper E. Heintz et al, Inefficient dust production in a massive, metal-rich galaxy at z=7.13 uncovered by JWST and ALMA, arXiv (2025). DOI: 10.48550/arxiv.2510.07936

Journal information: arXiv

---

Explore further

• Astronomers discover ultra-luminous infrared galaxy lurking behind quasar

---

Discovery of a Brown Dwarf Orbiting a Red Dwarf through the Synergy of Ground- and Space-Based Observatories

Figure 1: Infrared image of the brown dwarf companion J1446B (marked by the arrow). The host star (J1446) is masked in white during image processing. The white bar at the lower right corresponds to an angular distance equivalent to 10 astronomical units (roughly the distance between Saturn and the Sun). (Credit: Taichi Uyama (Astrobiology Center/CSUN) / W. M. Keck Observatory)

By combining the power of ground-based and space-based telescopes, astronomers have discovered a new brown dwarf—a type of object that lies between a star and a planet—orbiting a small star about 55 light-years from Earth. In addition, infrared observations revealed variations in its brightness, suggesting that clouds and storms may be forming and moving within the brown dwarf’s atmosphere.

In our Milky Way Galaxy, the most common type of stars is small, cool stars known as M dwarfs, or red dwarfs. They make up more than half of the all stars in our Galaxy. Because M dwarfs are intrinsically faint, it has been difficult to determine how many of them have planets or brown dwarfs as companions. Brown dwarfs are too light to shine like normal stars, yet heavier than planets—objects, so they bridge the gap between the two. Understanding how frequently such companions exist, and what masses they have, is essential for learning how stars and planets form and evolve.

An international research team led by the Astrobiology Center, California State University Northridge, and Johns Hopkins University has now discovered a brown dwarf companion orbiting a nearby M dwarf LSPM J1446+4633 (hereafter J1446), located about 55 light-years from Earth (Figure 1). The companion, J1446B, has a mass of about 60 times that of Jupiter and orbits its host star at a distance 4.3 times the Earth–Sun separation, completing one orbit in about 20 years. In addition, near-infrared observations revealed brightness variations of about 30%, indicating possible cloud activity or atmospheric circulation on the brown dwarf.

"Studying the weather on these distant objects not only helps us to understand how their atmosphere form, but also informs our larger search for life planets beyond the solar system" says Taichi Uyama, researcher with the Astrobiology Center of Japan and lead author of the study.

The key to this discovery was the combination of three complementary observation techniques: (1) precise radial velocity measurements using InfraRed Doppler (IRD) on the Subaru Telescope, (2) direct imaging with the W. M. Keck Observatory, and (3) astrometric measurements of the host star’s motion with the Gaia spacecraft.

By analyzing all three datasets together, the team accurately determined the mass and orbit of the companion (Figure 2). In particular, the Subaru Telescope’s six years of data from its strategic program (IRD-SSP) were crucial. Radial velocity data alone cannot break the degeneracy between mass and orbital inclination, but adding direct imaging and Gaia astrometry resolves this ambiguity.

Figure 2: Orbit modeling of J1446B. (Left) The projected orbit inferred from W. M. Keck Observatory’s direct imaging (blue dot at upper right) and the acceleration in the host star’s motion measured by Gaia (red arrow). Axes show right ascension and declination in arcseconds. The black curve represents the most probable orbit, while the colored curves indicate other possible orbits; color corresponds to the estimated mass of J1446B (color scale shown on right). (Right) Radial velocity variations of the host star measured by IRD (red points), along with simulated orbital solutions color-coded by companion mass. The lower panel shows residuals from the fit. (Credit: Qier An (UCSB) / Uyama et al. (2025))

Previous studies have demonstrated the power of combining Hipparcos and Gaia astrometry (Note 1) with direct imaging to detect and characterize companions (Note 2). However, Hipparcos was unable to measure the positions of faint red dwarfs like J1446. This study is the first to apply Gaia-only data to such a system, successfully constraining the orbit and dynamical mass of a brown dwarf companion.

This discovery provides a critical benchmark for testing brown dwarf formation scenarios and atmospheric models. Future observations may even allow researchers to map the weather patterns of this intriguing object. This result highlights the power of combining ground-based and space-based telescopes to uncover hidden worlds beyond our Solar System.

These results appeared as Uyama et al. "Direct Imaging Explorations for Companions from the Subaru/IRD Strategic Program II; Discovery of a Brown-dwarf Companion around a nearby Mid-M-dwarf LSPM J1446+4633" in the Astronomical Journal on October 20, 2025.

This research was supported by JSPS KAKENHI (Grant Numbers: 24K07108, 24K07086). The development and operation of IRD were supported by JSPS KAKENHI (Grant Numbers: 18H05442, 15H02063, and 22000005).

These results appeared as Uyama et al. "Direct Imaging Explorations for Companions from the Subaru/IRD Strategic Program II; Discovery of a Brown-dwarf Companion around a nearby Mid-M-dwarf LSPM J1446+4633" in the Astronomical Journal on October 20, 2025.

This research was supported by JSPS KAKENHI (Grant Numbers: 24K07108, 24K07086). The development and operation of IRD were supported by JSPS KAKENHI (Grant Numbers: 18H05442, 15H02063, and 22000005).

Source: Subaru Telescope

---

(Note 1) The Gaia spacecraft, launched in 2013, is an astrometric mission designed to create a detailed 3D map of stars in the Milky Way. Its extremely precise positional measurements enable the detection of companions and planets through the astrometric method, which relies on subtle stellar motions. Hipparcos, launched in 1989, was Gaia’s predecessor and provided the first space-based astrometric catalog.

(Note 2) For details on the research methods, please refer to the Science Results on January 2023.

---

Relevant Links

• W. M. Keck Observatory October 20, 2025 Press Release Astrobiology Center October 21, 2025 Press Release

---

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.

---