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NuSTAR image of the Galactic center region. Sgr A* is the position of supermassive black hole at the center of the Milky Way galaxy. Green dashed ellipses show the areas of giant molecular clouds. The distance from the Bridge to Sgr A* is 200 light years. Credit: Mori 2015.Download Image
At the center of our Milky Way galaxy is a black hole with a mass more than a million times the mass of the Sun, called Sgr A*. This has been directly confirmed by detailed radio imaging of material close to the black hole by the event horizon telescope as well as the motions of stars in the center of the galaxy effected by the gravitational pull of this supermassive black hole. The low luminosity of Sgr A* indicates that the system is in a relatively quiescent state compared to Active Galactic Nuclei (AGN) in other galaxies which may harbor more massive black holes. However, this has not always been the case, and evidence of higher luminosity in the past is indicated by the increasing X-ray brightness of giant molecular clouds near Sgr A*. Over the past four years observations by NuSTAR of regions close to the center of our galaxy have confirmed that X-ray emission from one of these clouds, called “The Bridge” has been increasing and is likely due to reflection of X-rays from a past Sgr A* outburst approximately 200 years ago. NuSTAR observations last week of The Bridge will add to the detailed investigation of the full profile of this Sgr A* illumination event. Characterizing past Sgr A* outbursts is a necessary step towards understanding the physical mechanisms that triggered major outbursts from a quiescent supermassive black hole, possibly similar to a tidal disruption event seen in other AGN. Observations of The Bridge will continue in 2027, for a proposal selected to be part of cycle 12 of the NuSTAR General Observer program.
Artist’s conception of this research showing an imagined time sequence as a star passes behind a TNO with an atmosphere. Credit: NAOJ. Image (961KB)
A team of professional and amateur Japanese astronomers foundidence for a thin atmosphere around a small body in the outer Solarystem. The object is so small that it should not have a sustainableatmosphere, raising questions about when and how the atmosphere formd. Future observations to better characterize the atmosphere will help solve these mysteries.
In the cold reaches of the outer Solar System lie thousands of small objects known as trans-Neptunian objects (TNOs) because they lie outside
the orbit of Neptune. A thin atmosphere has been observed around Pluto, the most famous TNO, but studies of other TNOs have yielded negative
results. Most TNOs are so cold, and their surface gravity so weak, that they are not expected to retain atmospheres.
But astronomers like to expect the unexpected, so they took advantage of a lucky “natural experiment” to look for an atmosphere around a TNO
known as (612533) 2002 XV93. This object, abbreviated as 2002 XV93, has a diameter of approximately 500 km. For reference, Pluto’s diameter is 2,377 km. The orbit of 2002 XV93 is such that, as seen from Japan, it passed directly in front of a star
on January 10, 2024. As the star disappears behind 2002 XV93, it might gradually fade, indicating that the light is being attenuated
as it passes through a thin atmosphere; or it might suddenly wink out as it slips behind the solid surface of the TNO.
A team of professional and amateur astronomers, led by Ko Arimatsu at NAOJ Ishigakijima Astronomical Observatory, observed the star as 2002
XV93 passed in front of it from multiple sites in Japan. The obtained data are consistent with attenuation by an atmosphere.
Calculations show that the atmosphere found around 2002 XV93 is expected to last less than 1000 years unless it is replenished. So
it must have been created or replenished recently. Observations by the James Webb Space Telescope show no signs of frozen gases on the surface
of 2002 XV93 that might sublimate to form an atmosphere. One possibility is that some event brought frozen or liquid gases from deep
inside the TNO to the surface. Another possibility is that a comet crashed into 2002 XV93, releasing gas that formed a temporary atmosphere. Further observations are needed to distinguish between these two scenarios.
A conceptual visualization of ENDTRANZ, the transition zone at the envelope–disk boundary, which is shown as a red colored, belt-like annulus where the gas motion gradually transitions from the infalling envelope to the Keplerian rotation within the protoplanetary disk surrounding a young star. This is an AI-generated illustration based on a two-dimensional spatial map of the specific angular momentum in the equatorial plane, as obtained from the numerical simulations. The specific angular momentum map offers an intuitive lens to ‘see’ ENDTRANZ, making its dynamics more apparent than in the rotational velocity map. (Image Credit: Indrani Das/ASIAA)
The figure shows the radial variation of rotational velocity and specific angular momentum with distance from the star, in astronomical units (au), on the left- and right-hand axes, respectively, as obtained from the global collapse simulations. The orange-colored region represents the ENDTRANZ of a young stellar system. The vertical dashed and dotted lines represent the outer and inner boundaries of ENDTRANZ. (Image Credit: Indrani Das/ASIAA.)
New study identifies a long-sought transition zone where infalling gas becomes a rotating disk.
Every planet — including everyone in the Solar System — was born inside a rotating disk of gas and dust swirling around a young star. Astronomers have long understood that these disks exist and that planets take shape within them. What they couldn't explain was how the raw material gets there in the first place. Now, a new study led by Indrani Das of the Academia Sinica Institute of Astronomy and Astrophysics (ASIAA) has found the missing piece: a distinct transition zone where chaotic, infalling gas gradually settles into the orderly rotation of a planet-forming disk. The team named it ENDTRANZ — the Envelope Disk Transition Zone — and detected it for the first time in an actual young stellar system using the Atacama Large Millimeter/submillimeter Array (ALMA).
From chaos to order
Young stars are surrounded by a vast shroud of gas and dust called an envelope. Gravity pulls this material inward, feeding both the growing star and the disk around it. But the infalling gas moves differently than the disk — more slowly and chaotically — and the point at which one becomes the other had never been clearly observed.
Earlier theoretical models assumed the switch was sharp, almost instantaneous. The new study shows it isn't. Using numerical simulations
with the FEOSAD code, the team tracked how a collapsing cloud core evolves into a star-disk system — and found that the transition unfolds
gradually across a finite region, leaving a tell-tale signature: a characteristic "jump" in the distribution of specific angular momentum, a
measure of how gas rotates as a function of its distance from the star.
"The existence of ENDTRANZ naturally results from the redistribution of mass and angular momentum during the formation of disks around young
stars. This process ultimately governs how infalling material from the envelope, which rotates more slowly than the Keplerian speed, spreads
out to form the disk and gradually settles into ordered Keplerian rotation," explained Das.
ALMA finds the fingerprint
To test whether ENDTRANZ exists in nature, the team turned to L1527 IRS, a young protostar about 450 light-years away in the Taurus molecular cloud. Using data from the ALMA Large Program eDisk (Embedded Disks in Planet Formation), they found exactly the same angular momentum signature that the simulations had predicted — spanning a zone roughly 16 astronomical units wide, or about 16 times the distance from Earth to the Sun.
"This ENDTRANZ tracer essentially manifests from the gradual transition in the rotational velocity, which offers a diagnostic framework for understanding the physical processes at play that drive the disk evolution," said Shantanu Basu, Interim Director of the Canadian Institute for Theoretical Astrophysics and co-author of the study.
ALMA's extraordinary resolution was essential to making this detection possible, resolving the structure at the precise interface
between the envelope and the disk — a regime that had previously been beyond reach.
"A careful inspection and comparison of the radial dependence of specific angular momentum between the observational data and the
simulations helped identify the evidence of ENDTRANZ in L1527 IRS," said Nagayoshi Ohashi, principal investigator of the ALMA eDisk Large
Program and co-author of the study.
A new window on planet formation
The discovery establishes ENDTRANZ as a fundamental feature of how stars and planetary systems assemble — and opens the door to searching for the same signature in other young systems across the galaxy.
"In many ways, we believe this is just the beginning!" Das said.
This article is based on the original press release by the National Astronomical Observatory of Japan (NAOJ), an ALMA partner on behalf of East Asia.
The Atacama Large Millimeter/submillimeter Array (ALMA), an international astronomy facility, is a partnership of the European Southern Observatory (ESO), the U.S. National Science Foundation (NSF), and the National Institutes of Natural Sciences (NINS) of Japan in cooperation with the Republic of Chile. ALMA is funded by ESO on behalf of its Member States, by NSF in cooperation with the National Research Council of Canada (NRC) and the National Science and Technology Council (NSTC) in Taiwan, and by NINS in cooperation with the Academia Sinica
(AS) in Taiwan and the Korea Astronomy and Space Science Institute (KASI).
ALMA construction and operations are led by ESO on behalf of its Member States; by the National Radio Astronomy Observatory (NRAO), managed by Associated Universities, Inc. (AUI), on behalf of North America; and by the National Astronomical Observatory of Japan (NAOJ) on behalf of East Asia. The Joint ALMA Observatory (JAO) provides the unified leadership and management of ALMA's construction, commissioning, and operation.
Due to distinctive features in the spectra of the 'Little Red Dots', a new class of objects spotted by the James Webb Space Telescope, it was thought that these were distant galaxies with massive black holes at their centres. However, new research suggests that the light from these galaxies is shaped not only by the motion of gas near the central black hole, but also by the effects of radiation. MPA scientists have modelled three key processes – resonance, Raman, and Thomson scattering – and found that these, acting together, can explain the formation of hydrogen emission lines in the Little Red Dots.
Little Red Dots (LRDs) are among the most surprising discoveries of the James Webb Space Telescope. These compact, reddish sources appear
in the early universe, within the first billion years of cosmic history, and exhibit unusual hydrogen spectra. Their light shows broad hydrogen
emission lines, Balmer absorption features, and a pronounced break between ultraviolet and optical wavelengths. At first glance, these
properties seem to point to active galactic nuclei, where broad hydrogen lines are typically interpreted as signatures of rapidly moving gas
surrounding a supermassive black hole.
Yet this interpretation creates a major puzzle. If the widths of these hydrogen lines are directly interpreted as tracers of gas motion around a black hole, many Little Red Dots appear to host black holes that are unexpectedly massive compared to their young host galaxies. Such enormous black holes would challenge current ideas of how quickly black holes and galaxies could have formed and grown in the early universe. This tension raises an important question: do these spectral features truly provide a direct measure of black hole mass, or are they significantly shaped by the
dense environments through which the radiation propagates?
This work explores a new possibility. Rather than assuming that hydrogen line widths primarily trace gas dynamics near a black hole, it investigates
how radiative transfer through dense surrounding gas can fundamentally alter the observed spectrum. The presence of Balmer absorption and strong spectral breaks already hints that light in these systems may undergo substantial scattering and reprocessing. If so, some of the broad and complex hydrogen features in Little Red Dots may arise not only from fast-moving gas, but also from the way photons interact with thick, hydrogen-rich environments before escaping.
Understanding how radiative transfer shapes these spectral signatures therefore offers more than an alternative explanation for broad lines: it provides a new tool for probing the physical conditions, structure, and nature of Little Red Dots themselves, revealing how gas, radiation, and black hole growth interact in some of the earliest galaxies. Our focus is on three key processes:
Resonance scattering, where photons interact with hydrogen atoms in the excited n=2 state.
Raman scattering, where ultraviolet photons are converted into optical emission through inelastic scattering by atomic hydrogen.
Thomson scattering, where photons scatter off free electrons. Each process contributes differently to the observed spectral features.
Resonance scattering: shaping line profiles and ratios
Resonance scattering plays a crucial role when hydrogen atoms populate the n=2 or Balmer state, as indicated by Balmer absorption features and strong Balmer breaks. In this regime, Balmer photons can undergo multiple scatterings before escaping, which significantly modifies the emerging line profiles. These repeated interactions can produce asymmetric line shapes, particularly in the presence of gas motions such as outflows.
Notably, the radiative transfer of Hα and Hβ differs due to the atomic structure of hydrogen. While Hα photons predominantly remain in the same transition, Hβ photons can be converted into other lines, such as Paschen-α and Hα, through cascades involving the n=3 state. Consequently, Hβ photons are efficiently depleted in optically thick gas, while more Hα photons are produced. This leads to enhanced Hα
emission and naturally increases the Hα/Hβ flux ratio beyond its intrinsic value.
Raman scattering introduces a distinct spectral signature. Ultraviolet (UV) photons near the hydrogen Lyman series can be inelastically scattered by neutral hydrogen into optical wavelengths, producing broad wings around emission lines and showing systematic differences between certain hydrogen transitions. In particular, Raman scattering predicts that the wings of Hα should be significantly broader than those of Hβ.
Although broad emission lines are a defining feature of the Little Red Dots, such strong differences between lines are not always observed. This suggests that, although Raman scattering may contribute to the observed spectra, it is unlikely to be the dominant origin of the broad emission features. than those of Hβ.
Thomson scattering: similar broad wings in hydrogen emission lines
Among the processes considered, Thomson scattering by free electrons provides a particularly compelling explanation for the broad components observed. Since electrons move thermally, the scattering introduces a symmetric broadening that depends on the electron temperature rather than on the motion of the bulk gas. Under typical conditions, this naturally produces line widths of around 1000 km/s, which is consistent with observations of the Little Red Dots. than those of Hβ.
The resulting profiles often exhibit exponential wings — a distinctive feature of electron scattering that has also been identified in other astrophysical environments. Importantly, this mechanism affects all emission lines in a similar way, which is consistent with the observed spectra. than those of Hβ.
The combined effects of resonance, Raman and Thomson scattering demonstrate that the Little Red Dots' diverse spectral features can naturally arise from radiative transfer in dense gas. Broad wings, absorption features and differences between hydrogen lines do not necessarily require extreme gas velocities or a classical broad-line region.
This has important consequences. If line widths are interpreted purely as indicators of gas motion, the mass of black holes may be significantly overestimated. Instead, the spectra of Little Red Dots encode the physical properties of their surrounding gas, such as
density, temperature and ionisation state, through radiative processes.
These results provide a new framework for interpreting the spectra of Little Red Dots and similar systems in the early universe, offering a new
perspective on early galaxy evolution. Rather than being straightforward indicators of black hole dynamics, hydrogen emission lines can reflect
the complex interplay between radiation and dense gas.
Understanding this interplay is essential for correctly inferring the physical properties of galaxies and black holes at high redshifts and for developing a consistent model of their co-evolution during the first billion years of cosmic history. Current work focuses on analysing observed line profiles and using these models to decode the physical conditions imprinted in their shapes.
Chang, Seok-Jun; Gronke, Max; Matthee, Jorryt; Mason, Charlotte
Impact of resonance, Raman, and Thomson scattering on hydrogen line formation in Little Red Dots
MNRAS, 545, 4, id.staf2131, 21 pp
This digital illustration shows a stellar-mass object crashing through the accretion disk surrounding a supermassive black hole. This is one of several scenarios that could produce the repeated X-ray bursts from the galaxy SDSS J133519.91+072807.4. Credit: ESA
The fuzzy yellow galaxy at the center of this image is home to ZTF19acnskyy. Credit: Sloan Digital Sky Survey
Ansky Awakens
Nearly seven years ago, the Zwicky Transient Facility saw the galaxy SDSS J133519.91+072807.4 suddenly brighten at optical wavelengths, with the source given the moniker ZTF19acnskyy or “Ansky.” Within the next few years, Ansky brightened at other wavelengths, possibly signaling the first recorded case of a slumbering supermassive black hole grumbling to alertness.
In 2024, Ansky entered a new phase of behavior, exhibiting a series of semi-regular X-ray flares called quasi-periodic eruptions. The leading explanations for these flares, which have been detected from several nearby galaxies, involve a star-sized object spiraling toward a supermassive black hole. The repeating X-ray flares arise when the object crashes through an accretion disk around the black hole, or when the object loses mass each time it passes closest to the black hole. In either scenario, the time between flares is expected to decrease over time — but as new work shows, Ansky is behaving in ways that fail to fit existing theories of quasi-periodic eruptions.
Soft X-ray observations of Ansky’s bursts from 2024 to 2026. These plots clearly show that in 2025 and 2026, the peak luminosities of the bursts have remained roughly constant while the time between bursts has increased. Click to enlarge. Credit: Chakraborty et al. 2026
An Unexpected Slowdown
Astronomers first reported on Ansky’s strange behavior in 2025, finding evidence that the time between eruptions was increasing rather than decreasing as expected. To investigate this emerging trend, Joheen Chakraborty (Massachusetts Institute of Technology) and collaborators analyzed data from the Neil Gehrels Swift Observatory’s X-ray Telescope, XMM-Newton, and the Neutron star Interior Composition Explorer (NICER).
This X-ray monitoring campaign spanned from January 2025 to January 2026 and captured 23 bursts, including 19 consecutive bursts — the most seen from a quasi-periodic eruption source to date. The bursts each lasted about three days, and the burst luminosity and total energy remained roughly constant, but the time between bursts increased smoothly from 9.9 days in January 2025 to 13.5 days in January 2026.
Possible Explanations
What physical process can produce X-ray bursts that are roughly consistent in energy and peak luminosity, last for approximately three days, and become more spaced out over time? The team considered five possibilities:
1. A star orbiting a black hole could transfer a bit of mass to the black hole each time it draws close… but it’s not clear whether the energy of each burst would remain the same as the star loses mass, nor is it clear how a three-day eruption duration could be achieved.
2. A star partially disrupted by a black hole could be kicked progressively farther from the black hole due to asymmetric mass loss or the reformation of its core… but this scenario cannot explain the bursts’ consistent energies and luminosities.
3.An object orbiting a black hole with an accretion disk could be experiencing general relativistic precession… but no combination of known sources of precession can reproduce Ansky’s behavior.
4. A second supermassive black hole could cause reflex motion of the inner black hole, changing how far the signal must travel… but even though this scenario can increase the time between bursts, the rate of increase is three orders of magnitude too small.
5. Instabilities in the black hole’s accretion disk could trigger recurrent bursts of accretion… but it’s not yet clear how an instability scenario could produce such predictable behavior.
While none of these models can fully solve the mystery of Ansky’s slackening X-ray flares, this work provides new avenues for exploration. In the meantime, we may get new clues simply from waiting to see what this source does next!
“A Positive Period Derivative in the Quasiperiodic Eruptions of ZTF19acnskyy,” Joheen Chakraborty et al 2026 ApJL 1001 L6. doi:10.3847/2041-8213/ae548b
These images of a special object, dubbed the “X-ray dot,” represent a discovery from Chandra that could help explain the nature of a mysterious class of sources in the early Universe. The optical and infrared image from Hubble show the region around the X-ray dot, while the Chandra X-ray image shows the close up. Prior to this discovery, “little red dots” seen by the Webb telescope had not been known to emit X-rays. This one does, which leads researchers to propose that the X-ray dot represents a previously unknown transition phase of growing supermassive black holes. X-ray, Infrared, and Optical images of X-ray Dot 3DHST-AEGIS-12014 Credit: X-ray: NASA/CXC/Max Plank Inst./R. Hviding et al.; Optical/IR; NASA/ESA/STScI/HST; Image Processing: NASA/CXC/SAO/N. Wolk
NASA’s Chandra X-ray Observatory has found a “little red dot” (LRD) — a class of red, distant objects — that is giving off X-rays, unlike others observed so far.
This suggests that this so-called X-ray dot represents a previously unseen phase of supermassive black holes in the early Universe.
In the proposed scenario, gas surrounding the growing black hole becomes patchy as the black hole consumes it.
Over time X-rays from material falling onto the black hole are then able to poke through, which Chandra can detect.
This image of a special object, dubbed the “X-ray dot,” represents a discovery from NASA’s Chandra X-ray Observatory that could help explain the nature of a mysterious class of sources in the early Universe as described in our latest press release. Officially known as 3DHST-AEGIS-12014, the X-ray dot is located about 11.8 billion light-years from Earth and may provide a crucial bridge between young black holes embedded in dense gas and typical growing supermassive black holes.
Shortly after NASA’s James Webb Space Telescope started its science observations, scientists reported a new class of unexplained objects. Astronomers found sources that were relatively small and red and located about 12 billion light-years from Earth or farther. (One reason for this redness is their great distances, causing their light to be shifted toward the part of the infrared spectrum with the longest wavelengths, which results in red colors in Webb images.) These became known as “little red dots” (LRDs), and since then astronomers have been trying to determine what exactly these LRDs are.
Recently, a team of researchers found one special object that could help, the X-ray dot depicted in this graphic. An optical and infrared composite image is centered on the position of the X-ray dot and shows its key features as an LRD – small and red. Optical light from NASA’s Hubble Space Telescope is colored blue and green and infrared light from Hubble is colored orange and red. The Chandra X-ray image of the X-ray dot (purple) is in the inset, showing it is bright in X-rays.
The X-ray dot was discovered when comparing new data from Webb with a deep survey previously performed by Chandra. Up until then, all the other LRDs didn’t appear to emit X-rays. This was perplexing because if LRDs were early black holes, as many suspected they were, then they should commonly produce bright X-rays.
Therefore, it was significant to find an LRD that does. The researchers suggest that the X-ray dot could represent a transition phase from an LRD to a typical growing supermassive black hole. As the black hole in an LRD consumes gas surrounding it, patchy holes in the clouds of gas appear. This allows X-rays from material falling onto the black hole to poke through, which are observed by Chandra. Eventually all the gas is consumed, and the “black hole star” ceases to exist. A snapshot of this scenario is depicted in the artist’s illustration below.
The artist’s impression of the X-ray dot shows the research team’s understanding of this new object: a growing supermassive black hole at the center of a patchy sphere of gas.
Artist's Illustration of a Close-Up View of X-ray Dot, 3DHST-AEGIS-12014.
Credit: NASA/CXC/SAO/M. Weiss; adapted by K. Arcand & J. Major
There are also hints in the Chandra data of the X-ray dot that there are variations in X-ray brightness, which supports the idea that the black hole is partly obscured. As the cloud of gas rotates, patches of denser and less dense gas can move across the black hole, causing changes in X-ray brightness.
An alternate idea for the X-ray dot is that it is a more common type of growing supermassive black hole but is veiled in an exotic type of dust that astronomers have not seen before. Future observations are planned that should be able to shed light on the truth.
A paper describing these results has been published in The Astrophysical Journal with the lead author of Raphael Hviding (Max Planck Institute for Astronomy in Germany). A full list of authors can be found in the paper available at https://arxiv.org/abs/2601.09778
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.
Today's release features a composite image with an X-ray insert, and an artist's illustration of a little dot located 11.8 billion light-years from Earth.
Shortly after NASA's James Webb Space Telescope started its observations, reports of a new class of curious objects emerged. Astronomers discovered small red specks more than about 12 billion light-years from Earth. These mysterious objects were given the accurate and descriptive name "little red dots," or LRDs.
One such dot sits at the heart of the primary image of this release. The composite optical and infrared image features a smattering of distant galaxies and other cosmic objects and phenomena in a variety of colors, set against the blackness of space. At the center of the square image is a small, somewhat pixelated, little red dot, outlined in a white box for clarity.
This curious, but inconspicuous, little dot is enlarged in an X-ray insert at our upper right, because it does something no other LRD has been found to do; it emits X-rays! In the insert, the dot appears as a much larger white sphere in the Chandra image, ringed with a neon purple glow. This exciting discovery has earned this little dot the nickname the "X-ray dot."
The X-ray dot is further enlarged in an artist's illustration. Many scientists think LRDs are supermassive black holes embedded in clouds of dense gas. Here, the dot is a round, patchy cloud of brilliant red gas. At its core is a relatively tiny black sphere, the black hole, floating in a swirling pool of pale purple mist. Research suggests that the X-ray dot represents a transition phase from an LRD to a typical growing supermassive black hole. As the black hole star consumes its surrounding gas, patchy holes appear in the cloud. This allows X-rays to poke through, which are then observed by Chandra.
Fast Facts for 3DHST-AEGIS-12014
Credit: X-ray: NASA/CXC/Max Plank Inst./R. Hviding et al.; Optical/IR; NASA/ESA/STScI/HST;Image Processing: NASA/CXC/SAO/N. Wolk Release Date: April 28, 2026 Scale: Image is about 20 arcsec (500,000 light-years) across. Category:Quasars & Active Galaxies, Black Holes Coordinates (J2000): RA 14h 20m 47.5s | Dec +53° 02´ 32.83" Constellation:Ursa Major Observation Dates: 29 Observations from Mar 2005 to Jun 2008 Observation Time: 214 hours 42 minutes (8 days 22 hours 42 minutes) Obs. ID: 5845,5846, 6214, 6215, 9450-9453, 9720-9726, 9793-9797, 9842-9844, 9863, 9866, 9870, 9873, 9875, 9876 Instrument: ACIS References: Hviding, R.E., et al., 2026, ApJL, 1000, L18. Color Code: X-ray: purple; Optical/IR: red, orange, green, and blue Distance Estimate: About 11.8 billion light-years from Earth (z~3.28)
The image shows the 30Dor-10 region in the Large Magellanic Cloud, as seen by the James Webb Space Telescope through a filter that highlights emission from ionized gas. The box on the left represents one of the two clusters considered in this study, "Clump 52," as seen by ALMA before these new results, at a resolution of approximately 20,000 astronomical units. The box on the right shows the stunning new images at 2,000 astronomical units, where the cluster can be seen separating into tworio protoclusters. The brightest and most massive one is in the bottom-right box. Credit: A. Traficante et al.Original Image
Highlights
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ALMA has enabled the first measurement of the core mass function in a galaxy beyond the Milky Way
Observations of the Large Magellanic Cloud show that star-forming cores follow similar patterns to those in our Galaxy
The results suggest that the earliest stages of star formation may be universal across different galactic environments
Astronomers have used the Atacama Large Millimeter/submillimeter Array (ALMA) to map, for the first time, the mass distribution of the gas and dust clumps from which new stars are born—the so-called core mass function (CMF)—in a star-forming region outside the Milky Way.
The study, led by the Italian National Institute for Astrophysics and published in Nature Communications, focuses on the 30 Dor-10 region in the Large Magellanic Cloud, a nearby galaxy located about 160,000 light-years from Earth. ALMA's combination of high sensitivity and angular resolution enables the resolution of the small-scale structure of star-forming regions even in nearby galaxies, opening a new window for studying the earliest stages of star formation beyond the Milky Way.
To achieve this result, the research team pushed ALMA to the limits of its capabilities for this type of study, reaching an angular resolution of 0.05 arcseconds—equivalent to distinguishing a one-euro coin from 100 kilometers away. This precision allowed them to resolve structures as small as 2,000 astronomical units, identifying 70 dense cores embedded within four protoclusters at a distance of 160,000 light-years. To confirm the nature of these structures and exclude contamination from ionized gas—a particular challenge in such active regions—the team combined ALMA observations with data from the Hubble Space Telescope and the James Webb Space Telescope, which also confirmed that the detected cores are still in an early phase of their evolution.
"We are truly excited about the results achieved with this study. Thanks to ALMA, studying core masses in our Galaxy is becoming almost 'routine,' suggesting in particular that the mass of our cores seems to evolve, especially in high-mass regions," says Alessio Traficante, lead author of the study. "Until now, no one had attempted to push this type of research into extra-galactic regions, which require significantly higher resolution and sensitivity than studies conducted within the Milky Way. The identification of more than 70 cores in 30Dor-10 was by no means guaranteed, considering we were observing an environment with an interstellar medium whose characteristics are profoundly different from those found in the main massive star-forming regions of our Galaxy. We had no idea what to expect before seeing the highly detailed images obtained by ALMA."
By comparing the mass distribution of these cores with those observed in the Milky Way, the researchers found that both follow a similar trend consistent with Salpeter's Law—a notable result given the markedly different conditions in the Large Magellanic Cloud, including lower metallicity, different turbulence regimes, and a more strongly ionized interstellar medium. Crucially, while the initial mass function of stars in such extreme environments can show an excess of massive stars, the earliest phase of core formation appears to follow the same patterns seen in our Galaxy, suggesting that these young cores continue to accrete mass over time regardless of their surroundings.
The findings suggest that the initial fragmentation of molecular clouds—the process that leads to the formation of dense cores—may be largely independent of the surrounding galactic environment. This work, connected to ALMA Large Programs such as ALMA-IMF and ALMAGAL, opens the door to a systematic study of star formation in other galaxies using techniques previously applied only within the Milky Way, and allows astronomers to begin testing whether the physical laws governing the birth of stars hold constant across the universe.
This article is an adaptation of the original press release by the Italian National Institute of Astrophysics (INAF).
The Atacama Large Millimeter/submillimeter Array (ALMA), an international astronomy facility, is a partnership of the European Southern Observatory (ESO), the U.S. National Science Foundation (NSF), and the National Institutes of Natural Sciences (NINS) of Japan in cooperation with the Republic of Chile. ALMA is funded by ESO on behalf of its Member States, by NSF in cooperation with the National Research Council of Canada (NRC) and the National Science and Technology Council (NSTC) in Taiwan, and by NINS in cooperation with the Academia Sinica (AS) in Taiwan and the Korea Astronomy and Space Science Institute (KASI).
ALMA construction and operations are led by ESO on behalf of its Member States; by the National Radio Astronomy Observatory (NRAO), managed by Associated Universities, Inc. (AUI), on behalf of North America; and by the National Astronomical Observatory of Japan (NAOJ) on behalf of East Asia. The Joint ALMA Observatory (JAO) provides the unified leadership and management of ALMA's construction, commissioning, and operation
Ingredients of an Active Galactic Nucleus
Credit: Rebull, IPAC, Caltech Download Image
During this week, NuSTAR performed an observation of the nearby radio galaxy 3C390.3 coordinated with the JAXA/NASA/ESA XRISM observatory. This target is a classic example of an Active Galactic Nucleus (AGN) where evidence of relativistic motion is observed in the spectrum of emission lines from material in and around an accretion disk close to a supermassive black hole. 3C290.3 is an ideal target for studying AGN variability, accretion disk structure, and the geometry of multi-temperature plasmas surronding the black hole through reverberation mapping campaigns. Data from the simultaneous XRISM and NuSTAR observations offers an unprecedented look at the structure of the accretion flow. Combining the high spectral resolution of XRISM and the broad X-ray energy sensitivity of NuSTAR provides detailed constraints on the intrinsic radiation emission and the reprocessing by the gas that surrounds, and is accreting onto, the black hole. This will lead to a clean, broadband benchmark to map the AGN structure in this prototypical radio galaxy.
Last week, members of the NuSTAR Calibration Team hosted one of our semi-regular “calibration coffees” with the NuSTAR science user community. During this meeting the focus was on understanding the transition between “on-sky” science data and “occulted by the Earth” science data, specifically for bright X-ray sources. In addition, the NuSTAR team updated the science users on the continued monitoring of the science impact of the suspected tears in the MLI covers on both of the NuSTAR telescopes. The Calibration Coffee was attended by over twenty members of the science community and all of the calibration slides are now available to the large science community via the NuSTAR public GitHub pages.
Author: Elias Kammoun, Postdoctoral Scholar, Caltech
Artist’s impression of two young stars orbiting each other inside the dusty Orion star-forming complex. Because clouds of gas and dust hide these systems at visible and infrared wavelengths, astronomers used the NSF Very Long Baseline Array to observe them in radio light and measure their orbital motion and masses directly. Credit: NRAO/AUI/NSF.Hi-Res File
Artist’s impression of two young stars orbiting each other inside the dusty Orion star-forming complex. Because clouds of gas and dust hide these systems at visible and infrared wavelengths, astronomers used the NSF Very Long Baseline Array to observe them in radio light and measure their orbital motion and masses directly. Credit: NRAO/AUI/NSF -Youtube Vieeo
A star’s mass determines its entire life story, from how it shines to how it dies. For young stars…
A star’s mass determines its entire life story, from how it shines to how it dies. For young stars shrouded in dust, getting an accurate mass has long been difficult…but new radio measurements are beginning to change that. Astronomers are helping unravel the mass mystery of young stars in the Orion star-forming complex by measuring their masses with unprecedented precision.
Lightweight Sun-like stars burn steadily for 10 billion years, while massive ones blaze briefly before exploding as supernovae in mere millions of years. Mass also determines what heavy elements they forge, such as carbon, oxygen, and iron, which form the building blocks of planets and life. In addition, it influences what types of planets can form around them.
Using the U.S. National Science Foundation Very Long Baseline Array (NSF VLBA), a network of radio telescopes spread across the United States that work together as one giant instrument, the team tracked the orbital motions of a sample of young binary star systems in Orion. Binary stars are pairs that orbit a shared center of mass, like dance partners spinning each other around. By watching these “dances” with extraordinary precision at radio wavelengths, researchers were able to calculate the stars’ true masses without relying on theoretical models. As lead researcher Dr. Sergio Abraham Dzib Quijano, from the Max Planck Institute for Radio Astronomy explains, “Stellar mass is the most fundamental property of a star, yet it is notoriously difficult to measure for young, embedded systems.”
Young stars in Orion are shrouded in dense clouds of gas and dust, blocking visible and even infrared light from reaching most telescopes. The NSF VLBA overcomes this by observing at radio wavelengths (5 GHz), where dust is transparent and the array’s extreme resolution (sub-milliarcsecond) resolves tight binaries that blur together at other wavelengths.
The NSF VLBA can also detect motions on the sky smaller than the width of a human hair seen from thousands of kilometers away, showcasing the remarkable technical achievement behind these mass measurements. In practice, this means measuring tiny shifts in a star’s apparent position on the sky over months and years, using repeated observations to trace out its path. Each NSF VLBA radio telescope in the array records the incoming radio waves with exquisite timing. By combining the signals from antennas spread across the country from Hawaii to the Virgin Islands, astronomers can pinpoint a star’s position with milliarcsecond accuracy, far finer than what is possible with a single dish. By comparing how that position changes from epoch to epoch, they can see the subtle orbital motion caused by the gravity of a companion star and use that motion to infer the mass of each star in the system.
In the systems where the measured masses could be compared with standard models of young-star evolution, the results were mixed: some were reproduced well, while at least one showed a clear mismatch, suggesting that the models may still need refinement. The observations also uncovered previously hidden close companions and evidence that strong magnetic activity can persist in relatively massive young stars.
Young stars in Orion are the building blocks of future planetary systems, much like our own Solar System. “These accurate mass measurements now turn Orion into a precision laboratory for testing how young stars form and evolve,” says Dr. Jazmin Ordonez-Toro, postdoctoral Orquídeas fellow at the Astronomical Observatory at the University of Nariño, who co-led the study, “These measurements vastly expand our understanding of how stellar neighborhoods like our own are built.”
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This artist’s impression compares the semi-heavy water content of the interstellar comet 3I/ATLAS (left) and Earth (right). Insets illustrate the relative abundance of deuterated water (HDO) molecules, showing that 3I/ATLAS contains over 30 times more HDO than is found in Earth’s oceans. This elevated ratio suggests the comet formed in an extremely cold environment, very different from the conditions that shaped our Solar System. Credit: NSF/AUI/NSF NRAO/M.Weiss
First-ever measurement of deuterated water in an interstellar object shows its home system formed under extreme conditions
New observations from the Atacama Large Millimeter/submillimeter Array (ALMA) have yielded the first-ever measurement of deuterated water — also known as semi-heavy water — in an interstellar object. The discovery reveals that the interstellar comet 3I/ATLAS contains at least 30 times the proportion of semi-heavy water found in comets from our own Solar System, providing a direct chemical window into the frigid conditions under which its home star system formed.
The research was led by PhD student Luis E. Salazar Manzano at the University of Michigan, working with assistant professor Teresa Paneque-Carreño, who served as Principal Investigator of the ALMA Director's Discretionary Time program that made these observations possible. The data were obtained with ALMA's Atacama Compact Array (ACA) just six days after 3I/ATLAS reached its closest point to the Sun — a narrow observing window made possible by ALMA's unique ability to point toward the solar direction, unlike most optical telescopes.
"Our new observations show that the conditions that led to the formation of our Solar System are much different from how planetary systems evolved in different parts of our Galaxy," said Salazar Manzano.
Comets are often nicknamed dirty snowballs, in part because of their high water content — water that carries frozen chemical records of the environment in which they formed. Alongside ordinary water (H₂O), comets contain a molecular variant called deuterated water (HDO), in which one hydrogen atom is replaced by deuterium, a hydrogen atom with an extra neutron. In Solar System comets, roughly one molecule of semi-heavy water exists for every ten thousand molecules of ordinary water. In 3I/ATLAS, that ratio is at least 30 times higher — and over 40 times the proportion found in Earth's oceans.
Notably, ordinary water (H₂O) itself fell below ALMA's detection threshold during these observations. The team constrained the D/H ratio indirectly, by detecting HDO directly and inferring the water production rate through the excitation of methanol lines — a sophisticated modeling approach that showcases ALMA's unique analytical capabilities.
This elevated ratio points to an origin in an exceptionally cold and chemically distinct environment. "The chemical processes that lead to the enhancement of deuterated water are really sensitive to temperature and usually require environments colder than about 30 Kelvin, or about minus 406 degrees Fahrenheit," explained Salazar Manzano. The ratio was set as the comet's home system formed and has been preserved intact throughout its interstellar journey.
ALMA's instrumental role in this discovery was essential. Paneque-Carreño noted: "Most instruments can't point toward the Sun, but radio telescopes like ALMA can. We were able to observe the comet within days after perihelion, just as it peeked out from its transit behind the Sun. This gave us a constraint on these molecules that's not possible using other instruments."
Beyond being a chemical fingerprint of a distant planetary system, the HDO/H₂O ratio carries a special cosmological significance: the abundances of deuterium and hydrogen were set during the Big Bang itself, making this measurement a uniquely fundamental probe of the conditions under which other worlds are born. "Each interstellar comet brings a little bit of its history, its fossils, from elsewhere. We don't know exactly where, but with instruments like ALMA we can begin to understand the conditions of that place and compare them to our own," said Paneque-Carreño.
This research is published in Nature Astronomy on April 24, 2026, under the title "A Direct View of the Chemical Properties of Water from Another Planetary System: Water D/H in 3I/ATLAS" by Salazar Manzano, Paneque-Carreño et al.
The original press release was issued by the National Radio Astronomy Observatory (NRAO), an ALMA partner on behalf of North America.
The Atacama Large Millimeter/submillimeter Array (ALMA), an international astronomy facility, is a partnership of the European Southern Observatory (ESO), the U.S. National Science Foundation (NSF), and the National Institutes of Natural Sciences (NINS) of Japan in cooperation with the Republic of Chile. ALMA is funded by ESO on behalf of its Member States, by NSF in cooperation with the National Research Council of Canada (NRC) and the National Science and Technology Council (NSTC) in Taiwan, and by NINS in cooperation with the Academia Sinica (AS) in Taiwan and the Korea Astronomy and Space Science Institute (KASI).
ALMA construction and operations are led by ESO on behalf of its Member States; by the National Radio Astronomy Observatory (NRAO), managed by Associated Universities, Inc. (AUI), on behalf of North America; and by the National Astronomical Observatory of Japan (NAOJ) on behalf of East Asia. The Joint ALMA Observatory (JAO) provides the unified leadership and management of ALMA's construction, commissioning, and operation.
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The strong stellar wind from the supergiant star pushes the jets launched by the black hole away from the star. This causes the jet direction to vary as the black hole and the supergiant star move around their orbit. Credit: ICRAR/Curtin University
The direction of the radio jet changes as the black hole and the star move around their orbit (shown in red).
In a paper published in Nature Astronomy, researchers found the power of the jets in Cygnus X-1 – a system comprised of the first confirmed black hole and a supergiant star – was equivalent to the power output of 10,000 Suns.
To record the measurement, researchers used an array of linked up telescopes separated by large distances to observe the black hole jets being buffeted by the winds of the star as the black hole moved around its orbit – much like how strong winds on Earth can push around water in a fountain.
By knowing the power of the wind and measuring how much the jets were bent, the researchers could determine the instantaneous power of the jets for the first time.
In addition, they were able to determine the speed of the black hole’s jets – about half the speed of light, or 150,000 km per second – another measurement that has challenged scientists for decades.
Lead author Dr Steve Prabu, who worked at CIRA at the time of the research and who is now based at the University of Oxford, said researchers were able to make the measurement using a sequence of images of the “dancing jets” – a term he used to describe the jets’ movement pattern as they were repeatedly deflected indifferent directions by the supergiant star’s powerful winds as the star and black hole moved around their orbits.
Dr Prabu said the measurement allowed scientists to understand what fraction of the energy released around black holes could be deposited into the surrounding environment, thereby changing the environment.
“A key finding from this research is that about 10 per cent of the energy released as matter falls in towards the black hole is carried away by the jets,” Dr Prabu said.
“This is what scientists usually assume in large-scale simulated models of the Universe, but it has been hard to confirm by observation until now.”
Co-author Professor James Miller-Jones, from CIRA and the Curtin node of ICRAR, said previous methodscould only measure the average jet power over thousands or even millions of years, preventing accurate comparisons with the X-ray energy released instantaneously from the infalling matter.
“And because our theories suggest that the physics around black holes is very similar, we can now use this measurement to anchor our understanding of jets, whether they are from black holes 10 or 10 million times the mass of the Sun,” Professor Miller-Jones said.
“With radio telescope projects such as the Square Kilometre Array Observatory currently under construction in Western Australia and South Africa, we expect to detect jets from black holes in millions of distant galaxies, and the anchor point provided by this new measurement will help calibrate their overall power output.
“Black hole jets provide an important source of feedback to the surrounding environment and are critical to understanding the evolution of galaxies.”
Other collaborating institutions included the University of Barcelona, the University of Wisconsin-Madison, the University of Lethbridge and the Institute of Space Science.
Authors: Seiji Fujimoto et al. First Author’s Institution: University of Toronto; The University of Texas at Austin Status: Published in ApJ
You, me, your laptop, my $8 matcha, and just about everything else on Earth was forged in the fiery bellies of dying stars. Generations of stars had to live and die before the universe became enriched with any elements heavier than helium (what astronomers call “metals”). The first stars to undergo this cosmic cycle are known as Population III (Pop III) stars. Though their existence has been hypothesized since the 1960s, astronomers have failed to observe these distant metal-free stars or the faint, low-mass galaxies that host them.
The first Pop III stars likely formed around 100 million years after the Big Bang in pristine pockets of hydrogen gas. Although these are too
distant for us to observe, we expect that as the universe started to become metal enriched, there were still existing pockets of gas introverted enough to survive unpolluted and form metal-free Pop III stars up to a redshift of z ~ 6–7 (when the universe was around 900 million years old)!
JWST is the perfect instrument to search for these systems. You can read other astrobites on the search for possible Pop III systems with
JWST here and here. The authors of today’s article seek to develop the most efficient way
of using JWST’s Near-Infrared Camera (NIRCam) to find the galaxies hosting Pop III stars. Using their selection method on existing NIRCam
data, the authors identified one promising Pop III galaxy candidate.
Figure 1: Color–color diagram for selecting Pop III galaxies where the x and y-axes show the different NIRCam filters being subtracted. The cyan symbols are different Pop III models while the other colored dots are different metal-rich galaxy models. Adapted from Fujimoto et al. 2025
I’m Not Like Other Galaxies
In order to find a Pop III galaxy, we need to take a look at galaxies’ spectral energy distributions (SEDs). These are graphs that show the energy emitted by a galaxy at
different wavelengths of light. Pop III galaxies are expected to have SEDs that differ from your everyday, metal-enriched galaxy. NIRCam will
be especially sensitive to three key spectral features that show up in the SEDs of Pop III galaxies: an absent [O III] line (light emitted by
doubly ionized oxygen atoms), a strong H-alpha line (light emitted when a hydrogen atom transitions from its third to its second energy level),
and a significant Balmer jump (light absorbed to ionize electrons in the second energy level of a hydrogen atom). To identify these key SED
characteristics, the authors use SED fitting and color–color diagrams to execute an efficient Pop III search with NIRCam.
The first selection method involves SED fitting. Astronomers create template SEDs that represent different types of galaxies and then compare these templates to the observed SEDs to see which one matches best. In this work, the authors use metal-rich galaxy templates and Pop III templates to fit the galaxies observed with NIRCam. They then calculate the chi-squared χ2 (a statistical measure of best fit) between the data and all the SED
templates. A galaxy is selected as a Pop III candidate if the Pop III model provides a good fit (χ2 < 10) to the photometry and
is significantly better than any metal-rich model. It’s kind of like looking for Cinderella by making every woman in the kingdom try on the
glass slipper.
A color–color diagram plots the difference in magnitude between two filters on each axis. NIRCam filters are specially chosen to emphasize the SED characteristics above. When these filters are chosen, Pop III galaxies occupy a distinct region of this diagram as compared to metal-rich galaxies. For example, subtracting the F356W filter from the F277W filter is sensitive to the presence of the [O III] line and the Balmer jump. Figure 1 demonstrates how this color selection separates Pop III galaxies from typical galaxies.
Figure 2: SED of GLIMPSE-16043 with the best-fit Pop III template (blue) and best-fit metal-enriched template (gray). The top panel is the galaxy imaged in different filters from NIRCam and the Hubble Space Telescope. Credit: Fujimoto et al. 2025
O Pop III, Pop III, Wherefore Art Thou?
The authors apply their fresh new selection criteria to publicly available NIRCam data from large surveys. And (drum roll please) the slipper fits! The Pop III galaxy candidate GLIMPSE-16043 is an ultra-faint galaxy at z = 6.5. It was imaged in the GLIMPSE survey, which uses the technique of gravitational lensing to observe faint and distant galaxies.
The GLIMPSE survey targeted a massive galaxy cluster, Abell S1063. The cluster bends the light from distant galaxies and, like a giant lens, magnifies faraway objects, providing some of the deepest JWST imaging to date. The Pop III candidate passes both tests: it resides in the Pop III region of the color–color diagram, and its SED is best fit by a Pop III model, not a metal-rich galaxy model (see Figure 2). Next, spectroscopic follow-up is needed to ensure that this galaxy is truly metal free and not just extremely metal poor.
The authors conclude that our best shot at identifying additional Pop III galaxy candidates is using NIRCam to image large numbers of gravitationally lensed clusters. Without magnification from gravitational lensing, it may be impossible to see these ultra-faint Pop III galaxies. Once candidates have been identified, they can be followed up with deep spectroscopy to confirm their redshift and their lack of metals. Who knows? With these new methods, we may soon get a glimpse of the universe’s very first stars.
Original astrobite edited by Chris Layden and Margaret Verrico.
I am a first-year PhD student in astronomy and NSF Graduate Research Fellow at the University of Arizona. I study galaxy formation and evolution in the distant universe and am particularly interested in dusty star-forming galaxies. In my free time, I love reading, hiking, and baking bread!
Editor’s Note: Astrobites is a graduate-student-run organization that digests astrophysical literature for undergraduate students. As part of the partnership between the AAS and astrobites, we occasionally repost astrobites content here at AAS Nova. We hope you enjoy this post from astrobites; the original can be viewed atastrobites.org.
An illustration of a star and a brown dwarf in a binary system.
Generated with ChatGPT by the University of Hawaiʻi .
Results Test Brown Dwarf Theory challenging astrophysicists
Maunakea, Hawaiʻi – Astronomers using W. M. Keck Observatory on Maunakea, Hawaiʻi Island, have measured one of the most precise ages yet for a Sun-like star hosting a brown dwarf companion. The result offers a powerful new test of how brown dwarfs cool and evolve over time, helping to address a long-standing challenge in astrophysics.
The study focused on the nearby system HR 7672, which includes a Sun-like star and a faint brown dwarf companion. Using Keck Observatory’s Keck Planet Finder (KPF), the team detected subtle oscillations in the star’s surface, ripples that revealed its age to be 2.3 billion years.
Because the brown dwarf formed alongside the star, this precise stellar age serves as a benchmark for the companion’s evolution, offering a rare chance to directly test theoretical models of brown dwarf cooling.
“The 18% age uncertainty establishes the HR7672 system as a valuable benchmark for years to come,” said Yaguang Li, lead author and researcher at the University of Hawaiʻi at Mānoa.
The HR 7672 system has played a historic role in the study of substellar objects. The companion, known as HR 7672B, was first discovered by researcher Michael Liu, co-author and professor at the University of Hawaiʻi Institute for Astronomy. HR 7672B was the first directly imaged brown dwarfs orbiting a Sun-like star.
Using Keck Observatory’s Near-Infrared Camera (NIRC2) and the telescope’s Adaptive Optics system to correct for atmospheric blurring, Liu obtained a sharper image of the brown dwarf, which is 2,000 times fainter than its bright host star.
“Pioneering observations with Keck Observatory helped illuminate the so-called “brown dwarf desert,” the scarcity of such companions around Sun-like stars at close separations,” said Liu.
Now, more than two decades later, a new generation of Keck Observatory instrumentation continues to advance that legacy. Using ultra-precise measurements of the host star with the Keck Planet Finder (KPF) instrument, astronomers detected tiny stellar pulsations that reveal the star’s internal structure and age with unprecedented precision.
“The unique fast-readout mode of the Keck Planet Finder makes it the only instrument in the Northern Hemisphere capable of sampling oscillations on such short timescales,” added Li.
Testing How Brown Dwarfs Cool Over Time
Brown dwarfs are failed stars that are too small to sustain stable hydrogen fusion, so they gradually cool and fade as they age. Their brightness, therefore, depends sensitively on both their mass and age. However, astronomers have had difficulty testing theoretical models of this cooling, in part because reliable ages are rarely available.
Now, with this new and precise age measurement, combined with HR 7672B’s well-known luminosity and mass, the system becomes an exceptional “benchmark” for testing brown dwarf evolutionary models.
Comparing the observations with six different theoretical cooling models, the team found the best agreement with the most recent models that incorporate updated interior physics. Without the new data, the team would not have been able to distinguish this model from the five other possibilities.
These results demonstrate that high-precision stellar ages are essential for understanding substellar evolution — and show that precision spectroscopy with the next generation of observations will finally provide this information.
“Yaguang’s research has made this object even more valuable for our theoretical understanding of brown dwarfs,” said Liu.
As a next step, the researchers plan to generalize this method to a broader set of benchmark systems and test brown dwarf evolutionary models across different regimes.
