SPACE/COSMOS

Unusual carbon dioxide-rich disk detected around young star challenges planet formation models

Stockholm University

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An image of the star-forming region NGC 6357 with the young star XUE 10. Observations with JWST/MIRI reveal a planet-forming disk whose spectrum shows clear detections of four distinct forms of carbon dioxide (CO2), but only little water, providing new insights into the chemical environment where planets are taking shape. Photo credit: Stockholm University (SU) and María Claudia Ramírez-Tannus, Max Planck Institute for Astronomy (MPIA).

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Credit: Stockholm University (SU) and María Claudia Ramírez-Tannus, Max Planck Institute for Astronomy (MPIA).

A study led by Jenny Frediani at Stockholm University has revealed a planet-forming disk with a strikingly unusual chemical composition: an unexpectedly high abundance of carbon dioxide (CO₂) in regions where Earth-like planets may one day form. The discovery, made using the James Webb Space Telescope (JWST), challenges long-standing assumptions about the chemistry of planetary birthplaces. The study is published in Astronomy & Astrophysics.

“Unlike most nearby planet-forming disks, where water vapor dominates the inner regions, this disk is surprisingly rich in carbon dioxide,” says Jenny Frediani, PhD student at the Department of Astronomy, Stockholm University.

“In fact, water is so scarce in this system that it’s barely detectable — a dramatic contrast to what we typically observe.”

A newly formed star is initially deeply embedded in the gas cloud from which it was formed and creates a disk around itself where planets in turn can be formed. In conventional models of planet formation, pebbles rich in water ice drift from the cold outer disk toward the warmer inner regions, where the rising temperatures cause the ices to sublimate. This process usually results in strong water vapor signatures in the disk's inner zones. However, in this case, the JWST/MIRI spectrum shows a puzzlingly strong carbon dioxide signature instead.

“This challenges current models of disk chemistry and evolution since the high carbon dioxide levels relative to water cannot be easily explained by standard disk evolution processes,” Jenny Frediani explains.

Arjan Bik, researcher at the Department of Astronomy, Stockholm University, adds, “Such a high abundance of carbon dioxide in the planet-forming zone is unexpected. It points to the possibility that intense ultraviolet radiation — either from the host star or neighbouring massive stars — is reshaping the chemistry of the disk.”

The researchers also detected rare isotopic variants of carbon dioxide, enriched in either carbon-13 or the oxygen isotopes ¹⁷O and ¹⁸O, clearly visible in the JWST data. These isotopologues could offer vital clues to long-standing questions about the unusual isotopic fingerprints found in meteorites and comets — relics of our own Solar System's formation.

This CO₂-rich disk was found in the massive star-forming region NGC 6357, located approximately 1.7 kiloparsecs (about 53 quadrillion kilometers) away. The discovery was made by the eXtreme Ultraviolet Environments (XUE) collaboration, which focuses on how intense radiation fields impact disk chemistry.

Maria-Claudia Ramirez-Tannus from the Max Planck Institute for Astronomy in Heidelberg and lead of the XUE collaboration says that it is an exciting discovery: “It reveals how extreme radiation environments — common in massive star-forming regions — can alter the building blocks of planets. Since most stars and likely most planets form in such regions, understanding these effects is essential for grasping the diversity of planetary atmospheres and their habitability potential.”

Thanks to JWST’s MIRI instrument, astronomers can now observe distant, dust-enshrouded disks with unprecedented detail at infrared wavelengths — providing critical insights into the physical and chemical conditions that govern planet formation. By comparing these intense environments with quieter, more isolated regions, researchers are uncovering the environmental diversity that shapes emerging planetary systems. Astronomers at Stockholm University and Chalmers have helped develop the MIRI instrument which is a camera and a spectrograph that observes mid- to long-wavelength infrared radiation from 5 microns to 28 microns. It also has coronagraphs, specifically designed to observe exoplanets.

The study “XUE: The CO_2-rich terrestrial planet-forming region of an externally irradiated Herbig disk” is published in Astronomy & Astrophysics.

 

Jenny Frediani, Stars, Planets and Astrobiology, Department of Astronomy, Stockholm University. Photo: Adriana Todorovic/Stockholm University

Credit

Adriana Todorovic/Stockholm University

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Journal

Astronomy and Astrophysics

DOI

10.1051/0004-6361/202555718 

Method of Research

Observational study

Subject of Research

Not applicable

Article Title

XUE: The CO_2-rich terrestrial planet-forming region of an externally irradiated Herbig disk

Article Publication Date

29-Aug-2025

SCI-FI-TEK X 2

AI advances boost safety and performance in fusion reactors

Hefei Institutes of Physical Science, Chinese Academy of Sciences

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Architecture of the Multi-Task Learning Neural Network (MTL-NN) for the automatic identification of plasma confinement states.

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Credit: DENG Guohong

A research team led by Prof. SUN Youwen from the Hefei Institutes of Physical Science of the Chinese Academy of Sciences, has developed two innovative artificial intelligence (AI) systems to enhance the safety and efficiency of fusion energy experiments. 

Their findings were recently published in Nuclear Fusion and Plasma Physics and Controlled Fusion.

Fusion energy holds the promise of providing clean and virtually limitless power. However, for future reactors, they must operate reliably and avoid dangerous phenomena such as disruptions—sudden, intense events that can damage the reactor—and precisely control the plasma’s confinement state to sustain high performance.

To address these challenges, the team created two specialized AI systems.

The first AI system acts as a disruption predictor. It uses decision tree models to detect early warning signs of disruptions caused by so-called "locked modes"—a common plasma instability. Unlike typical black-box AI, this model is interpretable: it doesn’t just say that something’s wrong, it also explains why, pointing to the physical signals behind its predictions. In tests, it correctly gave early warnings 94% of the time, with alerts coming 137 milliseconds ahead of the disruption—enough time to act.

The second AI tool monitors the plasma’s state. Instead of using separate models to identify operational modes (like L-mode and H-mode) and detect edge-localized modes (ELMs), the researchers developed a multi-task learning model that does both jobs at once. This approach improves accuracy and robustness. The result: a 96.7% success rate in recognizing plasma conditions in real time.

These AI tools not only improve reactor safety but also deepen our understanding of plasma behavior. The technologies developed in this work lay a crucial foundation for the intelligent control systems required in next-generation fusion reactors.

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Journal

Nuclear Fusion

DOI

10.1088/1741-4326/ade3ed 

Article Title

Automatic identification of tokamak plasma confinement states (L-mode, ELM-free H-mode, and ELMy H-mode) with multi-task learning neural network

GREENWASHING

Net zero pledges: corporate buzzword or genuine commitment? 

University of Birmingham

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Many of the world’s largest corporations have adopted ‘net-zero’ carbon reduction pledges because they feel the need to conform to expected ‘appropriate behaviour’ or risk reputational damage, a new study reveals. 

While ‘net zero’ has become a dominant theme for companies communicating their climate change credentials, many corporate pledges lack the substance needed to drive real change. 

Publishing their findings in Applied Corpus Linguistics, researchers from the University of Birmingham conclude that companies' net-zero narratives often serve as symbolic reputation management rather than a blueprint for transformative climate action. 

Drs Matteo Fuoli and Annika Beelitz used advanced linguistic techniques to analyse over 1,200 sustainability reports from Fortune Global 500 companies between 2020 and 2022.  

The study is the first large-scale linguistic analysis of net-zero discourse among these companies. It combines quantitative text analysis with qualitative interpretation to reveal how language shapes corporate climate narratives. 

They discovered that adoption of net-zero targets is driven by a mix of pressures such as legal mandates, peer imitation, and social expectations. Oil and gas companies, under intense scrutiny, appear motivated by legitimacy concerns, while financial firms emphasize alliances and peer alignment. 

Dr Fuoli commented: “While net-zero pledges are a step forward, their credibility hinges on transparency and measurable progress. Our findings suggest that net zero is often used as a symbolic tool to maintain legitimacy rather than a framework for transformative action. Without clearer strategies and stronger commitments, these pledges risk becoming another chapter in the long history of corporate greenwashing.” 

The study highlights recent rollbacks in climate commitments by major players like BP and Shell, raising concerns about the resilience of corporate climate strategies in the face of geopolitical and economic pressures. 

Dr Beelitz commented: "Regulators, investors, and civil society must scrutinise corporate net-zero claims more rigorously. We need to move beyond aspirational talk - real climate leadership requires not just words, but measurable, enforceable action.” 

The researchers found that the term ‘net zero’ appeared in reports from nearly three-quarters of the companies analysed, but many organisations use vague, aspirational language - framing net zero as a ‘journey’ or ‘ambition’.  

Many strategies include setting emission targets and reporting. However, more impactful measures like renewable energy and structural reform are less emphasised – reflecting a broader ‘techno-optimistic’ narrative prioritising innovation over systemic change. 

While some companies pledged to address all categories of emissions, many—particularly in the oil and gas sector—focused only on direct emissions, omitting the substantial indirect emissions generated by their products. 

Financial services firms frequently referenced participation in net-zero alliances, such as the UN-convened Net-Zero Asset Owner Alliance. These affiliations were used to legitimize their climate credentials, yet the actual strategies for achieving net zero remained vague. 

ENDS 

For more information, please contact the Press Office at the University of Birmingham on pressoffice@contacts.bham.ac.uk or +44 (0)121 414 2772  

Notes to editor: 

• The University of Birmingham is ranked amongst the world’s top 100 institutions. Its work brings people from across the world to Birmingham, including researchers, teachers and more than 8,000 international students from over 150 countries. 

• ‘Corporate buzzword or genuine commitment? A corpus-assisted analysis of corporate ‘net-zero’ pledges by major global corporations’ - Matteo Fuoli and Annika Beelitz is published in Applied Corpus Linguistics. 

 

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Journal

Applied Corpus Linguistics

Method of Research

Data/statistical analysis

Subject of Research

People

Article Title

‘Corporate buzzword or genuine commitment? A corpus-assisted analysis of corporate ‘net-zero’ pledges by major global corporations

Article Publication Date

28-Aug-2025

 

Why seismic waves are slower shortly after an earthquake

Friction along grain contacts as a culprit for temporary seismic velocity changes

GFZ Helmholtz-Zentrum für Geoforschung

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Rock sample of Bentheim sandstone, inside a protective neoprene jacket and with all the sensors glued to its surface, before going into GFZ's experimental press.

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Credit: Manuel Asnar/GFZ

Solid as they are, rocks are not static materials with constant properties. Even small loads are enough to alter their mechanical properties; their reaction to being deformed is a loss of stiffness. Rocks which have been damaged in such a way are then less able to withstand loads, such as gravity or tectonic stresses. This phenomenon is therefore of relevance for understanding the occurrence of material failure, as in landslides or earthquakes. Such changes in elastic properties are commonly observed in heterogeneous and granular materials such as rocks, concrete or sediments. As a result, they play a role in geotechnics as well as in the stability of man-made structures.

These effects have been observed in laboratory experiments for years using acoustic methods. The development of seismic interferometry made such observations possible in the field by exploiting the so-called “seismic noise”. A key observation using these methods is the sudden decrease in the velocity of seismic waves in the subsurface in the wake of an earthquake (damage). This decrease is followed by a slow re-increase, which can extend over several years (recovery).

Despite these studies and many years of research, the physical origins of these processes have still not been clearly determined. It is however commonly agreed that the contrast between the very stiff grains and vastly softer grain contact planes, as well as the stress concentrations at these contact points, is responsible for these effects. Manuel Asnar and a team of collaborators from the GFZ, the University of Edinburgh in the UK, and the Université de Lorraine in France, have managed to make a breakthrough in laboratory experiments carried out at the GFZ’s High-Pressure Labs. Their experimental setup allowed them to measure wave velocities in a 10-centimetre sandstone cylinder along various directions of propagation to an extremely high degree of precision.

The sample was subjected to varying levels of stress along the cylinder’s axis. Doing so showed that, as expected, the static effects of the loading strongly impacted waves along the main axis, while leaving the waves along the diameter relatively unaffected. The time-dependent effects however, that is, the sudden damage and long healing, were consistently observed along every direction of propagation.

These results show that the time-dependent effects are not caused by grain contacts that are being more or less compressed against each other. Rather, these effects can be traced back to contact planes sliding against each other, irrespective of whether the load is being applied or released.

The effects of friction along contacts within the material have long been suggested as being responsible for these time-dependent changes in wave velocities; but this study of the anisotropy of velocity changes – meaning, their directional dependence – provides meaningful evidence in favour of this interpretation. Based on those findings, models can be developed to better describe and predict the time-dependent changes of mechanical properties in rocks and geotechnical materials.

 

Original study: Asnar, M., Sens-Schönfelder, C., Bonnelye, A. et al. Anisotropy reveals contact sliding and aging as a cause of post-seismic velocity changes. Nat Commun 16, 7587 (2025). https://doi.org/10.1038/s41467-025-62667-0

 

Scientific contacts

Dr. Manuael Asnar

Manuel.asnar@gfz.de

 

Dr. Christoph Sens-Schönfelder

sens-schoenfelder@gfz.de

 

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Journal

Nature Communications

DOI

10.1038/s41467-025-62667-0 

Article Title

Anisotropy reveals contact sliding and aging as a cause of post-seismic velocity changes

Article Publication Date

25-Aug-2025

 

Microalgae are more significant for carbon dioxide absorption in the Southern Ocean than previously thought

In the past, these tiny single-celled organisms slowed down the increase of CO₂ in the atmosphere – at a time when greenhouse gas levels were rising sharply

Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research

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At the end of the last ice age, algal blooms of the species Phaeocystis absorbed large quantities of carbon dioxide in the Southern Ocean and thus significantly slowed the rise of the greenhouse gas in the atmosphere.

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Credit: Gerhard Drebes

Some Fourteen thousand years ago, algal blooms in the Southern Ocean helped to massively reduce the global carbon dioxide content of the atmosphere – as has now been revealed by new analyses of ancient DNA published by a team from the Alfred Wegener Institute in the journal Nature Geoscience. In the ocean around the Antarctic continent, these algal blooms had a significant impact on global carbon dynamics. The current and expected future decline in sea ice in this region now poses a serious threat to these algae, which could incur global consequences.

At the end of the last ice age, the warming in the southern hemisphere slowed temporarily in a phase known as the Antarctic Cold Reversal (ACR). A new study by the Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research (AWI) reveals that the special climatic conditions of this period – in particular involving a vast sea ice cover in winter, followed by strong seasonal melting in the springtime – favoured massive algal blooms of the genus Phaeocystis in the Southern Ocean. These blooms absorbed large amounts of carbon dioxide, markedly slowing the increase of this climate-damaging gas in the atmosphere. The AWI research team was able to prove this connection for the first time by examining so-called sedimentary ancient DNA (sedaDNA) – genetic material that has been preserved in the seabed for thousands of years. This is due to the fact that Phaeocystis does not leave behind classic microfossils and therefore remained invisible in previous climate archives. To date, it has not been possible to detect its presence by way of classic geochemical methods.

In conducting their study, the AWI team examined a sediment core from a depth of almost 2,000 metres in the Bransfield Strait north of the Antarctic Peninsula. The core contains sedaDNA from the last 14,000 years. The researchers extracted this from the sediment cores to study changes in biological communities over time. "Our study shows that these algal blooms contributed to a significant reduction in global atmospheric CO₂ levels during a climatically important transition phase characterized by high sea ice extent," explains Josefine Friederike Weiß from AWI, lead author of the study. This is because the sediment core exhibits a high ratio of barium (Ba) to iron (Fe) for this phase – a ratio considered as an indicator of organic carbon input and deposition, due to the fact that it is linked to biological productivity in surface water.

"The further the sea ice expands in winter, the larger the area in spring where nutrient-rich meltwater enters the surface sea – and therefore the zone where Phaeocystis algae find ideal growth conditions. As a result, greater sea ice extent leads directly to a larger region with high algal productivity." Such biological processes in the ocean are closely linked to global climate events – even if they remain invisible to the human eye. In addition, the large-scale Phaeocystis blooms impacted on food webs and nutrient distribution in the Southern Ocean, triggering a complex chain reaction: From changes in plankton composition and shifted biogeochemical cycles through to increased carbon transport into the depths, they influenced the ecological balance and the carbon cycle over long periods of time.

Today, Phaeocystis is particularly endangered in Antarctica, given that the long-term trend towards sea ice loss and, in particular, the recent dramatic decline in the Southern Ocean is altering its living conditions significantly. The loss of these important algal blooms could destabilise local ecosystems. Although other algae species such as diatoms could benefit from ice-free conditions, the structure of the  food web would change fundamentally. What is more, Phaeocystis is particularly efficient in transporting carbon to the deep sea. Therefore, a decline in its blooms could mean that less carbon is stored in the ocean overall, which could exacerbate climate change in the long term.

Furthermore, Phaeocystis produces dimethyl sulphide (DMS), a gas that promotes cloud formation, thereby increasing the reflection of sunlight. Consequently, the loss of algal blooms could also incur a negative impact on cloud formation and therefore on climate regulation, which in turn would lead to an additional, amplifying impact on climate.

On the one hand, the study by the AWI scientists provides new insights into the role of the Southern Ocean and its microorganisms in the global climate events of the past, which could not have previously been detected using traditional methods in sediment archives. On the other hand, it shows for the first time that previous geological investigation methods, in combination with sedimentary ancient DNA, give rise to a more realistic reconstruction of past ecosystems and our understanding of earlier carbon dioxide fluctuations. This will pave the way for more differentiated assessments of future developments in the climate system. The analysis of these geological processes underscores the crucial role that biological processes play in climate regulation. This finding highlights the significance of giving greater consideration to marine ecosystems in current climate research and in future forecasts.

With regard to further research, this means that the combination of DNA analyses and geological methods should be further improved in order to obtain and outline an even more accurate picture of past climate changes. In addition, individual significant organisms, such as Phaeocystis, should be studied in greater detail to be able to better understand their influence on the carbon cycle and climate. This will not only result in better climate predictions, but also allow potential profound ecological changes in the ocean to be identified at an early juncture and their impacts assessed accordingly.

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Journal

Nature Geoscience

DOI

10.1038/s41561-025-01761-w 

Article Title

Carbon drawdown by algal blooms during Antarctic Cold Reversal from sedimentary ancient DNA

Article Publication Date

25-Aug-2025

 

Study reveals how a popular fentanyl additive affects breathing and heart rate

Supplies of fentanyl mixed with the animal tranquilizer xylazine have been on the rise across the U.S.

Michigan Medicine - University of Michigan

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While the grip of the opioid epidemic is loosening, thanks in part to extensive public health efforts and rescue medications like Narcan, deaths from accidental overdose still threaten those who use synthetic opioids like fentanyl. The drug is increasingly mixed with other potent substances, including animal tranquilizers such as xylazine, making it even more dangerous.

States across the country, including Michigan, are seeing a drastic increase in xylazine-involved fatalities, according to a report from the Michigan Department of Health and Human Services.

However, very little is known about how the sedative, which is not approved for human use and causes severe skin ulcers, affects breathing when mixed with fentanyl.

A new U-M study from the laboratories of John Traynor and Erica Levitt in the Edward F. Domino Research Center uncovers how fentanyl and xylazine interact in a mouse model.  

“We don’t have any clear data as to whether xylazine increases the risk of overdose, so we needed to test its physiological effects in an animal model,” said Jess Anand, Ph.D., research assistant professor of pharmacology at the U-M Medical School and author on the study.

Working with first author, graduate student Catherine Demery, the team set out to test their hypothesis that xylazine would worsen the often-deadly decrease in breathing rate that is characteristic of fentanyl use.  

Fentanyl-induced pauses in inhalation, or apneas, correlated with a drop in blood oxygen levels. But xylazine did not amplify the extent to which fentanyl reduced oxygen levels.

“What we found is the breathing rate depression is not a one plus one amplification. We didn’t see a drastic synergism of these drugs in their respiratory effects, which is good and somewhat surprising,” said Demery.  

However, they did find that xylazine reduced heart rate more than fentanyl. A potentially more important driver of increased risk of overdose is this decrease in heart rate caused by xylazine, said Demery.  

Thankfully, overdose reversal medications such as Narcan, which work by blocking the opioid receptors in the brain, are typically enough to overcome an overdose caused by fentanyl adulterated with xylazine, they stress.  

Their insights, say the authors, may open other avenues of research into polysubstance use involving opioids.  

“It’s crucially important to keep research up to pace with what’s going on in real life, otherwise the people facing issues now might not get the help they need,” said Anand.

Additional authors: Sierra C. Moore, Erica S. Levitt, and John Traynor

Funding: This work was supported by the National Institutes of Health grants UG3 DA056884, R21DA051723, R01 DA061320, R01 HL174547, and T32 GM132046.

Paper cited: “Xylazine Exacerbates Fentanyl-Induced Respiratory Depression and Bradycardia,” The Journal of Pharmacology and Experimental Therapeutics. DOI: 10.1016/j.jpet.2025.103616  

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Journal

Journal of Pharmacology and Experimental Therapeutics

DOI

10.1016/j.jpet.2025.103616