Kleptomaniacs can even take a hint

Impulsive control disorder driven by situational-cue mechanism similar to drug addiction

Peer-Reviewed Publication

KYOTO UNIVERSITY

 

IMAGE: PATIENTS WITH KLEPTOMANIA EXHIBIT DISTINCT PATTERNS OF GAZING AND BRAIN ACTIVITY WHEN SHOWN IMAGES WITH ENVIRONMENTAL CUES RELEVANT TO THEIR SYMPTOMS. view more 

CREDIT: KYOTOU/JAKE TOBIYAMA

Kyoto, Japan -- Don't call a kleptomaniac a crook. Not only are the underlying motives for stealing different, brain activity also shows contrasting images.

A team of researchers at Kyoto University has recently found that patients with kleptomania exhibit distinct patterns of gazing and brain activity when shown images with environmental cues relevant to their symptoms. Such characteristics were not observed in healthy subjects, including those who may have occasionally nabbed from the cookie jar.

"Studies such as ours could help deter impulsively committed crimes like shoplifting and contribute to realizing a better society," says lead author Yukiori Goto.

Investigations of patients with alcohol addiction also revealed environmental cues leading to cravings, a phenomenon known as cue-induced craving.

"Although the sample size was small and still preliminary, our study reports for the first time that kleptomania may also involve the mechanisms that could be similar, if not identical, to those related to drug addiction," notes Goto.

Other behavioral addictions observed in gambling, gaming, and Internet use share these mechanisms, clinically termed substance use disorder.

Kleptomania is characterized by pathological, compulsive, and repetitive stealing for the sake of the act itself and not motivated by any sense of material gain. Therapeutic treatments are becoming more important in preventing repeated convictions than conventional criminal penalties, which have been shown to be ineffective in curbing this maladaptive behavior.

While kleptomania meets the criteria of addiction and is classified as a "Disruptive, Impulse-Control, and Conduct Disorder" by the American Psychiatry Society, few studies of the condition have been published to date.

Goto's research examined 11 patients with behavioral addiction and 27 healthy adult subjects. Each was shown still and video images, some containing symptom-relevant environmental cues -- such as shops and their merchandise -- with others depicting irrelevant ones such as natural scenery.

Using eye-tracking technology, all subjects' gaze patterns were monitored while they viewed the test materials. Their brain activity was simultaneously measured with functional near-infrared spectroscopy, a non-invasive method that detects hemoglobin changes in the prefrontal cortex.

The team's fNIRS recordings revealed compromised activity in the right prefrontal cortex of kleptomania patients during task performance. These results correlated with other behavioral addicts exhibiting an inability to estimate probability of risk and finding themselves in a reward system trap.

"Our study may lead to the development of therapeutic treatments targeting maladaptive learning, not only for drug addiction, but also impulse control disorders such as kleptomania," reflects Goto

The paper "Distinct Situational Cue Processing in Individuals with Kleptomania: A Preliminary Study" was published on 2 February 2023 in the International Journal of Neuropsychopharmacology with doi: 10.1093/ijnp/pyad005

Visual situational cues influence physiological alteration causing craving and addictive behavior

Kleptomania seems to fulfill criteria of behavioral addiction.

Cause and effect relationship between stimuli and response　through incentive sensitization and habit

Functional near-infrared spectroscopy (fNIS) revealed compromised activity in prefrontal cortex of patients with behavioral addiction.

About Kyoto University

Kyoto University is one of Japan and Asia's premier research institutions, founded in 1897 and responsible for producing numerous Nobel laureates and winners of other prestigious international prizes. A broad curriculum across the arts and sciences at both undergraduate and graduate levels is complemented by numerous research centers, as well as facilities and offices around Japan and the world. For more information please see: http://www.kyoto-u.ac.jp/en

---

DOI

10.1093/ijnp/pyad005 

METHOD OF RESEARCH

Experimental study

SUBJECT OF RESEARCH

People

ARTICLE TITLE

Distinct Situational Cue Processing in Individuals with Kleptomania: A Preliminary Study

Scientists warn of many dangerous climate feedback loops

Current plans to mitigate climate change may be inadequate

Peer-Reviewed Publication

CONSERVATION BIOLOGY INSTITUTE

 

IMAGE: THE WILDFIRE-CLIMATE CHANGE FEEDBACK LOOP. view more 

CREDIT: CHRIS WOLF, WILLIAM RIPPLE BACKGROUND PHOTO BY PETER BUSCHMANN

A new report written by an international team of researchers, including scientists from Oregon State University (OSU), warns of many risky climate feedback loops and the need for action in both research and policy. Published in the scientific journal One Earth today, the report states that partly due to amplifying climate feedbacks, “a very rapid drawdown in emissions will be required to limit future warming.”

Researchers from the United States and Europe listed and described 41 climate feedback loops that have major implications for the outlook on climate change. Climate feedback loops are processes that can either amplify or diminish the effects of our greenhouse gas emissions, initiating a cyclical chain reaction that keeps repeating again and again. There are many large amplifying feedbacks that accentuate warming. In total, the researchers identified 27 amplifying feedbacks, 7 dampening feedbacks, and 7 uncertain feedbacks.

The lead authors, Christopher Wolf, a postdoctoral researcher at OSU, and William Ripple, a distinguished professor of ecology at OSU, were joined by several US and international scientists who are credited as co-authors on the report. Ripple is also an affiliate scientist with the Conservation Biology Institute.

The authors highlight several particularly troubling feedback loops such as the permafrost feedback wherein rising temperatures lead to permafrost thawing, which results in more carbon dioxide and methane emissions, leading to further warming. Other potentially dangerous feedbacks include drying or smoldering peatlands and forest dieback. Because these feedbacks may not yet be fully incorporated into climate models, current emissions drawdown plans could fail to adequately limit future warming. In addition, “some climate feedback loops are associated with tipping points, which will make it difficult to reverse their effects,” said coauthor Jillian Gregg, a scientist at Terrestrial Ecosystems Research Associates.

Motivated by the many amplifying climate feedbacks, the authors make two recommendations. With regard to climate research, a rapid transition toward integrated Earth system science is needed in order to fully account for biological, social, and other interactions that may influence the climate. In terms of climate policy, more ambitious plans for emissions drawdown should be pursued given both ongoing climate disasters and long-term catastrophic risks. Such plans could include employing nature-based solutions to sequester more carbon from the atmosphere. “The strategic establishment of large natural carbon sinks such as forests is a critical step toward reaching carbon neutrality,” said Ripple.

The authors concluded by issuing a call for transformative change to address the climate crisis and dangers posed by feedback loops. According to Wolf, “policies are needed to facilitate transformative and socially just changes across many sectors, including energy and food production.”

The paper is accompanied by the launch of a feedback loops website with animated feedback loops inspired by the study.

In addition to Wolf, Ripple, and Gregg, five other scientists are co-authors of the paper:

Timothy M. Lenton of University of Exeter, Susan M. Natali and Philip B. Duffy of the Woodwell Climate Research Center, Johan Rockström and Hans Joachim Schellnhuber of the Potsdam Institute for Climate Impact Research.

Permafrost

CREDIT

Brandt Meixell, USGS

Sea ice

CREDIT

Patrick Kelley, U.S. Coast Guard

Wildfire

CREDIT

Peter Buschmann

JOURNAL

One Earth

METHOD OF RESEARCH

Meta-analysis

SUBJECT OF RESEARCH

Not applicable

ARTICLE TITLE

Scientists warn of many dangerous climate feedback loops

ARTICLE PUBLICATION DATE

17-Feb-2023

Feedback loops make climate action even more urgent, scientists say

Peer-Reviewed Publication

OREGON STATE UNIVERSITY

 

IMAGE: FIRE DAMAGE IN THE CITY OF DETROIT, OREGON, AND THE OREGON CASCADES CAN BE SEEN IN THIS AERIAL IMAGE. PHOTO COURTESY OREGON STATE UNIVERSITY. view more 

CREDIT: OREGON STATE UNIVERSITY

CORVALLIS, Ore. – An international collaboration led by Oregon State University scientists has identified 27 global warming accelerators known as amplifying feedback loops, including some that the researchers say may not be fully accounted for in climate models.

They note that the findings, published today in the journal One Earth, add urgency to the need to respond to the climate crisis and provide a roadmap for policymakers aiming to avert the most severe consequences of a warming planet.

In climate science, amplifying feedback loops are situations where a climate-caused alteration can trigger a process that causes even more warming, which in turn intensifies the alteration. An example would be warming in the Arctic, leading to melting sea ice, which results in further warming because sea water absorbs rather than reflects solar radiation.

OSU College of Forestry postdoctoral scholar Christopher Wolf and distinguished professor William Ripple led the study, which in all looked at 41 climate change feedbacks.

“Many of the feedback loops we examined significantly increase warming because of their connection to greenhouse gas emissions,” Wolf said. “To the best of our knowledge, this is the most extensive list available of climate feedback loops, and not all of them are fully considered in climate models. What’s urgently needed is more research and modeling and an accelerated cutback of emissions.”

The paper makes two calls to action for “immediate and massive” emissions reductions:

• Minimize short-term warming given that “climate disasters” in the form of wildfires, coastal flooding, permafrost thaw, intense storms and other extreme weather are already occurring.
• Mitigate the possible major threats looming from climate tipping points that are drawing ever-closer due to the prevalence of the many amplifying feedback loops. A tipping point is a threshold after which a change in a component of the climate system becomes self-perpetuating.

“Transformative, socially just changes in global energy and transportation, short-lived air pollution, food production, nature preservation and the international economy, together with population policies based on education and equality, are needed to meet these challenges in both the short and long term,” Ripple said. “It’s too late to fully prevent the pain of climate change, but if we take meaningful steps soon while prioritizing human basic needs and social justice, it could still be possible to limit the harm.”

Ripple, Wolf and co-authors from the University of Exeter, the Potsdam Institute for Climate Impact Research, the Woodwell Climate Research Center and Terrestrial Ecosystems Research Associates considered both biological and physical feedbacks. Biological feedbacks include forest dieback, soil carbon loss and wildfire; physical feedbacks involve changes such as reduced snow cover, increased Antarctic rainfall and shrinking arctic sea ice.

Even comparatively modest warming is expected to heighten the likelihood that the Earth will cross various tipping points, the researchers say, causing big changes in the planet’s climate system and potentially strengthening the amplifying feedbacks.

“Climate models may be underestimating the acceleration in global temperature change because they aren’t fully considering this large and related set of amplifying feedback loops,” Wolf said. “The accuracy of climate models is crucial as they help guide mitigation efforts by telling policymakers about the expected effects of human-caused greenhouse gas emissions. While recent climate models do a much better job of incorporating diverse feedback loops, more progress is needed.”

Emissions have risen substantially over the last century, the researchers note, despite several decades of warnings that they should be significantly curbed. The scientists say interactions among feedback loops could cause a permanent shift away from the Earth’s current climate state to one that threatens the survival of many humans and other life forms.

“In the worst case, if amplifying feedbacks are strong enough, the result is likely tragic climate change that’s moved beyond anything humans can control,” Ripple said. “We need a rapid transition toward integrated Earth system science because the climate can only be fully understood by considering the functioning and state of all Earth systems together. This will require large-scale collaboration, and the result would provide better information for policymakers.”

In addition to the 27 amplifying climate feedbacks the scientists studied were seven that are characterized as dampening – they act to stabilize the climate system. An example is carbon dioxide fertilization, where rising concentrations of atmospheric CO2 lead to increasing carbon uptake by vegetation.

The effects of the remaining seven feedbacks, including increased atmospheric dust and reduced ocean stability, are not yet known.

The paper in One Earth has a corresponding website that features more about climate feedback loops, including infographics and interactive animations.

---

JOURNAL

One Earth

METHOD OF RESEARCH

Literature review

SUBJECT OF RESEARCH

Not applicable

ARTICLE TITLE

Many risky feedback loops amplify the need for massive climate action

ARTICLE PUBLICATION DATE

17-Feb-2023

Evolution: Miniproteins appeared “from nowhere”

Peer-Reviewed Publication

MAX DELBRÜCK CENTER FOR MOLECULAR MEDICINE IN THE HELMHOLTZ ASSOCIATION

 

IMAGE: THE MICROPROTEIN IN THE MITOCHONDRIA (GREEN) AND IN THE NUCLEUS (BLUE) WAS OVEREXPRESSED IN HUMAN CELLS. THE YELLOW AND PINK AREAS SHOW THAT THE SIGNAL OF THE MICROPROTEIN OVERLAPS WITH THE MITOCHONDRIAL AND NUCLEAR SIGNALS. view more 

CREDIT: CLARA SANDMANN, MAX DELBRÜCK CENTER

Every biologist knows that small structures can sometimes have a big impact: Millions of signaling molecules, hormones, and other biomolecules are bustling around in our cells and tissues, playing a leading role in many of the key processes occurring in our bodies. Yet despite this knowledge, biologists and physicians long ignored a particular class of proteins – their assumption being that because the proteins were so small and only found in primates, they were insignificant and functionless. The discoveries made by Professor Norbert Hübner at the Max Delbrück Center and Dr. Sebastiaan van Heesch at the Princess Máxima Center for Pediatric Oncology in the Netherlands changed this view a few years ago: “We were the first to prove the existence of thousands of new microproteins in human organs,” says Hübner.

In a new paper published in Molecular Cell, the team led by Hübner and van Heesch now describe how they systematically studied these miniproteins, and what they learned from them: “We were able to show which genome sequences the proteins are encoded in, and when DNA mutations occurred in their evolution,” explains Dr. Jorge Ruiz-Orera, an evolutionary biologist in Hübner’s lab and one of the paper’s three lead authors, who work at the Max Delbrück Center and the German Center for Cardiovascular Research (DZHK). Ruiz-Orera’s bioinformatic gene analyses revealed that most human microproteins developed millions of years later in the evolutionary process than the larger proteins currently known to scientists.

Yet the huge age gap doesn’t appear to prevent the proteins from “talking” to each other. “Our lab experiments showed that the young and old proteins can bind to each other – and in doing so possibly influence each other,” says lead author Dr. Jana Schulz, a researcher in Hübner’s team and at the DZHK. She therefore suspects that, contrary to long-held assumptions, the microproteins play a key role in a variety of cellular functions. The young proteins might also be heavily involved in evolutionary development thanks to comparatively rapid “innovations and adaptations.” “It’s possible that evolution is more dynamic than previously thought,” says van Heesch.

Proteins only found in humans

The researchers were surprised to find that the vastly younger microproteins could interact with the much older generation. This observation came from experiments performed using a biotechnical screening method developed at the Max Delbrück Center in 2017. In collaboration with Dr. Philipp Mertins and the Proteomics Platform, which the Max Delbrück Center operates jointly with the Berlin Institute of Health at Charité (BIH), the miniproteins were synthesized on a membrane and then incubated with a solution containing most of the proteins known to exist in a human cell. Sophisticated experimental and computer-aided analyses then allowed the researchers to identify individual binding pairs. “If a microprotein binds to another protein, it doesn’t necessarily mean that it will influence the workings of the other protein or the processes that the protein is involved in,” says Schulz. However, the ability to bind does suggest the proteins might influence each other’s functioning. Initial cellular experiments conducted at the Max Delbrück Center in collaboration with Professors Michael Gotthardt and Thomas Willnow confirm this assumption. This leads Ruiz-Orera to suspect that the microproteins “could influence cellular processes that are millions of years older than they are, because some old proteins were present in the very earliest life forms.”

Unlike the known, old proteins that are encoded in our genome, most microproteins emerged more or less “out of nowhere – in other words, out of DNA regions that weren’t previously tasked with producing proteins,” says Ruiz-Orera. Microproteins therefore didn’t take the “conventional” and much easier route of being copied and derived from existing versions. And because these small proteins only emerged during human evolution, they are missing from the cells of most other animals, such as mice, fish and birds. These animals, however, have been found to possess their own collection of young, small proteins.

The smallest proteins so far

During their work, the researchers also discovered the smallest human proteins identified to date: “We found over 200 super-small proteins, all of which are smaller than 16 amino acids,” says Dr. Clara Sandmann, the study’s third lead author. Amino acids are the sole building blocks of proteins. Sandmann says this raises the question of how small a protein can be – or rather, how big it must be to be able to function. Usually, proteins consist of several hundred amino acids.

The small proteins that were already known to scientists are known as peptides and function as hormones or signal molecules. They are formed when they split off from larger precursor proteins. “Our work now shows that peptides of a similar size can develop in a different way,” says Sandmann. These smallest-of-the-small proteins can also bind very specifically to larger proteins – but it remains unclear whether they can become hormones or similar: “We don’t yet know what most of these microproteins do in our body,” says Sandmann.

Yet the study does provide an inkling of what the molecules are capable of: “These initial findings open up numerous new research opportunities,” says van Heesch. Clearly, the microproteins are much too important for researchers to keep ignoring them. Van Heesch says the biomolecular and medical research communities are very enthusiastic about these new findings. One conceivable scenario would be “that these microproteins are involved in cardiovascular disease and cancer, and could therefore be used as new targets for diagnostics and therapies,” says Hübner. Several U.S. biotech companies are already doing research in this direction. And the team behind the current paper also has big plans: Their study investigated 281 microproteins, but the aim now is to expand the experiments to include many more of the 7,000 recently cataloged microproteins – in the hope that this will reveal many as-yet-undiscovered functions.

 

Further information

Unchartered territory in the human genome

Unknown miniproteins in the heart

Hübner Lab

Van Heesch Lab

 

Literature

Clara-L. Sandmann, Jana F. Schulz, Jorge Ruiz-Orera, et al. (2023): “Evolutionary origins and interactomes of human, young microproteins and small peptides translated from short open reading frames,” Molecular Cell, DOI: 10.1016/j.molcel.2023.01.023
 

Downloads

An evolutionarily young protein that arose de novo in Old World monkeys: The microprotein in the mitochondria (green) and in the nucleus (blue) was overexpressed in human cells. The yellow and pink areas show that the signal of the microprotein overlaps with the mitochondrial and nuclear signals. Photo: Clara Sandmann, MDC

 

Max Delbrück Center

The Max Delbrück Center for Molecular Medicine in the Helmholtz Association (Max Delbrück Center) is one of the world’s leading biomedical research institutions. Max Delbrück, a Berlin native, was a Nobel laureate and one of the founders of molecular biology. At the Center’s locations in Berlin-Buch and Mitte, researchers from some 70 countries analyze the human system – investigating the biological foundations of life from its most elementary building blocks to systems-wide mechanisms. By understanding what regulates or disrupts the dynamic equilibrium in a cell, an organ, or the entire body, we can prevent diseases, diagnose them earlier, and stop their progression with tailored therapies. Patients should benefit as soon as possible from basic research discoveries. The Max Delbrück Center therefore supports spin-off creation and participates in collaborative networks. It works in close partnership with Charité – Universitätsmedizin Berlin in the jointly run Experimental and Clinical Research Center (ECRC), as well as with the Berlin Institute of Health (BIH) at Charité and the German Center for Cardiovascular Research (DZHK). Founded in 1992, the Max Delbrück Center today employs 1,800 people and is funded 90 percent by the German federal government and 10 percent by the State of Berlin. www.mdc-berlin.de

---

JOURNAL

Molecular Cell

DOI

10.1016/j.molcel.2023.01.023 

SUBJECT OF RESEARCH

Cells

ARTICLE TITLE

Evolutionary origins and interactomes of human, young microproteins and small peptides translated from short open reading frames

ARTICLE PUBLICATION DATE

17-Feb-2023

Serial dependance bias: Does it affect higher- or lower-order processing of perception?

Guessing coins value quickly demonstrates bias mechanism in cognition

Peer-Reviewed Publication

OSAKA METROPOLITAN UNIVERSITY

 

IMAGE: STUDY PARTICIPANTS WERE ASKED TO GUESS THE NUMBER, OR THE VALUE OF COINS DISPLAYED ON SCREEN FOR HALF A SECOND. BECAUSE GUESSING THE VALUE OF THE COINS REQUIRED SOME COGNITIVE PROCESSING, RESEARCHERS WERE ABLE TO TEST THE EFFECTS OF SERIAL DEPENDENCE BIAS FOR PERCEPTUAL AND COGNITIVE PROCESSING SEPARATELY. view more 

CREDIT: OSAKA METROPOLITAN UNIVERSITY

Osaka, Japan – Serial dependence is a bias affecting perceptual experience, in which what you currently perceive tends to be biased toward what you have perceived immediately before. This phenomenon has been observed in tasks using different stimuli, including tilt perception, number perception, and motion perception, but it was not known if this bias occurred during sensory perception or cognition.

A research team, led by Professor Shogo Makioka from the Osaka Metropolitan University Graduate School of Sustainable System Sciences, conducted experiments on the serial dependence of number perception using coins, to see if serial perception bias occurred in lower-order perceptual or higher-order perceptual and cognitive processing.

Experiments were conducted in which between 8 to 32 Japanese coins of three types—silver one yen, gold five yen, and copper ten yen—were displayed on screen for half a second. In the first experiment, the 24 participants guessed the total number of coins that appeared on the screen 250 times; in the second experiment, participants saw coins appear on the screen, but guessed the total value of the money displayed 250 times. Serial dependence was confirmed for both tasks: it was found that a participant’s last guess, not the coins that they had just seen for half a second, had the greatest effect on how they answered. These results indicate that higher-order cognitive processing has a greater influence on the occurrence of serial dependence. Their findings were published in Scientific Reports.

 “The results of this study show that our perceptual experiences and our decisions themselves influence our next decisions, which may be useful in capturing the tendency to misjudge and misunderstand in our daily lives,” explained Professor Makioka. “We believe that research advances on biases—such as the serial dependence bias—should be applied to how information is presented and can be used to create an environment that minimizes human error.”

###

About OMU

Osaka Metropolitan University is a new public university established by a merger between Osaka City University and Osaka Prefecture University in April 2022. For more science news, see https://www.omu.ac.jp/en/ or follow @OsakaMetUniv_en and #OMUScience.

---

JOURNAL

Scientific Reports

DOI

10.1038/s41598-022-24236-z 

METHOD OF RESEARCH

Experimental study

SUBJECT OF RESEARCH

People

ARTICLE TITLE

Serial dependence in estimates of the monetary value of coins

 Tadpole Playing Around Black Hole

Peer-Reviewed Publication

NATIONAL INSTITUTES OF NATURAL SCIENCES

 

IMAGE: ARTIST’S IMPRESSION OF THE “TADPOLE” MOLECULAR CLOUD AND THE BLACK HOLE AT THE GRAVITATIONAL CENTER OF ITS ORBIT. view more 

CREDIT: KEIO UNIVERSITY

A peculiar cloud of gas, nicknamed the Tadpole due to its shape, appears to be revolving around a space devoid of any bright objects. This suggests that the Tadpole is orbiting a dark object, most likely a black hole 100,000 times more massive than the Sun. Future observations will help determine what is responsible for the shape and motion of the Tadpole.

A team of Japanese researchers led by Miyuki Kaneko at Keio University used data from the James Clerk Maxwell Telescope, operated by the East Asian Observatory, and NAOJ’s Nobeyama 45-m Radio Telescope to identify an unusual cloud of gas about 27,000 light-years away in the constellation Sagittarius. The curved “Tadpole” shape of the molecular gas cloud strongly suggests that it is being stretched as it orbits around a massive compact object. The only problem is, at the center of the Tadpole’s orbit, there are no bright objects which could be massive enough to gravitationally hold the Tadpole. The best candidate for this massive compact invisible object is a black hole.

Because black holes don’t emit light, the only way to detect them is when they interact with other objects. This leaves astronomers in the dark about just how many black holes, and with what range of masses, might be lurking in the Milky Way.

Now the team plans to use ALMA (Atacama Large Millimeter/submillimeter Array) to search for faint signs of a black hole, or other object, at the gravitational center of the Tadpole’s orbit.

These results appeared as Kaneko et al. “Discovery of the Tadpole Molecular Cloud near the Galactic Nucleus” in The Astrophysical Journal on January 10, 2023.

---

JOURNAL

The Astrophysical Journal

DOI

10.3847/1538-4357/aca66a 

METHOD OF RESEARCH

Observational study

SUBJECT OF RESEARCH

Not applicable

ARTICLE TITLE

Discovery of the Tadpole Molecular Cloud near the Galactic Nucleus

Astrophysics: Scientists observe high-

speed star formation

Peer-Reviewed Publication

UNIVERSITY OF COLOGNE

 

IMAGE: OBSERVATION OF THE CYGNUS X REGION WITH THE FLYING OBSERVATORY SOFIA REVEALED THAT STARS FORM THERE MORE QUICKLY THAN PREVIOUSLY ASSUMED. view more 

CREDIT: NASA SPITZER/IRAC MIPS, USRA/SOFIA (L. PROUDFIT, L. BONNE) AND UNIVERSITY OF COLOGNE (N. SCHNEIDER)

Gas clouds in the Cygnus X Region, a region where stars form, are composed of a dense core of molecular hydrogen (H2) and an atomic shell. These ensembles of clouds interact with each other dynamically in order to quickly form new stars. That is the result of observations conducted by an international team led by scientists at the University of Cologne’s Institute of Astrophysics and at the University of Maryland. Until now, it was unclear how this process precisely unfolds. The Cygnus X region is a vast luminous cloud of gas and dust approximately 5,000 light years from Earth. Using observations of spectral lines of ionized carbon (CII), the scientists showed that the clouds have formed there over several million years, which is a fast process by astronomical standards. The results of the study ‘Ionized carbon as a tracer for the assembly of interstellar clouds’ will appear in the next issue of Nature Astronomy. The paper is already accessible online.

The observations were carried out in an international project led by Dr Nicola Schneider at the University of Cologne and Prof Alexander Tielens at the University of Maryland as part of the FEEDBACK programme on board the flying observatory SOFIA (Stratospheric Observatory for Infrared Astronomy). The new findings modify previous perceptions that this specific process of star formation is quasi-static and quite slow. The dynamic formation process now observed would also explain the formation of particularly massive stars.

By comparing the distribution of ionized carbon, molecular carbon monoxide and atomic hydrogen, the team found that the shells of interstellar gas clouds are made of hydrogen and collide with each other at speeds of up to twenty kilometres per second. “This high speed compresses the gas into denser molecular regions where new, mainly massive stars form. We needed the CII observations to detect this otherwise ‘dark’ gas,” said Dr Schneider. The observations show for the first time the faint CII radiation from the periphery of the clouds, which could not be observed before. Only SOFIA and its sensitive instruments were capable of detecting this radiation.

SOFIA was operated by NASA and the German Aerospace Center (DLR) until September 2022. The observatory consisted of a converted Boeing 747 with a built-in 2.7-metre telescope. It was coordinated by the German SOFIA Institute (DSI) and the Universities Space Research Association (USRA). SOFIA observed the sky from the stratosphere (above 13 kilometres) and covered the infrared region of the electromagnetic spectrum, just beyond what humans can see. The Boeing thus flew above most of the water vapour in the Earth’s atmosphere, which otherwise blocks out infrared light. This allowed the scientists to observe a wavelength range that is not accessible from Earth. For the current results, the team used the upGREAT receiver installed on SOFIA in 2015 by the Max Planck Institute for Radio Astronomy in Bonn and the University of Cologne.

Even though SOFIA is no longer in operation, the data collected so far are essential for basic astronomical research because there is no longer an instrument that extensively maps the sky in this wavelength range (typically 60 to 200 micrometres). The now active James Webb Space Telescope observes in the infrared at shorter wavelengths and focuses on spatially small areas. Therefore, the analysis of the data collected by SOFIA is ongoing and continues to provide important insights – also regarding other star-forming regions: “In the list of FEEDBACK sources, there are other gas clouds in different stages of evolution, where we are now looking for the weak CII radiation at the peripheries of the clouds to detect similar interactions as in the Cygnus X region,” Schneider concluded.

---

JOURNAL

Nature Astronomy

METHOD OF RESEARCH

Observational study

SUBJECT OF RESEARCH

Not applicable

ARTICLE TITLE

Ionized carbon as a tracer for the assembly of interstellar clouds’

ARTICLE PUBLICATION DATE

16-Feb-2023