(Press-News.org)
Astronomers have gained insights into star formation by capturing the first spatially resolved detection of protostellar outflows and jets in the Milky Way’s outer region. The discovery, made using the Atacama Large Millimeter/submillimeter Array (ALMA), revealed that although the fundamental physics of star formation remains the same across different galactic environments, different chemistry or dust composition is observed in the outer Galaxy source.
The research focused on the protostellar source Sh 2-283-1a SMM1, located about 7.9 kiloparsecs (26,000 light-years) from the Sun and 15.7 kiloparsecs (51,000 light-years) from the Galactic center. This outer-Galaxy region contains only about one-third of the heavy elements found near the Sun. Such low-metallicity environments resemble those of the early Milky Way, making the site a rare natural laboratory for understanding star formation process in primitive environments.
ALMA’s observations revealed a striking bipolar system: narrow jets of high-velocity gas streaming away from the protostar, surrounded by broader, slower-moving outflows. This study tracked gas moving toward and away Earth using blue and red contours, respectively. The surrounding outflow appeared in gray, and the protostar itself was marked with a green star. These captured images provided the first clear view of protostellar jets resolved at such a large galactocentric distance.
Analysis of the velocity structure revealed that the jets are episodic rather than continuous. Instead of a steady flow, the protostar undergoes bursts of mass ejection recurring every 900–4,000 years. This stop-and-start rhythm regulates star growth, allowing it to accrete material from its disk while expelling excess mass and angular momentum. Although episodic ejections have been observed in nearby star-forming regions, this study reported such activity in a source more than 15 kiloparsecs from the Galactic center for the first time.
“By resolving jets and outflows in a protostar so far out in the Galaxy, we can see that the same physics shaping stars near the Sun also operates in low-metallicity environments. This discovery unlocks a unique opportunity to fundamentally advance our understanding of how stars are born across diverse cosmic environments,” said lead author Toki Ikeda of Niigata University.
The chemistry of the jets reflects their unusual environment. Measurements of carbon monoxide (CO) and silicon monoxide (SiO) show that the N(SiO)/N(CO) ratio appears lower in the outer-Galaxy protostellar core than in comparable sources in the inner Galaxy. This suggests that shock chemistry or dust properties differ in the outer Galaxy, where heavy elements are scarce. The finding reinforces that the physics of star formation is universal, whereas the chemistry varies depending on the local conditions.
Further analysis classified Sh 2-283-1a SMM1 as a hot core, i.e., a compact, warm, and chemically rich region surrounding a forming star This marks only the second detection of a hot core in the outer Galaxy, highlighting the rarity of such chemically complex regions so far from the Galactic center. The team further estimates the luminosity of protostar at approximately 6,700 times that of the Sun, placing it in the intermediate-to-high–mass category.
“Finding such a clean jet structure in the outer Galaxy was unexpected,” said Takashi Shimonishi, a co-author from Niigata University. “Even more exciting, the protostar was found to harbor complex organic molecules, opening up new opportunities to study star formation in more primitive environments from both physical and chemical perspectives.”
Beyond Sh 2-283-1a SMM1, ALMA also detected molecular outflows from four additional protostars in the outer Galaxy, confirming that star formation in these remote regions is both active and widespread.
These findings have great implications for astrophysics. By resolving jets and outflows from a protostar in a low-metallicity environment, the study confirms that the blueprint for star formation holds across the Milky Way, regardless of chemical composition. Moreover, the distinct chemical signatures of the outflows offer a glimpse into various conditions that shaped the earliest generations of stars.
The breakthrough underscores ALMA’s ability to extend the frontier of star formation studies. Until now, resolved studies of protostellar molecular jets were limited to objects only a few thousand light-years away. By extending this capability to the outer Galaxy, astronomers can now test whether models developed in nearby star-forming regions apply throughout the Galaxy.
Looking ahead, the team plans to expand their survey to additional outer-Galaxy protostars. Broader surveys could reveal whether episodic ejection cycles vary with metallicity, and whether molecules like SiO behave differently across environments. These efforts will build a fuller picture of how stars and planetary systems emerge in the diverse chemical landscapes of the Milky Way.
By capturing the first resolved jets in Sh 2-283-1a SMM1, identifying their episodic nature, and confirming the source as a rare hot core, this study bridges today’s star formation with the processes that shaped the early Universe. It shows that while chemistry changes with environment, the physics of stellar birth is a constant, i.e., linking the Milky Way’s outskirts to the Universe’s ancient past.
END
A new species of a native bushland marsupial – closely related to the kangaroo – has been discovered but is already likely extinct, new research shows.
Analysing fossils collected from caves of the Nullarbor and southwest Australia, researchers from Curtin University, the Western Australian Museum and Murdoch University uncovered a completely new species of bettong as well as two new subspecies of woylie.
Woylies are ecosystem engineers capable of turning over several tonnes of earth each year in search for their favourite mushroom treats. The cute kangaroo relatives, native to Western Australia, are the country’s ...
Former male high-level rugby players in New Zealand have a 22 percent increased risk of developing Alzheimer’s and other dementias later in life compared to men in the general population, according to new research from the University of Auckland.
The project is co-led by senior lecturer Dr Stephanie D’Souza from the COMPASS Research Centre in the University’s Faculty of Arts and Education and Dr Ken Quarrie from New Zealand Rugby.
Researchers examined long-term neurodegenerative disease risk outcomes for almost 13,000 men who played provincial-level or higher rugby between 1950 and 2000 and compared them with 2.4 million New Zealand men, matched on age, ...
In the criminal justice system, decisions about when and how long to detain people have historically been made by other people, like judges and parole boards. But that process is changing: Decision-makers increasingly include artificial intelligence systems in a variety of tasks, from predicting crime to analyzing DNA to recommending prison sentences. The use of AI in these domains raises pressing questions about how these computing systems use data to make predictions and recommendations, as well as larger questions about how to safeguard fairness in an AI age.
Notably, many AI systems are “black ...
Less than half of England has access to tirzepatide (Mounjaro) through their GP, despite the NHS roll-out of the weight-loss jab officially starting over two months ago, an investigation by The BMJ has found.
Due to the large number of people who could benefit from tirzepatide - an estimated 3.4 million people - and the drug’s price, NHS England and its spending watchdog, the National Institute for Health and Care Excellence, agreed the injections would be rolled out in phases over a 12-year period, which commenced on 23 June 2025, explains Elisabeth Mahase. Yet just 18 out of 42 commissioning bodies (43%) across the country ...
Researchers observed mother–infant interactions in urban UK and rural Ugandan communities, focussing on how mothers soothed their babies following naturally occurring episodes of distress.
They found that although the UK mothers responded to their babies' distress more quickly, Ugandan infants actually recovered faster.
This challenges long-standing assumptions rooted in Western models of parenting by showing that maternal promptness is not the only factor influencing how infants manage ...
From images of fruit to claims of being ‘sugar-free’, baby foods often feature misleading claims aimed at convincing parents the products are a healthy choice, new research shows.
The study led by the University of Auckland, reviewed packaging of more than 200 processed foods for infants and toddlers and found all featured marketing and nutrition claims, which didn’t necessarily stack up when they examined the ingredients. See Nutrition and Dietetics.
“These little packages are cluttered ...
September 4, 2025 -- A team of researchers found there is a possible molecular connection between air pollution and an increased risk of developing Lewy body dementia. The study builds on a decade of research linking exposure to fine particulate air pollution (PM2.5) -- from industrial activity, residential burning, wildfires, and vehicle exhaust—to a higher risk of developing these diseases. The findings add to a growing body of evidence indicating how environmental factors may trigger harmful protein changes in the brain that lead to neurodegeneration. The research is published in Science.
Lewy body diseases ...
Research Highlights:
An analysis of 25 years of the CDC WONDER database for death rates from hypertension-related kidney disease (also called hypertensive kidney disease or hypertensive renal disease) in the U.S. through 2023 found persistent differences across race, ethnicity, gender and region.
The highest death rates for hypertensive kidney disease were among Black individuals, followed by Hispanic individuals.
More men died from hypertensive kidney disease than women, and states in the South had the highest death rates from hypertensive kidney disease.
These findings highlight the urgent ...
Research Highlights:
Despite their effectiveness in lowering sodium intake and managing blood pressure, salt substitutes were rarely used by people with high blood pressure, according to a review of almost 20 years of U.S. health survey data.
Researchers recommend increasing awareness of salt substitutes as a strategy to help effectively treat blood pressure, especially for individuals with difficult-to-treat or treatment-resistant high blood pressure.
Note: The study featured in this news release is a research abstract. Abstracts presented ...
LA JOLLA, CA—Despite vaccines and treatments, SARS-CoV-2—the virus that causes COVID-19—continues to pose a global health threat, driven by new variants and its ability to hijack human cells in ways that still aren’t fully understood. Now, scientists at Scripps Research have pinpointed dozens of human proteins that SARS-CoV-2 needs to complete its full life cycle, from entering a cell to replicating and releasing new viral particles.
Published in PLOS Biology on June 12, 2025, these findings could open ...
