Japanese researchers have proposed that immense gas streams may explain how high-mass stars manage to grow despite releasing powerful stellar winds and radiation that should otherwise halt their formation.
The birth of massive stars involves enormous outflows of mass, raising the question of how these stars can continue to accumulate material and reach sizes far greater than our Sun. Previous theories suggested that accretion disks—rotating structures composed of dust and gas—might provide the necessary fuel to sustain young stars during their early growth stages.
Peering Across the Universe
A new study, led by scientists from Kyoto University and the University of Tokyo, takes star formation theory in a new direction. Instead of accretion disks, the researchers point to vast streamers, flows of gas extending over a thousand astronomical units, that act as “cosmic highways” feeding material directly into developing stars.
“Our work seems to show that these structures are being fed by streamers, which are flows of gas that bring matter from scales larger than a thousand astronomical units, essentially acting as massive gas highways,” says co-author Fernando Olguin.
Their work builds on previous research, utilizing new data with higher angular resolution to observe the previously targeted star system with greater precision. Chile’s Atacama Large Millimeter/submillimeter Array (ALMA) provided the required data. ALMA’s antenna array offers such high precision that it can observe dust and molecular line emissions down to millimeter wavelengths, which are essential for the team’s work, as high-mass stars reside much farther from the Earth than lower-mass ones.
Star Food Revealed
When the team analyzed the ALMA data, they discovered that a young star in the system appeared to possibly be feeding on two streamers. Peering closely at one of the streamers, the team discerned that it seemed to be connected to the star’s central region. That streamer also appears to display a velocity gradient, suggesting rotation and perhaps infall. From these observations, the team believes that the streamer supplies an adequate amount of mass to the young star at a rate fast enough to mitigate the star’s feedback effects, thereby contributing to the highly dense region seen surrounding the massive central star over time.
The results were surprising to the scientists, as their expectation had been to see an accretion disk composed of dust or a torus roughly a few hundred astronomical units in diameter. Instead, the team found these unusual spiral arms reaching close to the central source.
“We found streamers feeding what at that time was thought to be a disk, but to our surprise, there is either no disk or it is extremely small,” says Olguin.
Rethinking Star Growth
The results challenge long-standing assumptions about the formation of massive stars. The study demonstrates that streamers can transport large amounts of gas without requiring a central disk, effectively overcoming the disruptive forces of stellar feedback.
The team’s next step is to determine the extent to which this process is widespread. They plan to expand their observations to other star-forming regions in search of additional evidence of streamer-fed growth. They also intend to conduct more detailed studies of their initial target, probing the surrounding gas to see if small hidden disks may still play a role in fueling the star.
The paper, “Massive Extended Streamers Feed High-Mass Young Stars,” appeared in Science Advances on August 20, 2025.
Ryan Whalen covers science and technology for The Debrief. He holds an MA in History and a Master of Library and Information Science with a certificate in Data Science. He can be contacted at ryan@thedebrief.org, and follow him on Twitter @mdntwvlf.