Stellar Growth Fueled by Gas “Highways,” New Research Reveals
For decades, astronomers believed that massive stars gained their size by accumulating material from large, rotating disks of dust adn gas.However, a recent study conducted by an international team, including researchers from Kyoto University and the University of Tokyo, challenges this long-held assumption.
The research suggests that young stars are primarily fed by “streamers” – substantial flows of gas extending from distances greater than 1,000 astronomical units,effectively acting as vast conduits delivering material to the star. According to lead author Fernando Olguin, these streamers represent a new understanding of how stars build mass.
To investigate this hypothesis, the team focused on observing star-forming regions in greater detail than previously possible. Because high-mass stars form further away than their smaller counterparts, a powerful observatory was required. Thay utilized the Atacama Large millimeter/submillimeter Array (ALMA) in Chile, a network of antennas designed to detect faint millimeter-wavelength emissions from dust and molecules.
ALMA’s high precision allowed the team to observe a young star receiving material from two distinct streamers. One streamer exhibited a velocity pattern indicative of both rotation and inward movement, suggesting it’s rapidly delivering a important amount of gas to the star’s core, overcoming the outward pressure generated by the star itself.
Surprisingly, the researchers did not find the expected large dust disk, typically predicted to span hundreds of astronomical units. “We found streamers feeding what was thought to be a disk, but to our surprise, there is either no disk or it is indeed extremely small,” Olguin explained.
This revelation indicates that streamers can efficiently transport large quantities of gas to star-forming regions, even in the presence of stellar feedback, regardless of whether a disk is present around the central star.
The team intends to expand their investigation by studying additional star-forming regions to determine if this streamer-fed accretion process is a common mechanism for the formation of massive stars. They also plan to analyze the gas closer to the star to confirm or refute the existence of smaller disks.
This research,published on August 20,2025,in Science Advances (DOI: 10.1126/sciadv.adw4512),offers a new pathway to understanding stellar growth and challenges existing models of star formation.
