Free Astronomy Magazine November-December 2026

47 ASTRO PUBLISHING NOVEMBER-DECEMBER 2026 A n artist’s impression of the for- mation of a close massive binary system, showing misaligned disks around two young stars. [Y. Zhang] had few opportunities to catch the actual moment of assembly. An international team led by Yichen Zhang of Shanghai Jiao Tong Univer- sity set out to change that by study- ing IRAS 07299−1651, a system containing two massive protostars, stars still growing by pulling in sur- rounding gas and dust. The team had studied this system before, in 2019, when ALMA observations first provided direct dynamical con- straints on the pair. At the time, the results seemed broadly consistent with the standard picture: two stars forming together from the frag- mentation of one large disk. But one detail didn’t quite fit: the disks around the two stars already looked oddly misaligned. To dig deeper, the researchers spent nearly eight years measuring ex- tremely subtle shifts in the two stars’ positions on the sky, a technique that requires exceptional precision and is well within ALMA’s capabilities. “For the first time, we were able to watch two massive stars move around one another while they were still being born,” said Yichen Zhang, correspon- ding author of the study. The team combined this long-term ALMA monitoring with data from