Free Astronomy Magazine November-December 2026

NOVEMBER-DECEMBER 2026 T he inset circle shows an ALMA 0.9 mm continuum image of the central binary system of IRAS 07299−1651 with the reconstructed orbital trajectories over- laid. The red- and blue-shifted hydrogen recombination line emission traces the rotation of the ionized circumstellar disks around the two forming stars, while the arrows indicate the directions of the bipolar jets. Background: Mid-infrared image of the region obtained with JWST. [NASA, ESA, CSA, STScI, J. DePasquale (STScI), ALMA (ESO/NAOJ/NRAO), Y. Zhang] study’s first author. “Each new ob- servation added another piece, and eventually the orbit, disks, and jets all came together into a single, co- herent picture.” This mismatched, chaotic-looking ar- chitecture is hard to explain if the two stars grew up together in the same disk — in that scenario, they’d be expected to inherit similar, well- aligned spins. Instead, the evidence points to a different origin story: the two stars likely began forming sep- arately, in their own individual pock- ets of gas, before a chance close encounter brought them into their present configuration while they were still wrapped in their birth cloud. In representative orbital solu- tions, the stars passed closest to each other only about 60 years before the observations, practically an instant on cosmic timescales. The compact disks seen today appear to have sur- vived the encounter, retaining well- defined rotational structures. “This study demonstrates that the early lives of stars can be quite chaotic, with a chance encounter leading to this gravitational dance and stellar coupling,” said Jonathan C. Tan, a co-author of the study. It’s still not certain whether the two stars will stay gravitationally bound to each other for good — their cur- rent motion sits close to the dividing line between a bound orbit and one that could eventually fly apart, and interactions with the surrounding gas may still nudge their fate one way or the other. Future observa- tions will help pin that down. More broadly, the study opens a new way of investigating how massive binary stars come together. By applying the same long-term monitoring ap- proach to other young massive bina- ries, astronomers hope to learn how often close encounters like this one—rather than shared birth in a single disk—build the massive binary systems seen across our galaxy. the U.S. National Science Founda- tion’s Very Large Array (VLA), as well as infrared images from the James Webb Space Telescope (JWST) and ESO’s Very Large Telescope (VLT), which traced jets of material streaming away from the young stars. Together, these observations let the team reconstruct, for the first time, the system’s full three-di- mensional architecture, how the stars orbit each other, how their disks are tilted, and how their jets point into space. “Each telescope re- vealed a different piece of the puz- zle,” said Rubén Fedriani, a co- author of the study. “The combina- tion of radio and infrared observa- tions provides the most exquisite detail on the formation of this mas- sive protobinary system.” What they found surprised them. In- stead of a neat, roughly circular orbit, the stars are following a highly eccentric trajectory, with the preferred orbital solutions lying close to a parabolic path. And rat- her than being aligned, as would be expected if the stars formed from the same disk, their surrounding disks are tilted at a sharp angle to each other and to the orbit itself. “It felt like solving a three-dimen- sional puzzle,” said Yao Wang, the !