doi.eso.org

• Kraus, Stefan [University of Exeter, UK]
• Kluska, Jacques [University of Exeter, UK]
• Kreplin, Alexander [University of Exeter, UK]
• Bate, Matthew [University of Exeter, UK]
• Harries, Timothy [University of Exeter, UK]
• Hofmann, Karl-Heinz [Max-Planck-Institut für Radioastronomie, Bonn, Germany]
• Hone, Edward [University of Exeter, UK]
• Monnier, John [University of Michigan, Ann Arbor, USA]
• Weigelt, Gerd [Max-Planck-Institut für Radioastronomie, Bonn, Germany]
• Anugu, Narsireddy [University of Exeter, UK]
• de Wit, Willem-Jan [European Southern Observatory (ESO)]
• Wittkowski, Markus [European Southern Observatory (ESO)]

High-mass stars exhibit a significantly higher multiplicity frequency than low-mass stars, likely reflecting differences in how they formed. Theory suggests that high-mass binaries may form by the fragmentation of self-gravitational discs or by alternative scenarios such as disc-assisted capture. Near-infrared interferometric observations reveal the high-mass young stellar object IRAS 17216-3801 to be a close high-mass protobinary with a separation of 0.058 arcseconds (~ 170 au). This is the closest high-mass protobinary system imaged to date. We also resolve near- infrared excess emission around the individual stars, which is associated with hot dust in circumstellar discs. These discs are strongly misaligned with respect to the binary separation vector, indicating that tidal forces have not yet had time to realign. We measure a higher accretion rate towards the circumsecondary disc, confirming a hydrodynamic effect where the secondary star disrupts the primary star’s accretion stream and effectively limits the mass that the primary star can accrete. NACO L′-band imaging may also have resolved the circumbinary disc that feeds the accretion onto the circumstellar discs. This discovery demonstrates the unique capabilities of the VLTI, creating exciting new opportunities to study the dynamical processes that govern the architecture of close multiple systems.