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Two scenarios have been proposed to match the existing observationalconstraints of the object HR 6819. The system could consist of a close innerB-type giant plus a black hole (BH) binary with an additional Be companion in awide orbit. Alternatively, it could be a binary composed of a stripped B starand a Be star in a close orbit. Either scenario makes HR 6819 a cornerstoneobject as the stellar BH closest to Earth, or as an example of an importanttransitional, non-equilibrium phase for Be stars with solid evidence for itsnature. We aimed to distinguish between the two scenarios for HR 6819. Bothmodels predict two luminous stars but with very different angular separationsand orbital motions. Therefore, the presence of bright sources in the 1-100milliarcsec (mas) regime is a key diagnostic for determining the nature of theHR 6819 system. We obtained new high-angular resolution data with VLT/MUSE andVLTI/GRAVITY of HR 6819. The MUSE data are sensitive to bright companions atlarge scales, whilst the interferometric GRAVITY data are sensitive down toseparations on mas scales and large magnitude differences. The MUSEobservations reveal no bright companion at large separations and the GRAVITYobservations indicate the presence of a stellar companion at an angularseparation of ~1.2 mas that moves on the plane of the sky over a timescalecompatible with the known spectroscopic 40-day period. We conclude that HR 6819is a binary system and that no BH is present in the system. The unique natureof HR 6819, and its proximity to Earth make it an ideal system forquantitatively characterising the immediate outcome of binary interaction andprobing how Be stars form.

HR 6819 is a binary system with no black hole -- revisiting the source with infrared interferometry and optical integral field spectroscopy