Detection of Achernar B from the GRAVITY observation of 22 November 2016 at UT 02:58:15 with PMOIRED. T3ϕ is the closure phase for each of the four telescope triplets, and |V| the amplitude of the fringe visibility for each of the six baselines. For comparison, the data are shown as black curves, and the best-fit binary star model for all observing epochs as red curves. This diagram represents one of the GRAVITY data set used for the global fit, and the individual diagrams corresponding to the other data sets are presented in Fig. B.1.