Comparison of the sensitivity of Gaia and GRAVITY for a K=6 mag star at 40 pc. The Gaia sensitivity curve is adapted from Sozzetti (2010). The scaling of the K-magnitude with the mass is estimated from the observations of Gaia…6464 B analyzed in this paper and previous companion observations from the ExoGRAVITY program. The dashed red line shows the current K-magnitude limit in the SC of GRAVITY.