Magnitude difference versus projected angular separation diagram for observations of potential companions around AD Leo. Detections should be above and to the right of the lines (gray shaded region). Inaccurate detection claims are indicated with open symbols. Measurements from Gaia EDR3 are indicated with an extended arrow to the right to demonstrate it continues for many more arcseconds. The upwards green arrow represents a rough difference in magnitude interval from the astrometric masses indicated by Reuyl (1943), which are difficult to pinpoint as they are subject to huge uncertainties. The bright binary γ Leo in the background of AD Leo is discussed in Sect. 2.3. References: CC17: Cortés-Contreras et al. (2017); Bra14: Brandt et al. (2014); Dae07: Daemgen et al. (2007); BB85: Balega & Balega (1985); Bal84: Balega et al. (1984); Reu43: Reuyl (1943), astrometry; Gaia EDR3: Gaia Collaboration (2021), astrometry.