Lower masses of exomoons that can in principle synchronise their host planets for 580 known exoplanet systems, in units of the mass of the Moon. The M₋ limits are derived from the estimated reduced Hill radii and refer to the Scenario 1 pathway, when the exomoon is initially above the synchronous radius. The M₊ limits are derived from the estimated Roche radii and refer to the Scenario 2 pathway, when the exomoon is initially below the synchronous radius.