Upper panel: EW(Hα)_Chr as a function of the α_c index. Lower panel: Log α_c index as a function of the V − I color (dots). Empty squares are the objects from the CMFS and triangles indicate the objects selected as accretors. Filled circles are the active candidate members selected on the basis of the α_c index, while asterix symbols are those selected on the basis of the EW(Hα)_Chr. The dashed line indicates the lower limit used for the selection with the α_c index.