5σ detection limits in terms of the magnitude contrast in the L′-band as a function of the distance from the central star. The black dashed line represents the binary separation upper limit of ~11.7 au at the time of the observations. The dash-dotted line marks the saturation radius of ~0.085′′. The red solid lines mark the expected contrasts for a G2 V star of 1 M_⊙ and a M0 V star of 0.5 M_⊙,  from top to bottom.