Locus of the habitable zone in the effective temperature – incident flux plane. The green filled area is delimited on the right by the maximum greenhouse limit and on the left by the moist greenhouse limit. The solid black curve represents the position of the runaway greenhouse limit. The position of the candidate planets are marked with different symbols, as indicated in the legend. The straight lines connect the current positions of the candidates with the positions they had when their host stars were 1 Gyr old (indicated by plus signs), according to the PARSEC evolution tracks (see text for detail). The grey points are giant planets (Msini> 0.1M_Jup) orbiting non-evolved stars (ΔM_V< 2.0; Wright 2005).