Colour–magnitude diagram showing the absolute magnitude M_V versus. B − V. The contour plot shows the distribution of the stars in the Hipparcos catalogue with σ_ϖ/ϖ ≤ 0.1 and σ_{B − V} ≤ 0.05 (van Leeuwen 2007). The spectra of the 33 sibling candidates are indicated with triangles. The solid line shows an isochrone with the age (5 Gyr) and metallicity of the Sun (Demarque et al. 2004). The vertical dashed line indicates our cut-off at B − V = 0.4.