Distribution of probable members of the cluster HSC 1640 (gray circles) in different spaces, including the color–magnitude diagram (upper left), position (upper right), proper motion (lower left), and parallax space (lower right). The position of the λ Boo stars is indicated in the plots (blue diamonds). The cluster center is marked in the coordinate space (red plus signs). The best isochrone fit is shown with a red continuous line in the color–magnitude diagram (upper left).