Element abundance ratios [X/Fe] versus [Fe/H] for the samples of stars without planets (green empty squares), stars with planets (red empty triangles), BD-host stars (blue filled circles), stars without known BD companions from the CORALIE sample (blue empty circles), and stars with discarded BD candidates (violet filled circles). At the top-left corner of each panel, the mean standard deviation of the abundance measurements are shown for the stars without planetary companion (σ_NP), stars with planets (σ_WP), and stars with confirmed BD companions (σ_BD).

Histogram of element abundances, [X/H], of the samples of stars without planets (green continuous line), stars with low-mass planets (black dashed-triple-dotted line), stars with giant planets (red dashed-dotted line), stars with confirmed BD companions (blue dashed line), and stars with discarded BD candidates (violet dotted line). The left y-axis of the top panel is labeled with the number of stars with and without small and giant planets, whereas the right y-axis shows the number of stars with BD companion candidates.

Element abundances, [X/H], versus the minimum mass of the most massive companion, m_C sin i. Black empty triangles refer to stars with small planets, red empty triangles to stars with giant planets, blue filled circles to stars with confirmed BDs, and violet filled circles to stars with discarded BD candidates. At the bottom of each panel, standard deviations of the mean element abundances are shown for stars without planets (σ_NP), stars with planets (σ_WP), and stars with confirmed BD companions (σ_BD).

Mean element abundances versus the minimum mass of the most massive companion, m_C sin i, computed in equal-size bins appropriated for the logarithmic scale of companion masses. Error bars represent the standard deviation of the mean.