All Figures

$\begin{figure} {\includegraphics[width=7.2cm,clip]{9383fig1.ps} } \end{figure}$ Figure 1: Heliocentric radial velocity distribution of the NEP sample stars with respect to spectral type (temperature). We assumed that the weighted mean of three independent measures is our estimate of radial velocity for each star. The uncertainty was computed by combining in quadrature the uncertainties of the measures.
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In the text

$\begin{figure} {\includegraphics[width=7.2cm,clip]{9383fig2.ps} } \end{figure}$ Figure 2: Histogram of the heliocentric radial velocities, the Sun velocity with respect to the Local Standard of Rest (LSR) is indicated ( $\vert v_{\rm LSR}\vert=13.4$ km s^-1, Binney & Merrifield 1998). The superimposed Gaussian radial velocity distribution for the targets with a standard deviation of 13 km s^-1, is shown.
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In the text

$\begin{figure} {\includegraphics[width=7.2cm,clip]{9383fig3.ps} } \end{figure}$ Figure 3: Calibration curve used for the $v\sin i$ estimation from the width of the cross-correlation peak. The curve was created by cross-correlating the spectrum of the template star with a set of synthetic spectra with different rotational velocities.
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In the text

$\begin{figure} {\includegraphics[width=7.2cm,clip]{9383fig4.ps} } \end{figure}$ Figure 4: Histogram of the rotational velocities; almost all of the sample stars have rotational velocities that are comparable or higher than that of the Sun ( $\approx$ 2 km s^-1).
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In the text

$\begin{figure} {\includegraphics[width=8cm,clip]{9383fig5.eps} } \end{figure}$ Figure 5: Example of peaks of the cross-correlation function produced by cross-correlating a binary with our template star. Relative radial velocities of the two components are indicated in the panel.
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In the text

$\begin{figure} {\includegraphics[width=7.2cm,clip]{9383fig6.ps} } \end{figure}$ Figure 6: Spectra in the lithium region for two NEP sources: nep 3220 does not show the lithium line while nep 4780 shows a prominent line. The spectra have been continuum subtracted and offset on the vertical axis.
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In the text

$\begin{figure} {\includegraphics[width=7.2cm,clip]{9383fig7.ps} } \end{figure}$ Figure 7: Distribution of lithium equivalent widths of single NEP stars (filled dots) and binary stars (ringed dots; `` $\times$ '' for nep 5520), with respect to spectral type, compared to Pleiades (empty squares) and Hyades (empty dots) distributions. Arrows indicate EW upper limits for those stars in which no lithium line was visible in the spectrum.
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In the text

$\begin{figure} \par\includegraphics[width=7.2cm,clip]{9383fig8.ps}\end{figure}$ Figure 8: Rotational velocity distribution with respect to spectral type (temperature); average trends of rotational velocity of Pleiades, Hyades and field stars, are shown (Favata et al. 1995; Kraft 1967; Soderblom 1983a,b; Skumanich 1972). With squares we indicate stars that have Na I(D₁,D₂) emission; `` $\times$ '' indicates the presence of H $\alpha$ emission and diamonds are for stars that have both H $\alpha$ and Na I(D₁,D₂) emission.
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In the text

$\begin{figure} {\includegraphics[width=7.2cm,clip]{9383fig9.ps} } \end{figure}$ Figure 9: Lithium abundances as a function of the rotational velocity: diamonds indicate stars with $v\sin i$ greater than those of Pleiades; ``x'' indicate $v\sin i$ values between the average curves of Pleiades and Hyades; dots indicate $v\sin i$ values between the average curves of Hyades and field stars; down-pointing arrows indicate upper limits of lithium abundances.
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In the text

$\begin{figure} {\includegraphics[width=7.2cm,clip]{9383fig10.ps} } \end{figure}$ Figure 10: Lithium abundances as a function of the effective temperatures: symbols as in Fig. 9. We indicate Pleiades and Hyades fits, obtained by Favata et al. (1993).
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In the text

$\begin{figure} {\includegraphics[width=7.2cm,clip]{9383fig1.ps} } \end{figure}$	Figure 1: Heliocentric radial velocity distribution of the NEP sample stars with respect to spectral type (temperature). We assumed that the weighted mean of three independent measures is our estimate of radial velocity for each star. The uncertainty was computed by combining in quadrature the uncertainties of the measures.
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$\begin{figure} {\includegraphics[width=7.2cm,clip]{9383fig2.ps} } \end{figure}$	Figure 2: Histogram of the heliocentric radial velocities, the Sun velocity with respect to the Local Standard of Rest (LSR) is indicated ( $\vert v_{\rm LSR}\vert=13.4$ km s^-1, Binney & Merrifield 1998). The superimposed Gaussian radial velocity distribution for the targets with a standard deviation of 13 km s^-1, is shown.
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$\begin{figure} {\includegraphics[width=7.2cm,clip]{9383fig3.ps} } \end{figure}$	Figure 3: Calibration curve used for the $v\sin i$ estimation from the width of the cross-correlation peak. The curve was created by cross-correlating the spectrum of the template star with a set of synthetic spectra with different rotational velocities.
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$\begin{figure} {\includegraphics[width=7.2cm,clip]{9383fig4.ps} } \end{figure}$	Figure 4: Histogram of the rotational velocities; almost all of the sample stars have rotational velocities that are comparable or higher than that of the Sun ( $\approx$ 2 km s^-1).
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$\begin{figure} {\includegraphics[width=8cm,clip]{9383fig5.eps} } \end{figure}$	Figure 5: Example of peaks of the cross-correlation function produced by cross-correlating a binary with our template star. Relative radial velocities of the two components are indicated in the panel.
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$\begin{figure} {\includegraphics[width=7.2cm,clip]{9383fig6.ps} } \end{figure}$	Figure 6: Spectra in the lithium region for two NEP sources: nep 3220 does not show the lithium line while nep 4780 shows a prominent line. The spectra have been continuum subtracted and offset on the vertical axis.
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$\begin{figure} {\includegraphics[width=7.2cm,clip]{9383fig7.ps} } \end{figure}$	Figure 7: Distribution of lithium equivalent widths of single NEP stars (filled dots) and binary stars (ringed dots; `` $\times$ '' for nep 5520), with respect to spectral type, compared to Pleiades (empty squares) and Hyades (empty dots) distributions. Arrows indicate EW upper limits for those stars in which no lithium line was visible in the spectrum.
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$\begin{figure} {\includegraphics[width=7.2cm,clip]{9383fig9.ps} } \end{figure}$	Figure 9: Lithium abundances as a function of the rotational velocity: diamonds indicate stars with $v\sin i$ greater than those of Pleiades; ``x'' indicate $v\sin i$ values between the average curves of Pleiades and Hyades; dots indicate $v\sin i$ values between the average curves of Hyades and field stars; down-pointing arrows indicate upper limits of lithium abundances.
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$\begin{figure} {\includegraphics[width=7.2cm,clip]{9383fig10.ps} } \end{figure}$	Figure 10: Lithium abundances as a function of the effective temperatures: symbols as in Fig. 9. We indicate Pleiades and Hyades fits, obtained by Favata et al. (1993).
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