blend with CN lines. These figures show examples of the cases of no inteference by CN lines (BW-f8), a moderate or negligible presence of CN lines (BWc-4), and strong contaminating CN lines (B6-f1, B6-f8), leading us not to consider the line for such stars. Star B6-f8 shows a detectable good fit to the CN line on the red side of the 6362 [Å]{} line, but this indicator was discarded as well.

As regards non-LTE corrections, Takeda et al. (2005) have computed non-LTE effects on both the 4810 and 6362 [Å]{} lines used here. The corrections are below 0.1 dex for the metal-poor stars and below 0.05 for stars with \[Fe/H\] $>$ $-$1.0. Consequently, in the present work, we do not correct the abundances for this effect.

Errors
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We have adopted uncertainties in the atmospheric parameters of $\pm$ 150 K for effective temperature, $\pm$ 0.20 for surface gravity, and $\pm$ 0.10 in \[Fe/H\] and $\pm$ 0.10 kms$^{-1}$ for microturbulent velocity, as explained in Barbuy et al. (2013).

The errors in \[Zn/Fe\] are computed by using model atmospheres with parameters changed by these uncertainties, applied to the stars B6-f1 and BW-f8. The errors are estimated from the differences in \[Zn/Fe\], derived 