The results of new spectroscopic analyses of 20 recently reported extrasolar planet parent stars are presented .
The companion of one of these stars , HD 10697 , has recently been shown to have a mass in the brown dwarf regime ; we find [ Fe/H ] = +0.16 for it .
For the remaining sample , we derive [ Fe/H ] estimates ranging from -0.41 to +0.37 , with an average value of +0.18 \pm 0.19 .
If we add the 13 stars included in the previous papers of this series and 6 other stars with companions below the 11 M _ { Jup } limit from the recent studies of Santos et al. , we derive \langle [ Fe/H ] \rangle = +0.17 \pm 0.20 .

Among the youngest stars with planets with F or G0 spectral types , [ Fe/H ] is systematically larger than young field stars of the same Galactocentric distance by 0.15 to 0.20 dex .
This confirms the recent finding of Laughlin that the most massive stars with planets are systematically more metal rich than field stars of the same mass .
We interpret these trends as supporting a scenario in which these stars accreted high-Z material after their convective envelopes shrunk to near their present masses .
Correcting these young star metallicities by 0.15 dex still does not fully account for the difference in mean metallicity between the field stars and the full parent stars sample .

The stars with planets appear to have smaller [ Na/Fe ] , [ Mg/Fe ] , and [ Al/Fe ] values than field dwarfs of the same [ Fe/H ] .
They do not appear to have significantly different values of [ O/Fe ] , [ Si/Fe ] , [ Ca/Fe ] , or [ Ti/Fe ] , though .
The claim made in Paper V that stars with planets have low [ C/Fe/ ] is found to be spurious , due to unrecognized systematic differences among published studies .
When corrected for these differences , they instead display slightly enhanced [ C/Fe ] ( but not significantly so ) .
If these abundance anomalies are due to the accretion of high-Z matter , it must have a composition different from that of the Earth .