Chemical abundances of old metal-rich stars in the solar neighborhood

We report on chemical abundances for 15 old metal-rich stars in the solar neighborhood based on high-resolution, high signal-to-noise ratio observations. It is found that [O/Fe], [S/Fe], and probably [Ba/Fe] decrease with increasing metallicity, while the remaining elements, C, Na, Mg, Al, Si, Ca, Sc, Ti, V, Cr, Mn, Co, and Ni, generally have solar [X/Fe] ratios irrespective of metallicity. The kinematic data indicate a slight lag in the Galactic rotation for most stars. In combination with their low maximum distance perpendicular to the Galactic plane, Z(max), we suggest that most of the sample stars originate from the inner thin disk. This suggestion is supported by the similar abundance pattern of these stars as that of thin-disk stars. The connection of the old metal-rich stars with the old population of the inner disk suggests an inside-out formation of the disk. One exceptional case in our sample is HD 190360. It is suspected to be a thick-disk star based on the enhanced O, S, Mg, and Si abundances as well as the special kinematics, V-LSR = -40 km s(-1) and Z(max) = 1.0 kpc. It shows that stars from a population other than the thin disk exist among old metal-rich stars in the solar neighborhood. The location of these stars, presently in the solar neighborhood, may indicate that orbit diffusion effects of old stars are quite significant.