Abundance Analyses of 12 Parent Stars of Extrasolar Planets Observed with the SUBARU/HDS

Abstract

Abstract High $\mathrm{S/N}$ ratio (350–600) and high resolution ($R \sim 90000$) spectral data covering the wavelength region between 4200–8800$\,{Å}$ were obtained for 12 planet-harboring stars with the SUBARU/HDS. Detailed abundance analyses were carried out for these stars using the solar spectrum as a reference. Atmospheric parameters ($T_\mathrm{eff}, \log g$, microturbulent velocity $\xi_\mathrm{t}$, and $[\mathrm{Fe/H}]$) were determined spectroscopically using selected Fe I and Fe II lines. The abundances of 25 other elements have been determined relative to the Sun in a strictly differential manner. Three out of 12 stars (HD 82943, HD 92788, and HD 134987) are definitely metal rich, and two stars (HD 114762 and HD 190228) are metal deficient. The abundances in the remaining seven stars (HD 106252, HD 130322, HD 141937, HD 168746, HD 187123, HD 192263, HD 209458) coincide with the Sun. We find that the abundances of both volatile and refractory elements behave similarly in these stars, and do not confirm any significant dependence on the condensation temperature, $T_\mathrm{c}$. Comparisons of the $[\mathrm{X/Fe}]$ vs $[\mathrm{Fe/H}]$ relations for 19 elements between planet-harboring stars and nearby field stars reveal no distinct anomaly, except for possible enhancements of V and Co in the former group. These results suggest that the observed over-abundances of metallic elements in planet-harboring stars relative to normal disk stars in the solar neighborhood are primordial, and can be interpreted as being a consequence of the galactic chemical evolution.