Chemical abundance of G type giants

Abstract

We started a survey project for planets around G type giants at Okayama astrophysical observatory by using High Precision Dispersion Spectroscopy (HIDES) in 2001, and now continued. And we have found some objects have a radial velocity change like have planets. It is important that we know chemical abundances of parent stars to understand how planets are formed, but those of G type giants have not been studied so many times. Therefore, we also get high precision spectroscopy data to study chemical abundance in this project. We determined atmosphere parameters of some decades of G type giants including stars may have planets and describe about those.