Poster Abstracts

Name/Affiliation:  Sohei Kondo (Koyama Astronomical Observatory, Kyoto Sangyo University)

Title:  The metallicities of Arcturus and mu Leo from z-, Y-, and J-bands spectra with the high resolution spectrograph, WINERED 

We present the metallicities of two bright and well studied K-giants, Arcturus and mu Leo with iron lines in the short NIR region (0.9-1.35 um). We obtained these high resolution spectra (R=28,300) using the infrared echelle spectrograph, WINERED, attached to the 1.3 m Araki Telescope in Japan. WINERED can provide a wide spectral coverage of entire z-, Y-, and J-bands in a single exposure, which provides an advantage for the chemical abundance study of stars. We identify 85 unblended FeI lines in the spectra of these two objects with the excitation potentials from 2.176 eV to 6.320 eV. The metallicity of each line is estimated by least squared fitting to the synthetic spectra by SPTOOL software package (Takeda 1995). We assume (Teff, log g)=(4275, 1.70) for producing the synthetic spectra of Arcturus and (4550, 2.10) for that of mu Leo (Smith et al. 2013). The microturbulence velocities, which are significant parameters, are determined to be 1.2 km/s and 1.0 km/s for Arcturus and mu Leo, respectively, with the same method using the expected line strength "X" proposed by Gratton et al. (2006). The resultant metallicities of Arcturus and mu Leo are e(Fe) = 6.94 pm 0.02 and 7.71 pm 0.02, respectively, which are well consistent with the previous studies using the other wavelength region (e.g., Jofre et al 2013 for the optical, Smith et al. 2013 for H-band). We conclude that we first established the method and procedure of the chemical abundance estimation in the short NIR region.