High-Resolution Spectroscopy of T Tauri Stars

We have conducted high-resolution spectroscopic observations of a sample of both classical and weak-line T Tauri stars embedded in the Taurus-Auriga molecular Cloud using the Okayama Astrophysical Observatory's 188 cm telescope equipped with HIDES (HIgh Dispersion Echelle Spectrograph). Utilizing the ratios of equivalent widths of specific lines, we efficiently eliminated the effects of veiling and determined the atmospheric parameters individually for each object. Eight pairs of temperature-sensitive line-ratios were selected to derive the effective temperature with high precision and reliability. As for the Surface gravity, we have developed a new method to determine the value. The method was first tested on observed spectral standards, and the derived Surface gravities had a less than 5% deviation from the values in the literature. The derived surface gravities are well within the range of the assumed values for T Tauri stars.