Radial velocities and spectral types of T Tauri stars

Abstract

The paper presents measurements of the absorption-line radial velocities of about 50 T Tauri stars on spectrograms covering the spectral region from 5850 to 6700 A with a dispersion of 34 A/mm. Emission-line velocities are examined along with absorption reversals in H-alpha, and the forbidden lines observed in several spectra. Spectral classifications are given for all the T Tauri stars observed, and the frequency distribution of types in the Taurus-Auriga dark nebulae (Tau-Aur) is analyzed. It is concluded that: (1) the absorption-line velocities of these stars are the same, within the errors of measurement, as the velocities of the molecular clouds upon which they are projected: (2) there is no evidence that newly formed stars are systematically being ejected from the nebula; (3) red emission lines yield velocities that are, in the mean, not far from the absorption line values; (4) the spectral types of the Tau-Aur stars range from early G to about M4, with a frequency peak near M0, and almost all these stars are of luminosity class V.