Long-Slit Spectroscopy of Parsec-Scale Jets from DG Tauri

TL;DR

This paper presents optical long-slit spectroscopic observations of DG Tauri's parsec-scale jets, analyzing their kinematics and physical properties, and providing detailed measurements of velocities, densities, ionization, and mass-loss rates.

Contribution

It provides new detailed spectroscopic data on DG Tauri's jets, including velocity, density, and ionization profiles, extending previous studies to larger distances from the source.

Findings

Radial velocities range from -50 to -250 km/s.

Electron density decreases from ~10^4 to ~10^2 /cm^3 with distance.

Mass-loss rate is about 10^{-7} solar masses per year.

Abstract

We present observational results from optical long-slit spectroscopy of parsec-scale jets of DG Tau. From HH 158 and HH 702, the optical emission lines of H_alpha, [O I] 6300, 6363, [N II] 6548, 6584, and [S II] 6716, 6731 are obtained. The kinematics and physical properties (i.e., electron density, electron temperature, ionization fraction, and mass-loss rate) are investigated along the blueshifted jet up to 650 arcseconds distance from the source. For HH 158, the radial velocity ranges from -50 to -250 km/s. The proper motion of the knots is 0.196 - 0.272 /yr. The electron density is ~ 10^{4}/cm^{3} close to the star, and decreases to ~ 10^{2} /cm^{3} at 14 arcseconds away from the star. Ionization fraction indicates that the gas is almost neutral in the vicinity of the source. It increases up to over 0.4 along the distance. HH 702 is located at ~ 650 arcseconds from the source. It shows ~ -80 km/s in the radial velocity. Its line ratios are similar to those at knot C of HH 158. The mass-loss rate is estimated to be about ~ 10^{-7} M_{sun}/yr, which is similar to values obtained from previous studies.