Time Variability of Emission Lines for Four Active T Tauri Stars (I): October--December in 2010

TL;DR

This study monitors four active T Tauri stars over six epochs in 2010 to analyze the variability of emission lines and their relation to mass ejection and accretion, revealing long-term variability and supporting steady accretion models.

Contribution

First high-resolution optical spectrophotometric monitoring of four T Tauri stars over multiple epochs to study emission line variability and its link to jet and accretion processes.

Findings

Confirmed long-term variability in emission line profiles (3-20 years).

Observed correlations between line luminosities and equivalent widths.

Supported steady magnetospheric accretion paradigm.

Abstract

We present optical spectrophotometric monitoring of four active T Tauri stars (DG Tau, RY Tau, XZ Tau, RW Aur A) at high spectral resolution ($R \ga 1 \times 10^4$), to investigate the correlation between time variable mass ejection seen in the jet/wind structure of the driving source and time variable mass accretion probed by optical emission lines. This may allow us to constrain the understanding of the jet/wind launching mechanism, the location of the launching region, and the physical link with magnetospheric mass accretion. In 2010, observations were made at six different epochs to investigate how daily and monthly variability might affect such a study. We perform comparisons between the line profiles we observed and those in the literature over a period of decades and confirm the presence of time variability separate from the daily and monthly variability during our observations. This is so far consistent with the idea that these line profiles have a long term variability (3-20 years) related to episodic mass ejection suggested by the structures in the extended flow components. We also investigate the correlations between equivalent widths and between luminosities for different lines. We find that these correlations are consistent with the present paradigm of steady magnetospheric mass accretion and emission line regions that are close to the star.