Mass-accretion, spectral, and photometric properties of T Tauri stars in Taurus based on TESS and LAMOST

TL;DR

This study analyzes 16 T Tauri stars in Taurus using TESS and LAMOST data, revealing their spectral, photometric, and accretion properties, including flare activity, accretion bursts, and variability timescales, with implications for disk and star interactions.

Contribution

First comprehensive analysis combining TESS and LAMOST data on T Tauri stars, highlighting accretion bursts, flare activity, and variability timescales with new correlations to disk inclination.

Findings

Average mass-accretion rate of $1.76\times10^{-9} M_{\odot}yr^{-1}$.

Detection of accretion bursts in DL Tau and Haro 6-13.

Thirteen stellar flares observed with high activity levels.

Abstract

We present the analysis of 16 classical T Taur stars using LAMOST and TESS data, investigating spectral properties, photometric variations, and mass-accretion rates. All 16 stars exhibit emissions in H$\alpha$ lines, from which the average mass-accretion rate of $1.76\times10^{-9}~M_{\odot}yr^{-1}$ is derived. Two of the stars, DL Tau and Haro 6-13, show mass-accretion bursts simultaneously in TESS, ASAS-SN, and/or ZTF survey. Based on these observations, we find that the mass-accretion rates of DL Tau and Haro 6-13 reach their maximums of $2.5 \times 10^{-8}~M_{\odot}yr^{-1}$ and $2 \times 10^{-10}~M_{\odot}yr^{-1}$ during the TESS observation, respectively. We detect thirteen flares among these stars. The flare frequency distribution shows that the CTTSs' flare activity is not only dominated by strong flares with high energy but much more active than those of solar-type and young low-mass stars. By comparing the variability classes reported in the literature, we find that the transition timescale between different classes of variability in CTTSs, such as from Stochastic (S) to Bursting (B) or from quasi-periodic symmetric (QPS) to quasi-periodic dipping (QPD), may range from 1.6 to 4 years. We observe no significant correlation between inclination and mass-accretion rates derived from the emission indicators. This suggests that inner disk properties may be more important than that of outer disk. Finally, we find a relatively significant positive correlation between the asymmetric metric "M" and the cold disk inclination compared to the literature. A weak negative correlation between the periodicity metric "Q" value and inclination has been also found.