Identifying the population of T-Tauri stars in Taurus: UV-optical synergy

Abstract

With the third data release of the Gaia mission $Gaia$ DR3 with its precise photometry and astrometry, it is now possible to study the behaviour of stars at a scale never seen before. In this paper, we developed new criteria to identify T-Tauri stars (TTS) candidates using UV and optical CMDs by combining the GALEX and Gaia surveys. We found 19 TTS candidates and 5 of them are newly identified TTS in the Taurus Molecular Cloud (TMC), not catalogued before as TMC members. For some of the TTS candidates, we also obtained optical spectra from several Indian telescopes. We also present the analysis of the distance and proper motion of young stars in the Taurus using data from $Gaia$ DR3. We found that the stars in Taurus show a bimodal distribution with distance, having peaks at $130.17_{-1.24}^{1.31}$ pc and $156.25_{-5.00}^{1.86}$ pc. The reason for this bimodality, we think, is due to the fact that different clouds in the TMC region are at different distances. We further show that the two populations have similar ages and proper motion distribution. Using the $Gaia$ DR3 colour-magnitude diagram, we show that the age of Taurus is consistent with 1 Myr.