Pre-main-sequence variable stars in young open cluster NGC 1893

Abstract

We present results of multi-epoch (14 nights during 2007–2010) V-band photometry of the cluster NGC 1893 region to identify photometric variable stars in the cluster. The study identified a total of 53 stars showing photometric variability. The members associated with the region are identified on the basis of spectral energy distribution, J − H/H − K twocolour diagram and V/V − I colour–magnitude diagram. The ages and masses of the majority of pre-main-sequence sources are found to be ≤5Myr and in the range 0.5 ≤ M/M☉≤ 4, respectively. These pre-main-sequence sources hence could be T Tauri stars. We also determined the physical parameters like disc mass and accretion rate from the spectral energy distribution of these T Tauri stars. The periods of majority of the T Tauri stars range from 0.1 to 20 d. The brightness of Classical T Tauri stars is found to vary with larger amplitude in comparison to weak line T Tauri stars. It is found that the amplitude decreases with increase in mass, which could be due to the dispersal of discs of massive stars.