Survey of Hα emission-line stars in the star-forming region IC 5070

Abstract

Actively accreting young stellar objects show Hα emission line in their spectra. We present the results of survey for Hα emission-line stars in the star-forming region IC 5070 taken with 2-m Himalyan Chandra Telescope. Based on the Hα slitless spectroscopy data, we identified 131 emission-line stars in ∼0.29 square degrees area of the IC 5070 region. Using Gaia early data release 3, we estimated the mean proper motion and parallax of the emission-line stars. We also estimated the mean distance and reddening toward the region using the emission-line stars, which are ∼833 pc and ∼2 mag, respectively. By examining the locations of these stars in the color–magnitude diagrams constructed using Gaia and PanSTARRS1 data, we found that a majority of the Hα emitters are young low-mass (<1.5M⊙) stars. We also compared our catalog of emission-line stars with the available young stellar catalogs and found that most of them are class II/flat spectrum sources with the spectral type ranging from K to M. Based on the proper motion/parallax values and locations on the color–magnitude diagrams, about 20 emission-line stars are flagged as non-members. The relative proper motion of the emission-line stars with respect to the ionizing source suggest the possibility of the 'rocket effect' scenario in the remnant cloud (BRC 31).