A multiwavelength study of galactic H II region Sh 2-294

Abstract

We present the observational results of Galactic H II region Sh 2-294, using optical photometry, narrowband imaging, and radio continuum mapping at 1280 MHz, together with archival data from the 2MASS, MSX, and IRAS surveys. The stellar surface density profile indicates that the radius of the cluster associated with the Sh 2-294 region is ~2.3'. We estimate the minimum reddening E(B - V) = 1.35 mag and a distance of 4.8 ± 0.2 kpc to the region. The ratio of the total to the selective extinction (R_V) is found to be 3.8 ± 0.1, indicates an anomalous reddening law for the dust inside the cluster region. We identified the ionizing source of the H II region, and spectral type estimates are consistent with a star of spectral type ~B0 V. The 2MASS JHK_s images reveal a partially embedded cluster associated with the ionizing source along with a small cluster towards the eastern border of Sh 2-294. The radio continuum and Hα images show the ionization front along the direction of the small cluster. An arc-shaped diffuse molecular hydrogen emission and a half-ring of dust emission are also seen in the direction of the ionization front at 2.12 and 8 µm (MSX), respectively. Self-consistent radiative transfer model of mid- to far-infrared continuum emission detected near small cluster is in good agreement with the observed spectral energy distribution of a B1.5 ZAMS star. The morphological correlation between the ionized and molecular gas, along with probable timescale involved between the ionizing star, evolution of H II region, and small cluster, indicates that the star formation activity observed at the border is probably triggered by the expansion of H II region.