Abstract:
We present a comprehensive analysis of the Galactic mid-infrared bubble [HKS2019] E70 (E70) by adopting a
multiwavelength approach to understand the physical environment and star formation scenario around it. We
identified a small (radius ∼1.7 pc) stellar cluster inside the E70 bubble, and its distance is estimated as
3.26 ± 0.45 kpc. This cluster is embedded in the molecular cloud and hosts massive stars, as well as young stellar
objects (YSOs), suggesting active star formation in the region. The spectral type of the brightest star (M1) of the
E70 cluster is estimated as O9V, and a circular ring/shell of gas and dust is found around it. The diffuse radio
emission inside this ring/shell, the excess pressure exerted by the massive star M1 at the YSO’s core, and the
distribution of photodissociation regions, a class I YSO, and two ultracompact H II regions on the rim of this ring/
shell clearly suggest positive feedback of the massive star M1 in the region. We also found a low-density shell-like
structure in the 12CO(J = 1–0) molecular emission along the perimeter of the E70 bubble. The velocity structure of
the 12CO emission suggests that the feedback from the massive star appears to have expelled the molecular
material, and the subsequent swept-up material is what appears as the E70 bubble.
