A CO Outflow and a Molecular Cloud Core Associated with a Young Massive Star IRAS 22134$+$5834

Abstract

Abstract We present the results of the recent 12CO ($J=1$-0), 13CO ($J=1-0$), and C 18O ($J=1-0$) observations carried out toward a bright IRAS point source (22134$+$5834) using the 45 m telescope at Nobeyama Radio Observatory (NRO) equipped with the 4 multi-beam receiver system. The IRAS source exhibits a cold color spectrum in the far infrared wavelengths and has a high luminosity of $\simeq 1700 \,{{{L}_{\odot}}}$ at the adopted distance of 900 pc, indicating that the IRAS source is a good candidate for an embedded young massive star whose luminosity is equivalent to that of an early B-type star having $\simeq 8 \,{{{M}_{\odot}}}$. A bipolar outflow and a dense core associated with IRAS 22134$+$5834 were detected by the present observations. It is remarkable that the outflow has a very large total molecular mass of $26 \,{{{M}_{\odot}}}$, which makes this source one of the most massive outflows reported to date. We derived the dynamical time scale ($\simeq 7\times 10^4 \,\mathrm{yr}$), mechanical momentum ($\simeq 140 \,{{{M}_{\odot}}}\,\mathrm{km} \,\mathrm{s}^{-1}$), and kinetic energy ($\simeq 400 \,{{{M}_{\odot}}} \,\mathrm{km}^2 \,\mathrm{s}^{-2}$) of the outflow. The dense core traced in C18O is also massive ($206 \,{{{M}_{\odot}}}$) extending over $\simeq 1 \,\mathrm{pc}$. The core shows an elliptical shape with its major axis inclined by $-45 {{}^{\circ }}$ to the north. A velocity gradient of $0.9 \,\mathrm{km} \,\mathrm{s}^{-1} \,\mathrm{pc}^{-1}$ along the core major axis was observed, indicating a rotation of the core. We also detected blue and red velocity-shifted components in C18O along the core minor axis separated by $\simeq 0.7 \,\mathrm{km} \,\mathrm{s}^{-1}$ from the systemic velocity at $-18.2 \,\mathrm{km} \,\mathrm{s}^{-1}$, which are most likely to trace the mixture of the dense gas being swept up by the powerful outflow and the matter in the core infalling toward the central star.