Spatio-kinematical model of molecular gas of IRAS 16342−3814. Panel a: geometry of the spatio-kinematical model of the molecular envelope of IRAS 16342−3814. It should be noted that the y-axis is angular size along the line-of-sight and the x-axis is angular size on the plane of the sky. We assume an inclination of the major axis of the nebula of 45° with respect to the plane of the sky (Claussen et al. 2009). The grey region indicates the LVC component. The black region indicates the HVC component. Panel b: expansion velocity as a function of the separation from the center of the system. The grey and black lines are the velocity laws for the LVC and HVC components, respectively. The mathematical expression for the velocity laws is given in Eq. (1).