IRS 31 14 in Vela C: Observations of wind driven turbulence

Abstract

ABSTRACT We report three millimeter line observations of young stellar object (YSO) cluster IRAS 08563−4225 in the Vela C molecular cloud, detecting outflow aligned with an unidentified 2MASS infrared emission maximum. Emission features such as velocity dispersion ridges converging on intermediate mass Class I protostar IRS 31 14 indicate cluster wind driven turbulence, a scenario supported within an evolutionary framework derived from a range of star-forming regions. Prestellar–pre-main-sequence evolution is regulated by internal core turbulence and tracked on a Δ(σ2)–log ma diagram in four stages: disc formation, wind generation, outflow collimation, and birthline emergence, where ma  = $\dot{M}_{\text{acc}}\, t_{\mathrm{out}}$ is a mass parameter given by $\dot{M}_{\text{acc}}$, the accretion rate and tout, the outflow dynamical time, and Δ(σ2)  = log ($\frac{\sigma ^2_{\mathrm{outer}}}{\sigma ^2_{\mathrm{inner}}}$) with σinner, the inner and σouter, the outer core velocity dispersion. A turnover in Δ(σ2) indicates the generation of supersonic turbulence in star-forming regions with inner core collapse; in sets of low, intermediate, and high mass protostellar regions, a negative turbulent index at  = $\frac{\text{d}{\Delta }\sigma ^2}{\text{dlog}m_a}$ corresponds to increasing age. Inner core collapse driven turbulence may apply at kiloparsec scales with turbulence amplification in a series of interacting YSO cluster cores in different evolutionary stages.