Erosion of a dense molecular core by a strong outflow from a massive protostar

Abstract

Context. Molecular outflows from massive protostars can impact the interstellar medium in different ways, adding turbulence on different spatial scales, dragging material at supersonic velocities, producing shocks and heating, and physically impinging onto dense structures that may be harboring other protostars. Aims. We aim to quantify the impact of the outflow associated with the high-mass protostar GGD 27-MM2(E) on its parent envelope and how this outflow affects its environment. Methods. We present Atacama Large Millimeter/submillimeter Array Band 3 observations of N₂H⁺ (1–0) and CH₃CN (5–4), as well as Band 7 observations of the H₂CO molecular line emissions from the protostellar system GGD 27-MM2(E). Through position–velocity diagrams along and across the outflow axis, we studied the kinematics and structure of the outflow. We also fit extracted spectra of the CH₃CN emission to obtain the physical conditions of the gas. We use the results to discuss the impact of the outflow on its surroundings. Results. We find that N₂H⁺ emission traces a dense molecular cloud surrounding GGD 27-MM2(E). We estimate that the mass of this cloud is ~13.3–26.5 M_⊙. The molecular cloud contains an internal cavity aligned with the H₂CO-traced molecular outflow. The outflow, also traced by CH₃CN, shows evidence of a collision with a molecular core (MC), as indicated by the distinctive increases in the distinct physical properties of the gas such as the excitation temperature, column density, line width, and velocity. This collision results in an X-shaped structure in the northern part of the outflow around the position of the MC, which produces spray-shocked material downstream in the north of MC, as observed in position–velocity diagrams both along and across the outflow axis. The outflow has a mass of 1.7–2.1 M_⊙, a momentum of 7.8–10.1 M_⊙ km s^‑1, a kinetic energy of 5.0–6.6×10⁴⁴ erg, and a mass-loss rate of 4.9–6.0×10^‑4 M_⊙ yr^‑1. Conclusions. The molecular outflow from GGD 27-MM2(E) significantly perturbs and erodes its parent cloud, compressing the gas of sources such as the MC and ALMA 12. The feedback from this powerful protostellar outflow helps maintain the turbulence in the surrounding area.