Driving Turbulence and Triggering Star Formation by Ionizing Radiation

TL;DR

This study uses high-resolution simulations to show how ionizing radiation from massive stars influences the turbulent interstellar medium, leading to pillar formation and star creation, while also sustaining turbulence in molecular clouds.

Contribution

Introduces the iVINE simulation software combining ionization, SPH, and gravity to model star-ISM interactions, revealing new insights into turbulence and star formation processes.

Findings

Radiation heats and amplifies gas over-densities in turbulent ISM.

Formation of pillar-like structures explained by radiation-driven processes.

UV radiation from O-stars sustains and drives turbulence in molecular clouds.

Abstract

We present high resolution simulations on the impact of ionizing radiation of massive O-stars on the surrounding turbulent interstellar medium (ISM). The simulations are performed with the newly developed software iVINE which combines ionization with smoothed particle hydrodynamics (SPH) and gravitational forces. We show that radiation from hot stars penetrates the ISM, efficiently heats cold low density gas and amplifies over-densities seeded by the initial turbulence. The formation of observed pillar-like structures in star forming regions (e.g. in M16) can be explained by this scenario. At the tip of the pillars gravitational collapse can be induced, eventually leading to the formation of low mass stars. Detailed analysis of the evolution of the turbulent spectra shows that UV-radiation of O-stars indeed provides an excellent mechanism to sustain and even drive turbulence in the parental molecular cloud.