The Answer, My Friend, is Blowing in the Stellar Wind: The Impact of Early Stellar Feedback on the Interstellar Medium

Abstract

The mechanism of stellar feedback -- a star's injection of mass, energy, and momentum into the interstellar medium (ISM) -- not only plays a key role in moderating star formation at the parsec scale, but is also thought to impact galactic mass and structure at the kiloparsec scale. Stellar feedback consists of a number of distinct processes, including supernova blasts and "early" pre-supernova phenomena such as radiative heating, photoionization, and stellar winds. However, due to the complexity of modeling a complete picture of stellar feedback, the interactions between the different forms of feedback are poorly understood. In particular, the effect of early feedback on the efficacy of later supernova feedback remains unclear. To address this problem, we seek to simulate and study a simplified model of stellar feedback consisting only of stellar winds and supernovae. For these simulations, we use TIGRESS, an extension of the Athena MHD code developed to study the ISM and star formation; on top of TIGRESS's nuanced treatment of supernova feedback, we implement a new algorithm for stellar wind feedback based on equations describing the evolution of "superbubbles," typical environments carved out of the ISM by correlated supernova blasts and stellar winds. Based on simple tests, our algorithm produces results in reasonably good agreement with physical predictions, therefore making our feedback module a reliable resource for the further study of star formation and star formation feedback.