A Massive Star is Born: How Feedback from Stellar Winds, Radiation Pressure, and Collimated Outflows Limits Accretion onto Massive Stars

TL;DR

This study uses advanced 3D simulations to explore how stellar winds, radiation, and outflows influence the formation of massive stars, revealing wind feedback's role in limiting accretion and shaping circumstellar environments.

Contribution

First simulation to include isotropic stellar winds alongside radiation and collimated outflows, demonstrating their impact on massive star formation and accretion processes.

Findings

Winds create bipolar adiabatic bubbles, shaping the circumstellar environment.

Wind feedback can halt accretion onto stars around 30 solar masses.

Magnetic fields delay wind bubble growth, affecting feedback efficiency.

Abstract

Massive protostars attain high luminosities as they are actively accreting and the radiation pressure exerted on the gas in the star's atmosphere may launch isotropic high-velocity winds. These winds will collide with the surrounding gas producing shock-heated ($T\sim 10^7$ K) tenuous gas that adiabatically expands and pushes on the dense gas that may otherwise be accreted. We present a suite of 3D radiation-magnetohydrodynamic simulations of the collapse of massive prestellar cores and include radiative feedback from the stellar and dust-reprocessed radiation fields, collimated outflows, and, for the first time, isotropic stellar winds to model how these processes affect the formation of massive stars. We find that winds are initially launched when the massive protostar is still accreting and its wind properties evolve as the protostar contracts to the main-sequence. Wind feedback drives asymmetric adiabatic wind bubbles that have a bipolar morphology because the dense circumstellar material pinches the expansion of the hot shock-heated gas. We term this the "wind tunnel effect." If the core is magnetized, wind feedback is less efficient at driving adiabatic wind bubbles initially because magnetic tension delays their growth. We find that wind feedback eventually quenches accretion onto $\sim$30 $\rm{M_{\rm \odot}}$ protostars that form from the collapse of the isolated cores simulated here. Hence, our results suggest that $\gtrsim$30 $\rm{M_{\rm \odot}}$ stars likely require larger-scale dynamical inflows from their host cloud to overcome wind feedback. Additionally, we discuss the implications of observing adiabatic wind bubbles with \textit{Chandra} while the massive protostars are still highly embedded.