Blowing Bubbles around Intermediate-Mass Stars: Feedback from Main-Sequence Winds is not Enough

Abstract

Numerous spherical "shells" have been observed in young star-forming environments that host lowand intermediate-mass stars. These observations suggest that these shells may be produced by isotropic stellar wind feedback from young main-sequence stars. However, the driving mechanism for these shells remains uncertain because the momentum injected by winds is too low to explain their sizes and dynamics due to their low mass-loss rates. However, these studies neglect how the wind kinetic energy is transferred to the ISM and instead assume it is instantly lost via radiation, suggesting that these shells are momentum-driven. Intermediate-mass stars have fast (v w 1000 km/s) stellar winds and therefore the energy injected by winds should produce energy-driven adiabatic wind bubbles that are larger than momentum-driven wind bubbles. Here, we explore if energy-driven wind feedback can produce the observed shells by performing a series of 3D magneto-hydrodynamic simulations of wind feedback from intermediate-mass and high-mass stars that are placed in a magnetized, turbulent molecular cloud. We find that, for the high-mass stars modeled, energy-driven wind feedback produces ∼pc scale wind bubbles in molecular clouds that agree with the observed shell sizes but winds from intermediate-mass stars can not produce similar shells because of their lower mass-loss rates and velocities. Therefore, such shells must be driven by other feedback processes inherent to low-and intermediate-mass star formation.

The dynamics and outcome of star formation with jets, radiation, winds, and supernovae in concert

“…𝑓 w = 0.1 and 𝑓 K = 1, the momentum would be similar but the jet velocities would approach ∼ 10 3 km s −1 for > 10𝑀 stars, which has been observed (Carrasco-González et al 2010). Such jets would shock to temperatures 𝑇 ∼ 𝑚 p 𝑣 2 /𝑘 B >> 10 6 K, above the peak of the atomic cooling curve, and hence would have an energy-conserving phase in which PdV work is done (Rosen et al 2021), enhancing feedback efficiency and potentially regulating massive SF. Our simulations with 𝑓 W = 0.1 and 𝑓 K = 1 in Paper II do show a hint of suppression of massive SF compared to the fiducial parameters, and we are following this up with full feedback physics.…”

Far and extreme UV radiation feedback in molecular clouds and its influence on the mass and size of star clusters

“…In these clouds, SNe occurs and evacuates the gas from the clouds (e.g., Geen et al 2016). Stellar wind pushes out surrounding gas (e.g., Dale et al 2014;Decataldo et al 2020;Geen et al 2021;Rosen et al 2021), and heats up the gas to ( 10 5 K) via the shock (e.g., Lancaster et al 2021a,b). Indeed, X-ray emission is observed from the region inside the expanding shell (Luisi et al 2021), which is likely to be induced by the stellar wind.…”

A wind-blown bubble in the Central Molecular Zone cloud G0.253+0.016

“…this effect (e.g., Gentry et al 2019). Indeed, the recent numerical simulations of Rosen et al (2021) also show that wind bubbles blown by individual high-mass stars do not experience efficient mixing in the presence of magnetic fields (Pillai et al 2015, estimate a total magnetic field strength of 5.4 ± 0.5 mG in G0.253+0.016). The magnetic field provides a confining and stabilising effect and suppresses the development of instabilities that otherwise lead to effective mixing and cooling (Lancaster et al 2021a,b).…”