Modeling UV Radiation Feedback from Massive Stars. II. Dispersal of Star-forming Giant Molecular Clouds by Photoionization and Radiation Pressure

UV radiation feedback from young massive stars plays a key role in the evolution of giant molecular clouds (GMCs) by photoevaporating and ejecting the surrounding gas. We conduct a suite of radiation hydrodynamic simulations of star cluster formation in marginally bound, turbulent GMCs, focusing on...

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Bibliographic Details
Published in:The Astrophysical journal 2018-05, Vol.859 (1), p.68
Main Authors: Kim, Jeong-Gyu, Kim, Woong-Tae, Ostriker, Eve C.
Format: Article
Language:English
Subjects:
Astrophysics
Cloud dispersal
Cloud formation
Clouds
Computer simulation
Density
Dispersal
Dispersion
Disruption
Ejection
Feedback
Ionization
ISM: clouds
ISM: kinematics and dynamics
Massive stars
Mathematical models
methods: numerical
Molecular clouds
Numerical simulations
Photoionization
Radiation
Radiation pressure
radiation: dynamics
regions
Star & galaxy formation
Star clusters
Star formation
Stars & galaxies
stars: formation
Stellar evolution
Ultraviolet radiation
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Summary:UV radiation feedback from young massive stars plays a key role in the evolution of giant molecular clouds (GMCs) by photoevaporating and ejecting the surrounding gas. We conduct a suite of radiation hydrodynamic simulations of star cluster formation in marginally bound, turbulent GMCs, focusing on the effects of photoionization and radiation pressure on regulating the net star formation efficiency (SFE) and cloud lifetime. We find that the net SFE depends primarily on the initial gas surface density, 0, such that the SFE increases from 4% to 51% as 0 increases from 13 to . Cloud destruction occurs within 2-10 Myr after the onset of radiation feedback, or within 0.6-4.1 freefall times (increasing with 0). Photoevaporation dominates the mass loss in massive, low surface density clouds, but because most photons are absorbed in an ionization-bounded Strömgren volume, the photoevaporated gas fraction is proportional to the square root of the SFE. The measured momentum injection due to thermal and radiation pressure forces is proportional to , and the ejection of neutrals substantially contributes to the disruption of low mass and/or high surface density clouds. We present semi-analytic models for cloud dispersal mediated by photoevaporation and by dynamical mass ejection, and show that the predicted net SFE and mass loss efficiencies are consistent with the results of our numerical simulations.
ISSN:0004-637X
1538-4357
DOI:10.3847/1538-4357/aabe27