Date : 7/19 (Wed) [14:00 - ] @ F313
Speaker: Mr. Hajime Fukushima (Tohoku University)
Title : Upper stellar mass limit by radiative feedback at low-metallicities: metallicity and accretion rate dependence
Abstract: Massive star play dominant role in the formation and evolution of galaxies. They impact the mechanical feedback to the interstellar medium, such as the formation of HII regions, wind-driven bubbles, chemical evolution by ejecting heavy element. Detailed knowledge of massive star formation in young, and low-metallicity environment is essential in understanding the early structure formation. In massive star formation, radiative feedback is a key mechanism which regulate the stellar mass growth via accretion. In solar-metallicity, the radiation force on to the dust cocoon is dominant suppression mechanism of mass accretion. Also, in the primordial star formation, feedback is caused by an HII region created around the protostar. In this seminar, I will discuss the metallicity and accretion rate dependence of the protostar mass above which each feedback effect begin to affect the mass accretion flow. I will show the results of our numerical model of an accretion envelope around the protostar. Finally, I will discuss how the spectrum of massive star-forming cores changes with decreasing metallicity.

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