Title: Mass distribution of first stars 

　　Speaker: Wako Aoki (National Astronomical Observatory of Japan) 　　  

　　Time: Friday,3:30pm, Nov 28th 　　  

　　Location: the middle conference room 　　  

　　Abstract:  Large surveys of metal-poor stars and follow-up high resolution spectroscopy have been revealing the chemical composition of low-mass halo stars that could record the nucleosynthesis of massive first-generation stars. This provides a unique constraint on the mass estimates of first stars, which is a key to understanding of the structure formation and enrichment of the early universe. I'll review the progress of observational studies of halo stars in the past decade, and show our recent result suggesting existence of very-massive stars among first stars.