Disc fragmentation and oligarchic growth of protostellar systems in low-metallicity gas clouds

Understand

We study low-metallicity star formation with a set of high-resolution hydrodynamics simulations for various gas metallicities over a wide range $0$--$10^{-3} \ {\rm Z}_{\bigodot}$.

• Our simulations follow non-equilibrium chemistry and radiative cooling by adopting realistic elemental abundance and dust size distribution.
• We examine the condition for the fragmentation of collapsing clouds (cloud fragmentation; CF) and of accretion discs (disc fragmentation; DF).
• We find that CF is suppressed due to rapid gas heating accompanied with molecular hydrogen formation even with efficient dust cooling for metallicities $\gtrsim 10^{-5} \ {\rm Z}_{\bigodot}$.