Observational study of the fragmentation process in nearby star-forming regions
Speaker: Kousuke Ishihara
Abstract:
Star formation is the process of forming protostars from diffuse interstellar clouds by gravitational contraction, and it is known from both observation and theory that hierarchical structures called clumps, filaments, and cores are formed in this process. The collapse and fragmentation of those structures is thought to contribute to the determination of the spatial distribution and initial mass of stars. The most fundamental mechanism controlling the fragmentation is the balance between the self-gravity and the thermal pressure that supports the structure against it (Jeans instability). Furthermore, non-thermal pressures such as turbulence, and magnetic fields are thought to have an inhibitory effect on fission. But the mechanism is not clear.
In this presentation, I introduce the results of the analysis applied to 15 nearby regions of the Herschel Gould Belt Survey. Especially, closer regions (d<200 pc) such as CoronaAustralis, Lupus, and Polaris areas show distributions below the jeans parameter and cannot be explained by the jeans fragmentation.