Related papers: Protostellar collapse induced by compression. II: …
We discuss star formation in the turbulent interstellar medium. We argue that morphological appearance and dynamical evolution of the gas is primarily determined by supersonic turbulence, and that stars form via a process we call…
The first stars are known to form in primordial gas, either in minihalos with about $10^6$~M$_\odot$ or so-called atomic cooling halos of about $10^8$~M$_\odot$. Simulations have shown that gravitational collapse and disk formation in…
Non-axisymmetric features are found in the core collapse of a rapidly rotating massive star, which might have important implications for magnetic field amplification and production of a bipolar outflow that can explode the star, as well as…
Radiative feedback and magnetic field are understood to have a strong impact on the protostellar collapse. We present high resolution numerical calculations of the collapse of a 1 solar mass dense core in solid body rotation, including both…
We simulate the formation and collapse of prestellar cores at few-AU resolution in a set of radiation-magneto-hydrodynamic simulations of giant molecular clouds (GMCs) using the grid-based code RAMSES-RT. We adopt, for the first time to our…
We have carried out hydro-dynamical simulations to investigate the formation and evolution of protostar and circumstellar disks from the prestellar cloud. As the initial state, we adopt the molecular cloud core with two non-dimensional…
Stars generally form faster than the ambipolar diffusion time, suggesting that several processes short circuit the delay and promote a rapid collapse. These processes are considered here, including turbulence compression in the outer parts…
We present results from the first three-dimensional calculations ever to follow the collapse of a molecular cloud core (~ 10^{-18} g cm^{-3}) to stellar densities (> 0.01 g cm^{-3}). The calculations resolve structures over 7 orders of…
When they first appear in the HR diagram, young stars rotate at a mere 10\% of their break-up velocity. They must have lost most of the angular momentum initially contained in the parental cloud, the so-called angular momentum problem. We…
We revisit our original papers on the burst mode of accretion by incorporating a detailed energy balance equation into a thin-disk model for the formation and evolution of circumstellar disks around low-mass protostars.Our model includes…
Fragmentation in a gravitationally unstable accretion disk can be an important pathway for forming stellar/planetary companions. To characterize quantitatively the condition for and outcome of fragmentation under realistic thermodynamics,…
The birth process of circumstellar disks remains poorly constrained due to observational and numerical challenges. Recent numerical works have shown that the small-scale physics, often wrapped into a sub-grid model, play a crucial role in…
The majority of stars are in binary/multiple systems. How such systems form in turbulent, magnetized cores of molecular clouds in the presence of non-ideal MHD effects remains relatively under-explored. Through ATHENA++-based non-ideal MHD…
The evolution of radiation emitted during the dynamical collapse of metal-free protostellar clouds is investigated within a spherically symmetric hydrodynamical scheme that includes the transfer of radiation and the chemistry of the…
We investigate the formation of circumstellar disks and outflows subsequent to the collapse of molecular cloud cores with the magnetic field and turbulence. Numerical simulations are performed by using an adaptive mesh refinement to follow…
Cloud evolution for various metallicities is investigated by three-dimensional nested grid simulations, in which the initial ratio of rotational to gravitational energy of the host cloud \beta_0 (=10^-1 - 10^-6) and cloud metallicity Z (=0…
Outflows and jets are intimately related to the formation of stars, and play an important role in redistributing mass, energy and angular momentum within the dense core and parent cloud. The interplay between magnetic field and rotation is…
We examine the problem of the collapse and fragmentation of molecular clouds with a Gaussian density distribution with high resolution, double precision numerical simulations using the GADGET-2 code. To describe the thermodynamic properties…
Protostellar feedback, both radiation and bipolar outflows, dramatically affects the fragmentation and mass accretion from star-forming cores. We use ORION, an adaptive mesh refinement gravito-radiation-hydrodynamics code, to simulate the…
In the context of star and planet formation, understanding the formation of disks is of fundamental importance. Previous studies found that the magnetic field has a very strong impact on the collapse of a prestellar cloud, particularly in…