Related papers: The Hall effect in star formation
We consider the evolution of magnetic fields under the influence of Hall drift and Ohmic decay. The governing equation is solved numerically, in a spherical shell with r_i/r_o = 0.75. Starting with simple free decay modes as initial…
We present an investigation of massive star formation that results from the gravitational collapse of massive, magnetized molecular cloud cores. We investigate this by means of highly resolved, numerical simulations of initial magnetized…
The Hall effect is an important nonlinear mechanism affecting the evolution of magnetic fields in neutron stars. Studies of the governing equation, both theoretical and numerical, have shown that the Hall effect proceeds in a turbulent…
Among many physical processes involved in star formation, radiation transfer is one of the key processes since it dominantly controls the thermodynamics. Because metallicities control opacities, they are one of the important environmental…
The early evolution of protostellar, star-forming discs, including their density structure, turbulence, magnetic dynamics, and accretion variability, remains poorly understood. We present high-resolution magnetohydrodynamic simulations,…
While it is generally accepted that the magnetic field and its non-ideal effects play important roles during the stellar formation, simple models of pure hydrodynamics and angular momentum conservation are still widely employed in the…
We study mass accretion and ejection in the vicinity of massive star forming cores using high-resolution (5 au) 3D AMR numerical simulations. We investigate the mechanisms at the origin of outflows and characterise the properties of the…
The spin of dark halos has been shown to significantly affect bar formation and evolution in disk galaxies. To understand the physical role of the halo spin on bar formation, we run $N$-body simulations of isolated, Milky Way-sized galaxies…
The stability properties of inviscid protostellar disks are examined taking into account the Hall effect and buoyancy. Depending on the parameters, different types of instabilities can exist in different regions of disks. In a very low…
The Herschel Gould Belt Survey showed that stars form in dense filaments in nearby molecular clouds. Recent studies suggest that massive filaments are bound by the slow shocks caused by accretion flows onto the filaments. The slow shock is…
The role of MHD turbulence in astrophysical environments is still highly debated. An important question that permeates this debate is the transport of magnetic flux. This is particularly important, for instance, in the context of star…
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…
The Hall effect arises in a plasma when electrons are able to drift with the magnetic field but ions cannot. In a fully-ionized plasma this occurs for frequencies between the ion and electron cyclotron frequencies because of the larger ion…
Star formation in the centers of galaxies is thought to yield massive stars with a possibly top-heavy stellar mass distribution. It is likely that magnetic fields play a crucial role in the distribution of stellar masses inside star-forming…
The origin of supermassive black holes (with $\gtrsim\!10^9\,M_{\odot}$) in the early universe (redshift $z \sim 7$) remains poorly understood. Gravitational collapse of a massive primordial gas cloud is a promising initial process, but…
Stars form from the gravitational collapse of turbulent, magnetized molecular cloud cores. Our non-ideal MHD simulations reveal that the intrinsically anisotropic magnetic resistance to gravity during the core collapse naturally generates…
Magnetic fields play a crucial role at all stages of the formation of low mass stars and planetary systems. In the final stages, in particular, they control the kinematics of in-falling gas from circumstellar discs, and the launching and…
Magnetic stresses collimate protostellar winds into a common distribution of force with angle. Sweeping into the ambient medium, such winds drive bipolar molecular outflows whose properties are insensitive to the distribution of ambient gas…
Understanding the complex evolution of protoplanetary disks (PPDs) and their dispersal via energetic stellar radiation are prominent challenges in astrophysics. It has recently been established that specifically the X-ray luminosity from…
Using numerical hydrodynamics simulations we studied the gravitational collapse of pre-stellar cores of sub-solar mass embedded into a low-density external environment. Four models with different magnitude and direction of rotation of the…