相关论文: Singular Isothermal Disks and the Formation of Mul…
We review the difficulties of the classical fission and fragmentation hypotheses for the formation of binary and multiple stars. A crucial missing ingredient in previous theoretical studies is the inclusion of dynamically important levels…
Abridged. A large fraction of stars are found in binary systems. It is therefore important for our understanding of the star formation process, to investigate the fragmentation of dense molecular cores. We study the influence of the…
Fragmentation of highly differentially rotating massive stars that undergo collapse has been suggested as a possible channel for binary black hole formation. Such a scenario could explain the formation of the new population of massive black…
(Abridged) Context. Most massive stars are located in multiple stellar systems. Magnetic fields are believed to be essential in the accretion and ejection processes around single massive protostars. Aims. Our aim is to unveil the influence…
In the standard scenario of isolated low-mass star formation, strongly magnetized molecular clouds are envisioned to condense gradually into cores, driven by ambipolar diffusion. Once the cores become magnetically supercritical, they…
This is the first paper about the fragmentation and mass outflow in the molecular cloud by using three-dimensional MHD nested-grid simulations. The binary star formation process is studied paying particular attention to the fragmentation of…
Isolated low-mass stars are formed in dense cores of molecular clouds. In the standard picture, the cores are envisioned to condense out of strongly magnetized clouds through ambipolar diffusion. Most previous calculations based on this…
We construct both aligned and unaligned (logarithmic spiral) stationary configurations of nonaxisymmetric magnetohydrodynamic (MHD) disks from either a full or a partial razor-thin power-law axisymmetric magnetized singular isothermal disk…
Magnetic fields are usually considered dynamically important in star formation when the dimensionless mass-to-flux ratio is close to, or less than, unity (lambda<~1). We show that, in disk formation, the requirement is far less stringent.…
Stars rarely form in isolation. Nearly half of the stars in the Milky Way have a companion, and this fraction increases in star-forming regions. However, why some dense cores and filaments form bound pairs while others form single stars…
We study the non-axisymmetric evolution of magnetized clouds, using a 2D MHD code based on the physically motivated thin-disk approximation. We found that such clouds become unstable to non-axisymmetric perturbations after the supercritical…
We construct aligned and unaligned stationary perturbation configurations in a composite system of stellar and coplanarly magnetized gaseous singular isothermal discs (SIDs) coupled by gravity. In comparison with SID problems studied…
The gas from which stars form is magnetized, and strong magnetic fields can efficiently transport angular momentum. Most theoretical models of this phenomenon find that it should prevent formation of large (>100 AU), rotationally-supported…
This paper considers gravitational perturbations in geometrically thin disks with rotation curves dominated by a central object, but with substantial contributions from magnetic pressure and tension. The treatment is general, but the…
We present numerical investigations into the formation of massive stars from centrally condensed turbulent cores. The results of five hydrodynamical simulations are described, following the collapse of the core, fragmentation and the…
Differential rotation in stars generates toroidal magnetic fields whenever an initial seed poloidal field is present. The resulting magnetic stresses, along with viscosity, drive the star toward uniform rotation. This magnetic braking has…
We argue that gravitational instability of typical protostellar disks is not a viable mechanism for the fragmentation into multiple systems -- binary stars, brown dwarf companions, or gas giant planets -- except at periods above roughly…
Massive stars are often found in multiple systems, yet how binary-star systems with very close separations ($\lesssim$ au) assemble remains unresolved. We investigate the formation and inward migration of massive-star binaries in…
Our understanding of population III star formation is still in its infancy. They are formed in dark matter minihalos of $\rm 10^5-10^6 M_{\odot}$ at $z=20-30$. Recent high resolution cosmological simulations show that a protostellar disk…
Binary stars produce an array of dramatic astrophysical phenomena. They allow us to probe stellar structure, nuclear physics, and gravitational wave physics. They also produce the powerful supernovae that allow us to measure the scale of…