相关论文: Transport-driven super-Jeans fragmentation in dyna…

We examine whether massive-star accretion disks are likely to fragment due to self-gravity. Rapid accretion and high angular momentum push these disks toward fragmentation, whereas viscous heating and the high protostellar luminosity…

Gravitational merging (or clustering) of cosmic objects is regarded as a possible source of the extra-acceleration of the universe at large scale. The merging/clustering of cosmic objects introduces a correction term in the equation of…

The turbulent motion within molecular clouds is a key factor controlling star formation. Turbulence supports molecular cloud cores from evolving to gravitational collapse and hence sets a lower bound on the size of molecular cloud cores in…

It is assumed that a galaxy starts as a dark halo of a few million Jeans clusters (JCs), each of which consists of nearly a trillion micro brown dwarfs, MACHOs of Earth mass. JCs in the galaxy center heat up their MACHOs by tidal forces,…

Massive stars influence the surrounding universe far out of proportion to their numbers through ionizing radiation, supernova explosions, and heavy element production. Their formation requires the collapse of massive interstellar gas clouds…

Chemical compositions of giant planets provide a means to constrain how and where they form. Traditionally, super-stellar elemental abundances in giant planets were thought to be possible due to accretion of metal-rich solids. Such…

The first stars in the universe, termed Population III, are thought to have been very massive compared to the stars that form in the present epoch. As feedback from the first generation of stars altered the contents of the interstellar…

In order to understand the physical mechanisms at work during the formation of massive early-type galaxies, we performed six zoomed hydrodynamical cosmological simulations of halos in the mass range 4.3 10^12 < M_vir < 8.0 10^13 M_sun at…

During plastic deformation of crystalline materials, point defects such as vacancies and interstitials are generated by jogs on moving dislocations. A detailed model for jog formation and transport during plastic deformation was developed…

It is now a widely held view that, in their formation and early evolution, stars build up mass in bursts. The burst mode of star formation scenario proposes that the stars grow in mass via episodic accretion of fragments migrating from…

Strong iron lines are a common feature of the optical spectra of active galactic nuclei (AGNs) and quasars from $z\sim 6-7$ to the local Universe, and [Fe/Mg] ratios do not show cosmic evolution. During active episodes, accretion disks…

Although the basic physics of star formation is classical, numerical simulations have yielded essential insights into how stars form. They show that star formation is a highly nonuniform runaway process characterized by the emergence of…

The self-enrichment of massive star clusters by p-processed elements is shown to increase significantly with increasing gas density as a result of enhanced star formation rates and stellar scatterings compared to the lifetime of a massive…

Convection is ubiquitous in stars and occurs under many different conditions. Here we explore convection in main-sequence stars through two lenses: dimensionless parameters arising from stellar structure and parameters which emerge from the…

Herschel surveys of Galactic clouds support a paradigm for low-mass star formation in which dense filaments play a crucial role. The detailed fragmentation properties of star-forming filaments remain poorly understood, however, and the…

The formation mechanism of massive stars remains one of the main open problems in astrophysics, in particular the relationship between the mass of the most massive stars, and that of the cores in which they form. Numerical simulations of…

Accretion-driven luminosity outbursts are a vivid manifestation of variable mass accretion onto protostars. They are known as the so-called FU Orionis phenomenon in the context of low-mass protostars. More recently, this process has been…

We use 3D MHD simulations to investigate nonlinear development of the Parker, magneto-Jeans (MJI), and swing mechanisms in galactic disks. The model disks are local, isothermal, and begin from a vertically-stratified equilibrium. We first…

Over the last two decades, realistic studies have often concluded that the first bound objects to form can be very small, much smaller than a solar mass. After recombination, the Jeans mass drops rapidly to the order of a Giant Molecular…

We study the Jeans gravitational instability for a mixture of baryonic and dark matter particles, in the post-Newtonian approximation. We adopt a kinetic model consisting of a coupled system of post-Newtonian collisionless Boltzmann…