相关论文: Low-mass star formation triggered by early superno…
Current numerical studies suggest that the first galaxies formed a few stars at a time and were enriched only gradually by the first heavy elements. However, the large box sizes in these models cannot resolve primordial supernova explosions…
We present the results of SPH simulations in which two clouds, each having mass $M_{_{\rm{o}}}\!=\!500\,{\rm M}_{_\odot}$ and radius $R_{_{\rm{o}}}\!=\!2\,{\rm pc}$, collide head-on at relative velocities of $\Delta v_{_{\rm{o}}}…
Although the theoretical study of very low metallicity (Z) and metal-free stars is not new, their importance has recently greatly increased since two related fields have been developing rapidly. The first is cosmological simulations of the…
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…
We propose a new model for the ignition of star formation in low-mass halos by a self-sustaining shock front in cosmic filaments at high redshifts. The gaseous fuel for star formation resides in low mass halos which can not cool on their…
We investigate the supernova explosions that end the lives of massive Population III stars in low-mass minihalos (M~10^6 M_sun) at redshifts z~20. Employing the smoothed particle hydrodynamics method, we carry out numerical simulations in a…
We study star cluster formation in a low-metallicity environment using three dimensional hydrodynamic simulations. Starting from a turbulent cloud core, we follow the formation and growth of protostellar systems with different metallicities…
Supermassive primordial stars are expected to form in a small fraction of massive protogalaxies in the early universe, and are generally conceived of as the progenitors of the seeds of supermassive black holes (BHs). Supermassive stars with…
The collapse of dense cores with different metallicities is studied by hydrodynamical calculations coupled with detailed chemical and radiative processes. For this purpose, we construct a simple chemical network with non-equilibrium…
The formation of stars is a key process in the early universe with far reaching consequences for further cosmic evolution. While stars forming from truly primordial gas are thought to be considerably more massive than our Sun, stars in the…
The genesis and chemical patterns of the metal poor stars in the galactic halo remains an open question. Current models do not seem to give a satisfactory explanation for the observed abundances of Lithium in the galactic metal-poor stars…
To constrain the nature of the very first stars, we investigate the collapse and fragmentation of primordial, metal-free gas clouds. We explore the physics of primordial star formation by means of three-dimensional simulations of the dark…
We studied the gravitational collapse of a warm (~8000 K) primordial-gas cloud as a candidate progenitor for a supermassive star (SMS; >10^5 Msun) using a three-dimensional hydrodynamical simulation, including all the relevant cooling…
While the abundances of Be and B observed in metal-poor halo stars are well explained as resulting from spallation of CNO-enriched cosmic rays (CRs) accelerated by supernova shocks, accounting for the observed $^6$Li in such stars with…
Low-mass protostars form from condensations inside molecular clouds when gravity overwhelms thermal and magnetic supporting forces. The first phases of the formation of a solar-type star are characterized by dramatic changes not only in the…
The earliest stars to form in the Universe were the first sources of light, heat and metals after the Big Bang. The products of their evolution will have had a profound impact on subsequent generations of stars. Recent studies of primordial…
The process that leads to the formation and early evolution of low-mass stars is in a broad sense well understood theoretically and carefully traced observationally. The largest uncertainties in this framework reside in the poorly known…
Supermassive stars forming at $z \sim$ 15 - 20 are one of the leading contenders for the origin of the first quasars, over 200 of which have now been discovered at $z >$ 6. These stars likely form in pristine, atomically cooled haloes…
We present numerical simulations to describe the evolution of pre-Galactic clouds in a model which is motivated by cold dark matter simulations of hierarchical galaxy formation. We adopt a SN-induced star-formation mechanism within a model…
We describe how star formation is expected to proceed in the early metal-free Universe, focusing on the very first generations of stars. We then discuss how the star formation process may change as the effects of metallicity, external…