相关论文: Angular Momentum and the Formation of Stars and Bl…
Nearly all of the initial angular momentum of the matter that goes into each forming star must somehow be removed or redistributed during the formation process. The possible transport mechanisms and the possible fates of the excess angular…
The importance of angular momentum in regulating the sizes of galactic disks and by this their star formation history is highlighted. Tidal torques and accretion of satellites in principle provide enough angular momentum to form disks with…
Our current understanding of the physical processes of star formation is reviewed, with emphasis on processes occurring in molecular clouds like those observed nearby. The dense cores of these clouds are predicted to undergo gravitational…
Star formation is thought to be triggered by gravitational collapse of the dense cores of molecular clouds. Angular momentum conservation during the collapse results in the progressive increase of the centrifugal force, which eventually…
The formation of massive stars in close binary systems is complicated due to their high radiation pressure, the crowded environment and the expected minimum separation for fragmentation being many times greater than the orbital separation.…
A prerequisite for the formation of stars and planetary systems is that angular momentum is transported in some way from the inner regions of the accretion disc. Tidal effects may play an important part in this angular momentum transport.…
I describe the current state of our knowledge of the mapping between the initial masses of stars and the compact objects -- particularly neutron stars and black holes -- that they produce. Most of that knowledge is theoretical in nature,…
Cold Dark Matter with a large cosmological constant (LambdaCDM) appears to fit large scale structure observations well. Of the possible small scale problems, the Central Cusps and Too Many Satellites problems now appear to be at least…
Supermassive stars born from pristine gas in atomically-cooled haloes are thought to be the progenitors of supermassive black holes at high redshifts. However, the way they accrete their mass is still an unsolved problem. In particular, for…
Angular momentum plays very important roles in the formation of PBHs in the matter-dominated phase if it lasts sufficiently long. In fact, most collapsing masses are bounced back due to centrifugal force, since angular momentum…
Angular momentum plays a crucial role in the formation of stars and planets. It has long been noticed that parcels of gas in molecular clouds need to reduce their specific angular momentum by 6 to 7 orders of magnitude to participate in the…
The end state of a coalescing binary of compact objects depends strongly on the final total mass M and angular momentum J. Since gravitational radiation emission causes a slow evolution of the binary system through quasi-circular orbits…
Rotation plays a key role in the star-formation process, from pre-stellar cores to pre-main-sequence (PMS) objects. Understanding the formation of massive stars requires taking into account the accretion of angular momentum during their PMS…
It is now clear that a subset of supernovae display evidence for jets and are observed as gamma-ray bursts. The angular momentum distribution of massive stellar endpoints provides a rare means of constraining the nature of the central…
We develop a semi-analytic model to investigate how accretion onto wide low-mass binary stars can result in a close high-mass binary system. The key ingredient is to allow mass accretion while limiting the gain in angular momentum. We…
Small perturbations in spherical and thin disk stellar clusters surrounding massive a black hole are studied. Due to the black hole, stars with sufficiently low angular momentum escape from the system through the loss cone. We show that…
The presence of young massive stars orbiting on eccentric rings within a few tenths of a parsec of the supermassive black hole in the Galactic centre is challenging for theories of star formation. The high tidal shear from the black hole…
A mechanism of creation of stellar-like objects in the very early universe, from the QCD phase transition till BBN and somewhat later, is studied. It is argued that in the considered process primordial black holes with masses above a few…
The processes are investigated by which gas loses its angular momentum during the protogalactic collapse phase, leading to disk galaxies that are too compact with respect to the observations. High-resolution N-body/SPH simulations in a…
Disk accretion may be the fundamental astrophysical process. Stars and planets form through the accretion of gas in a disk. Black holes and galaxies co-evolve through efficient disk accretion onto the central supermassive black hole.…