Related papers: Bondi-Hoyle-Lyttleton Accretion onto Star Clusters
There are now two dominant models of how stars form: gravitational collapse theory holds that star-forming molecular clumps, typically hundreds to thousands of solar masses in mass, fragment into gaseous cores that subsequently collapse to…
The validity of the hypothesis that the massive black holes in high redshift quasars grew from stellar-sized "seeds" is contingent on a seed's ability to double its mass every few ten million years. This requires that the seed accrete at…
This chapter reviews the dynamical processes in young stellar clusters. The accretion of gas by individual stars affects the dynamics of the cluster, and the masses of the stars. Dynamical mass segregation cannot explain the degree of mass…
Using the Eris zoom-in cosmological simulation of assembly of a Milky Way analog, we study chemical enrichment of stars due to accretion of metal-enriched gas from the interstellar medium during the Galaxy's development. We consider…
We discuss the possibility that gravitational focusing, is responsible for the power-law mass function of star clusters $N(\log M) \propto M^{-1}$. This power law can be produced asymptotically when the mass accretion rate of an object…
Following up our recent analysis devoted to the impact of non steady accretion on the location of young low-mass stars or brown dwarfs in the Herzsprung-Russell diagram, we perform a detailed analysis devoted to the effect of burst…
A new theory of quasars is presented in which the matter of thin accretion disks around black holes is supplied by stars that plunge through the disk. Stars in the central part of the host galaxy are randomly perturbed to highly radial…
This paper reports results from numerical simulations of the gravitational radiation emitted from non--rotating compact objects(both neutron stars and Schwarzschild black holes) as a result of the accretion of matter. A hybrid procedure is…
We present a model for the formation of massive ($M > 10 M_\odot$) stars through accretion-induced collisions in the cores of embedded dense stellar clusters. This model circumvents the problem of accreting onto a star whose luminosity is…
We study very-high rate spherically symmetric accretion flows onto a massive black hole (BH; 10^2 < M_BH < 10^6 Msun) embedded in a dense gas cloud with a low abundance of metals, performing one-dimensional hydrodynamical simulations which…
In the earliest phases of their evolution, stars gain mass through the acquisition of matter from their birth clouds. The widely accepted classical concept of early stellar evolution neglects the details of this accretion phase and assumes…
Spectral and kinematic studies suggest that the nonthermal radio source Sgr A*, located at the center of the Milky Way, is a supermassive compact object with a mass 2-3 million solar masses. Winds from nearby stars, located approximately…
Dynamical interactions in dense star clusters could significantly influence the properties of black holes, leaving imprints on their gravitational-wave signatures. While previous studies have mostly focused on repeated black hole mergers…
Binary stars are common. While only those with small separations may exchange gas with one another, even the widest binaries interact with their gaseous surroundings. Drag forces and accretion rates dictate how these systems are transformed…
We briefly describe the three existing scenarios for forming massive stars and emphasize that the arguments often used to reject the accretion scenario for massive stars are misleading. It is usually not accounted for the fact that the…
For most of their lives, galaxies are surrounded by large and massive coronae of hot gas, which constitute vast reservoirs for gas accretion. This Chapter describes a mechanism that allows star-forming disc galaxies to extract gas from…
A compact object moving relative to surrounding gas accretes material and perturbs the density of gas in its vicinity. In the classical picture of Bondi-Hoyle-Lyttleton accretion, the perturbation takes the form of an overdense wake behind…
The accretion process in a typical S-type symbiotic star, targeting~AG Draconis, is investigated through 3D hydrodynamical simulations using the FLASH code. Regardless of the wind velocity of the giant star, an accretion disk surrounding…
Identifying the processes that determine strength, duration and variability of protostellar mass growth is a fundamental ingredient of any theory of star formation. I discuss protostellar mass accretion rates dM/dt from numerical models…
We investigate the properties of accretion flows onto a black hole (BH) with a mass of $M_{\rm BH}$ embedded in an initially uniform gas cloud with a density of $n_{\infty}$ in order to study rapid growth of BHs in the early Universe. In…