Related papers: Formation of Be star decretion discs through bound…
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…
The origin of the spins of giant planets is an open question in astrophysics. As planets and stars accrete from discs, if the specific angular momentum accreted corresponds to that of a Keplerian orbit at the surface of the object, it is…
Abridged: We use three-dimensional SPH simulations to investigate the collapse of low-mass prestellar cores and the formation and early evolution of protostellar discs. The initial conditions are slightly supercritical Bonnor-Ebert spheres…
We study rapidly accreting, gravitationally unstable disks with a series of global, three dimensional, numerical experiments using the code ORION. In this paper we conduct a numerical parameter study focused on protostellar disks, and show…
We consider misaligned accretion discs formed after tidal disruption events occurring when a star encounters a supermassive rotating black hole. We use the linear theory of warped accretion discs to find the disc shape when the stream…
We investigate the continuum emission of viscous decretion discs around Be stars in this paper. The results obtained from non-LTE (local thermodynamic equilibrium) radiative transfer models show two regimes in the disc surface brightness…
The slow rotation of some young stars and the extreme rotation periods of some Ap stars have so far defied explanation. The absence of sufficiently efficient braking mechanisms for newly formed stars points to the star formation process…
The formation of a star is a dynamic process fed by the gravitational collapse of a molecular cloud core. Theoretical models and observations suggest that the majority of this infalling material settles into a protoplanetary disk before…
Newly formed stars are often observed to possess circumstellar disks, from which mass continues to be accreted onto the star and fed into outflowing jets, and which eventually may evolve into dusty debris disks and planetary systems. Recent…
Be stars are rapidly-rotating B stars that have shown emission lines originating in a circumstellar disk. The mechanisms that lead to disk formation and dissipation are not known although progress has been made with some systems. We present…
It is assumed that Be star discs are driven by viscosity. Emission from disc models is calculated and is confronted with continuum observations. It is found that the outflowing viscous disc models can reproduce the observed IR continuum…
Pebble accretion refers to the assembly of rocky planet cores from particles whose velocity dispersions are damped by drag from circumstellar disc gas. Accretion cross-sections can approach maximal Hill-sphere scales for particles whose…
Long-term evolution of a stellar orbit captured by a massive galactic center via successive interactions with an accretion disc has been examined. An analytical solution describing evolution of the stellar orbital parameters during the…
Radiative feedback from luminous, massive stars during their formation is a key process in moderating accretion onto the stellar object. In the prior papers in this series, we showed that one form such feedback takes is UV line-driven disc…
Be stars are rapidly rotating B type stars. The origin of their rapid rotation is not certain, but binary interaction remains to be a possibility. In this work we investigate the formation of Be stars resulting from mass transfer in…
Structure of a quasi-stationary stellar cluster is modelled assuming that it is embedded in the gravitational field of a super-massive black hole. Gradual orbital decay of stellar trajectories is caused by the dissipative interaction with…
A popular model for the circumstellar disks of Be stars is that of a geometrically thin disk with a density in the equatorial plane that drops as a power law of distance from the star. It is usually assumed that the vertical structure of…
We study the effect of density distribution evolution on the global one-armed oscillation modes in low viscosity disks around isolated and binary Be stars. Observations show that some Be stars exhibit evidence of formation and dissipation…
We consider rotating magnetic stars with winds and disks. We establish a theorem that relates the angular velocity of a disk region with no meridional motion to the angular velocity of the star. Also, we show that for a given value of the…
We investigate the formation and early evolution of a protostellar disc from a magnetized pre-stellar core using non-ideal magnetohydrodynamic (MHD) simulations including ambipolar diffusion and Ohmic dissipation. The dynamical contraction…