Related papers: Alfven Waves in Disks, Outflows and Jets
The temperatures of observed protoplanetary disks are not sufficiently high to produce the accretion rate needed to form stars, nor are they sufficient to explain the volatile depletion patterns in CM, CO, and CV chondrites and terrestrial…
An investigation of the magnetospheric accretion and outflow signatures in sub-stellar objects is a natural extension of similar studies conducted on classical T Tauri stars (CTTS), and helps understand if brown dwarfs (BDs) follow the same…
We study the global bending modes of a thin annular disc subject to both an internally generated magnetic field and a magnetic field due to a dipole embedded in the central star with axis aligned with the disc rotation axis. When there is a…
A significant fraction of white dwarfs (WDs) exhibit signs of ongoing accretion of refractory elements at rates $\sim10^3$--$10^7$ kg s$^{-1}$, among which, 37 WDs were detected to harbor dusty debris disks. Such a concurrence requires not…
Magnetar flares excite strong Alfv\'{e}n waves in the magnetosphere of the neutron star. The wave energy can (1) dissipate in the magnetosphere, (2) convert to "fast modes" and possibly escape, and (3) penetrate the neutron star crust and…
We examine various ways in which disk accretion can heat an accreting star. These include 1) radiation emitted from the disk surface which is intercepted by the stellar surface, 2) radiative flux directly across the disk-star interface, and…
Stars form by accreting material from their surrounding disks. There is a consensus that matter flowing through the disk is channelled onto the stellar surface by the stellar magnetic field. This is thought to be strong enough to truncate…
The theory of magnetically accelerated outflows and jets from accretion disks is reviewed at an introductory level, with special attention to problem areas like the launching conditions of the flow at the disk surface, stability of the…
Heating by the central star is one of the key factors determining the physical structure of protoplanetary disks. Due to the large optical thickness in the radial direction, disk midplane regions are heated by the infrared radiation from…
The inner region of a luminous accretion disk is radiation pressure dominated. We estimate the surface temperature of a radiation pressure dominated accretion disk, \Theta=(c_s/r\Omega_K)^2<<(H/r)^2, which is significantly lower than that…
The detectability of gravitational wave (GW) radiation from accretion disks is discussed based on various astrophysical contexts. In order to emit GW radiation, the disk shape should lose axial symmetry. We point out that a significant…
Hot stars are the main source of ionization of the interstellar medium and its enrichment due to heavy elements. Constraining the physical conditions of their environments is crucial to understand how these stars evolve and their impact on…
Sudden relaxation of the magnetic field in the core of a magnetar produces mechanical energy primarily in the form of shear waves which propagate to the surface and enter the magnetosphere as relativistic Alfv\'en waves. Due to a strong…
We construct detailed vertical structure models of irradiated accretion disks around T Tauri stars with interstellar medium dust uniformly mixed with gas. The dependence of the structure and emission properties on mass accretion rate,…
An axisymmetric model of a cool, dynamo-active accretion disc is applied to protostellar discs. Thermally and magnetically driven outflows develop that are not collimated within 0.1 AU. In the presence of a central magnetic field from the…
Two mechanisms of gravitational waves (GWs) emission in fast-spinning white dwarfs (WDs) are investigated: accretion of matter and magnetic deformation. In both cases, the GW emission is generated by an asymmetry around the rotation axis of…
Semi-analytical models of disk outflows have successfully described magnetically-driven, self-confined super-Alfv\'enic jets from near Keplerian accretion disks. These Jet Emitting Disks are possible for high levels of disk magnetization…
Alfv\'en waves (AWs) excited by the cosmic-ray (CR) streaming instability (CRSI) are a fundamental ingredient for CR confinement. The effectiveness of self-confinement relies on a balance between CRSI growth rate and damping mechanisms…
One of the most important and poorly-understood issues in structure formation is the role of outflows driven by active galactic nuclei (AGN). Using large-scale cosmological simulations, we compute the impact of such outflows on the…
Complex turbulent motions are ubiquitously observed in many astrophysical systems. Their origin, however, is still poorly understood. When cosmic structures form, they grow in mass via accretion from the surrounding environment. We propose…