Related papers: Magnetic Accretion Onto White Dwarfs
Qualitative arguments are presented to demonstrate that the energy density of magnetic fields in matter accreting onto a black hole inside the marginally stable orbit is automatically comparable to the rest-mass energy density of the…
Rotating magnetized white dwarfs are studied within the framework of general relativity using Hartle's formalism. Matter inside magnetized white dwarfs is described by an equation of state of particles under the action of a constant…
I present a brief review of the present status of X-ray emission from Magnetic Cataclysmic Variables (MCVs). A short introduction to the types of Cataclysmic Variables (CVs) is followed by a presentation of some of the properties of the two…
The mean white dwarf (WD) mass in the Galactic bulge cataclysmic variables (CVs) was measured by applying the the shock temperature-WD mass correlation of magnetic cataclysmic variables (mCVs) to the Galactic Bulge X-ray Emission (GBXE)…
A large number of white dwarf and donor masses in cataclysmic variables have been found via modelling the primary eclipse, a method that relies on untested assumptions. Recent measurements of the mass of the white dwarf in the cataclysmic…
Little is known about the incidence of magnetic fields among the coolest white dwarfs. Their spectra usually do not exhibit any absorption lines as the bound-bound opacities of hydrogen and helium are vanishingly small. Probing these stars…
Magnetic activity in M-dwarfs present enigmatic questions: On the one hand they have higher field strengths and larger filling factors than the magnetic field on the Sun, on the other hand, they are fully convective and their atmospheres…
We explain the physics of compressional heating of the deep interior of an accreting white dwarf (WD) at accretion rates low enough so that the accumulated hydrogen burns unstably and initiates a classical nova (CN). In this limit, the WD…
Over a quarter of white dwarfs have photospheric metal pollution, which is evidence for recent accretion of exoplanetary material. While a wide range of mechanisms have been proposed to account for this pollution, there are currently few…
Due to the short settling times of metals in DA white dwarf atmospheres, any white dwarfs with photospheric metals must be actively accreting. It is therefore natural to expect that the metals may not be deposited uniformly on the surface…
We present HST spectroscopy for 45 cataclysmic variables (CVs), observed with HST/COS and HST/STIS. For 36 CVs, the white dwarf is recognisable through its broad Ly$\alpha$ absorption profile and we measure the white dwarf effective…
Current estimates for white dwarfs with fields in excess of 1MG are about 10%; according to our first high-precision circular-polarimetric study of 12 bright white dwarfs with the VLT (Aznar Cuadrado et al. 2004) this number increases up to…
Heavy elements are observed in the atmospheres of many DA and DB white dwarfs, and their presence is attributed to the accretion of matter coming from debris disks. Several authors have deduced accretion rates from the observed abundances,…
The magnetic white dwarfs (MWDs) are found either isolated or in interacting binaries. They divide into two groups: a high field group (0.1-1,000MegaGauss) comprising some 13% of all white dwarfs (WDs), and a low field group (B<0.1MG) whose…
We present results from a circular polarimetric survey of candidate detached magnetic white dwarf - M dwarf binaries obtained using the Nordic Optical Telescope, La Palma. We obtained phase resolved spectropolarimetry and imaging…
Magnetic fields play a fundamental role for interior and atmospheric properties of M dwarfs and greatly influence terrestrial planets orbiting in the habitable zones of these low-mass stars. Determination of the strength and topology of…
The disc instability mechanism (DIM) is widely accepted to account for the transient behaviour of dwarf novae (DNe), which experience short outbursts separated by long quiescence. The duty cycle (the ratio between the outburst duration and…
Cataclysmic variable (CVs) are close interacting binaries in which a white dwarf accretes materials from a low mass main sequence companion. CVs can experience nova eruptions due to low mass transfer rates. In the standard theory of CV…
Weak magnetic field has been searched for on only a small number of white dwarfs. Current estimates for white dwarfs with fields in excess of 1MG are about 10%; according to previous studies this number increases up to about 25% in the kG…
Our ongoing spectroscopic survey of high proper motion stars is a rich source of new magnetic white dwarfs. We present a few examples among cool white dwarfs showing the effect of field strength and geometry on the observed optical…