Related papers: Metal pollution of the solar white dwarf by solar …
Polluted white dwarfs are generally accreting terrestrial-like material that may originate from a debris belt like the asteroid belt in the solar system. The fraction of white dwarfs that are polluted drops off significantly for white…
About 25-50% of white dwarfs (WDs) show metal lines in their spectra. Among the widely accepted explanations for this effect is that the these WDs are accreting asteroids that are perhaps flung onto the WDs by a planet via resonance, for…
Novae are cataclysmic variable binary systems in which a white dwarf primary is accreting material from a low mass companion. The importance of this accretion takes on added significance if the WD can increase its mass to reach the…
Atmospheric heavy elements have been observed in more than a quarter of white dwarfs (WDs) at different cooling ages, indicating ongoing accretion of asteroidal material, whilst only a few per cent of the WDs possess a dust disk, and all…
Polluted white dwarfs serve as astrophysical mass spectrometers - their photospheric abundances are used to infer the composition of planetary objects that accrete onto them. We show that due to asymmetries in the accretion process, the…
Extrapolating from the solar system's asteroid belt, we propose that externally-contaminated white dwarfs without an infrared excess may be experiencing continuous accretion of gas-phase material that ultimately is derived from the tidal…
Polluted white dwarfs offer a unique way to study the bulk compositions of exoplanetary material, but it is not always clear if this material originates from comets, asteroids, moons, or planets. We combine N-body simulations with an…
I review various phenomena associated with mass-accreting white dwarfs (WDs) in the view of supersoft X-ray sources. When the mass-accretion rate is low (\dot M_{acc} < a few \times 10^{-7} M_\sun yr^{-1}), hydrogen nuclear burning is…
(Abridged) We present the results of the first unbiased survey for metal pollution among H-atmosphere (DA) white dwarfs with cooling ages of 20-200 Myr and 17000K < Teff < 27000K, using HST COS in the far UV between 1130 and 1435 A. The…
A significant fraction of white dwarfs show metal lines indicative of pollution with planetary material but the accretion process remains poorly understood. The main aim of this paper is to produce a road-map illustrating several potential…
The atmospheres of a large proportion of white dwarf stars are polluted by heavy elements that are expected to sink out of visible layers on short timescales. This has been interpreted as a signature of ongoing accretion of debris from…
Cataclysmic Variables (CVs) are close binary star systems with one component an accreting white dwarf (WD) and the other a larger cooler star that fills its Roche Lobe. One consequence of the WDs accreting material, is the possibility that…
We study C/O white dwarfs with masses of 1.0 to 1.4 Msun accreting solar-composition material at very high accretion rates. We address the secular changes in the WDs, and in particular, the question whether accretion and the thermonuclear…
Accreting white dwarfs (WDs) with non-degenerate companions are expected to emit in soft X-rays and the UV, if accreted H-rich material burns stably. They are an important component of the unresolved emission of elliptical galaxies, and…
Many isolated white dwarfs (WDs) show spectral evidence of atmospheric metal pollution. Since heavy element sedimentation timescales are short, this most likely indicates ongoing accretion. Accreted metals encounter a variety of mixing…
Recent infrared observations have revealed presence of compact (radii < R_Sun) debris disks around more than a dozen of metal-rich white dwarfs (WD), likely produced by tidal disruption of asteroids. Accretion of high-Z material from these…
A non negligible fraction of white dwarf stars show the presence of heavy elements in their atmospheres. The most accepted explanation for this contamination is the accretion of material coming from tidally disrupted planetesimals, which…
As the descendants of stars with masses less than 8 M$_{\odot}$ on the main sequence, white dwarfs provide a unique way to constrain planetary occurrence around intermediate-mass stars (spectral types BAF) that are otherwise difficult to…
A growing sample of white dwarfs (WDs) with metal-enriched atmospheres are accompanied by excess infrared emission, indicating that they are encircled by a compact dusty disk of solid debris. Such `WD debris disks' are thought to originate…
When a white dwarf (WD) is weakly magnetized and its accretion disk is thin, accreted material first reaches the WD's surface at its equator. This matter slows its orbit as it comes into co-rotation with the WD, dissipating kinetic energy…