Related papers: A white dwarf accreting planetary material determi…
The emission of hard X-rays associated with white dwarfs (WD) can be generated by the presence of a stellar companion either by the companion's coronal emission or by an accretion disk formed by material stripped from the companion. Recent…
A recent analysis of Chandra X-ray data of the metal-polluted white dwarf (WD) G29-38 has revealed X-ray emission that can be attributed to the accretion of debris from a planetary body. In the light of this detection we revisit here…
We present a brief summary of the Single Degenerate Scenario for the progenitors of Type Ia Supernovae in which it is assumed that a low mass carbon-oxygen white dwarf is growing in mass as a result of accretion from a secondary star in a…
A growing number of debris discs have been detected around metal-polluted white dwarfs. They are thought to be originated from tidally disrupted exoplanetary bodies and responsible for metal accretion onto host WDs. To explain (1) the…
High-energy data of accreting white dwarfs give access to the regime of the primary accretion-induced energy release and the different proposed accretion scenarios. We perform XMM-Newton observations of polars selected due to their ROSAT…
A significant fraction of white dwarfs (WDs) are observed to be polluted with metals despite high surface gravities and short settling times. The current theoretical model for this pollution is accretion of rocky bodies delivered to the WD…
Although 25%-50% of white dwarfs (WDs) display evidence for remnant planetary systems, their orbital architectures and overall sizes remain unknown. Vibrant close-in (~1 Solar radius) circumstellar activity is detected at WDs spanning many…
Metals observed in the atmospheres of white dwarfs suggest that many have recently accreted planetary bodies. In some cases, the compositions observed suggest the accretion of material dominantly from the core (or the mantle) of a…
The accretion of tidally disrupted planetary bodies is the current consensus model for the presence of photospheric metals commonly detected in white dwarfs. While most dynamical studies have considered a single star and associated…
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…
We present near- and mid-infrared photometry and spectroscopy from PAIRITEL, IRTF, and Spitzer of a metallicity-unbiased sample of 117 cool, hydrogen-atmosphere white dwarfs from the Palomar-Green survey and find five with excess radiation…
Planetary systems that orbit white dwarf stars can be studied via spectroscopic observations of the stars themselves. Numerous white dwarfs are seen to have accreted mostly rocky minor planets, the remnants of which are present in 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…
Brown dwarfs and giant planets orbiting close to a host star are subjected to significant irradiation that can modify the properties of their atmospheres. In order to test the atmospheric models that are used to describe these systems, it…
Most observations of polluted white dwarf atmospheres are consistent with accretion of water depleted planetary material. Among tens of known cases, merely two cases involve accretion of objects that contain a considerable mass fraction of…
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…
The bulk abundances of exoplanetesimals can be measured when they are accreted by white dwarfs. Recently, lithium from the accretion of exoplanetesimals was detected in relatively high levels in multiple white dwarfs. There are presently…
With XMM-Newton and the Spitzer Space Telescope, we obtain upper bounds to the X-ray fluxes from G29-38 and GD 362, and the 70 micron flux from G29-38. These data provide indirect evidence that G29-38 is accreting from a tidally-disrupted…
Almost every known planet host will evolve into a white dwarf, and the surviving planetary material will continue to orbit this stellar remnant. Asteroids perturbed onto star-grazing orbits will become disrupted, forming an accretion disk…
An XMM-Newton observation of the nearby "pre-cataclysmic" short-period (P_orb = 3.62 hr) binary QS Vir (EC 13471-1258) revealed regular narrow X-ray eclipses when the white dwarf passed behind its M2-4 dwarf companion. The X-ray emission…