Related papers: A cool, magnetic white dwarf accreting planetary d…

We present an analysis of 40 cool helium-rich white dwarfs found in the Hamburg/ESO survey. They were selected for follow-up spectroscopy because of their U-B colour below -0.18, the absence of strong absorption lines, and a continuum shape…

We present an analysis of intermediate-dispersion spectra and photometric data of the newly identified cool, polluted white dwarf NLTT19868. The spectra obtained with X-shooter on the Very Large Telescope (VLT)-Melipal show strong lines of…

Many white dwarfs are observed in compact double white dwarf binaries and, through the emission of gravitational waves, a large fraction are destined to merge. The merger remnants that do not explode in a Type Ia supernova are expected to…

Gaseous and dust debris disks around white dwarfs (WDs) are formed from tidally disrupted planetary bodies. This offers an opportunity to determine the composition of exoplanetary material by measuring element abundances in the accreting…

Some white dwarfs undergo significant changes in atmospheric composition owing to the diffusion and mixing of residual hydrogen in a helium-rich envelope. Of particular interest are a few objects exhibiting hydrogen and helium line…

The detection of a dust disc around G29-38 and transits from debris orbiting WD1145+017 confirmed that the photospheric trace metals found in many white dwarfs arise from the accretion of tidally disrupted planetesimals. The composition of…

White dwarfs have atmospheres that are expected to consist nearly entirely of hydrogen and helium, since heavier elements will sink out of sight on short timescales. However, observations have revealed atmospheric pollution by heavier…

We analyze an HST/STIS ultraviolet spectrum of the young brown dwarf 2MASSW J1207334-393254, a member of the ten million-year old TW Hya Association that has a planetary-mass companion. We detect and identify numerous emission lines. CIV…

White dwarf stars frequently experience external pollution by heavy elements, and yet the intrinsically carbon-enriched DQ spectral class members fail to exhibit this phenomenon, representing a decades-old conundrum. This study reports a…

We present spectroscopic observations of the dust- and gas-enshrouded, polluted, single white dwarf star SDSSJ104341.53+085558.2 (hereafter SDSSJ1043+0855). Hubble Space Telescope Cosmic Origins Spectrograph far-ultraviolet spectra combined…

Around 10% of white dwarfs exhibit global magnetic structures with fields ranging from 1 kG to hundreds of MG. Recently, the first radiation magnetohydrodynamics simulations of the atmosphere of white dwarfs showed that convection should be…

Near-infrared photometry and spectroscopy is obtained for a heterogeneous sample of nearby white dwarfs with possible excess flux as identified primarily in the Two Micron All Sky Survey. Among the sample of 43 stars are a number of white…

We present new results on PHL 5038AB, a widely separated binary system composed of a white dwarf and a brown dwarf, refining the white and brown dwarf parameters and determining the binary separation to be $66^{+12}_{-24}$~AU. New spectra…

The nature of the excess near-infrared emission associated with the magnetic white dwarf commonly known as SDSS 1212 is investigated primarily through spectroscopy, and also via photometry. The inferred low mass secondary in this system has…

White dwarfs with emission lines from gaseous debris discs are among the rarest examples of planetary remnant hosts, but at the same time they are key objects for studying the final evolutionary stage of planetary systems. Making use of the…

We report the discovery of weak magnetic fields in three white dwarfs within the local 20pc volume (WD 0816-310, WD 1009-184, and WD 1532+129), and we confirm the magnetic nature of a fourth star (WD 2138-332) in which we had previously…

Nine metal-polluted white dwarfs are observed with medium-resolution optical spectroscopy,where photospheric abundances are determined and interpreted through comparison against solar system objects. An improved method of making such…

We have searched the Gaia DR2 catalogue for previously unknown hot white dwarfs in the direction of young open star clusters. The aim of this experiment was to try and extend the initial-final mass relation (IFMR) to somewhat higher masses,…

It is generally assumed that metals detected in the spectra of a few cool white dwarfs cannot be of primordial origin and must be accreted from the interstellar medium. However, the observed abundances of hydrogen, which should also be…

White dwarfs are the end state of most stars, including the Sun, after they exhaust their nuclear fuel. Between 1/4 and 1/2 of white dwarfs have elements heavier than helium in their atmospheres, even though these elements should rapidly…