Related papers: PEWDD: A database of white dwarfs enriched by exo-…

White dwarfs accreting planetary debris provide detailed insight into the bulk composition of rocky exo-planetesimals. However, only one Kuiper-Belt analogue has been identified in that way so far. Here, we report the accretion of an icy…

The Teff = 20,800 K white dwarf WD 1536+520 is shown to have broadly solar abundances of the major rock forming elements O, Mg, Al, Si, Ca, and Fe, together with a strong relative depletion in the volatile elements C and S. In addition to…

With the goal of using externally-polluted white dwarfs to investigate the water fractions of extrasolar planetesimals, we assemble from the literature a sample that we estimate to be more than 60% complete of DB white dwarfs warmer than…

It was recently proposed that metal-rich white dwarfs (WDs) accrete their metals from compact debris disks found to exist around more than a dozen of them. At the same time, elemental abundances measured in atmospheres of some WDs imply…

White dwarf spectroscopy shows that nearly half of white dwarf atmospheres contain metals that must have been accreted from planetary material that survived the red giant phases of stellar evolution. We can use metal pollution in white…

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…

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 performed a chemical analysis of the asteroid-bearing white dwarf WD 1145+017 using optical and ultraviolet spectroscopic data from 25 epochs between 2015 and 2023. We present an updated gas disk model with improved opacity calculations…

Recent Kepler photometry has revealed that about half of white dwarfs (WDs) have periodic, low-level (~ 1e-4 - 1e-3), optical variations. Hubble Space Telescope (HST) ultraviolet spectroscopy has shown that up to about one half of WDs are…

Seven ultra low-mass and small-radius white dwarfs (LSPM J0815+1633, LP 240-30, BD+20 5125B, LP 462-12, WD J1257+5428, 2MASS J13453297+4200437, and SDSS J085557.46+053524.5) have been recently identified with masses ranging from $\sim$0.02…

Cool white dwarf stars are usually found to have an outer atmosphere that is practically pure in hydrogen or helium. However, a small fraction have traces of heavy elements that must originate from the accretion of extrinsic material, most…

Tidal disruption and subsequent accretion of planetesimals by white dwarfs can reveal the elemental abundances of rocky bodies in exoplanetary systems. Those abundances provide information on the composition of the nebula from which the…

We present observations and analyses of eight white dwarf stars that have accreted rocky material from their surrounding planetary systems. The spectra of these helium-atmosphere white dwarfs contain detectable optical lines of all four…

We present a series of systematic abundance measurements for a group of hot DA white dwarfs in the temperature range 20,000-75,000K, based on far-UV spectroscopy with STIS on HST, IUE and FUSE. Using our latest heavy element blanketed…

We present a population synthesis model which addresses the different mass distributions of the metal-polluted and non-metal-polluted hydrogen-atmosphere white dwarfs identified in volume-limited samples. Specifically, metal-pollution has…

We present a series of systematic abundance measurements for 89 hydrogen atmosphere (DA-type) white dwarfs with temperatures spanning 16000-77000K drawn from the FUSE spectral archive. This is the largest study to date of white dwarfs where…

We report the discovery of a subtle infrared excess associated with the young white dwarf EC\,05365--4749 at 3.35 and 4.6\,$\mu$m. Follow-up spectroscopic observations are consistent with a hydrogen atmosphere white dwarf of effective…

Here, we present near-infrared spectroscopic observations of 15 helium atmosphere, metal-rich white dwarfs obtained at the NASA Infrared Telescope Facility. While a connection has been demonstrated between the most highly polluted, hydrogen…

Prior studies have hypothesized that some polluted white dwarfs record continent-like granitic crust--which is abundant on Earth and perhaps uniquely indicative of plate tectonics. But these inferences derive from only a few elements, none…

About a dozen hot white dwarfs with effective temperatures Teff = 65,000-120,000 K exhibit unusual absorption features in their optical spectra. These objects were tentatively identified as Rydberg lines of ultra-high excited metals in…