Related papers: Two New Variable Hot DQ Stars

The spectroscopic class of subdwarf A-type (sdA) stars has come into focus in recent years because of their possible link to extremely low-mass white dwarfs, a rare class of objects resulting from binary evolution. Although most sdA stars…

We quantify the variability of faint unresolved optical sources using a catalog based on multiple SDSS imaging observations. The catalog covers SDSS Stripe 82, and contains 58 million photometric observations in the SDSS ugriz system for…

Early data taken during commissioning of the SDSS have resulted in the discovery of a very cool white dwarf. It appears to have stronger collision induced absorption from molecular hydrogen than any other known white dwarf, suggesting it…

The Southern African Large Telescope (SALT) survey of helium-rich hot subdwarfs aims to explore evolutionary pathways amongst groups of highly-evolved stars. The selection criteria mean that several hot white dwarfs and related objects have…

Using high-cadence observations from the Zwicky Transient Facility at low Galactic latitudes, we have discovered a new class of pulsating, hot, compact stars. We have found four candidates, exhibiting blue colors ($g-r\leq-0.1$ mag),…

We have obtained Hubble Space Telescope UV spectra of the white dwarf in GW Lib, the only known non-radially pulsating white dwarf in a cataclysmic variable, and the first known DAZQ variable. The UV light curve reveals large amplitude…

Photometric data from the ASAS - South (declination less than 29 deg) survey have been used for identification of bright stars located near the sources from the ROSAT All Sky Survey Bright Source Catalog (RBSC). In total 6028 stars brighter…

This paper reports the ULTRACAM discovery of dipolar surface spots in two cool magnetic white dwarfs with Balmer emission lines, while a third system exhibits a single spot, similar to the prototype GD 356. The light curves are modeled with…

In this paper we present high time-resolution observations of GW Librae and SDSS J161033.64-010223.3 -- two cataclysmic variables which have shown periodic variations attributed to non-radial pulsations of the white dwarf. We observed both…

We have identified 7 new magnetic DA white dwarfs in the Early Data Release of the Sloan Digital Sky Survey. Our selection strategy has also recovered all the previously known magnetic white dwarfs contained in the SDSS EDR, KUV03292+0035…

In recent years, approximately 150 low-mass white dwarfs (WDs), typically with masses below 0.4 solar masses, have been discovered. Observational evidence indicates that most of these low-mass WDs are found in binary systems, supporting…

At present, a large number of pulsating white dwarf (WD) stars is being discovered either from Earth-based surveys such as the Sloan Digital Sky Survey, or through observations from space (e.g., the Kepler mission). The asteroseismological…

A sample of 4 thousands Gaia sources with apparent $G$-band magnitudes of $<17$ and trigonometric parallaxes of $>3.33$ milli-arcseconds were cross-matched to the Transiting Exoplanet Survey high level science products and the Full-Frame…

Hot subdwarf variables (sdBVs) that display large-amplitude ($>$1%), short-period variability, as a result of radial-mode pulsations, have recently become objects of interest as they show unique properties among the sdBV classes. Since the…

Measuring g-mode pulsations of isolated white dwarfs can reveal their interior properties to high precision. With a spectroscopic mass of ~0.51 M_{\odot} (log g = 7.82), the DAV white dwarf HS 1824+6000 is near the transition between…

We conduct a systematic search for periodic variables in the hot subdwarf catalogue using data from the Zwicky Transient Facility. We present the classification of 67 HW Vir binaries, 496 reflection effect, pulsation or rotation sinusoids,…

We analyzed the light curves of 1376 early-to-late, nearby M dwarfs to search for white-light flares using photometry from the All-Sky Automated Survey for Supernovae (ASAS-SN). We identified 480 M dwarfs with at least one potential flare…

We summarize our findings on three cool ZZ Ceti type pulsating white dwarfs. We determined eight independent modes in HS 0733+4119, of which seven are new findings. For GD 154, we detected two new eigenmodes, and the recurrence of the…

Following our recent discovery of a new magnetic DQ white dwarf (WD) with CH molecular features, we report the results for the rest of the DQ WDs from our survey. We use high signal-to-noise spectropolarimetric data to search for magnetic…

We present some of the results of a survey aimed at exploring the asteroseismological potential of the newly-discovered carbon-atmosphere white dwarfs. We show that, in certains regions of parameter space, carbon-atmosphere white dwarfs may…