Related papers: Detached white-dwarf close-binary stars -- CV's ex…
We present a set of white dwarf-main sequence (WDMS) binaries identified spectroscopically from the Large sky Area Multi-Object fiber Spectroscopic Telescope (LAMOST, also called the Guo Shou Jing Telescope) pilot survey. We develop a color…
Hot subdwarfs in close binaries with either M dwarf, brown dwarf or white dwarf companions show unique light variations. In hot subdwarf binaries with M dwarf or brown dwarf companions we can observe the so-called reflection effect and in…
Many pulsating low-mass white-dwarf stars have been detected in the last years in the field of our Galaxy. Given that some of them exhibit multiperiodic variation of brightness, it is possible to probe their interiors through…
Many open clusters have a deficit of observed white dwarfs (WDs) compared with predictions of the number of stars to have evolved into WDs. We evaluate the number of WDs produced in open clusters and the number of those WDS detectable using…
As part of our search for young M dwarfs within 25 pc, we acquired high-resolution spectra of 185 low-mass stars compiled by the NStars project that have strong X-ray emission. By cross-correlating these spectra with radial velocity…
Mounting evidence from subdwarf B (sdB) stars in the galactic field and their recently discovered counterparts in old open clusters indicates that at least two thirds of local disk sdB stars are binaries. Our recent radial velocity survey…
In an edge-on and detached binary system, including a white dwarf (WD) and a main-sequence star (WDMS), when the source star is passing behind the compact companion its light is bent and magnified. Meanwhile, some part of its images' area…
Interacting binaries in which a white dwarf accretes material from a companion --- cataclysmic variables (CVs) in which the mass loss is via Roche-lobe overflow, and symbiotic stars in which the white dwarf captures the wind of a late type…
We present an overview and catalogue of all known mass-transferring binary systems that have white dwarf accretors and orbital periods shorter than 70 minutes, including the AM CVn-type binary systems and a number of related objects. In…
The origin of the bright and hard X-ray emission flux among the gamma Cas subgroup of B-emission line (Be) stars may be caused by gas accretion onto an orbiting white dwarf (WD) companion. Such Be+WD binaries are the predicted outcome of a…
During post-main-sequence evolution, radial expansion of the primary star, accompanied by intense winds, can significantly alter the binary orbit via tidal dissipation and mass loss. The fate of a given binary system is determined by the…
The identification and characterization of massive ($\gtrsim 0.8~M_\odot$) white dwarfs is challenging in part due to their low luminosity. Here we present two candidate single-lined spectroscopic binaries, Gaia DR3 4014708864481651840 and…
The third data release of Gaia introduced a large catalog of astrometric binaries, out of which about 3,200 are likely main-sequence stars with a white-dwarf (WD) companion. These binaries are typically found with orbital separations of ~1…
Hot subdwarf (sdB) stars in binary systems with main-sequence (MS) companions provide valuable insights into mass transfer and envelope ejection processes in binary evolution. Their mass ratios, orbital periods, and stellar properties…
The fundamental properties of low-mass stars are not as well understood as those of their more massive counterparts. The best method for constraining these properties, especially masses and radii, is to study eclipsing binary systems, but…
We report on the results of a survey for radial velocity variability in a heterogeneous sample of very low-mass stars and brown dwarfs. One distinguishing characteristic of the survey is its timespan, which allows an overlap between…
We describe new radial velocity and X-ray observations of extremely low-mass white dwarfs (ELM WDs, ~0.2 Msol) in the Sloan Digital Sky Survey Data Release 4 and the MMT Hypervelocity Star survey. We identify four new short period binaries,…
We carried out a spectroscopic investigation of single lined white dwarfs (WDs) in double degenerate (DD) systems and discuss their binary evolution. Simulated spectra of the Halpha region are used to derive upper limits on the temperature…
White dwarfs are the burnt out cores of Sun-like stars and are the final fate of 97% of all stars in our Galaxy. The internal structure and composition of white dwarfs are hidden by their high gravities, which causes all elements, apart…
This paper investigates the frequency of transiting planetary systems around metal-polluted white dwarfs using high-cadence photometry from ULTRACAM and ULTRASPEC on the ground, and space-based observations with TESS. Within a sample of 313…