Related papers: A Search for Unresolved Double Degenerates Using I…

We present a study of the iron abundance pattern in hot hydrogen-rich (DA) white dwarfs. The study is based on new and archival far ultraviolet spectroscopy of a sample of white dwarfs in the temperature range 30,000 K < T_eff < 64,000 K.…

We report our findings on a spectroscopic survey of seven unresolved DA+DB binary white dwarf candidates. We have discovered extreme spectroscopic variations in one of these candidates, SDSS J084716.21+484220.40. Previous analysis failed to…

We report the discovery, in an Extreme Ultraviolet Explorer (EUVE) short wavelength spectrum, of an unresolved hot white dwarf companion to the 5th-magnitude B5Vp star HR2875. This is the first time that a non-interacting white dwarf$+$ B…

We present the first brown dwarf spectral binary characterized with JWST: WISE J014656.66+423410.0, the coldest blended-light brown dwarf binary straddling the T/Y transition. We obtained a moderate resolution (R$\sim$2700) G395H spectrum…

Type Ia Supernovae (SNe Ia) are securely understood to come from the thermonuclear explosion of a white dwarf as a result of binary interaction, but the nature of that binary interaction and the secondary object is uncertain. Recently, a…

We assembled a catalogue of bright, hot subdwarf and white dwarf stars extracted from a joint ultraviolet, optical, and infrared source list. The selection is secured using colour criteria that correlate well with effective temperatures…

We report the identification, in an Extreme Ultraviolet Explorer (EUVE) spectrum, of a hot white dwarf companion to the 3rd magnitude late-B star Theta Hya (HR3665, HD79469). This is the second B star + white dwarf binary to be conclusively…

The progenitor systems and explosion mechanism of Type Ia supernovae are still unknown. Currently favoured progenitors include double-degenerate systems consisting of two carbon-oxygen white dwarfs with thin helium shells. In the…

We present a catalogue of 1602 white dwarf-main sequence binaries (WDMS) from the spectroscopic Sloan Digital Sky Survey Data Release 6 (SDSS DR6). Among these we identify 440 as new WDMS binaries. We select WDMS binary candidates from…

With tens to hundreds of spectra of white dwarfs being taken each night from multi-object spectroscopic surveys, automated spectral classification is essential as part of efficient data processing. In this study, we design a neural network…

A large experimental program is being mounted to search for neutrinoless double-beta decay over the next decade. Multiple experiments using different target isotopes are being prepared to explore the whole parameter space allowed for…

Gaia DR3 mission has identified and provided about 440,000 binary systems with orbital solutions, offering a valuable resource for searching binaries including a compact component. By combining the Gaia DR3 data with radial velocities (RVs)…

The multiplicity properties of brown dwarfs are critical empirical constraints for formation theories, while multiples themselves provide unique opportunities to test evolutionary and atmospheric models and examine empirical trends. Studies…

We present the results of a search of infrared excess candidates in a comprehensive (29\,000 stars) magnitude limited sample of dwarf stars, spanning the spectral range F2-K0, and brighter than V$=$15 mag. We searched the sample within the…

We present spectrophotometry in the 3600-9700 A region for a sample of 39 H II regions in the Galaxy and Magellanic Clouds, for which independent information is available on the spectral types and effective temperatures of the ionizing…

Mergers of double white dwarfs are considered significant potential progenitors of type Ia supernovae. Although there is no direct observational evidence to definitively determine the formation pathways of SNe Ia, studying the physical…

In the course of our search for double degenerate (DD) binaries as potential progenitors of type Ia supernovae with the UVES spectrograph at the ESO VLT (ESO SN Ia Progenitor surveY - SPY) we discovered that the white dwarf HE 1414-0848 is…

We review the current observational status of the ROSAT sources RX J1914.4+2456 and RX J0806.3+1527, and the evidence that these are ultra-short period (<10min) binary systems. We argue that an Intermediate Polar interpretation can be ruled…

The third data release of Gaia was the first to include orbital solutions assuming non-single stars. Here, we apply the astrometric triage technique of Shahaf et al. to identify binary star systems with companions that are not single…

A number of efforts are underway to detect close binary stars in planetary nebulae. The primary goal of these studies is to determine the binary fraction of central stars. The next stage is a detailed analysis of the binaries to determine…