Related papers: A new code for low-resolution spectral identificat…

Accreting binary white dwarf systems are among the sources expected to emanate gravitational waves that the Laser Interferometer Space Antenna (LISA) will detect. We investigate how accurately the binary parameters may be measured from LISA…

Infrared excess is an important probe of sub-stellar companions and/or debris disks around white dwarfs (WDs). Such systems are still rare for in-depth understanding of their formation and long-term evolution. One of the largest…

The current theory predicts that hot subdwarf binaries are produced from evolved low-mass binaries that have undergone mass transfer and drastic mass loss during either a common envelope phase or a stable Roche lobe overflow while on the…

We use the data provided by the Gaia Early Data Release 3 to search for a highly-complete volume-limited sample of unresolved binaries consisting of a white dwarf and a main sequence companion (i.e. WDMS binaries) within 100pc. We select…

We present the discovery of 255 binary and six multiple system candidates with wide > 5" separation composed by ultracool dwarfs companions to stars, plus nine double ultracool dwarf systems. These systems were selected based on common…

We report the discovery of SDSS J133725.26+395237.7 (hereafter SDSS J1337+3952), a double-lined white dwarf (WD+WD) binary identified in early data from the fifth generation Sloan Digital Sky Survey (SDSS-V). The double-lined nature of the…

Many problems in contemporary astrophysics---from understanding the formation of black holes to untangling the chemical evolution of galaxies---rely on knowledge about binary stars. This, in turn, depends on discovery and characterization…

We present high-resolution spectroscopy of two nearby white dwarfs with inconsistent spectroscopic and parallax distances. The first one, PG 1632+177, is a 13th magnitude white dwarf only 25.6 pc away. Previous spectroscopic observations…

Binary stellar systems form a large fraction of the Galaxy's stars. They are useful as laboratories for studying the physical processes taking place within stars, and must be correctly taken into account when observations of stars are used…

Binaries of two white dwarfs (WDs) are an important class of astrophysical objects that are theorized to lead to Type Ia supernovae and are also used to gain insight into complex processes involved in stellar binary evolution. We report the…

Approximately 150 low-mass white dwarfs, with masses below 0.4Msun, have been discovered. The majority of these low-mass WDs are observed in binary systems as they cannot be formed through single-star evolution within the Hubble time. In…

We present a spectroscopic component analysis of 18 candidate young, wide, non-magnetic, double-degenerate binaries identified from a search of the Sloan Digital Sky Survey Data Release 7 (DR7). All but two pairings are likely to be…

The census of the solar neighborhood is almost complete for stars and becoming more complete in the brown dwarf regime. Spectroscopic, photometric and kinematic characterization of nearby objects helps us to understand the local mass…

We present the second paper of a series of publications aiming at obtaining a better understanding regarding the nature of type Ia supernovae (SNIa) progenitors by studying a large sample of detached F, G and K main sequence stars in close…

The estimation of the binary fraction of hot subdwarfs is key to shed light on the different evolution scenarios proposed to explain the loss of the hydrogen envelope during the red giant branch phase. In this paper we analyse the spectral…

We present preliminary results of a study aimed at detecting double white dwarf systems using a method based on a comparison of optical and UV spectra for 141 DA stars drawn from the IUE archives. In particular, we are looking for…

The Galactic population of close white dwarf binaries is expected to provide the largest number of gravitational wave sources for low frequency detectors such as the Laser Interferometer Space Antenna (LISA). Current data analysis…

Over the last decade or so, we have been developing the possible existence of highly magnetized white dwarfs with analytical stellar structure models. While the primary aim was to explain the nature of the peculiar overluminous type Ia…

Coalescences of binary white dwarfs represent a copious source of information for gravitational wave interferometers operating in the decihertz band. Moreover, according to the double degenerate scenario, they have been suggested to be…

We present medium resolution spectroscopy and multi-epoch VRI photometry for 21 new nearby (< 50 pc) white dwarf systems brighter than V ~ 17. Of the new systems, ten are DA (including a wide double degenerate system with two DA…