Related papers: Double white dwarf ZTF J0538+1953 as the brightest…

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…

We present precise parameters for two compact double white dwarf binaries, SDSS J232230.20+050942.0 (J2322+0509) and SDSS J063449.92+380352.2 (J0634+3803), with orbital periods of 20 and 26.5 minutes, respectively. These systems will serve…

We present an analysis of new and archival data to the 20.506-minute LISA verification binary J052610.42$+$593445.32 (J0526$+$5934). Our joint spectroscopic and photometric analysis finds that the binary contains an unseen…

ZTF J153932.16+502738.8 (ZTFJ1539) is an eclipsing double-white-dwarf system with an orbital period of 6.91 minutes, and is a significant source of LISA detecting gravitational wave. However, the massive white dwarf (WD) with mass of about…

The Laser Interferometer Space Antenna (LISA) is expected to detect close white dwarf binaries (CWDBs) through their gravitational radiation. Around 3000 binaries will be spectrally resolved at frequencies > 3 mHz, and their positions on…

We report a single-lined white dwarf-main sequence binary system, LAMOST J172900.17+652952.8, which is discovered by LAMOST's medium resolution time-domain surveys. The radial velocity semi-amplitude and orbital period of the optical…

J191213.72-441045.1 is a binary system composed of a white dwarf and an M-dwarf in a 4.03-hour orbit. It shows emission in radio, optical, and X-ray, all modulated at the white dwarf spin period of 5.3 min, as well as various orbital…

In a search for eclipsing white dwarfs using the Zwicky Transient Facility lightcurves, we identified a deep eclipsing white dwarf with a dark, substellar companion. The lack of an infrared excess and an orbital period of 10 hours made this…

Compact Galactic binary systems with orbital periods of a few hours are expected to be detected in gravitational waves (GW) by LISA or a similar mission. At present, these so-called verification binaries provide predictions for GW frequency…

The discovery of the most compact detached white dwarf (WD) binary SDSS J065133.33+284423.3 has been discussed in terms of probing the tidal effects in white dwarfs. This system is also a verification source for the space-based…

Short-period Galactic double white dwarf (DWD) systems will be observable both in visible light through photometric monitoring and in mHz-range gravitational waves (GWs) with forthcoming space-based laser interferometry such as LISA. When…

We present radial velocity observations of four binary white dwarf candidates identified through their over-luminosity. We identify two new double-lined spectroscopic binary systems, WD 0311-649 and WD 1606+422, and constrain their orbital…

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…

SDSS J080434.20+510349.2 is the WZ type binary that displayed rare outburst in 2006 (Pavlenko et al., 2007). During the long-lasting tail of the late stage of the outburst binary shown the two-humped or four-humped profile of the orbital…

Using data from the extended Kepler mission in K2 Campaign 10 we identify two eclipsing binaries containing white dwarfs with cool companions that have extremely short orbital periods of only 71.2 min (SDSS J1205-0242, a.k.a. EPIC…

White dwarfs represent the last stage of evolution of stars with mass less than about eight times that of the Sun and, like other stars, are often found in binaries. If the orbital period of the binary is short enough, energy losses from…

We present the results from a Gemini snapshot radial-velocity survey of 44 low-mass white dwarf candidates selected from the Sloan Digital Sky Survey spectroscopy. To find sub-hour orbital period binary systems, our time-series spectroscopy…

We report the discovery of a rare close binary system, SMSS J160639.78-100010.7, comprised of a magnetic white dwarf with a field of about 30 MG and a brown dwarf. We measured an orbital period of 92 min which is consistent with 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…

Combining archival photometric observations from multiple large-area surveys spanning the past 17 years, we detect long-term variability in the light curves of ZTFJ032833.52-121945.27 (ZTFJ0328-1219), ZTFJ092311.41+423634.16 (ZTFJ0923+4236)…