Related papers: A precision study of two eclipsing white dwarf plu…
The Kepler mission has provided a treasure trove of eclipsing binaries (EBs), observed at extremely high photometric precision, nearly continuously for several years. We are carrying out a survey of ~100 of these EBs to derive dynamical…
The Transiting Exoplanet Survey Satellite (\tess) produces a large number of single-transit event candidates, since the mission monitors most stars for only $\sim$27\,days. Such candidates correspond to long-period planets or eclipsing…
The magnetic white dwarf SDSS J121209.31+013627.7 exhibits a weak, narrow Halpha emission line whose radial velocity and strength are modulated on a period of ~90 minutes. Though indicative of irradiation on a nearby companion, no cool…
The eclipsing binary system 2M 1938+4603 consists of a pulsating hot subdwarf B star and a cool M dwarf companion in an effectively circular three-hour orbit. The light curve shows both primary and secondary eclipses, along with a strong…
We report on precise Doppler measurements of L231-32 (TOI-270), a nearby M dwarf ($d=22$ pc, $M_\star = 0.39$ M$_\odot$, $R_\star = 0.38$ R$_\odot$), which hosts three transiting planets that were recently discovered using data from the…
We present here the results of astrometric, photometric and spectroscopic observations leading to the determination of the orbit and dynamical masses of the binary L dwarf 2MASSW J0746425+2000321. High angular resolution observations spread…
GK Dra is a detached eclipsing binary system containing two early-F stars, one evolved, in an orbit with a period of 9.974 d and a small eccentricity. Its eclipsing nature was discovered using Hipparcos data, and pulsations were found in…
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 present the characterization of 5 new short-period low-mass eclipsing binaries from the WFCAM Transit Survey. The analysis was performed by using the photometric WFCAM J-mag data and additional low- and intermediate-resolution…
We report nine years of optical spectroscopy of the metal-polluted white dwarf SDSS J104341.53+085558.2, which presents morphological variations of the line profiles of the 8600 \AA\ Ca II triplet emission from the gaseous component of its…
HD188112 is an extremely low mass white dwarf in a close binary system. According to a previous study, the mass of HD188112 is $\sim$0.24 Msun and a lower limit of 0.73 Msun could be put for the mass of its unseen companion, a compact…
The formation of hot subdwarf stars (sdBs), which are core helium-burning stars located on the extended horizontal branch, is still not understood. Many of the known hot subdwarf stars reside in close binary systems with short orbital…
Double white dwarf systems are of great astrophysical importance in the field of gravitational wave and Type Ia supernova. While the binary fraction of CO core white dwarf is about a few percents, the extremely low mass white dwarfs are all…
Precise measurements of black hole (BHs) masses are necessary to understand the coevolution of these sources and their host galaxies. Sometimes in the center of a galaxy there is not one, but two BHs. The BH duality of the quasar nucleus…
We present an updated version of the spectroscopic white dwarf-main sequence (WDMS) binary catalogue from the Sloan Digital Sky Survey (SDSS). 395 new systems are serendipitous discoveries from the spectroscopic SDSSI/II Legacy targets. As…
In a systematic search for eclipsing white dwarfs using Zwicky transient facility (ZTF) data, we found seven eclipsing double white dwarfs with orbital periods ranging from 45 minutes to 3 hours. We collected high-speed light curves,…
We increase the spectroscopic completeness of the 100 pc white dwarf sample in the SDSS footprint with 840 additional spectra. Our spectroscopy is 86% complete for white dwarfs hotter than $T_{\rm eff}= 5000$ K, where H$\alpha$ remains…
Binary evolution theory predicts that the second common envelope (CE) ejection can produce low-mass (0.32-0.36 Msun) subdwarf B (sdB) stars inside ultrashort-orbital-period binary systems, as their helium cores are ignited under…
We present the results of a radial velocity survey of 20 white dwarf plus M dwarf binaries selected as a follow up to a \textit{Hubble Space Telescope} study that aimed to spatially resolve suspected binaries. Our candidates are taken from…
We present a spectroscopic follow-up program targeting closely-separated dual quasar candidates selected from imaging of SDSS quasars with the Subaru Hyper Suprime-Cam Subaru Strategic Program (HSC-SSP). Using two-dimensional image…