Related papers: Mass Constraints from Eclipse Timing in Double Whi…
We identify two new tidally distorted white dwarfs (WDs), SDSS J174140.49+652638.7 and J211921.96-001825.8 (hereafter J1741 and J2119). Both stars are extremely low mass (ELM, < 0.2 Msun) WDs in short-period, detached binary systems.…
Although several dozen double white dwarfs (DWDs) have been observed, for many the exact nature of the evolutionary channel(s) by which they form remains uncertain. The canonical explanation calls for the progenitor binary system to undergo…
We report the discovery of two detached double white dwarf (WD) binaries, SDSS J082239.546+304857.19 and SDSS J104336.275+055149.90, with orbital periods of 40 and 46 min, respectively. The 40 min system is eclipsing; it is composed of a…
By analogy to Jovian radio emissions powered by the electromagnetic interaction between Jupiter and its moons, we propose that close magnetic-nonmagnetic white-dwarf pairs and white-dwarf planetary systems are strong radio sources. A simple…
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…
Measuring the mass-radius relation of individual white dwarfs is an empirically challenging task that has been performed for only a few dozen stars. We measure the white dwarf mass-radius relation using gravitational redshifts and radii of…
The ultimate fates of binary companions to stars (including whether the companion survives and the final orbit of the binary) are of interest in light of an increasing number of recently discovered, low-mass companions to white dwarfs…
From a sample of spectra of 439 white dwarfs (WDs) from the ESO-VLT Supernova-Ia Progenitor surveY (SPY), we measure the maximal changes in radial-velocity (DRVmax) between epochs (generally two epochs, separated by up to 470d), and model…
Recently, the LIGO-Virgo collaboration reported their first detection of gravitational wave (GW) signals from a low mass compact binary merger GW170817, which is most likely due to a double neutron star (NS) merger. With the GW signals…
We examine the capacity to identify binary systems from astrometric errors and deviations alone. Until the release of the fourth Gaia data release we lack the full astrometric time series that the satellite records, but as we show can still…
We analyze radial velocity observations of the 12 extremely low-mass <0.25 Msol white dwarfs (WDs) in the MMT Hypervelocity Star Survey. Eleven of the 12 WDs are binaries with orbital periods shorter than 14 hours; the one non-variable WD…
Fully convective M dwarfs typically remain rapidly rotating and magnetically active for billions of years, followed by an abrupt and mass-dependent transition to slow rotation and quiescence. A robust understanding of this process is…
Pulsars in close binary orbit around another neutron star or a massive white dwarf make ideal laboratories for testing the predictions of gravitational radiation and self-gravitational effects. We report new timing measurements of the…
Planetary debris is observed in the atmospheres of over 1,000 white dwarfs, and two white dwarfs are now observed to contain orbiting minor planets. Exoasteroids and planetary core fragments achieve orbits close to the white dwarf through…
We present 25 new eclipse times of the white dwarf binary NN Ser taken with the high-speed camera ULTRACAM on the WHT and NTT, the RISE camera on the Liverpool Telescope, and HAWK-I on the VLT to test the two-planet model proposed to…
(Summary of paper) High resolution optical spectroscopy of the white dwarf WD0137-349 reveals a weak Halpha line in emission, due to a low mass companion in a close orbit. Using this emission feature, and the narrow NLTE core of the white…
We present relativistic analyses of 9257 measurements of times-of-arrival from the first binary pulsar, PSR B1913+16, acquired over the last thirty-five years. The determination of the 'Keplerian' orbital elements plus two relativistic…
We present a high-precision I-band light curve for the Wolf-Rayet binary WR 20a, obtained as a sub-project of the Optical Gravitational Lensing Experiment. Rauw et al. have recently presented spectroscopy for this system, strongly…
During the motion of a binary pulsar around the Galactic center, the pulsar and its companion experience a wind of dark-matter particles that can affect the orbital motion through dynamical friction. We show that this effect produces a…
The expected distributions of eclipse-depth versus period for eclipsing binaries of different luminosities are derived from large-scale population synthesis experiments. Using the rapid Hurley et al. BSE binary evolution code, we have…