Related papers: Tidal synchronization of the subdwarf B binary PG …
Even though it was discovered more than a decade ago, LSR1610-0040 remains an enigma. This object has a peculiar spectrum that exhibits some features typically found in L subdwarfs, and others common in the spectra of more massive M dwarf…
We calculate the tidal response of helium and carbon/oxygen (C/O) white dwarf (WD) binaries inspiraling due to gravitational wave emission. We show that resonance locks, previously considered in binaries with an early-type star, occur…
The detection of pulsations from an X-ray binary is an unambiguous signature of the presence of a neutron star in the system. When the pulsations are missed in the radio band, their detection at other wavelengths, like X-ray or gamma-rays,…
Modelled searches for gravitational waves emitted by compact binary coalescences currently filter the data with template signals that ignore all effects related to the physics of dense-matter in neutron stars interiors, even when the masses…
The detection of O- and B-type stars with extremely low-mass companions is very important for understanding the formation and evolution of binary stars. However, their finding remains a challenge because the low-mass components in such…
Mounting evidence from subdwarf B (sdB) stars in the galactic field and their recently discovered counterparts in old open clusters indicates that at least two thirds of local disk sdB stars are binaries. Our recent radial velocity survey…
We have used the radial velocity variations of two sdB stars previously reported to be binaries to establish their orbital periods. They are PG0940+068, (P=8.33d) and PG1247+554 (P=0.599d). The minimum masses of the unseen companions,…
The project Massive Unseen Companions to Hot Faint Underluminous Stars from SDSS (muchfuss) aims to discover subdwarf-B stars with massive compact companions such as overmassive white dwarfs (M > 1.0 M_sun), neutron stars or black holes.…
We have used Aperture Masking Interferometry and Adaptive Optics (AO) at the Palomar 200'' to obtain precise mass measurements of the binary M dwarf GJ 623. AO observations spread over 3 years combined with a decade of radial velocity…
We study the detectability of gravitational-wave signals from sub-solar mass binary neutron star systems by the current generation of ground-based gravitational-wave detectors. We find that finite size effects from large tidal…
The recently discovered J0651+2844 is a detached, eclipsing white dwarf binary with an orbital period of 765 s. We investigate the prospects for the detection of gravitational radiation from this system and estimate the effect of the tidal…
Asynchronous rotation in binary stars produces non-radial oscillations that are known to cause observable variability on orbital timescales. The horizontal perturbations of the surface velocity fields are referred to as "tidal flows". In…
We report on 2MASS J01542930+0053266, a faint eclipsing system composed of two M dwarfs. The variability of this system was originally discovered during a pilot study of the 2MASS Calibration Point Source Working Database. Additional…
We perform three-dimensional numerical simulations of surface flows on the companion star in a semi-detached binary system and construct the corresponding Doppler maps. The mass ratio of the binary system, $q=M_2/M_1$, considered here is…
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…
Binary systems containing a magnetic white dwarf and a main-sequence star are considered extremely rare, perhaps non-existent. In the course of a search of magnetic fields in high-mass white dwarfs we have discovered a Sirius-like wide…
We report additional photometric CCD observations of KPD 0422+5421, a binary with an orbital period of 2.16 hours which contains a subdwarf B star (sdB) and a white dwarf. There are two main results of this work. First, the light curve of…
Double white dwarfs are important gravitational wave sources for LISA, as they are some of the most numerous compact systems in our universe. Here we consider finite-sized effects due to tidal interactions, as they are expected to have a…
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 study the possibility of orbital synchronization capture for a hierarchical quadrupole stellar system composed by two binaries emitting gravitational waves. Based on a simple model including the mass transfer for white dwarf binaries, we…