相关论文: Orbital Evolution of Compact White Dwarf Binaries

In spite of their importance for modern astronomy, we do not fully understand how close binary stars containing at least one white dwarf form from main sequence binary stars. The discovery of EL CVn binaries, close pre-white dwarfs with A/F…

We construct a set of binary evolutionary sequences for systems composed by a normal, solar composition, donor star together with a neutron star. We consider a variety of masses for each star as well as for the initial orbital period…

White dwarfs (WDs) represent the final evolutionary stage of most stars, typically originating from progenitor stars with masses below approximately 8 $M_{\odot}$ to 10 $M_{\odot}$. Formation through single-star evolution generally requires…

We present high-quality ULTRACAM photometry of the eclipsing detached double-white dwarf binary NLTT 11748. This system consists of a carbon/oxygen white dwarf and an extremely-low mass (< 0.2 Msun) helium-core white dwarf in a 5.6 hr…

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…

We reexamine evolutionary channels for the formation of binary millisecond pulsars in order to understand their observed orbital period distribution. The available paths provide a natural division into systems characterized by long orbital…

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…

An XMM-Mewton observation performed in May 2008 has confirmed that the 13 seconds pulsations in the X-ray binary HD 49798/RX J0648.0-4418 are due to a rapidly rotating white dwarf. From the pulse time delays induced by the 1.55 days orbital…

The observed orbital period distribution of cataclysmic variables (CVs), the space density derived from observations, and the observed orbital period minimum are known to disagree with theoretical predictions since decades. More recently,…

We perform stellar evolution calculations of the remnant of the merger of two He white dwarfs (WDs). Our initial conditions are taken from hydrodynamic simulations of double WD mergers and the viscous disc phase that follows. We evolve…

The astrophysical origins of the heaviest stable elements that we observe today in the Solar System are still not fully understood. Recent studies have demonstrated that H-accreting white dwarfs (WDs) in a binary sys- tem exploding as type…

We examine the exchange of angular momentum between the component spins and the orbit in semi-detached double white dwarf binaries undergoing mass transfer through direct impact of the transfer stream. We approximate the stream as a series…

I demonstrate that an effect similar to the Roemer delay, familiar from timing radio pulsars, should be detectable in the first eclipsing double white dwarf (WD) binary, NLTT 11748. By measuring the difference of the time between the…

Planets and other low-mass binary companions to stars face a variety of potential fates as their host stars move off the main sequence and grow to subgiants and giants. Stellar mass loss tends to make orbits expand, and tidal torques tend…

White dwarf main-sequence (WDMS) binaries provide important laboratories for studying binary evolution and the formation of low-mass white dwarfs. In this work, we identify 654 reliable WDMS candidates with FGK-type companions from an…

Using archival Hubble Space Telescope observations, we report the discovery of four variable low-mass white dwarfs ($0.18 \, M_\odot \leq M \leq 0.5 \,M_\odot$) in the globular cluster NGC 6397. One source exhibits a periodic optical…

The structure of plasma flows in close binary systems in which one of the components is a rapidly rotating magnetic white dwarf is studied. The main example considered is the AE Aquarii system; the spin period of the white dwarf is about a…

Wolf-Rayet (WR) stars are helium-burning, evolved massive stars which have had most of their hydrogen-rich outer layers removed either through stellar winds and/or binary stripping. Here we report on LMC173-1, a WN3+O binary located in the…

A significant fraction of white dwarfs (WDs) exhibit signs of ongoing accretion of refractory elements at rates $\sim10^3$--$10^7$ kg s$^{-1}$, among which, 37 WDs were detected to harbor dusty debris disks. Such a concurrence requires not…

We calculate the heating and cooling of the accreting white dwarf (WD) in the ultracompact AM Canum Venaticorum (AM CVn) binaries and show that the WD can contribute significantly to their optical and ultraviolet emission. We estimate the…