Related papers: Orbital Evolution of Compact White Dwarf Binaries

HD 188112 is a bright (V = 10.2 mag) hot subdwarf B (sdB) star with a mass too low to ignite core helium burning and is therefore considered as a pre-extremely low mass (ELM) white dwarf (WD). ELM WDs (M $\le$ 0.3 Msun) are He-core objects…

We present the discovery of 17 double white dwarf (WD) binaries from our on-going search for extremely low mass (ELM) <0.3 Msun WDs, objects that form from binary evolution. Gaia parallax provides a new means of target selection that we use…

We report the discovery of a nearby massive white dwarf with He-H atmosphere. The white dwarf is located at a distance of $74.5\pm0.9$ pc. Its radius, mass, effective temperature, H/He ratio and age are $R=2500\pm100$ km, $M=1.33\pm0.01$…

Theoretical work has shown that intermediate mass (0.01Msun<M_He<0.1Msun) Helium shells will unstably ignite on the accreting white dwarf (WD) in an AM CVn binary. For more massive (M>0.8Msun) WDs, these helium shells can be dense enough…

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 detection of a 0.2 Msun extremely low-mass white dwarf (EW) in a wide orbit (Porb about 450 days) with a 1.1 Msun main-sequence (MS) companion, KIC 8145411, challenges our current understanding of how EWs form. The traditional channel…

Helium core white dwarfs (WDs) with mass M <~ 0.20 Msun undergo several Gyrs of stable hydrogen burning as they evolve. We show that in a certain range of WD and hydrogen envelope masses, these WDs may exhibit g-mode pulsations similar to…

We analyze the spectrum of an unusually-low mass white dwarf, SDSSJ123410.37-022802.9 (0335-264-52000), found in our recent, white dwarf catalog from the SDSS DR1 data release. Two independent, model atmosphere fits result in an accurate…

Post-common envelope binaries (PCEBs) consisting of a white dwarf (WD) plus a main-sequence (MS) star can constrain current prescriptions of common envelope evolution (CEE) and calibrate theoretical models of binary formation and evolution.…

We demonstrate a method to fully characterize mass-transferring double white dwarf (DWD) systems with a helium-rich (He) WD donor based on the mass--radius relationship for He WDs. Using a simulated Galactic population of DWDs, we show that…

The evolution of helium stars with masses of 1.5 - 6.7 M_sun in binary systems with a 1.4 M_sun neutron-star companion is presented. Such systems are assumed to be the remnants of Be/X-ray binaries with B-star masses in the range of 8 - 20…

Close white dwarf binaries make up a wide variety of objects such as double white dwarf binaries, which are possible SN Ia progenitors, cataclysmic variables, super soft sources, or AM CVn stars. The evolution and formation of close white…

We present a method for modeling the evolution of detached double white dwarf (DWD) binaries hosting helium donors from the end of the common envelope (CE) phase to the onset of Roche Lobe overflow (RLOF). This is achieved by combining…

The formation of a double white dwarf binary likely involves a common envelope (CE) event between a red giant and a white dwarf (WD) during the most recent episode of Roche lobe overflow mass transfer. We study the role of recombination…

The white dwarf binary pathways survey is dedicated to studying the origin and evolution of binaries containing a white dwarf and an intermediate-mass secondary star of the spectral type A, F, G, or K (WD+AFGK). Here we present CPD-65\,264,…

Despite their unique astrophysical relevance, the outcome of white dwarf binary mergers has so far only been studied for a very restricted number of systems. Here we present the results of a survey with more than two hundred simulations…

We present seven evolutionary tracks for low-mass white dwarfs with helium cores, ranging in mass from 0.179 to 0.414 Msol. We generated the pre-white dwarf models from a 1 Msol sequence extending up to the tip of its red-giant branch by…

We present the discovery of the second binary with a Roche lobe-filling hot subdwarf transferring mass to a white dwarf (WD) companion. This 56 minute binary was discovered using data from the Zwicky Transient Facility. Spectroscopic…

The behaviour of carbon-oxygen white dwarfs (WDs) subject to direct helium accretion is extensively studied. We aim to analyze the thermal response of the accreting WD to mass deposition at different time scales. The analysis has been…

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…