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The theoretical and observed populations of pre-cataclysmic variables (pre-CVs) are dominated by systems with low-mass white dwarfs (WDs), while the WD masses in CVs are typically high. In addition, the space density of CVs is found to be…

Solar and Stellar Astrophysics · Physics 2016-01-27 G. Nelemans , L. Siess , S. Repetto , S. Toonen , E. S. Phinney

White dwarfs experience a thermal renaissance when they receive mass from a stellar companion in a binary. For accretion rates < 10^-8 Msun/yr, the freshly accumulated hydrogen/helium envelope ignites in a thermally unstable manner that…

Astrophysics · Physics 2009-11-07 Dean M. Townsley , Lars Bildsten

We present new results of a stability analysis of realistic models of post-extreme horizontal branch stars. We find that g-mode instabilities develop in some of these models as a result of a potent epsilon-mechanism associated with the…

Astrophysics · Physics 2009-10-30 S. Charpinet , G. Fontaine , P. Brassard , B. Dorman

We present the first X-ray observations with the XMM-Newton and INTEGRAL satellites of the recently discovered cataclysmic variable 1RXSJ173021.5-055933, together with simultaneous UV and coordinated optical photometry aiming at…

We present the first volume-limited sample of cataclysmic variables (CVs), selected using the accurate parallaxes provided by the second data release (DR2) of the ESA $\mathit{Gaia}$ space mission. The sample is composed of 42 CVs within…

While highly evolved cataclysmic variables (CVs) with brown dwarf donors, often called "period bouncers", are predicted to make up $\simeq40-70$ % of the Galactic CV population, only a handful of such systems are currently known. The…

Solar and Stellar Astrophysics · Physics 2018-10-01 Anna F. Pala , Linda Schmidtobreick , Claus Tappert , Boris T. Gänsicke , Andrea Mehner

We study the effect of a white dwarf on the spin-down of a cataclysmic variable system using a three-dimensional magnetohydrodynamic numerical model. The model includes the stellar corona, the stellar wind, and the WD mass and magnetic…

Solar and Stellar Astrophysics · Physics 2015-06-03 O. Cohen , J. J. Drake , V. L. Kashyap

Accreting white dwarfs (WDs) with non-degenerate companions are expected to emit in soft X-rays and the UV, if accreted H-rich material burns stably. They are an important component of the unresolved emission of elliptical galaxies, and…

Solar and Stellar Astrophysics · Physics 2015-09-16 Hai-Liang Chen , T. E. Woods , L. R. Yungelson , M. Gilfanov , Zhanwen Han

Our previous theoretical study of the impact of an accreting envelope on the thermal state of an underlying white dwarf (WD) has yielded equilibrium core temperatures, classical nova ignition masses and thermal luminosities for WDs…

Astrophysics · Physics 2009-11-10 Dean M. Townsley , Lars Bildsten

The Dwarf Nova Oscillations observed in Cataclysmic Variable (CV) stars are interpreted in the context of a Low Inertia Accretor model, in which accretion on to an equatorial belt of the white dwarf primary causes the belt to vary its…

Astrophysics · Physics 2009-11-07 Brian Warner , Patrick A. Woudt

We calculate the stellar evolution of both white dwarfs (WDs) in AM CVn binaries with orbital periods of $P_{\mathrm{orb}} \approx 5-70$ minutes. We focus on the cases where the donor starts as a $M_{\mathrm{He}} < 0.2 \, M_{\odot}$ Helium…

Solar and Stellar Astrophysics · Physics 2021-12-22 Tin Long Sunny Wong , Lars Bildsten

In over a thousand known cataclysmic variables (CVs), where a white dwarf is accreting from a hydrogen-rich star, only a dozen have orbital periods below 75 minutes. One way to achieve these short periods requires the donor star to have…

Context. White dwarfs (WDs) in cataclysmic variables (CVs) are important experimental laboratories where the electron degeneracy is taking place on a macroscopic scale. Magnetic CVs increase in number especially in the hard X-ray band (>10…

High Energy Astrophysical Phenomena · Physics 2015-05-19 Takayuki Yuasa , Kazuhiro Nakazawa , Kazuo Makishima , Kei Saitou , Manabu Ishida , Ken Ebisawa , Hideyuki Mori , Shin'ya Yamada

The mean white dwarf (WD) mass in the Galactic bulge cataclysmic variables (CVs) was measured by applying the the shock temperature-WD mass correlation of magnetic cataclysmic variables (mCVs) to the Galactic Bulge X-ray Emission (GBXE)…

High Energy Astrophysical Phenomena · Physics 2018-04-04 Zhuo-li Yu , Xiao-jie Xu , Xiang-Dong Li , Tong Bao , Ying-xi Li , Yu-chen Xing , Yu-fu Shen

Cataclysmic variable stars (CVs) are close binary systems consisting of a white dwarf (primary) that is accreting matter from a low-mass companion star (secondary). From time to time such systems undergo large-amplitude brightenings. The…

We derive metallicities for 41 cataclysmic variables (CVs) from near-infrared spectroscopy. We use synthetic spectra that cover the 0.8 $\mu$m $\leq \lambda \leq$ 2.5 $\mu$m bandpass to ascertain the value of [Fe/H] for CVs with K-type…

Solar and Stellar Astrophysics · Physics 2016-12-14 Thomas E. Harrison

We performed 3D MHD calculations of stream accretion in cataclysmic variable stars for which the white dwarf primary star possesses a strong and complex magnetic field. These calculations are motivated by observations of polars; cataclysmic…

High Energy Astrophysical Phenomena · Physics 2012-10-16 A. G. Zhilkin , D. V. Bisikalo , P. A. Mason

Ultra-massive hydrogen-rich (DA spectral type) white dwarf (WD) stars ($M_{\star} > 1M_{\odot}$) coming from single-star evolution are expected to harbor cores made of $^{16}$O and $^{20}$Ne, resulting from semi-degenerate carbon burning…

Solar and Stellar Astrophysics · Physics 2020-11-24 A. H. Córsico , F. C. De Gerónimo , M. E. Camisassa , L. G. Althaus

Dwarf novae are a subset of cataclysmic variables that accrete material intermittently in short-duration outbursts with sometimes long quiescent intervals in between. During the quiescent state, the white dwarf (WD) photosphere may be…

Solar and Stellar Astrophysics · Physics 2025-12-25 Praphull Kumar , Dean M. Townsley

To improve the understanding of the pulsational instabilities of some of the PG1159-type pre-white dwarfs we performed detailed stability analyses on helium star evolutionary models. With the canonical chemical compositions, pulsational…

Astrophysics · Physics 2007-05-23 Alfred Gautschy