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The average white dwarf (WD) masses in cataclysmic variables (CVs) have been measured to significantly exceed those of single WDs, which is the opposite of what is theoretically expected. We present the results of binary population…

Solar and Stellar Astrophysics · Physics 2015-10-28 Matthias R. Schreiber , Monica Zorotovic , Thomas P. G. Wijnen

I review our current understanding of the evolution of cataclysmic variables (CVs). I first provide a brief introductory "CV primer", in which I describe the physical structure of CVs, as well as their astrophysical significance. The main…

Solar and Stellar Astrophysics · Physics 2011-09-05 Christian Knigge

We apply population synthesis techniques to calculate the present day number of two types of white dwarf-main sequence star (WDMS) binaries within the cataclysmic variable period gap. The first are post-common envelope binaries with…

Astrophysics · Physics 2009-11-13 P. J. Davis , U. Kolb , B. Willems , B. T. Gänsicke

We present constraints on the space densities of both non-magnetic and magnetic cataclysmic variables, and discuss some implications for models of the evolution of CVs. The high predicted non-magnetic CV space density is only consistent…

Solar and Stellar Astrophysics · Physics 2014-07-14 Magaretha L. Pretorius

Using improved, up-to-date stellar input physics tested against observations of low-mass stars and brown dwarfs we calculate the secular evolution of low-mass donor cataclysmic variables (CVs), including those which form with a brown dwarf…

Astrophysics · Physics 2009-10-31 Ulrich Kolb , Isabelle Baraffe

Cataclysmic Variables (CV) are close binary systems, in which the primary, the more massive star, is a white dwarf. CVs usually exhibit a number of periodicities, most of which are now understood. However, recently, a new phenomenon was…

Astrophysics · Physics 2008-11-26 G. Tovmassian , S. Zharikov , V. Neustroev

We present the results of the study of cataclysmic variables (CVs) and AM Canum Venaticorum (AM CVn) stars with our double dynamo (DD) formalism of angular momentum loss (AML) by magnetic braking (MB). We show that (1) our MB model…

Solar and Stellar Astrophysics · Physics 2024-01-09 Arnab Sarkar , Hongwei Ge , Lev Yungelson , Christopher A. Tout

Recent observations show that the white dwarfs (WDs) in cataclysmic Variables (CVs) have an average mass significantly higher than isolated WDs and WDs in post-common envelope binaries (PCEBs), which are thought to the progenitors of CVs.…

Solar and Stellar Astrophysics · Physics 2016-12-07 Wei-Min Liu , Xiang-Dong Li

We use an independent new sample of cataclysmic variables (CVs), constructed by selecting objects for Halpha emission, to constrain the properties of the intrinsic CV population. This sample is restricted to systems that are likely to be…

Astrophysics · Physics 2009-11-13 Magaretha L. Pretorius , Christian Knigge

We have carried out an extensive population synthesis study of the ensemble properties of the present-day population of cataclysmic variables (PDCVs) that takes into account the nuclear evolution of high-mass donors close to the bifurcation…

Solar and Stellar Astrophysics · Physics 2016-07-22 J. Goliasch , L. Nelson

We extend a magnetic braking (MB) model, which has been used earlier to address the evolution of cataclysmic variables, to address the spin period $P_\mathrm{spin}$ evolution of fully convective M dwarf (FCMD) stars. The MB mechanism is an…

Solar and Stellar Astrophysics · Physics 2023-09-18 Arnab Sarkar , Lev Yungelson , Christopher A. Tout

One of the most important problems in the context of cataclysmic variables (CVs) is the lack of observations of systems with periods between 2 and 3.12 hours, known as the period gap. The orbital evolution of CVs with periods shorter than…

Solar and Stellar Astrophysics · Physics 2018-11-28 C. Garraffo , J. J. Drake , J. D. Alvarado-Gomez , S. P. Moschou , O. Cohen

The discrepancies between observations and theoretical predictions of cataclysmic variables (CVs) suggest that there exists unknown angular momentum loss mechanism(s) besides magnetic braking and gravitational radiation. Mass loss due to…

High Energy Astrophysical Phenomena · Physics 2024-10-22 Wen-Shi Tang , Xiang-dong Li , Zhe Cui

We report the discovery of two new magnetic cataclysmic variables with brown dwarf companions and long orbital periods ($P_{\rm orb}=95\pm1$ and $104\pm2$ min). This discovery increases the sample of candidate magnetic period bouncers with…

The general prediction that more than half of all CVs have evolved past the period minimum is in strong disagreement with observational surveys, which show that the relative number of these objects is just a few per cent. Here, we…

Solar and Stellar Astrophysics · Physics 2023-10-27 Matthias R. Schreiber , Diogo Belloni , Jan van Roestel

We model cataclysmic variables (CVs) with solar metallicity donors ($X=0.7,\:Z=0.02$) that evolve to form AM CVn stars through the Evolved CV formation channel using various angular momentum loss mechanisms by magnetic braking…

Solar and Stellar Astrophysics · Physics 2023-02-02 Arnab Sarkar , Hongwei Ge , Christopher A. Tout

We have known for a long time that many of the measured white dwarf (WD) masses in cataclysmic variables (CVs) significantly exceed the mean mass of single WDs. This was thought to be related to observational biases, but recent…

Solar and Stellar Astrophysics · Physics 2011-08-24 M. Zorotovic , M. R. Schreiber , B. T. Gänsicke

I discuss population synthesis methods in the context of low-mass compact binaries. Two examples, both constraining the largely unknown strength of orbital angular momentum losses, illustrate the power and problems of such studies. For CVs,…

Astrophysics · Physics 2007-05-23 Ulrich Kolb

We present the results of a systematic study of cataclysmic variables (CVs) and related systems, combining detailed binary-population synthesis (BPS) models with a grid of 120 binary evolution sequences calculated with a Henyey-type stellar…

Astrophysics · Physics 2007-05-23 Ph. Podsiadlowski , Z. Han , S. Rappaport

Low-mass helium-core white-dwarfs (WDs) with masses below 0.5 Msun are known to be formed in binary star systems but unexpectedly a significant fraction of them seem to be single. On the other hand, in Cataclysmic Variables (CVs) a large…

Solar and Stellar Astrophysics · Physics 2016-11-23 Monica Zorotovic , Matthias Schreiber