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Related papers: CV evolution: AM Her binaries and the period gap

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We have used a model of magnetic accretion to investigate the rotational equilibria of magnetic cataclysmic variables (mCVs). The results of our numerical simulations demonstrate that there is a range of parameter space in the P_spin /…

Astrophysics · Physics 2009-11-10 A. J. Norton , G. A. Wynn , R. V. Somerscales

We show the presence of CVs with orbital periods in the range 3.5-7 h and mass ratios q=M2/M1 above the critical values for dynamically stable mass transfer. We explore whether the magnetic fields produced in the secondaries alter the…

Astrophysics · Physics 2007-05-23 A. Bianchini , F. Tamburini , P. E. Johnson

Secondary stars in cataclysmic variables (CVs) follow a well defined period-density relation. Thus, canonical donor stars in CVs are generally low-mass stars of spectral type M. However, several CVs have been observed containing secondary…

Solar and Stellar Astrophysics · Physics 2015-06-19 A. Rebassa-Mansergas , S. G. Parsons , C. M. Copperwheat , S. Justham , B. T. Gaensicke , M. R. Schreiber , T. R. Marsh , V. S. Dhillon

The population synthesis of cataclysmic variables below the period is investigated. A grid of detailed binary evolutionary sequences has been calculated and included in the simulations to take account of additional angular momentum losses…

Astrophysics · Physics 2009-11-13 B. Willems , U. Kolb , E. L. Sandquist , R. E. Taam , G. Dubus

Cataclysmic variable (CVs) are close interacting binaries in which a white dwarf accretes materials from a low mass main sequence companion. CVs can experience nova eruptions due to low mass transfer rates. In the standard theory of CV…

Solar and Stellar Astrophysics · Physics 2025-07-31 Wenshi Tang , Xiangdong Li , Bo Wang

The magnetic cataclysmic variables (MCVs) present a wealth of observational diagnostics for studying accretion flows interacting with a magnetosphere. Spin-period pulsations from the rotation of the white dwarf are seen in optical light, in…

Solar and Stellar Astrophysics · Physics 2015-06-18 Coel Hellier

The influence of the magnetic field on process of the accretion onto White Dwarfs in Cataclysmic Variables (CVs) is discussed. Except for the Polars or AM Her objects, the strength of magnetic field can not be measured directly in CVs by…

Astrophysics · Physics 2009-11-10 G. H. Tovmassian

We review our knowledge of the origin and phenomenology of low states (also known as VY Scl states) in cataclysmic variables, making special emphasis on the cataclysmic variable population found just above the period gap. This orbital…

Solar and Stellar Astrophysics · Physics 2011-12-06 P. Rodríguez-Gil , L. Schmidtobreick , K. S. Long , T. Shahbaz , B. T. Gänsicke , M. A. P. Torres

The saturated, boosted, and disrupted magnetic braking (SBD MB) model is an empirical prescription that has recently gained support from close-binary observations. Different boosting ($K$) and disruption ($\eta$) parameters appear necessary…

Solar and Stellar Astrophysics · Physics 2026-05-18 Vladislav Dodon , Xiang-Dong Li , Xiao-jie Xu , Ilkham Galiullin , Askar Sibgatullin

We present a binary evolution study of cataclysmic variables (CVs) and related systems with white dwarf accretors, including for example, AM CVn systems, classical novae, supersoft X-ray sources, and systems with giant donor stars. Our…

Solar and Stellar Astrophysics · Physics 2016-12-14 B. Kalomeni , L. Nelson , S. Rappaport , M. Molnar , J. Quintin , K. Yakut

The predicted and observed space density of cataclysmic variables (CVs) have been for a long time discrepant by at least an order of magnitude. The standard model of CV evolution predicts that the vast majority of CVs should be period…

The population of non magnetic cataclysmic variables evolving under the influence of a circumbinary disk is investigated for systems above the upper edge of the period gap at orbital periods greater than 2.75hr. For a fractional mass input…

Astrophysics · Physics 2008-11-26 B. Willems , R. Taam , U. Kolb , G. Dubus , E. Sandquist

We suggest, that the magnetic field of the white dwarf in AM Her systems loses coupling to the secondary star when the latter becomes non-magnetic at the transition from a late main sequence star to a cool degenerate brown dwarf. This leads…

Astrophysics · Physics 2007-05-23 F. Meyer , E. Meyer-Hofmeister

Magnitude-limited samples have shown that 20-25 per cent of cataclysmic variables contain white dwarfs with magnetic fields of Mega Gauss strength, in stark contrast to the approximately 5 per cent of single white dwarfs with similar…

Solar and Stellar Astrophysics · Physics 2021-02-10 S. G. Parsons , B. T. Gänsicke , M. R. Schreiber , T. R. Marsh , R. P. Ashley , E. Breedt , S. P. Littlefair , H. Meusinger

We critically re-examine the available data on the spectral types, masses and radii of the secondary stars in cataclysmic variables (CVs) and low-mass X-ray binaries (LMXBs), using the new catalogue of Ritter & Kolb (1998) as a starting…

Astrophysics · Physics 2009-10-30 D. A. Smith , V. S. Dhillon

In this chapter we consider the processes which can lead to X-ray emission from different types of cataclysmic variable stars (CVs). CVs are semi-detached, binary star systems where material is transferred from the donor star (also known as…

High Energy Astrophysical Phenomena · Physics 2023-04-05 K. L. Page , A. W. Shaw

Magnetic braking causes the spin-down of single stars as they evolve on the main sequence. Models of magnetic braking can also explain the evolution of close binary systems, including cataclysmic variables. The well-known period gap in the…

Solar and Stellar Astrophysics · Physics 2012-02-24 G. A. J. Hussain

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,…

Solar and Stellar Astrophysics · Physics 2015-12-11 Matthias R. Schreiber , Monica Zorotovic , Thomas P. G. Wijnen

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…

Angular momentum loss in ultracompact binaries, such as the AM Canum Venaticorum stars, is usually assumed to be due entirely to gravitational radiation. Motivated by the outflows observed in ultracompact binaries, we investigate whether…

Solar and Stellar Astrophysics · Physics 2010-06-22 Alison Farmer , Gijs Roelofs