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

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Massive stars with solar metallicity lose important amounts of rotational angular momentum through their winds. When a magnetic field is present at the surface of a star, efficient angular momentum losses can still be achieved even when the…

Solar and Stellar Astrophysics · Physics 2017-12-27 H. F. Song , G. Meynet , A. Maeder , S. Ekstrom , P. Eggenberger , C. Georgy , Y. Qin , T. Fragos , M. Soerensen , F. Barblan , G. A. Wade

NN Ser is a non mass-transferring pre-cataclysmic variable containing a white dwarf with a mass of $\sim 0.5 M_{\odot}$ and an M dwarf secondary star with a mass of $\sim 0.2 M_{\odot}$. Based on the data detected by the high-speed CCD…

High Energy Astrophysical Phenomena · Physics 2009-05-21 Wen-Cong Chen

We present multi-wavelength temporal and spectral characteristics of a magnetic cataclysmic variable (MCV) Swift J0503.7-2819, using far ultraviolet (FUV) and X-ray data from AstroSat, supplemented with optical data from the Southern…

We present a long-term programme for timing the eclipses of white dwarfs in close binaries to measure apparent and/or real variations in their orbital periods. Our programme includes 67 close binaries, both detached and semi-detached and…

Recent theoretical and observational progress has substantially improved the definition of the lower main sequence and established a new basis for a comparison of main sequence stars and the secondaries in CVs. The evolutionary sequences of…

Astrophysics · Physics 2009-10-31 K. Beuermann

I review detached binaries consisting of white dwarfs with either other white dwarfs or low mass main-sequence stars in tight orbits around them. Orbital periods have been measured for 15 white dwarf/white dwarf systems and 22 white dwarf/M…

Astrophysics · Physics 2009-10-31 T. R. Marsh

Context: We present a new study of the eclipsing cataclysmic variable CzeV404 Her (Porb = 0.098 d) that is located in the period gap. Aims: This report determines the origin of the object and the system parameters and probes the accretion…

Solar and Stellar Astrophysics · Physics 2021-08-11 J. Kára , S. Zharikov , M. Wolf , H. Kučáková , P. Cagaš , A. L. Medina Rodriguez , M. Mašek

Recent work by Levitan et al has expanded the long-term photometric database for AM CVn stars. In particular, their outburst properties are well-correlated with orbital period, and allow constraints to be placed on the secular mass transfer…

Solar and Stellar Astrophysics · Physics 2015-06-23 John K. Cannizzo , Gijs Nelemans

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…

Solar and Stellar Astrophysics · Physics 2016-06-03 P. B. Isakova , N. R. Ikhsanov , A. G. Zhilkin , D. V. Bisikalo , N. G. Beskrovnaya

A substantial fraction of Cataclysmic Variables (CVs) reveals non-solar abundances. A comprehensive list of CVs which includes those that have been examined for these abundances is given. Three possible sources of these non-solar abundances…

Solar and Stellar Astrophysics · Physics 2021-06-23 Warren M. Sparks , Edward M. Sion

Accreting magnetic white dwarfs offer an opportunity to understand the interplay between spin-up and spin-down torques in binary systems. Monitoring of the white dwarf spin may reveal whether the white dwarf spin is currently in a state of…

The evolution of low-mass contact binaries is influenced by angular-momentum loss, mass and energy transfer, and the nuclear evolution of the components. They have periods shorter than one day, and we expect their period evolution to be…

Solar and Stellar Astrophysics · Physics 2025-10-22 Matthias Fabry , Andrej Prša

In our recent catalogue of BY Draconis (BY Dra) variables based on Zwicky Transient Facility data, we found traces of a period gap in the period-colour diagram. We combined our BY Dra database with catalogues from the {\sl Kepler} and K2…

Solar and Stellar Astrophysics · Physics 2023-09-01 Deepak Chahal , Devika Kamath , Richard de Grijs , Paolo Ventura , Xiaodian Chen

White dwarfs are often found in binary systems with orbital periods ranging from tens of minutes to hours in which they can accrete gas from their companion stars. In about 15% of these binaries, the magnetic field of the white dwarf is…

Solar and Stellar Astrophysics · Physics 2017-12-15 S. Scaringi , T. J. Macarone , C. D'Angelo , C. Knigge , P. J. Groot

New CCD photometry has been combined with published and unpublished earlier observations to study the three Cepheid variables in M13: V1, V2 and V6. The light curve characteristics in $B$, $V$ and $I_{\rm C}$ have been determined and the…

Solar and Stellar Astrophysics · Physics 2019-07-24 Wayne Osborn , Grzegorz Kopacki , Horace A. Smith , Barton J. Pritzl , Charles Kuehn , Mary Anderson

Cataclysmic variables (CVs) are binaries in which a compact white dwarf accretes material from a low-mass companion star. The discovery of two planets in orbit around the CV HU Aquarii opens unusual opportunities for understanding the…

Earth and Planetary Astrophysics · Physics 2015-06-11 Simon Portegies Zwart

We constrain the orbital period ($P_{\rm orb}$) distribution of low-mass detached main-sequence eclipsing binaries (EBs) with light curves from the Zwicky Transient Facility (ZTF), which provides a well-understood selection function and…

Solar and Stellar Astrophysics · Physics 2022-10-26 Kareem El-Badry , Charlie Conroy , Jim Fuller , Rocio Kiman , Jan van Roestel , Antonio C. Rodriguez , Kevin B. Burdge

Archival data on permanent superhump systems are compiled to test the thermal stability of their accretion discs. We find that their discs are almost certainly thermally stable as expected. This result confirms Osaki's suggestion (1996)…

Astrophysics · Physics 2009-10-31 A. Retter , T. Naylor

Cataclysmic variables (CVs) are interacting binary systems where a cool, rapidly rotating secondary star passes material to a white dwarf. If this mass loss is to continue then there must be continuous angular momentum loss from the system.…

Astrophysics · Physics 2009-11-07 N. A. Webb , T. Naylor , R. D. Jeffries

The NSF's Karl G. Jansky Very Large Array (VLA) is used to observe 122 magnetic cataclysmic variables (MCVs) during three observing semesters (13B, 15A, and 18A). We report radio detections of 33 stars with fluxes in the range 6--8031 uJy.…

Solar and Stellar Astrophysics · Physics 2020-06-16 Paul Barrett , Christopher Dieck , Anthony J. Beasley , Paul A Mason , Kulinder P. Singh