English
Related papers

Related papers: On the late spectral types of cataclysmic variable…

200 papers

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

A central hypothesis in the theory of cataclysmic variable (CV) evolution is the need to explain the observed lack of accreting systems in the ~2-3 h orbital period range, known as the period gap. The standard model, disrupted magnetic…

Although a large number of orbital periods of cataclysmic variable stars (CVs) have been measured, comparison of period and luminosity distributions with evolutionary theory is affected by strong selection effects. A test has been…

Astrophysics · Physics 2009-11-07 R. C. North , T. R. Marsh , U. Kolb , V. S. Dhillon , C. K. J. Moran

The spectrum of the recently discovered cataclysmic variable star (CV) ASAS-SN 13cl shows that a secondary star with spectral type K4 (+- 2 subclasses) contributes roughly half the optical light. The radial velocities of the secondary are…

Solar and Stellar Astrophysics · Physics 2015-06-23 John R. Thorstensen

We apply the angular momentum loss rates inferred from open cluster stars to the evolution of cataclysmic variables (CVs). We show that the angular momentum prescriptions used in earlier CV studies are inconsistent with the measured…

Astrophysics · Physics 2009-11-06 N. Andronov , M. Pinsonneault , A. Sills

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

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…

We review the recent knowledge base pertaining to causes for mass accretion variations (high/low states) in highly magnetic cataclysmic variables (i.e. polars). We then examine what theory has to say about the properties of the secondary…

Astrophysics · Physics 2007-05-23 Steve B. Howell

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

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

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 influence of a circumbinary (CB) disk on the evolution of cataclysmic variable (CV) binary systems is investigated. We show that CB mass surface densities sufficient to influence the evolution rate are plausibly provided by the outflows…

Astrophysics · Physics 2009-10-31 H. C. Spruit , Ronald E. Taam

VY Scl binaries are a sub-class of cataclysmic variable (CV) which show extended low states, but do not show outbursts which are seen in other classes of CV. To better determine how often these systems spend in low states and to resolve the…

Solar and Stellar Astrophysics · Physics 2024-11-13 C. Duffy , Kinwah Wu , G. Ramsay , Matt A. Wood , Paul A. Mason , Pasi Hakala , D. Steeghs

We have examined VTL/ISAAC 1-2.5 $\umu$m spectroscopy of a sample of short orbital period cataclysmic variables which are candidates for harboring substellar companions. We provide descriptions of the infrared spectrum of \hbox{EI Psc},…

Astrophysics · Physics 2009-11-10 R. E. Mennickent , M. P. Diaz , C. Tappert

We present spectroscopy of seven cataclysmic variable stars with orbital periods P(orb) greater than 5 hours, all but one of which are known to be dwarf novae. Using radial velocity measurements we improve on previous orbital period…

Astrophysics · Physics 2016-08-30 John R. Thorstensen , William H. Fenton , Cynthia J. Taylor

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

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

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 present HST spectroscopy for 45 cataclysmic variables (CVs), observed with HST/COS and HST/STIS. For 36 CVs, the white dwarf is recognisable through its broad Ly$\alpha$ absorption profile and we measure the white dwarf effective…

Strong selection effects are present in observational samples of cataclysmic variables (CVs), complicating comparisons to theoretical predictions. The selection criteria used to define most CV samples discriminate heavily against the…

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