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Related papers: The CV period gap: still there

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Period bouncers are cataclysmic variables (CVs) that have evolved past their orbital period minimum. The strong disagreement between theory and observations of the relative fraction of period bouncers is a severe shortcoming in the…

Solar and Stellar Astrophysics · Physics 2024-06-21 Arnab Sarkar , Antonio C. Rodriguez , Sivan Ginzburg , Lev Yungelson , Christopher A. Tout

Using photometric ULTRACAM observations of three new short period cataclysmic variables, we model the primary eclipse lightcurves to extract the orbital separation, masses, and radii of their component stars. We find donor masses of 0.060…

I discuss the case for an efficient orbital braking mechanism in CVs, and the effect of nova outbursts on the observed range of mass transfer rates. I review the continuing problem that models have in interpreting the short-period cut-off…

Astrophysics · Physics 2007-05-23 U. Kolb

We present a preliminary comparison of the post-nova population with that of general cataclysmic variables (CVs). We particularly focus on the mass-transfer rate and its potential relation to the nova eruption. We find that the known…

Solar and Stellar Astrophysics · Physics 2017-02-09 C. Tappert , I. Fuentes-Morales , E. Puebla , A. Ederoclite , L. Schmidtobreick , N. Vogt

We present measurements of the component masses in 15 Cataclysmic Variables (CVs) - 6 new estimates and 9 improved estimates. We provide new calibrations of the relationship between superhump period excess and mass ratio, and use this…

We conjecture that the pseudogap is an inhomogeneous condensate above the homogeneous state whose existence is granted by topological stability. We consider the simplest possible order parameter theory that provides this interpretation of…

Superconductivity · Physics 2015-06-22 Alfredo. A. Vargas-Paredes , Marco Cariglia , Mauro M. Doria

I review what we know about the donor stars in cataclysmic variables (CVs), focusing particularly on the close link between these binary components and the overall secular evolution of CVs. I begin with a brief overview of the "standard…

Solar and Stellar Astrophysics · Physics 2015-03-17 Christian Knigge

Recently, large and homogeneous samples of cataclysmic variables (CVs) identified by the Sloan Digital Sky Survey (SDSS) were published. In these samples, the famous orbital period gap, which is a dearth of systems in the orbital period…

Solar and Stellar Astrophysics · Physics 2024-02-06 Matthias R. Schreiber , Diogo Belloni , Axel D. Schwope

We construct a complete, semi-empirical donor sequence for CVs with orbital periods less than 6 hrs. All key physical and photometric parameters of CV secondaries (along with their spectral types) are given as a function of P_orb along this…

Astrophysics · Physics 2009-11-11 Christian Knigge

The mass-loss rate of donor stars in cataclysmic variables (CVs) is of paramount importance in the evolution of short-period CVs. Observed donors are oversized in comparison with those of isolated single stars of the same mass, which is…

Solar and Stellar Astrophysics · Physics 2015-05-19 Fedir V. Sirotkin , Woong-Tae Kim

A plot of the calcium emission versus color of late type stars exhibits a reduced population or gap at intermediate activity, somewhat higher than that of the Sun. We suggest that this gap, first noted by A. Vaughan and G. Preston in 1980…

Solar and Stellar Astrophysics · Physics 2018-10-17 Peter Foukal

This work on gap acceptance is based on the premise that the decision to accept/reject a gap happens in a person's mind and therefore must be based on the perceived gap and not the measured gap. The critical gap must also exist in a…

Methodology · Statistics 2025-12-25 Ankita Sharma , Partha Chakroborty , Pranamesh Chakraborty

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

New analysis confirms our earlier claim [1], [7] of circles of notably low temperature variance, often in concentric sets, in the cosmic microwave background (CMB), discernable in WMAP data. Their reality can be interpreted as evidence of…

Cosmology and Nongalactic Astrophysics · Physics 2011-05-04 V. G. Gurzadyan , R. Penrose

Accurate estimates of the reproduction ratio are crucial to project infectious disease epidemic evolution and guide public health response. Here, we prove that estimates of the reproduction ratio based on inference from surveillance data…

Physics and Society · Physics 2025-01-08 Piero Birello , Michele Re Fiorentin , Boxuan Wang , Vittoria Colizza , Eugenio Valdano

The problem of intermediates in the fossil record has been frequently discussed ever since Darwin. The extent of `gaps' (missing transitional stages) has been used to argue against gradual evolution from a common ancestor. Traditionally,…

Populations and Evolution · Quantitative Biology 2008-08-27 Mareike Fischer , Mike Steel

The two most common techniques for measuring planetary masses - the radial velocity (RV) and the transit timing variations (TTVs) techniques - have been observed to yield systematically different masses for planets of similar radii.…

Earth and Planetary Astrophysics · Physics 2017-04-19 Sean M. Mills , Tsevi Mazeh

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 report on a possible correlation between the mass ratio and period ratio of pairs of adjacent planets in extra-solar planetary systems. Monte-Carlo simulations show that the effect is significant to level of 0.7%, as long as we exclude…

Astrophysics · Physics 2007-05-23 Tsevi Mazeh , Shay Zucker

We investigate why the spectral type of most cataclysmic variable (CV) secondaries is significantly later than that of a ZAMS star with the same mean density. Using improved stellar input physics, tested against observations of low-mass…

Astrophysics · Physics 2015-06-24 I. Baraffe , U. Kolb