scholarly journals Secular Evolution of Cataclysmic Variables with Irradiation-Induced Mass Transfer

1996 ◽  
Vol 158 ◽  
pp. 449-452 ◽  
Author(s):  
H. Ritter ◽  
Z. Zhang ◽  
J. M. Hameury
Keyword(s):  
Mass Transfer ◽  
Cataclysmic Variables ◽  
Point Of View ◽  
External Irradiation ◽  
General Point ◽  
Mass Star ◽  
Compact Binaries ◽  
Secular Evolution ◽  
Low Mass

The possible importance of the reaction of a low-mass star to external irradiation for the long-term evolution of compact binaries has been noted only rather recently; first in the context of the evolution of low-mass X-ray binaries (e.g. Podsiadlowski 1991; Harpaz & Rappaport 1991; Frank, King & Lasota 1992; Hameury et al. 1993) and subsequently by Ritter, Zhang & Kolb (1995a,b, hereafter RZK) also for the evolution of cataclysmic variables (CVs). Based on a simple model for describing the reaction of a low-mass star to irradiation RZK showed that CVs can be dynamically unstable against irradiation-induced mass transfer and that, as a consequence of this, mass transfer could occur via cycles in which phases of high, irradiation-enhanced mass transfer alternate with phases of little or no mass transfer. The occurrence of such mass transfer cycles in CVs was subsequently discussed from a more general point of view by King (1995) and King et al. (1995). Whereas the possibility of mass transfer cycles in CVs is now fully recognised, the question as to which systems can undergo such cycles and which cannot has not yet been addressed in detail. It is the purpose of this contribution to provide at least a partial answer to this question.

scholarly journals The Reaction of Low-Mass Stars to Anisotropic Irradiation and its Implications for the Secular Evolution of Cataclysmic Binaries

1996 ◽  
Vol 165 ◽  
pp. 65-71
Author(s):  
H. Ritter ◽  
Z. Zhang ◽  
U. Kolb
Keyword(s):  
Mass Transfer ◽  
Time Scale ◽  
Mass Transfer Rate ◽  
Mass Star ◽  
Evolutionary Time ◽  
Low Mass Stars ◽  
Secular Evolution ◽  
Cataclysmic Binaries ◽  
Low Mass

A semi-analytic model for the reaction of a low-mass star to anisotropic irradiation of low incident flux is presented. By applying this model to the donor star of cataclysmic binaries (CBs) it is shown that CBs are likely to be unstable against irradiation-driven runaway mass transfer. The implications of this instability for the long-term evolution of CBs are examined. The possibility is discussed that because of this instability CBs evolve through a limit cycle in which phases of high and low mass transfer rate alternate on a time scale short compared to the evolutionary time scale.

scholarly journals Magnetic Braking in Cataclysmic and Low-Mass X-Ray Binaries

1984 ◽  
Vol 80 ◽  
pp. 287-294
Author(s):  
O. Vilhu
Keyword(s):  
Mass Transfer ◽  
Binary Stars ◽  
Cataclysmic Variables ◽  
Turnover Time ◽  
Coronal Emission ◽  
X Ray ◽  
Compact Binaries ◽  
Gradual Loss ◽  
Low Mass ◽  
Magnetic Braking

AbstractThe chromospheric-coronal emission of lower Main-Sequence single and binary stars can be correlated with an activity parameter of type R = g(B-V)P-1 where P is the rotation or orbital period and g(B-V) a function of the color resembling the convective turnover time. Observations indicate that the active region area coverage filling factor grows as R2, and the whole stellar surface becomes filled with closed loop structures at R ≂ 3. A braking formula is proposed (Equation 4) to include all periods (0.d1 ≲ R ≳ 30d) and spectral types F-M. On the basis of this equation, the mass transfer rates in compact binaries (driven by the gradual loss of orbital angular momentum) are discussed. It is concluded that the magnetic braking has good chances of being that mechanism which drives the mass transfer in cataclysmic variables and galactic bulge X-ray sources.

scholarly journals Irradiation Effects in Compact Binaries

2002 ◽  
Vol 187 ◽  
pp. 253-258
Author(s):  
Martin E. Beer ◽  
Philipp Podsiadlowski
Keyword(s):  
Binary Systems ◽  
Three Dimensional ◽  
Close Binary ◽  
Close Binaries ◽  
External Irradiation ◽  
Black Hole Binaries ◽  
Compact Binaries ◽  
Critical Configurations ◽  
Main Effects

AbstractIrradiation of the secondaries in close binary systems affects their appearance and can drastically change their internal structure and hence long-term evolution. In this paper we review the main effects of external irradiation in close binaries with compact primaries, such as the distortion of the shape of the secondary and the conditions for the occurrence of outer critical configurations, and apply these to normal X-ray binaries, including systems such as HZ Her/Her X-l, Vela X-l and black-hole binaries during outburst (e.g. Nova Sco). Particular emphasis will be given to the role of circulation driven by the external heating and the radiative surface stress. We have developed a three-dimensional fluid dynamics code for modelling these effects. We present initial results of self-consistent calculations for the circulation in irradiated systems and show how the inclusion of these effects is vital to the understanding and interpretation of any system where external irradiation of the secondary is significant.

scholarly journals Using X-Rays to Probe the Compact Binary Content of Globular Clusters

2004 ◽  
Vol 194 ◽  
pp. 75-76
Author(s):  
N. A. Webb ◽  
B. Gendre ◽  
D. Barret
Keyword(s):  
Globular Clusters ◽  
Cataclysmic Variables ◽  
Close Binaries ◽  
X Rays ◽  
X Ray ◽  
Compact Binaries ◽  
Compact Binary ◽  
Low Mass ◽  
Evolutionary Paths ◽  
New Generation

AbstractGlobular clusters (GCs) harbour a large number of close binaries which are hard to identify optically due to high stellar densities. Observing these GCs in X-rays, in which the compact binaries are bright, diminishes the over-crowding problem. Using the new generation of X-ray observatories, it is possible to identify populations of neutron star low mass X-ray binaries, cataclysmic variables and millisecond pulsars as well as other types of binaries. We present the spectra of a variety of binaries that we have identified in four GCs observed by XMM-Newton. We show that through population studies we can begin to understand the formation of individual classes of binaries in GCs and hence start to unfold the complex evolutionary paths of these systems.

scholarly journals SWSex Stars, Old Novae, and the Evolution of Cataclysmic Variables

2015 ◽  
Vol 2 (1) ◽  
pp. 188-191 ◽  
Author(s):  
L. Schmidtobreick ◽  
C. Tappert
Keyword(s):  
Mass Transfer ◽  
Transfer Rate ◽  
Mass Transfer Rate ◽  
Cataclysmic Variables ◽  
High Mass ◽  
Period Range ◽  
Transfer Rates ◽  
Low Mass ◽  
Orbital Periods ◽  
Nova Outburst

The population of cataclysmic variables with orbital periods right above the period gap are dominated by systems with extremely high mass transfer rates, the so-called SW Sextantis stars. On the other hand, some old novae in this period range which are expected to show high mass transfer rate instead show photometric and/or spectroscopic resemblance to low mass transfer systems like dwarf novae. We discuss them as candidates for so-called hibernating systems, CVs that changed their mass transfer behaviour due to a previously experienced nova outburst. This paper is designed to provide input for further research and discussion as the results as such are still very preliminary.

scholarly journals Transients from the Cataclysmic Deaths of Cataclysmic Variables

2021 ◽  
Vol 923 (1) ◽  
pp. 100
Author(s):  
Brian D. Metzger ◽  
Yossef Zenati ◽  
Laura Chomiuk ◽  
Ken J. Shen ◽  
Jay Strader
Keyword(s):  
Large Fraction ◽  
Cataclysmic Variables ◽  
Mass Star ◽  
Tidal Disruption ◽  
Classical Novae ◽  
Hydrogen Recombination ◽  
Low Mass ◽  
Hydrodynamical Simulations ◽  
Stellar Mergers ◽  
Optical Transient

Abstract We explore the observational appearance of the merger of a low-mass star with a white dwarf (WD) binary companion. We are motivated by recent work finding that multiple tensions between the observed properties of cataclysmic variables (CVs) and standard evolution models are resolved if a large fraction of CV binaries merge as a result of unstable mass transfer. Tidal disruption of the secondary forms a geometrically thick disk around the WD, which subsequently accretes at highly super-Eddington rates. Analytic estimates and numerical hydrodynamical simulations reveal that outflows from the accretion flow unbind a large fraction ≳90% of the secondary at velocities ∼500–1000 km s−1 within days of the merger. Hydrogen recombination in the expanding ejecta powers optical transient emission lasting about a month with a luminosity ≳1038 erg s−1, similar to slow classical novae and luminous red novae from ordinary stellar mergers. Over longer timescales the mass accreted by the WD undergoes hydrogen shell burning, inflating the remnant into a giant of luminosity ∼300–5000 L ⊙, effective temperature T eff ≈ 3000 K, and lifetime ∼104–105 yr. We predict that ∼103–104 Milky Way giants are CV merger products, potentially distinguishable by atypical surface abundances. We explore whether any Galactic historical slow classical novae are masquerading CV mergers by identifying four such post-nova systems with potential giant counterparts for which a CV merger origin cannot be ruled out. We address whether the historical transient CK Vul and its gaseous/dusty nebula resulted from a CV merger.

scholarly journals A spider timing model: accounting for quadrupole deformations and relativity in close pulsar binaries

2019 ◽  
Vol 492 (2) ◽  
pp. 1550-1565 ◽  
Author(s):  
Guillaume Voisin ◽  
René P Breton ◽  
Charlotte Summers
Keyword(s):  
Cataclysmic Variables ◽  
Quadrupole Deformation ◽  
Orbital Eccentricity ◽  
Companion Star ◽  
Compact Binaries ◽  
Timing Model ◽  
Pulsar Timing ◽  
Low Mass ◽  
Stellar Interiors ◽  
Made In

ABSTRACT Spider millisecond pulsars are, along with some eclipsing post-common envelope systems and cataclysmic variables, part of an expanding category of compact binaries with low-mass companions for which puzzling timing anomalies have been observed. The most prominent type of irregularities seen in them are orbital period variations, a phenomenon which has been proposed to originate from changes in the gravitational quadrupole moment of the companion star. A physically sound modelling of the timing of these systems is key to understanding their structure and evolution. In this paper we argue that a complete timing model must account for relativistic corrections as well as rotationally and tidally induced quadrupole distortions. We solve for the resulting orbital dynamics using perturbation theory and derive the corresponding timing model in the low eccentricity limit. We find that the expected strong quadrupole deformation of the companion star results in an effective minimum orbital eccentricity. It is accompanied by a fast periastron precession which, if not taken into account, averages out any measurement of the said eccentricity. We show that, with our model, detection of both eccentricity and precession is likely to be made in many if not all spider pulsar systems. Combined with optical light curves, this will allow us to measure the apsidal motion constant, connecting the quadrupole deformation to the internal structure, and thus opening a new window into probing the nature of their exotic stellar interiors. Moreover, more accurate timing may eventually lead spider pulsars to be used for high-precision timing experiments such as pulsar timing arrays.

scholarly journals Irradiation-Driven Mass Transfer in Low-Mass X-Ray Binaries

1992 ◽  
Vol 151 ◽  
pp. 457-460
Author(s):  
Philipp Podsiadlowski
Keyword(s):  
Mass Transfer ◽  
Relaxation Process ◽  
Internal Structure ◽  
Thermal Equilibrium ◽  
External Irradiation ◽  
Driving Mechanism ◽  
X Ray ◽  
Radiation Fluxes ◽  
Low Mass ◽  
X Ray Binaries

External irradiation can completely alter the internal structure of the secondary in a low-mass X-ray binary (LMXB). For radiation fluxes as are typically found in LMXBs, the secondary expands by a factor of 2 to 3 in order to relax towards a new state of thermal equilibrium. This relaxation process provides a new mass-transfer driving mechanism for LMXBs, which can drastically alter the evolution of these systems.

scholarly journals Recovery of Old Novae

2004 ◽  
Vol 194 ◽  
pp. 187-189
Author(s):  
L. Schmidtobreick ◽  
C. Tappert ◽  
R. E. Mennickent ◽  
A. Bianchini
Keyword(s):  
Mass Transfer ◽  
Optical Spectroscopy ◽  
Classical Novae ◽  
First Results ◽  
Multi Wavelength ◽  
Low Mass ◽  
Orbital Periods

AbstractIn the course of a long-term project investigating classical novae with large outburst amplitudes, we have performed multi-wavelength photometry and optical spectroscopy of several old nova candidates. We here introduce the aim of the project, the search for low mass-transfer novae with short orbital periods, and explain the method to recover these old novae via their colour characteristics. Finally we concentrate on first results for selected objects in our sample.

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