Secular Evolution of Cataclysmic Variables with Irradiation-Induced Mass Transfer

Author(s):  
H. Ritter ◽  
Z. Zhang ◽  
J. M. Hameury
1996 ◽  
Vol 158 ◽  
pp. 449-452 ◽  
Author(s):  
H. Ritter ◽  
Z. Zhang ◽  
J. M. Hameury

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.


1977 ◽  
Vol 42 ◽  
pp. 365-370
Author(s):  
Józef Smak

The mass loss from cataclysmic binaries seems an important and worth studying phenomenon for a number of reasons. It is probably enough to mention only two of them:(a) Whenever we can directly observe the ejected material, determine its amount and the rate of mass loss, as well as its chemical composition (this being the case of the expanding envelopes of novae), we are getting a good insight into the basic physical mechanisms responsible for the observed phenomena.(b) The mass loss (together with the mass transfer) and the loss of the orbital angular momentum are related directly to the dynamical evolution of a binary system and - indirectly - to the evolution of its components.


2004 ◽  
Vol 190 ◽  
pp. 15-21 ◽  
Author(s):  
Gaghik Tovmassian ◽  
Sergey Zharikov ◽  
Ronald Mennickent ◽  
Jochen Greiner

AbstractWe have observed several magnetic cataclysmic variables located in the range between 2 and 3 hours, known as the period gap. This work was prompted by the recent discovery of RXJ1554.2+2721. It has 2.54 hours orbital period and shows almost pure cyclotron continuum in a low luminosity state, similar to HS1023+3900, HS0922+1333 and RBS206. These are low accretion rate polars (LARPs) known to have mass transfer rates of order of a few 10-13M⊙/year. The aim of the study was to find out, if magnetic systems filling the period gap are in any way different from their counterparts outside that range of periods. The only significant difference we encounter is a much higher number of asynchronous magnetic systems towards longer periods than below the gap.


1990 ◽  
Vol 122 ◽  
pp. 313-324
Author(s):  
Hans Ritter

AbstractIn this paper we explore to what extent the TNR model of nova outbursts and our current concepts of the formation and secular evolution of cataclysmic binaries are compatible. Specifically we address the following questions: 1) whether observational selection can explain the high white dwarf masses attributed to novae, 2) whether novae on white dwarfs in the mass range 0.6M⊙ ≲ M ≲ 0.9M⊙ can occur and how much they could contribute to the observed nova frequency, and 3) whether the high mass transfer rates imposed on the white dwarf in systems above the period gap can be accommodated by the TNR model of nova outbursts.


1995 ◽  
Vol 444 ◽  
pp. L37 ◽  
Author(s):  
A. R. King ◽  
J. Frank ◽  
U. Kolb ◽  
H. Ritter

1992 ◽  
Vol 151 ◽  
pp. 225-234
Author(s):  
J. Craig Wheeler

Spectral calculations show that a model based on the thermonuclear explosion of a degenerate carbon/oxygen white dwarf provides excellent agreement with observations of Type Ia supernovae. Identification of suitable evolutionary progenitors remains a severe problem. General problems with estimation of supernova rates are outlined and the origin of Type Ia supernovae from double degenerate systems are discussed in the context of new rates of explosion per H band luminosity, the lack of observed candidates, and the likely presence of H in the vicinity of some SN Ia events. Re-examination of the problems of triggering Type Ia by accretion of hydrogen from a companion shows that there may be an avenue involving cataclysmic variables, especially if extreme hibernation occurs. Novae may channel accreting white dwarfs to a unique locus in accretion rate/mass space. Systems that undergo secular evolution to higher mass transfer rates could lead to just the conditions necessary for a Type Ia explosion. Tests involving fluorescence or absorption in a surrounding circumstellar medium and the detection of hydrogen stripped from a companion, which should appear at low velocity inside the white dwarf ejecta, are suggested. Possible observational confirmation of the former is described.


1996 ◽  
Vol 165 ◽  
pp. 65-71
Author(s):  
H. Ritter ◽  
Z. Zhang ◽  
U. Kolb

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.


1979 ◽  
Vol 53 ◽  
pp. 504-504
Author(s):  
B. Paczynski ◽  
W. Krzeminski

The shortest known orbital period of a cataclysmic binary with a hydrogen dwarf secondary filling its Roche lobe is about 80 minutes. Theoretically the shortest possible orbital period for such a system is less than 60 minutes. We tried to explain why the periods shorter than 80 minutes are not observed. We estimated the time scale of angular momentum loss of a cataclysmic binary and the resulting mass transfer rate. The minimum orbital period for a given Ṁ is obtained during the transition of the secondary from the Main Sequence onto the Degenerate Dwarf Sequence. Pmin ∝ Ṁ½ Therefore, only those systems can reach low P for which Ṁ is small. This explains why among the shortest period cataclysmic variables there are no novae: presumably their mass transfer rates are too large. It also indicates that “polars” (AM Her-type stars) and SU UMa-type stars should have low Ṁ.


1995 ◽  
Vol 12 (1) ◽  
pp. 60-65 ◽  
Author(s):  
Kinwah Wu ◽  
Dayal T. Wickramasinghe ◽  
Brian Warner

Abstract We investigate irradiation-driven mass transfer in cataclysmic variables in the presence of shielding of the radiation by an accretion disk. We have shown that the shielding can cause a temporal drop of 3–5 magnitudes in the brightness of systems with orbital periods shorter than about 4 hr. This provides a possible explanation for the brightness variations in the VY Scl stars.


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