scholarly journals Secular Mass Loss from Cataclysmic Variables

1977 ◽  
Vol 42 ◽  
pp. 365-370
Author(s):  
Józef Smak
Keyword(s):  
Mass Transfer ◽  
Angular Momentum ◽  
Chemical Composition ◽  
Mass Loss ◽  
Cataclysmic Variables ◽  
Dynamical Evolution ◽  
Good Insight ◽  
Physical Mechanisms ◽  
Cataclysmic Binaries ◽  
Insight Into

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.

scholarly journals The Theory of Novae and Nova-Like Systems

1974 ◽  
Vol 66 ◽  
pp. 155-167
Author(s):  
John Faulkner
Keyword(s):  
Mass Transfer ◽  
Angular Momentum ◽  
Mass Loss ◽  
Gravitational Radiation ◽  
Theoretical Work ◽  
Observational Evidence ◽  
Recent Theoretical Work ◽  
Term Response ◽  
Theoretical Developments

Recent observational and theoretical developments in the study of novae, particularly dwarf novae, are discussed. Mechanisms promoting mass transfer include (i) nuclear evolution or (ii) envelope instability of the red star and (iii) gravitational radiation of orbital angular momentum. Growing observational evidence against (ii) is supported by recent theoretical work on the medium and long term response of stellar radii to mass loss. Mechanisms (i) and (iii) may operate alone or in concert, depending on the circumstances.

scholarly journals Mass Loss in Algol-Type Stars: Implication on their Evolutionary Stage

1982 ◽  
Vol 69 ◽  
pp. 187-189
Author(s):  
F. Mardirossian ◽  
G. Giuricin
Keyword(s):  
Mass Transfer ◽  
Angular Momentum ◽  
Mass Loss ◽  
Observational Data ◽  
Mass Exchange ◽  
Total Mass ◽  
Evolutionary Stage ◽  
Momentum Loss ◽  
Evolutionary Scenario ◽  
Angular Momentum Loss

AbstractWe have examined the observational data of 102 Algols in order to clarify the implications on their evolutionary scenario of various assumptions concerning mass and angular momentum loss during mass transfer. We have found that case B mass exchange is strongly favoured for Algols of relatively low total mass (~ M < 7 Mʘ), while case A predominates, though not so widely as expected in Algols of higher total mass.

scholarly journals Minimum Orbital Period of Cataclysmic Variables

1979 ◽  
Vol 53 ◽  
pp. 504-504
Author(s):  
B. Paczynski ◽  
W. Krzeminski
Keyword(s):  
Mass Transfer ◽  
Angular Momentum ◽  
Orbital Period ◽  
Time Scale ◽  
Transfer Rate ◽  
Main Sequence ◽  
Mass Transfer Rate ◽  
Cataclysmic Variables ◽  
Transfer Rates ◽  
Angular Momentum Loss

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.

scholarly journals Aspects of Mass Loss and Angular Momentum Loss in Binaries Containing Cool Components

1992 ◽  
Vol 151 ◽  
pp. 167-173
Author(s):  
Peter P. Eggleton
Keyword(s):  
Angular Momentum ◽  
Mass Loss ◽  
Orbital Angular Momentum ◽  
Cataclysmic Variables ◽  
Close Binary ◽  
Rapid Rotation ◽  
Momentum Loss ◽  
Cool Stars ◽  
Angular Momentum Loss ◽  
Show Evidence

Cool stars show evidence of dynamo activity which is stronger with more rapid rotation. Tidal friction in a moderately close binary can be a cause of relatively rapid rotation, so that cool components in such binaries are presumably liable to stronger stellar winds than single cool stars. As a consequence, the binary can be subject to orbital angular momentum loss. Both the mass loss and the orbital angular momentum loss can be on a timescale comparable to nuclear evolution in a red subgiant, or even faster. RS CVn stars probably give the best possibility of measuring these processes, although some observational data are difficult to reconcile with simple theories.Barium stars, and symbiotics, may both be affected by these processes. They must be the products of evolution of moderately wide binaries, as must such objects as cataclysmic variables. I attempt to define the ranges of zero-age parameters necessary to produce such varied objects. A simplistic model of the distribution of stars brighter than 6th magnitude (a ‘Theoretical Bright Star Catalogue’) suggests that for every three Ba stars with a measurable orbit, there should be one main sequence ‘Ba star’.

scholarly journals Mass Loss from Contact Binary Systems and their Dynamical Evolution

1980 ◽  
Vol 88 ◽  
pp. 511-515
Author(s):  
Kyoji Nariai
Keyword(s):  
Angular Momentum ◽  
Mass Loss ◽  
Total Mass ◽  
Binary Systems ◽  
Dynamical Evolution ◽  
Major Axis ◽  
Semi Major Axis ◽  
Orbital Parameters ◽  
Contact Binary ◽  
Fractional Mass

When there is mass loss from a binary system, the lost mass carries energy and angular momentum out of the system. Therefore, the remaining system must adjust its orbital parameters to the changing values of the total kinematic energy E and the total angular momentum N as the total mass M decreases. The parameters concerned here are : the fractional mass μ, the semi-major axis a, and the eccentricity e.

scholarly journals Searches for Cataclysmic Variables in Globular Cluster Cores

1996 ◽  
Vol 174 ◽  
pp. 49-51
Author(s):  
Michael M. Shara
Keyword(s):  
Globular Clusters ◽  
Cataclysmic Variables ◽  
Dynamical Evolution ◽  
Close Binaries ◽  
Dwarf Novae ◽  
Sources And Sinks ◽  
Large Numbers ◽  
Cataclysmic Binaries ◽  
Contact Binaries ◽  
Cluster Cores

Close binaries are widely believed to exist in large numbers in the cores of globular clusters. If present, these binaries are critical sources and sinks of energy that drive the dynamical evolution of their host clusters. I report on HST searches for binaries (based on variability) in the outskirts and cores of several globular clusters; dwarf novae should be particularly easy to find. Dense and loose clusters have been thoroughly searched on timescales ranging from minutes to years. Detailed simulations demonstrate that virtually all binaries with M < 8, amplitudes > 0.1 mag and periods of 2–20 hours should have been found. This includes virtually all known contact binaries. At least 1/3 of all dwarf novae present in several globulars should also have been seen (very easily!) in eruption at M = 4 − 6.Simple tidal capture theory predicts that dozens of interacting binaries should have been found in our searches; the observed number is typically one or two objects per cluster. Unless tidal capture cataclysmic binaries are rapidly destroyed, ejected, or much fainter than most of their Galactic counterparts, we must conclude that very close binaries in globular cores are rare, and that their total influence on cluster dynamical evolution is less than currently claimed.

scholarly journals Angular Momentum Loss in Polars

2009 ◽  
Vol 5 (S262) ◽  
pp. 362-363
Author(s):  
Belinda Kalomeni
Keyword(s):  
Angular Momentum ◽  
Mass Loss ◽  
Cataclysmic Variables ◽  
Physical Parameters ◽  
Momentum Loss ◽  
Angular Momentum Loss ◽  
Loss Rates ◽  
Loss Mechanisms

AbstractWe discuss the possible angular momentum loss mechanisms in AM Her type cataclysmic variables and their corresponding mass loss rates using the observed physical parameters of them.

scholarly journals On the Modeling of Algol-Type Binaries

Galaxies ◽  
2021 ◽  
Vol 9 (1) ◽  
pp. 19
Author(s):  
Walter van van Rensbergen ◽  
Jean-Pierre de de Greve
Keyword(s):  
Magnetic Field ◽  
Mass Transfer ◽  
Angular Momentum ◽  
Mass Loss ◽  
Strong Magnetic Field ◽  
Stellar Wind ◽  
Orbital Parameters ◽  
Tidal Interaction ◽  
Magnetic Braking ◽  
Orbital Periods

In earlier papers, we presented a binary evolutionary code for the purpose of reproducing the orbital parameters, masses, radii, and location in the Hertzsprung Russell diagram (abbreviated as HRD) of well-observed Algol systems. In subsequent versions, the effects of mass and angular momentum losses and tidal coupling were included in order to produce the observed distributions of orbital periods and mass ratios of Algol-type binaries. The mass loss includes stellar wind and possible liberal evolution, when the gainer star is not capable to absorb all of the matter during mass transfer from the donor star. We added magnetic braking to our code to better reproduce the observed equatorial velocities. Large equatorial velocities of mass-gaining stars are now lowered by tidal interaction and magnetic braking. Tides are mainly at work at short orbital periods, leaving magnetic braking alone at work during longer orbital periods. The observed values of the equatorial velocities of mass gainers in Algol-type binaries are mostly well reproduced by our code. According to our models, Algols have short periods with a strong magnetic field.

scholarly journals Comments on the Evolution and Origin of cataclysmic Binaries

1979 ◽  
Vol 53 ◽  
pp. 474-477
Author(s):  
Charles A. Whyte ◽  
Peter P. Eggleton
Keyword(s):  
Mass Transfer ◽  
Angular Momentum ◽  
Initial Conditions ◽  
Numerical Procedure ◽  
Classical Novae ◽  
Momentum Loss ◽  
Cataclysmic Binaries ◽  
Short Period ◽  
Angular Momentum Loss ◽  
Low Mass

AbstractSome aspects of the observational data on cataclysmic binaries are discussed and some possible correlations between type of behaviour and binary period are noted. A gap between 2 and 3 hours in the histogram of binary periods is estimated to be real. A numerical procedure for following the evolution of Roche-lobe-fiUing stars using simplified equations is described. This procedure Is applied to white/red dwarf binaries for a variety of initial conditions, and of mass loss and angular momentum loss mechanisms. The results of these calculations, in which we ignore the short timescale behaviour of the systems, are classified into four modes of evolution: normal, nuclear evolution dominated, angular momentum loss dominated and hydrodynamical. The results are discussed in connection with cataclysmic binaries. The clustering in period below 2 hours is Interpreted in terms of evolution following the hydrodynamical mode, and it is suggested that such systems contain low mass white dwarfs as well as low mass secondaries. These may be the most common type of cataclysmic binary. A possible explanation of the clustering of classical novae systems to binary periods of 3 to 5 hours is mentioned, and evolutionary scenarios for cataclysmic binaries are outlined. We suggest, following Ritter and Webbink, that the short period systems (≲ 2 hrs) arise mainly from late Case B mass transfer in the original binary (original primary mass 1.5 to 3M⊙) and the longer period systems arise mainly from Case C mass transfer.Full text to be published in Monthly Notices of the Royal Astronomical Society.

scholarly journals Beryllium in Lithium–Deficient F Stars: Constraints on Stellar Evolution

1993 ◽  
Vol 137 ◽  
pp. 174-176 ◽  
Author(s):  
Constantine P. Deliyannis ◽  
M.H. Pinsonneault
Keyword(s):  
Angular Momentum ◽  
Mass Loss ◽  
Stellar Evolution ◽  
Meridional Circulation ◽  
Initial Surface ◽  
Physical Mechanisms ◽  
Vital Interest ◽  
Angular Momentum Loss ◽  
F Stars ◽  
Diffusion Mass

AbstractStandard stellar evolution predicts that F stars should retain their initial surface lithium (Li) abundance because their convection zones are too shallow to destroy it at their base. Yet, observations reveal a severe Li depletion (the “Boesgaard Gap”), perhaps by as much as about two orders of magnitude, in a narrow Teff range. Several physical mechanisms, not usually included in stellar evolution calculations, have been proposed to account for this Li deficiency. These include diffusion, mass loss, meridional circulation, and rotationally-induced mixing driven by angular momentum loss. Identifying which of these (if any) might really be at work is not only of vital interest to stellar evolution, but may also have serious implications elsewhere (e.g. cosmology, Deliyannis et al. 1991). We bring attention to beryllium (Be) observations in F stars, which are crucial for discriminating between scenarios. Particularly important is the star 110 Her, which is depleted in Be by about a factor of 5 -10, but still has a detectable Li abundance (depleted by a factor of 100 - 200). Depleting surface Be without having depleted nearly all of the surface Li requires specific circumstances; we discuss how this depletion property severely constrains or eliminates most of the proposed mechanisms. One mechanism, rotationally-induced mixing, predicts relative depletions for these elements that agree well with what is observed.

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