scholarly journals From Common Envelope to Pre-Cataclysmic Variables: An Observational Test of Common Envelope Evolution

1996 ◽  
Vol 158 ◽  
pp. 453-456
Author(s):  
M. J. Sarna
Keyword(s):  
Gravitational Radiation ◽  
Planetary Nebula ◽  
Cataclysmic Variables ◽  
Orbital Energy ◽  
Dwarf Star ◽  
Common Envelope ◽  
Evolutionary Scenario ◽  
Angular Momentum Loss ◽  
Red Giant ◽  
Detached Binaries

The generally accepted evolutionary scenario for cataclysmic variables (CVs) is common envelope (CE) evolution (Iben & Livio 1993) proposed by Paczyñski (1976). The secondary spirals towards the giant’s compact core converting orbital energy into kinetic energy of the giant’s envelope and the envelope is ejected. The dynamics of the red dwarf and red giant envelope interaction have been studied by several groups (Livio & Soker 1988; Taam & Bodenheimer 1991). After the ejection of the red giant envelope the post common envelope detached binaries (PCEBs) are formed. These can be divided into three groups:• Hot subdwarf with a red dwarf star inside a planetary nebula.• Hot subdwarf with a red dwarf star without a planetary nebula.• Hot white dwarf with a red dwarf star without a planetary nebula. Next, due to angular momentum loss by magnetic braking and/or gravitational radiation, the red dwarf component fills its Roche lobe and a cataclysmic variable is formed.

scholarly journals The evolutionary status of symbiotic stars

1982 ◽  
Vol 70 ◽  
pp. 275-282 ◽  
Author(s):  
Bronislaw Rudak
Keyword(s):  
Cataclysmic Variables ◽  
Evolutionary Status ◽  
Spherically Symmetric ◽  
Symbiotic Stars ◽  
Transfer Phase ◽  
Common Envelope ◽  
Long Period ◽  
Red Giant ◽  
Detached Binaries ◽  
Rapid Mass

AbstractThe evolutionary relations between symbiotic stars and cataclysmic variables are presented. The symbiotic stars are assumed to be long period detached binaries containing a carbon-oxygen degenerate primary and a red giant losing its mass through a spherically symmetric wind. Such systems can be obtained in Case C evolution, provided a common envelope during a rapid mass transfer phase was not formed. The same way recurrent novae containing a red giant as a secondary component may be produced. The factors influencing the differences between symbiotic stars and nova-type stars are discussed.

scholarly journals Common Envelope Binaries

1976 ◽  
Vol 73 ◽  
pp. 75-80 ◽  
Author(s):  
B. Paczynski
Keyword(s):  
Angular Momentum ◽  
Orbital Period ◽  
Planetary Nebula ◽  
Initial Period ◽  
Cataclysmic Variables ◽  
Lagrangian Point ◽  
Common Envelope ◽  
Evolutionary Scenario ◽  
Short Period ◽  
Contact Binary

When a contact binary expands so much that the stellar surface moves beyond the outer Lagrangian point, a common envelope binary is formed. The suggestion is made that while the two dense stellar nuclei spiral towards each other, the envelope expands and is eventually lost. Most of the angular momentum is lost with the envelope, and therefore the final orbital period may be orders of magnitude shorter than the initial period. V471 Tau could have formed from a binary with a ten year orbital period. Most probably, cataclysmic variables are products of the evolution of systems like V471 Tau. Observational discovery of a short period binary being a nucleus of a planetary nebula would provide very important support for the evolutionary scenario presented in this paper.

scholarly journals Problems in Common Envelope Evolution as a Pre-Stage of Cataclysmic Variables

1979 ◽  
Vol 53 ◽  
pp. 520-520
Author(s):  
F. Meyer ◽  
E. Meyer-Hofmeister
Keyword(s):  
Angular Momentum ◽  
Thermal Instability ◽  
Main Sequence ◽  
Cataclysmic Variables ◽  
Main Sequence Star ◽  
Common Envelope ◽  
Angular Momentum Transport ◽  
Binary Separation ◽  
Low Mass ◽  
Red Giant

We follow the evolution of an originally widely separated red-giant in orbit with a low mass main sequence star to a cataclysmic binary system. Angular momentum transport via differential rotation leads to a common envelope around the red giant core and the main sequence star. The internal binary separation shrinks by frictional transfer of angular momentum to the extended red giant envelope. This shrinkage continues at nearly constant luminosity until after several hundred years the binary “Roche lobe” cuts into the dense layers of the main sequence star. The envelope will then be lost by a thermal instability. Method and computations for a 5 M⊙ + 1 M⊙ binary are presented elsewhere (Astron. Astrophys. 1979, in press).

scholarly journals Common-envelope evolution with an asymptotic giant branch star

2020 ◽  
Vol 644 ◽  
pp. A60
Author(s):  
Christian Sand ◽  
Sebastian T. Ohlmann ◽  
Fabian R. N. Schneider ◽  
Rüdiger Pakmor ◽  
Friedrich K. Röpke
Keyword(s):  
Binary Systems ◽  
Three Dimensional ◽  
Asymptotic Giant Branch ◽  
Orbital Energy ◽  
Primary Star ◽  
Stellar Envelope ◽  
Asymptotic Giant Branch Star ◽  
Common Envelope ◽  
The Core ◽  
Red Giant

Common-envelope phases are decisive for the evolution of many binary systems. Cases with asymptotic giant branch (AGB) primary stars are of particular interest because they are thought to be progenitors of various astrophysical transients. In three-dimensional hydrodynamic simulations with the moving-mesh code AREPO, we study the common-envelope evolution of a 1.0 M⊙ early-AGB star with companions of different masses. Although the stellar envelope of an AGB star is less tightly bound than that of a red giant, we find that the release of orbital energy of the core binary is insufficient to eject more than about twenty percent of the envelope mass. Ionization energy that is released in the expanding envelope, however, can lead to complete envelope ejection. Because recombination proceeds largely at high optical depths in our simulations, it is likely that this effect indeed plays a significant role in the considered systems. The efficiency of mass loss and the final orbital separation of the core binary system depend on the mass ratio between the companion and the primary star. Our results suggest a linear relation between the ratio of final to initial orbital separation and this parameter.

scholarly journals The post-common-envelope binary central star of the planetary nebula PN G283.7−05.1

2020 ◽  
Vol 642 ◽  
pp. A108 ◽  
Author(s):  
D. Jones ◽  
H. M. J. Boffin ◽  
J. Hibbert ◽  
T. Steinmetz ◽  
R. Wesson ◽  
...  
Keyword(s):  
Planetary Nebula ◽  
Main Sequence ◽  
Planetary Nebulae ◽  
Central Star ◽  
Radial Velocity Curve ◽  
Common Envelope ◽  
Low Mass ◽  
Red Giant ◽  
Model Temperature ◽  
Temperature Surface

We present the discovery and characterisation of the post-common-envelope central star system in the planetary nebula PN G283.7−05.1. Deep images taken as part of the POPIPlaN survey indicate that the nebula may possess a bipolar morphology similar to other post-common-envelope planetary nebulae. Simultaneous light and radial velocity curve modelling reveals that the newly discovered binary system comprises a highly irradiated M-type main-sequence star in a 5.9-hour orbit with a hot pre-white dwarf. The nebular progenitor is found to have a particularly low mass of around 0.4 M⊙, making PN G283.7−05.1 one of only a handful of candidate planetary nebulae that is the product of a common-envelope event while still on the red giant branch. In addition to its low mass, the model temperature, surface gravity, and luminosity are all found to be consistent with the observed stellar and nebular spectra through comparison with model atmospheres and photoionisation modelling. However, the high temperature (Teff ∼ 95 kK) and high luminosity of the central star of the nebula are not consistent with post-RGB evolutionary tracks.

scholarly journals Evolutionary scenario for W UMa-type stars

2008 ◽  
Vol 4 (S252) ◽  
pp. 427-428 ◽  
Author(s):  
K. Stepień ◽  
K. Gazeas
Keyword(s):  
Thermal Equilibrium ◽  
Large Scale ◽  
Primary Component ◽  
Mass Ratio ◽  
Common Envelope ◽  
Evolutionary Scenario ◽  
Angular Momentum Loss ◽  
Temperature Equalization ◽  
The Common ◽  
Large Scale Flow

AbstractAn alternative to TRO model of a W UMa-type star is presented in which the binary is past mass exchange with mass ratio reversal. The secondary is hydrogen depleted and both components are in thermal equilibrium. Evolution in contact is driven by orbital angular momentum loss and mass transfer from the secondary to primary component, similarly as it is observed in Algols. Temperature equalization of both components results from an assumed energy transfer by a large scale flow encircling the whole system in the common envelope.

scholarly journals Surveying Planetary Nebulae Central Stars for Close Binaries: Constraining Evolution of Central Stars Based on Binary Parameters

Galaxies ◽  
2018 ◽  
Vol 6 (3) ◽  
pp. 85 ◽  
Author(s):  
Todd Hillwig
Keyword(s):  
Binary Stars ◽  
Planetary Nebula ◽  
Planetary Nebulae ◽  
Close Binary ◽  
Close Binaries ◽  
Common Envelope ◽  
Close Binary Stars ◽  
Red Giant ◽  
The Relationship ◽  
Central Stars

The increase in discovered close binary central stars of planetary nebulae is leading to a sufficiently large sample to begin to make broader conclusions about the effect of close binary stars on common envelope evolution and planetary nebula formation. Herein I review some of the recent results and conclusions specifically relating close binary central stars to nebular shaping, common envelope evolution off the red giant branch, and the total binary fraction and double degenerate fraction of central stars. Finally, I use parameters of known binary central stars to explore the relationship between the proto-planetary nebula and planetary nebula stages, demonstrating that the known proto-planetary nebulae are not the precursors of planetary nebulae with close binary central stars.

scholarly journals The Evolution of Moderately Close and Moderately Wide Binaries

1989 ◽  
Vol 107 ◽  
pp. 165-177
Author(s):  
P.P. Eggleton ◽  
C.A. Tout
Keyword(s):  
Mass Transfer ◽  
Mass Loss ◽  
Wide Binary ◽  
Convective Envelope ◽  
Tidal Friction ◽  
Common Envelope ◽  
Short Period ◽  
Angular Momentum Loss ◽  
Magnetic Braking ◽  
Red Giant

AbstractWe discuss evolutionary processes in binaries where the primary becomes a red giant with a deep convective envelope before it fills its Roche lobe. Such binaries (late Case B or late Case C, if they evolve conservatively) ought to suffer drastic mass transfer, on a hydrodynamic timescale. In some circumstances this may lead to a common envelope, spiral-in, and finally either a very short-period binary or coalescence. But there appear to be other circumstances in which the outcome is an ordinary Algol, or a wide binary with a white dwarf companion as in Barium stars and some symbiotics. We try to demonstrate that stellar-wind mass loss, enhanced one or two orders of magnitude by tidal interaction with a companion, can vitally affect the approach to RLOF, and indeed may prevent RLOF in binaries with periods over 1000 d. Such mass loss is probably accompanied by angular momentum loss, by magnetic braking combined with tidal friction. The result is that it will not be easy to predict definitively the outcome of evolution in a given zero-age binary.

scholarly journals Polarized Emission and the Discovery of New Magnetic CVs

2004 ◽  
Vol 190 ◽  
pp. 22-32
Author(s):  
Gary D. Schmidt
Keyword(s):  
Gravitational Radiation ◽  
Accretion Rate ◽  
Cataclysmic Variables ◽  
Selection Effects ◽  
Optical Polarization ◽  
Angular Momentum Loss ◽  
Cyclotron Emission ◽  
Magnetic Cataclysmic Variables ◽  
Current Sample ◽  
Cool White Dwarfs

AbstractRecent quasar surveys have identified several new magnetic cataclysmic variables accreting at remarkably low rates, ~10−13M⊙ yr−1. The new discoveries raise questions regarding selection effects that may influence the current sample and the traditional evolutionary conclusions that have been drawn. This paper reviews the techniques that have been used to identify polars, including a summary of the optical polarization as a function of accretion rate and magnetic field strength. The new, low-ṁ systems accrete without a shock and cooling is dominated by optical cyclotron emission in very well-defined harmonics. These binaries, which have been found to accrete at far below the rate corresponding to angular momentum loss by gravitational radiation, also appear to contain unusually cool white dwarfs, suggesting that they are either at an advanced age or in unusual evolutionary states.

Sign in / Sign up

Export Citation Format

Share Document