scholarly journals Energy and angular momentum deposition during common envelope evolution

New Astronomy ◽  
2004 ◽  
Vol 9 (5) ◽  
pp. 399-408 ◽  
Author(s):  
Noam Soker
Keyword(s):  
Angular Momentum ◽  
Common Envelope

5 Ceti: A Long-Period Binary Evolving Through Mass Exchange

1989 ◽  
Vol 106 ◽  
pp. 234-234
Author(s):  
Joel A. Eaton
Keyword(s):  
Angular Momentum ◽  
Orbital Angular Momentum ◽  
Mass Exchange ◽  
Main Sequence ◽  
Roche Lobe ◽  
Common Envelope ◽  
Long Period ◽  
Loss Of Mass

Binaries with very wide spearations are thought to evolve to small separations through a catastrophic form of mass exchange/loss known as common-envelope evolution. The theory of this process is fairly well developed, but proper tests remain elusive. Simply put, the theory argues that the rapidly shrinking Roche lobe of the mass losing giant will strip away the giant's main-sequence companion. Loss of mass from the system during the process carries away orbital angular momentum, thereby strengthening the effect.

scholarly journals The missing mass conundrum of post-common-envelope planetary nebulae

2018 ◽  
Vol 14 (S343) ◽  
pp. 239-243
Author(s):  
Miguel Santander-García ◽  
David Jones ◽  
Javier Alcolea ◽  
Roger Wesson ◽  
Valentín Bujarrabal
Keyword(s):  
Angular Momentum ◽  
Planetary Nebulae ◽  
Asymptotic Giant Branch ◽  
Close Binary ◽  
Missing Mass ◽  
Common Envelope ◽  
Molecular Masses ◽  
Pilot Sample ◽  
Progenitor Stars

AbstractMost planetary nebulae (PNe) show beautiful, axisymmetric morphologies despite their progenitor stars being essentially spherical. Angular momentum provided by a close binary companion is widely invoked as the main agent that would help eject an axisymmetric nebula, after a brief phase of engulfment of the secondary within the envelope of the Asymptotic Giant Branch (AGB) star, known as a common envelope (CE). The evolution on the AGB would thus be interrupted abruptly, its (still quite) massive envelope fully ejected to form the PN, which should be more massive than a PN coming from the same star were it single. We test this hypothesis by deriving the ionised+molecular masses of a pilot sample of post-CE PNe and comparing them to a regular PNe sample. We find the mass of post-CE PNe to be actually lower, on average, than their regular counterparts, raising some doubts on our understanding of these intriguing objects.

Modelling the Common Envelope Phase in Classical Novae

1990 ◽  
Vol 122 ◽  
pp. 297-298
Author(s):  
Anurag Shankar ◽  
James W. Truran ◽  
Andreas Burkert ◽  
Mario Livio
Keyword(s):  
Angular Momentum ◽  
Mass Loss ◽  
Orbital Plane ◽  
Orbital Energy ◽  
Classical Novae ◽  
Preliminary Results ◽  
Common Envelope ◽  
The Common

AbstractPreliminary results of 1– and 2– dimensional hydrodynamical calculations of the common envelope phase in very slow classical novae are presented. We show that frictional deposition of orbital energy and angular momentum into the envelope can potentially induce mass loss. Specifically, we find that despite rapid initial spin–up of the envelope, ejection of mass in the orbital plane continues at a substantial rate.

scholarly journals The Formation and Evolution of Compact Stars in Binaries

2004 ◽  
Vol 194 ◽  
pp. 81-84
Author(s):  
Ronald E. Taam
Keyword(s):  
Angular Momentum ◽  
Mass Loss ◽  
Crucial Role ◽  
Binary Systems ◽  
Compact Objects ◽  
Compact Stars ◽  
Common Envelope ◽  
Formation And Evolution ◽  
The Common ◽  
Magnetic Braking

AbstractThe stellar evolutionary processes responsible for the formation of compact objects in interacting binary systems and their evolution are described. The common envelope phase plays a crucial role in their formation and angular momentum losses associated with magnetic braking and/or mass loss are important for their evolution. An application of these processes provides the evolutionary link between classes of interacting binary systems.

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 Non-Conservative Evolution of Binary Stars

2011 ◽  
Vol 7 (S282) ◽  
pp. 417-424 ◽  
Author(s):  
Christopher A. Tout
Keyword(s):  
Mass Transfer ◽  
Angular Momentum ◽  
Orbital Angular Momentum ◽  
Stellar Wind ◽  
Binary Stars ◽  
Total Mass ◽  
Accretion Disc ◽  
Strong Wind ◽  
Common Envelope ◽  
Conservative Evolution

AbstractVarious processes can lead to non-conservative evolution in binary stars. Under conservative mass transfer, both the total mass and the orbital angular momentum of the system are conserved. Thus, the transfer of angular momentum between the orbit and the spins of the stars can represent one such effect. Stars generally lose mass and angular momentum in a stellar wind so, even with no interaction, evolution is non-conservative. Indeed, a strong wind can actually drive mass transfer. During Roche lobe overflow itself, mass transfer becomes non-conservative when the companion cannot accrete all the material transferred by the donor. In some cases, material is simply temporarily stored in an accretion disc. In others, the companion may swell up and initiate common envelope evolution. Often the transferred material carries enough angular momentum to spin the companion up to break-up, at which point it could not accrete more. We investigate how this is alleviated by non-conservative evolution.

scholarly journals Contact binaries

1986 ◽  
Vol 118 ◽  
pp. 159-172
Author(s):  
S.M. Ruciński
Keyword(s):  
Angular Momentum ◽  
Convective Zone ◽  
X Rays ◽  
Common Envelope ◽  
Contact Stage ◽  
Orbital Decay ◽  
Angular Momentum Loss ◽  
Contact Binaries ◽  
Contact Binary ◽  
The Common

The most promising mechanism for the formation of contact binaries involves the orbital angular momentum loss (AML) and the resulting orbital decay of detached but close synchronized binaries. The efficiency of magnetic wind braking should abruptly decrease upon formation of a contact binary because of the transformation into a system of earlier spectral type and (possibly) of longer orbital period. The new primary of the contact system should have convective zone thinner than indicated by the surface temperature of the common envelope. The decrease in the coronal (X-rays and radio) activity of contact binaries, which is indeed observed, is used as an agrument that the AML efficiency in contact is relatively low and that the contact stage is considerably prolonged relative to adjacent stages. This small modification to the AML models is capable of explaining why many different contact binaries are observed in old systems like NGC188. The AML evolution is not the only mechanism leading to formation of contact binaries; some of them may have originated via Algol-like evolution. Thus, the observed contact binaries are probably a mixture of systems formed in different ways.

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 Energy and Angular Momentum Deposition During Common Envelope Evolution

2004 ◽  
Vol 194 ◽  
pp. 30-32
Author(s):  
Noam Soker
Keyword(s):  
Angular Momentum ◽  
Mass Loss ◽  
Orbital Angular Momentum ◽  
White Dwarf ◽  
Early Stage ◽  
Mass Loss Rate ◽  
Orbital Energy ◽  
Giant Star ◽  
Common Envelope ◽  
The Common

AbstractI consider three processes which enhance mass loss rate from a common envelope of a giant star with a main sequence or a white dwarf companion spiraling-in inside its envelope. I consider deposition of orbital energy and orbital angular momentum to the giant's envelope, and the formation of jets by an accreting companion and their propagation in the envelope. I find that in many cases the deposition of orbital angular momentum to the envelope may be more important to the mass loss process than the deposition of orbital energy. Jets blown by an accreting companion, in particular a white dwarf, orbiting inside the outer regions of the giant's envelope may also dominate over orbital energy deposition at early stage of the common envelope evolution. These imply that, studies which ignore the deposition of angular momentum to the envelope and the effects of the accreting companion may reach wrong conclusions.

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