scholarly journals Symbiotic Binary Stars

1992 ◽  
Vol 151 ◽  
pp. 137-146
Author(s):  
Scott J. Kenyon
Keyword(s):  
White Dwarf ◽  
Binary Stars ◽  
Main Sequence ◽  
Cataclysmic Variables ◽  
Symbiotic Stars ◽  
Paper Briefly ◽  
Primary Star ◽  
Classical Novae ◽  
Long Period ◽  
Red Giant

This paper briefly reviews the physical properties of symbiotic stars: long-period interacting binaries composed of a red giant primary star and a hot companion. Two types of binaries produce symbiotic optical spectra: semi-detached systems with a main sequence secondary and detached systems with a white dwarf secondary. Semi-detached symbiotics resemble cataclysmic variables and Algol binaries, but on a much larger scale, and undergo dwarf nova-like eruptions. Wind accretion powers detached systems; occasional thermonuclear runaways produce symbiotic novae - distant cousins of classical novae.

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 Infrared and sub-mm observations of cataclysmic variables

2009 ◽  
Vol 5 (H15) ◽  
pp. 553-554
Author(s):  
A. Evans
Keyword(s):  
Main Sequence ◽  
Cataclysmic Variables ◽  
Accretion Disc ◽  
Lagrangian Point ◽  
Primary Star ◽  
Cool Component ◽  
Classical Novae ◽  
Compact Component ◽  
Thermonuclear Runaway ◽  
The Magnetic Field

Although cataclysmic variables (CVs) come in a wide variety of shapes and sizes, the essential ingredients are a compact primary star and a Roche-lobe-filling secondary. In most cases the cool component is a main sequence dwarf, and the compact component a white dwarf (WD). Material from the cool component flows through the inner Lagrangian point via an accretion disc onto the surface of the WD; the flow near the WD is significantly affected by the strength of the magnetic field the WD may have (see Warner for a review of CVs). CVs are characterised by regular eruptions, ranging in energetics and frequency from ‘dwarf novae’, in which eruptions of amplitude ~3-4 mag in the visual occur every few days to weeks, to classical novae (CNe) in which the eruption is explosive, due to thermonuclear runaway (TNR) in material accreted on the surface of the WD (see Bode & Evans for a review of CNe).

scholarly journals Two-dimensional simulations of mixing in classical novae: The effect of white dwarf composition and mass

2018 ◽  
Vol 619 ◽  
pp. A121 ◽  
Author(s):  
Jordi Casanova ◽  
Jordi José ◽  
Steven N. Shore
Keyword(s):  
White Dwarf ◽  
Binary Systems ◽  
Main Sequence ◽  
Chemical Species ◽  
Two Dimensions ◽  
Classical Novae ◽  
Nova Shells ◽  
Solar Abundances ◽  
Low Mass ◽  
Thermonuclear Runaway

Context. Classical novae are explosive phenomena that take place in stellar binary systems. They are powered by mass transfer from a low-mass main sequence star onto either a CO or ONe white dwarf. The material accumulates for 104–105 yr until ignition under degenerate conditions, resulting in a thermonuclear runaway. The nuclear energy released produces peak temperatures of ∼0.1–0.4 GK. During these events, 10−7−10−3 M⊙ enriched in intermediate-mass elements, with respect to solar abundances, are ejected into the interstellar medium. However, the origin of the large metallicity enhancements and the inhomogeneous distribution of chemical species observed in high-resolution spectra of ejected nova shells is not fully understood. Aims. Recent multidimensional simulations have demonstrated that Kelvin-Helmholtz instabilities that operate at the core-envelope interface can naturally produce self-enrichment of the accreted envelope with material from the underlying white dwarf at levels that agree with observations. However, such multidimensional simulations have been performed for a small number of cases and much of the parameter space remains unexplored. Methods. We investigated the dredge-up, driven by Kelvin-Helmholtz instabilities, for white dwarf masses in the range 0.8–1.25 M⊙ and different core compositions, that is, CO-rich and ONe-rich substrates. We present a set of five numerical simulations performed in two dimensions aimed at analyzing the possible impact of the white dwarf mass, and composition, on the metallicity enhancement and explosion characteristics. Results. At the time we stop the simulations, we observe greater mixing (∼30% higher when measured in the same conditions) and more energetic outbursts for ONe-rich substrates than for CO-rich substrates and more massive white dwarfs.

scholarly journals Classical Novae – Before and After Outburst

1988 ◽  
Vol 108 ◽  
pp. 226-231
Author(s):  
Mario Livio
Keyword(s):  
White Dwarf ◽  
Main Sequence ◽  
Orbital Parameters ◽  
Classical Novae ◽  
Classical Nova ◽  
Before And After ◽  
Low Mass ◽  
Orbital Periods ◽  
Thermonuclear Runaway ◽  
Nova Outburst

Classical nova (CN) and dwarf nova (DN) systems have the same binary components (a low-mass main sequence star and a white dwarf) and the same orbital periods. An important question that therefore arises is: are these systems really different ? (and if so, what is the fundamental difference ?) or, are these the same systems, metamorphosing from one class to the other ?The first thing to note in this respect is that the white dwarfs in DN systems are believed to accrete continuously (both at quiescence and during eruptions). At the same time, both analytic (e.g. Fujimoto 1982) and numerical calculations show, that when sufficient mass accumulates on the white dwarf, a thermonuclear runaway (TNR) is obtained and a nova outburst ensues (see e.g. reviews by Gallagher and Starrfield 1978, Truran 1982). It is thus only natural, to ask the question, is the fact that we have not seen a DN undergo a CN outburst (in about 50 years of almost complete coverage) consistent with observations of DN systems ? In an attempt to answer this question, we have calculated the probability for a nova outburst not to occur (in 50 years) in 86 DN systems (for which at least some of the orbital parameters are known).

scholarly journals The Ejecta of Classical Novae

2001 ◽  
Vol 205 ◽  
pp. 260-263
Author(s):  
T.J. O'Brien ◽  
R.J. Davis ◽  
M.F. Bode ◽  
S. P. S. Eyres ◽  
J.M. Porter
Keyword(s):  
Coherent Structures ◽  
White Dwarf ◽  
Binary Stars ◽  
Hubble Space Telescope ◽  
Classical Novae ◽  
Common Envelope ◽  
Physical Mechanisms ◽  
The Common ◽  
Thermonuclear Runaway ◽  
Prolate Ellipsoidal

Classical novae are interacting binary stars in which a thermonuclear runaway in material accreted onto a white dwarf from a companion red dwarf results in the ejection of around 10−4M⊙ at hundreds to thousands of kilometres per second. Recent Hubble Space Telescope and MERLIN imaging of the expanding ejecta from several classical novae are presented. In general the ejecta are clumpy but often display coherent structures, most notably equatorial rings of enhanced emission encircling prolate ellipsoidal shells. Physical mechanisms (including the common envelope phase and anisotropic irradiation of the shell) which may result in the generation of these structures are discussed.

scholarly journals Symbiotic Stars as Possible Progenitors of SNe Ia: Binary Parameters and Overall Outlook

2011 ◽  
Vol 7 (S281) ◽  
pp. 162-165 ◽  
Author(s):  
J. Mikołajewska
Keyword(s):  
White Dwarf ◽  
Physical Characteristics ◽  
Type Ia Supernovae ◽  
Symbiotic Stars ◽  
Type Ia ◽  
Red Giant ◽  
Ia Supernovae

AbstractSymbiotic stars are interacting binaries in which the first-formed white dwarf accretes and burns material from a red giant companion. This paper aims at presenting physical characteristics of these objects and discussing their possible link with progenitors of Type Ia supernovae.

scholarly journals Diagnostic of the Symbiotic Stars Environment by Thomson, Raman and Rayleigh Scattering Processes

2015 ◽  
Vol 2 (1) ◽  
pp. 282-285
Author(s):  
M. Sekeráš ◽  
A. Skopal
Keyword(s):  
White Dwarf ◽  
Rayleigh Scattering ◽  
Neutral Hydrogen ◽  
Circumstellar Matter ◽  
Thomson Scattering ◽  
Symbiotic Stars ◽  
Hydrogen Atoms ◽  
Circumstellar Material ◽  
Long Period ◽  
Ionization Structure

Symbiotic stars are long-period interacting binaries consisting of a cool giant as the donor star and a white dwarf as the acretor. Due to acretion of the material from the giant’s stellar wind, the white dwarf becomes very hot and luminous. The circumstellar material partially ionized by the hot star, represents an ideal medium for processes of scattering. To investigate the symbiotic nebula we modeled the wide wings of the resonance lines OVI λ1032 Å, λ1038 Å and HeII λ1640 Å emission line in the spectrum of AG Dra, broadened by Thomson scattering. On the other hand, Raman and Rayleigh scattering arise in the neutral part of the circumstellar matter around the giant and provide a powerful tool to probe e.g. the ionization structure of the symbiotic systems and distribution of the neutral hydrogen atoms in the giant’s wind.

scholarly journals A million binaries from Gaia eDR3: sample selection and validation of Gaia parallax uncertainties

2021 ◽  
Author(s):  
Kareem El-Badry ◽  
Hans-Walter Rix ◽  
Tyler M Heintz
Keyword(s):  
White Dwarf ◽  
Binary Stars ◽  
Main Sequence ◽  
Sample Selection ◽  
Mass Relation ◽  
The Sun ◽  
The Public ◽  
Spatially Resolved ◽  
The Masses

Abstract We construct from Gaia eDR3 an extensive catalog of spatially resolved binary stars within ≈ 1 kpc of the Sun, with projected separations ranging from a few au to 1 pc. We estimate the probability that each pair is a chance alignment empirically, using the Gaia catalog itself to calculate the rate of chance alignments as a function of observables. The catalog contains 1.3 (1.1) million binaries with >90% (>99%) probability of being bound, including 16,000 white dwarf – main sequence (WD+MS) binaries and 1,400 WD+WD binaries. We make the full catalog publicly available, as well as the queries and code to produce it. We then use this sample to calibrate the published Gaia DR3 parallax uncertainties, making use of the binary components’ near-identical parallaxes. We show that these uncertainties are generally reliable for faint stars (G ≳ 18), but are underestimated significantly for brighter stars. The underestimates are generally $\le 30\%$ for isolated sources with well-behaved astrometry, but are larger (up to ∼80%) for apparently well-behaved sources with a companion within ≲ 4 arcsec, and much larger for sources with poor astrometric fits. We provide an empirical fitting function to inflate published σϖ values for isolated sources. The public catalog offers wide ranging follow-up opportunities: from calibrating spectroscopic surveys, to precisely constraining ages of field stars, to the masses and the initial-final mass relation of white dwarfs, to dynamically probing the Galactic tidal field.

scholarly journals What Can Pre-Main Sequence Binary Star Populations Tell Us about Binary Formation Mechanisms?

2001 ◽  
Vol 200 ◽  
pp. 210-218 ◽  
Author(s):  
Andrea M. Ghez
Keyword(s):  
Star Formation ◽  
Binary Stars ◽  
Main Sequence ◽  
Binary Star ◽  
Open Clusters ◽  
Formation Mechanisms ◽  
Primary Star ◽  
Binary Formation ◽  
Review Current ◽  
Made In

We review current observations of binary star populations with particular attention to what insight these populations can give us into the problem of how binary stars form. Significant progress has been made in the past few years, revealing variations as a function of site, primary star mass, and binary star separations. The variations in the binary star population with type of star formation site in comparison with the field, suggests that ∼30% of the field binaries formed in loose T associations and ∼70% formed in the dense progenitors of open clusters. Variations with mass and separation on the whole are well matched by the predictions of fragmentation followed by competitive accretion. However, there remains much work to be done on both the observational and theoretical end before a complete picture of binary star formation can be developed.

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).

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