scholarly journals Non-Conservative Mass Exchange and Origin of X-Ray Close Binaries

1980 ◽  
Vol 88 ◽  
pp. 323-327
Author(s):  
Daiichiro Sugimoto ◽  
Shigeki Miyaji
Keyword(s):  
Mass Exchange ◽  
Binary Systems ◽  
Close Binary ◽  
Close Binaries ◽  
Type I ◽  
Optical Components ◽  
X Ray ◽  
Early Type Star ◽  
Orbital Periods ◽  
The Masses

Recently, masses of component stars have been determined for many X-ray close binaries (XCBS). For relatively well determined sources the masses of X-ray components are plotted against the masses of their optical components in Figure 1 and their orbital periods are summarized in Table 1 (Cowley 1977; Bradt, Doxsey, and Jernigan 1979; Wheeler 1978; and references quoted therein). Cowley (1977) prepared a table and noticed that there are two distinct types of XCBS. The Type I XCBS consists of an X-ray star and an early type star more massive than about 12 M⊙. On the contrary, the Type II XCBS consists of an X-ray star and a star less massive than about 2 M⊙. As seen in Figure 1, there is not any distinct intermediate type for which the mass of the optical component lies in the range of about 2-12 M⊙. The aim of the present paper lies in interpreting the origin of these types of XCBS on the bases of the conditions for the formation of a neutron star and of mass exchange in close binary systems.

scholarly journals Late Stages of Close Binary Systems

1976 ◽  
Vol 73 ◽  
pp. 35-61 ◽  
Author(s):  
E. P. J. Van Den Heuvel
Keyword(s):  
Angular Momentum ◽  
Mass Exchange ◽  
Binary Systems ◽  
Main Sequence ◽  
Supernova Explosion ◽  
Compact Stars ◽  
Close Binary ◽  
Close Binaries ◽  
X Ray ◽  
Loss Of Mass

The expected final evolution of massive close binaries (CB) in case B is reviewed. Primary stars with masses ≳ 12–15 M⊙ are, after loosing most of their envelope by mass exchange, expected to explode as supernovae, leaving behind a neutron star or a black hole.Conservative close binary evolution (i.e. without a major loss of mass and angular momentum from the system during the first stage of mass transfer) is expected to occur if the initial mass ratio q0 = M20/M10 is ≳ 0.3. In this case the primary star will be the less massive component when it explodes, and the system is almost never disrupted by the explosion. The explosion is followed by a long-lasting quiet stage (106–107 yr) when the system consists of a massive main-sequence star and an inactive compact companion. After the secondary has left the main-sequence and becomes a blue supergiant with a strong stellar wind, the system becomes a massive X-ray binary for a short while (2–5 × 104 yr).The numbers of Wolf-Rayet binaries and massive X-ray binaries observed within 3 kpc of the Sun are in reasonable agreement with the numbers expected on the basis of conservative CB evolution, which implies that several thousands of massive main-sequence stars with a quiet compact companion should exist in the Galaxy. About a dozen of these systems must be present among the stars visible to the naked eye. During the second stage of mass exchange, large loss of mass and angular momentum from the system is expected, leading to a rapid shrinking of the orbit. The supernova explosion of the secondary will in most cases disrupt the system. If it remains bound, the final system will consist of two compact stars and may resemble the binary pulsar PSR 1913 + 16.In systems with q0 ≲ 0.2–0.3 large mass loss from the system is expected during the first stage of mass exchange. The exploding primary will then be more massive than its unevolved companion and the first supernova explosion disrupts the system in most cases. In the rare cases that it remains bound, the system will have a large runaway velocity and, after a very long (108–109 yr) inactive stage evolves into a low-mass X-ray binary, possibly resembling Her X-1.

scholarly journals X-Ray Sources in Close Binary Systems

1974 ◽  
Vol 3 ◽  
pp. 89-107
Author(s):  
M. J. Rees
Keyword(s):  
Binary Systems ◽  
Close Binary ◽  
Rapid Variability ◽  
X Ray ◽  
Close Binary Systems ◽  
General Order ◽  
Typical Distances ◽  
Astronomical Research ◽  
Orbital Periods ◽  
Galactic Sources

The discovery by Giacconi and his colleagues of variable X-ray sources in close binary systems certainly ranks as one of the highlights of astronomical research during the last 3 years. These remarkable objects have already been extensively studied, by optical and radio observations as well as in the X-ray band; and they seem likely to prove as significant and far-reaching in their implications as pulsars.The ‘Third Uhuru Catalogue’ (Giacconi et al., 1973a) contains about 160 sources, of which about 100 lie in our Galaxy. Their distribution over the sky (together with other arguments) suggests that these sources have luminosities of the general order 1036–1038 erg s−1, and that their typical distances are ˜ 10kpc. These galactic sources generally display rapid variability. Little else is known about most of them, but they are probably of the same general class as systems such as Her X1, Cen X3, Cyg X1 and Cyg X3. These sources have been investigated in detail, and in all cases one infers a system where the X-ray source is orbiting around a relatively ordinary star. Six sources have been optically identified, and there are some others whose binary nature is established by the occurrence of an X-ray eclipse. Orbital periods range from 4.8 h (Cyg X3) up to ˜ 10 days.

scholarly journals Radio Aspects of Stellar Activity in Close Binaries

1980 ◽  
Vol 5 ◽  
pp. 857-857 ◽  
Author(s):  
R. M. Hjellming
Keyword(s):  
Circular Polarization ◽  
Binary Systems ◽  
Close Binary ◽  
Close Binaries ◽  
Radiation Mechanisms ◽  
Dynamo Action ◽  
Stellar Activity ◽  
X Ray ◽  
Close Binary Systems ◽  
Decay Times

Excluding single stars, star systems with very strong X-ray sources, thermally radiating winds and circumstellar envelopes, marginal detections, and binary systems that are far from “normal”, there are about 21 close binary systems that show clear signs of stellar activity in the form of variable radio emission. Sixteen of these are RS CVn binaries. Typical events are smoothly varying with time scales of from a few hours to a few days. In the RS CVn binaries UX Ari and V711 Tau variable circular polarization is sometimes observed, with occasional appearence of components with only one frequency and one circular polarization, part of which shows “oscillations” with “periods” of about 4 minutes. Different stars and different events typically have inferred electron energies of about 5 MeV and inferred magnetic fields of 1 - 30 Gauss. The radiation mechanisms are usually assumed to be synchrotron or gyro-synchrotron; however, radiation from plasma processes cannot be ruled out in some cases, and it will be very important to establish or rule out this possibility. Most radio binary events show clear signs of self-absorption, so the variations appear most strongly at the higher frequencies. Typical rise times of events are about 30% of decay times. Maximum radio luminosities range from 1013 to a few times 1017 ergs s-1 Hz-1. Most radio flares are mainly at cm-wavelenghts and have observable and inferred energies 104 - 106 times those for the largest solar events, a scaling which is similar to that for X-ray emission measures of these stars when compared to solar coronal loop emission measures. Most importantly, VLBI measurements of Algol indicate that the sizes of the radio emitting regions for very strong events are of the order of 2 - 3 stellar radii. Single stars appear to be active at radio wavelengths much less commonly than close binary systems. In many cases this may be due to the way dynamo action and convection near the surface are affected by increased rotation forced by the synchronization induced by the binary system.

Origin of Very-Short Orbital-Period Binary Systems

1983 ◽  
Vol 72 ◽  
pp. 263-267
Author(s):  
Shigeki Miyaji
Keyword(s):  
Binary System ◽  
Globular Cluster ◽  
Orbital Period ◽  
Binary Systems ◽  
Main Sequence ◽  
Cataclysmic Variables ◽  
Close Binaries ◽  
X Ray ◽  
Evolutionary Scenario ◽  
Orbital Periods

Recent observations of four close binaries have established that there is a group of very-short orbital-period (VSOP) binaries whose orbital periods are less than 60 minutes. The VSOP binaries consist of both x-ray close binaries (4U1626-67; Middleditch et al. 1981 and 4U1916 -0.5; White and Swank 1982) and cataclysmic variables (AM CVn; Faulkner et al. 1972 and G61-29; Nather et al. 1981). Their orbital periods are too short to have a main-sequence companion. However, four binaries, none of them belongs to any globular cluster, are too abundant to be explained by capturing mechanism of a white dwarf. Therefore it seemed to be worth to present an evolutionary scenario from an original binary system which can be applied for all of VSOP binaries.

scholarly journals Collapse of White Dwarfs in Close Binary Systems

1979 ◽  
Vol 53 ◽  
pp. 52-55
Author(s):  
R. Canal ◽  
J. Isern
Keyword(s):  
Neutron Star ◽  
White Dwarf ◽  
Binary Systems ◽  
Critical Density ◽  
Close Binary ◽  
Type I ◽  
X Ray ◽  
Close Binary Systems ◽  
Chandrasekhar Limit ◽  
Thermonuclear Runaway

The presence of neutron stars in close binary systems, shown by the pulsating X-ray sources, poses the problem of their origin. In the case of the low-mass (M1 + M2 ≤ 5 M⊙) X-ray binaries, the neutron star might have originated from a massive white dwarf, driven over the Chandrasekhar limit by mass transfer (Schatzman 1974). A similar scenario had been put forward by Whelan and Iben (1973) for type I supernovae. To solve the problem of the very low eccentricities observed for the orbits, and to facilitate keeping the system bound after neutron star formation, Canal and Schatzman (1976) suggested a non explosive collapse of the white dwarf to a neutron star. The occurence of this kind of collapse depended on the possibility of avoiding thermonuclear ignition by means of neutronization. Since there is a density interval where the electron captures on carbon go faster than the pycnonuclear reactions, just above the critical density for the beginning of the collapse, there seemed also to be a chance of escape from thermonuclear runaway. A closer examination of this picture leads, however, to significant changes.

scholarly journals Evolutionary Models For Be X-Ray Binaries

1987 ◽  
Vol 92 ◽  
pp. 514-515
Author(s):  
C. de Loore ◽  
C. H. B. Sybesma
Keyword(s):  
Spectral Type ◽  
Compact Star ◽  
Evolutionary Models ◽  
Optical Components ◽  
X Ray ◽  
Orbital Periods ◽  
The Masses ◽  
X Ray Binaries

Be X-ray binaries have the following general characteristics of interest for evolutionary scenarios: the spectral type of the non-compact star is B2 - 09 (e), the orbital periods are large, ranging from 16 to 581 days, the orbital eccentricities can be large, which could be related to the fact that the X-ray stages are transient; the masses of the optical components range from 10 to 20 M⊙ and their radii are relatively small (5 - 10 R⊙). The optical luminosity is lower than 3 x 10 4L⊙.

scholarly journals Binary X-Ray Stars and Supernovae of Type I

1976 ◽  
Vol 73 ◽  
pp. 19-25
Author(s):  
H. Gursky
Keyword(s):  
Black Hole ◽  
Neutron Star ◽  
White Dwarf ◽  
Binary Systems ◽  
Close Binary ◽  
Type I ◽  
Mass Limit ◽  
X Ray ◽  
Close Binary Systems ◽  
Low Mass

Most of the strong galactic X-ray sources must be low mass, close binary systems, such as Her X-1 and Sco X-1. Two evolutionary scenarios are discussed, both involving type I supernovae that occur when mass-accreting white dwarfs are driven over their mass limit. In one, accepting the correctness of the idea that a neutron star or black hole is the seat of the X-ray emission, the SN occurs before the system is an X-ray source. Another possibility is that the white dwarf is the X-ray source, just prior to its collapse and the ensuing SN.

Searching for Long-Period Binary Central Stars of Planetary Nebulae with SALT HRS

2017 ◽  
Vol 14 (S339) ◽  
pp. 330-330
Author(s):  
B. Miszalski ◽  
R. Manick ◽  
J. Mikołajewska ◽  
K. Iłkiewicz ◽  
D. Kamath ◽  
...  
Keyword(s):  
Binary Stars ◽  
Binary Systems ◽  
Binary Star ◽  
Planetary Nebulae ◽  
Close Binary ◽  
Close Binaries ◽  
Long Period ◽  
Orbital Periods ◽  
The Many ◽  
Made In

AbstractIn the last decade great strides have been made in understanding the role of binary stars in the evolution and shaping of planetary nebulæ (PNe). Observational efforts have mainly focused on finding close binaries with orbital periods of 1 day or less. Those close binary systems make up around 1 in 5 PNe, and constitute the youngest accessible window into the aftermath of the critical and unobserved common-envelope (CE) phase of binary-star evolution. The poster focused on our recent work with the High Resolution Spectrograph (HRS) on the Southern African Large Telescope (SALT) to search for long-period binaries in PNe. Considerably less is known about such long-period binaries with orbital periods of weeks to years, but they may be fundamental to improving CE population synthesis models and for determining the total binary fraction of PNe. The queue-mode operation of SALT and the excellent sensitivity and stability of HRS (which is enclosed in a vacuum tank) are ideally suited to detecting binaries with low radial-velocity amplitudes over the expected timescales of weeks to years. Many exciting new discoveries about binaries have already been made in this newly-accessible southern horizon in time-domain astronomy thanks to the many unique advantages of SALT.

The Formation and Evolution of Low-Mass Close Binaries with Compact Components

1987 ◽  
Vol 93 ◽  
pp. 15-33
Author(s):  
A.V. Tutukov ◽  
L.R. Yungelson
Keyword(s):  
Neutron Star ◽  
Mass Exchange ◽  
Stellar Wind ◽  
Close Binary ◽  
Close Binaries ◽  
Evolutionary Status ◽  
Contact Phase ◽  
Low Mass ◽  
Formation And Evolution ◽  
Orbital Periods

AbstractWe discuss the formation and evolution of interacting low-mass close binaries with a He-ICO- or ONe-dwarf neutron star or a black hole as a compact component. Mass exchange leads to cataclysmic events in such systems. The rate of semidetached low-mass close binary formation is 5×10−3 yr−1 if the accreting component is a He degenerate dwarf, 5×10−3 yr−1 if it is a CO-dwarf and 3×10−8 yr−1 if it is a neutron star. Systems with compact accretors arise as the result of the common envelope phase of close binary evolution or due to collisions of single neutron stars or dwarfs with low-mass single stars in dense stellar clusters. Evolution of LMCB to the contact phase in semi-detached stages is determined mainly by the angular momentum losses by a magnetic stellar wind and radiation of gravitational waves. Numerical computations of evolution with momentum loss explain observed mass exchange rates in such systems, the absence of cataclysmic variables with orbital periods 2h−3h, the low number and the evolutionary status of systems with orbital periods shorter than 80m. In conclusion we list unsolved problems related to magnetic stellar wind, the distribution of young close binaries over main initial parameters, stability of mass exchange.

scholarly journals Conditions for accretion disc formation and observability of wind-accreting X-ray binaries

2021 ◽  
Vol 38 ◽  
Author(s):  
Ryosuke Hirai ◽  
Ilya Mandel
Keyword(s):  
Angular Momentum ◽  
Binary Systems ◽  
Filling Factor ◽  
Accretion Disc ◽  
Roche Lobe ◽  
High Mass ◽  
Close Binary ◽  
Close Binaries ◽  
X Ray ◽  
X Ray Binaries

Abstract We explore the effect of anisotropic wind driving on the properties of accretion onto black holes (BHs) in close binaries. We specifically focus on line-driven winds, which are common in high-mass X-ray binaries (HMXBs). In close binary systems, the tidal force from the companion star can modify the wind structure in two different ways. One is the reduction of wind terminal velocity due to the weaker effective surface gravity. The other is the reduction in mass flux due to gravity darkening (GD). We incorporate these effects into the so-called CAK theory in a simple way and investigate the wind flow around the accretor on the orbital scale. We find that a focused accretion stream is naturally formed when the Roche lobe filling factor is ${\gtrsim}0.8$ –0.9, analogous to that of wind Roche lobe overflow, but only when the velocity reduction is taken into account. The formation of a stream is necessary to bring in sufficient angular momentum to form an accretion disc around the BH. GD effects reduce the amount of accreted angular momentum, but not enough to prevent the formation of a disc. Based on these results, we expect there to be a discrete step in the observability of HMXBs depending on whether the donor Roche lobe filling factor is below or above ${\sim}$ 0.8–0.9.

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