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1.
We review various aspects of the evolutionary history of massive X-ray binaries. It is expected that moderately massive close binaries evolve to Be X-ray binaries, while very massive systems evolve to standard X-ray binaries.The compact objects are formed through supernova explosions. The fairly low galactic latitudes of those systems indicate that the explosion should, in general, not have accelerated the system to a velocity larger than 50kms–1. This implies that the mass of the exploding stars is in general less than 5 to 6M .After the explosion, tidal forces will circularize the orbit of short period systems. Even if the tidal evolution has been completed, the expansion of the optical star during the course of its evolution will continously disturb the stability of the orbit. Short period systems with large mass ratio may eventually become tidally unstable. Cen X-3 may be an example of such a system. The predicted rate of the orbital period decrease of Cen X-3 is in agreement with the observed rate.A way to represent the rotational and magnetic evolution of neutron stars in close binary systems is presented. The observed distribution of the pulsation periods of X-ray pulsars with Be companions is consistent with initial magnetic fields of 1012–1013 G of the neutron stars. We suggest that the fast X-ray pulsars 4U 0115+63 and A 0538-66 are young neutron stars, while Cen X-3 and SMC X-1 are recycled pulsars.The evolutionary relationship between massive X-ray binaries, binary pulsars, and millisecond pulsars is also discussed.Invited paper presented at the IAU Third Asian-Pacific Regional Meeting, held in Kyoto, Japan, between 30 September–6 October, 1984.  相似文献   

2.
Main results of computations of evolution for massive close binaries (10M +9.4M , 16M +15M , 32M +30M , 64M +60M ) up to oxygen exhaustion in the core are described. Mass exchange starting in core hydrogen, shell hydrogen and core helium burning stages was studied. Computations were performed assuming both the Ledoux and Schwarzschild stability criteria for semiconvection. The influence of UFI-neutrino emission on evolution of close binaries was investigated. The results obtained allow to outline the following evolutionary chain: two detached Main-Sequence stars — mass exchange — Wolf-Rayet star or blue supergiant plus main sequence star — explosion of the initially more massive star appearing as a supernova event — collapsed or neutron star plus Main-Sequence star, that may be observed as a runaway star — mass exchange leading to X-rays emission — collapsed or neutron star plus WR-star or blue supergiant — second explosion of supernova that preferentially disrupts the system and gives birth to two single high spatial velocity pulsars.Numerical estimates concerning the number and properties of WR-stars, pulsars and X-ray sources are presented. The results are in favour of the existence of UFI-neutrino and of the Ledoux criterion for describing semiconvection. Properties of several well-known X-ray sources and the binary pulsar are discussed on base of evolutionary chain of close binaries.  相似文献   

3.
The lifetime of massive X-ray binaries is (2–5)×105 yr, this time close to the nuclear one. The lifetime of nonmassive X-ray binaries close to thermal one, (0.5–1)×107 yr. Massive systems may be conserved at supernova explosion, the probability of the conservation of nonmassive system is (1–3)×10–3.  相似文献   

4.
In this paper we calculate the number of close binaries formed during the evolution process of a globular cluster core. The globular cluster core is assumed to contain a massive black hole at its center. We show that the central black hole can drive binaries formation in the core and the rate of binaries formation depends on the mass of the black hole at its center. When the massM of the black hole is between 102 M and 3×103 M , there will be a few binaries formed. When the mass of the black hole is 4×103 M M6×103 M , the number of binary star formation will suddenly increase with a jump to the maximum value 58. When the mass of the black hole is 7×103 M M9×103 M , the number of binary star will immediately decrease. Whether cluster X-ray is produced mainly by the central black hole or by binaries in the core depends on the mass of the central black hole. Therefore, two cases arise: namely, black hole accretion domination and binaries radiation domination. We do think that we cannot exclude the possibility of the existence of a central black hole even when binary radiation characteristics have been observed in globular cluster X-ray sources.  相似文献   

5.
The evolution of close binary systems was followed for ten systems with the initial mass of the primary in the range 1–4M and with different initial mass ratios and initial separations. A brief discussion of the evolution of the contact component is presented for two separate cases: when the primary reaches its Roche lobe during central hydrogen burning (case A) and after the exhaustion of hydrogen in the center (case B).The models obtained are compared with observed semi-detached systems separately for massive (with total mass greater than 5M ) and low mass (with total mass below 4M ) binaries. It is shown that the contact components of the observed massive binaries are probably burning hydrogen in the core. On the contrary, the majority of contact components of the observed low-mass binaries are burning hydrogen in the shell. The observed distribution of such binaries as a function of different luminosity excesses of contact components seems to indicate that their origin is connected with case A rather than with case B.  相似文献   

6.
Comparison of the characteristics of groups of stars in various evolutionary phases and the study of individual systems allow to make estimates of the parameters governing mass loss and mass transfer. Observations enable us in a few cases to determine geometric models for binaries during or after the mass transfer phase (disks, rings, common envelopes, symbiotics, interacting binaries, compact components).From spectra taken at different phases, radial velocity curves can be derived and masses and radii can be determined. In special cases spectra in different spectral ranges (visual, UV, X-ray) are required for the determination of the radial velocities of the two components (for X-ray binaries, for systems with hot and cool components). Information on parameters related to the mass transfer process enables us to consider non conservative evolution — i.e. the computation of evolutionary sequences with the assumption that mass and angular momentum not only are transferred from one of the components towards the other one, but that also mass and angular momentum can leave the system. Careful and detailed analysis of the observations allows in certain cases to determine the parameters governing this mass and angular momentum loss, and for contact phases, to determine the degree of contact.Paper presented at the Lembang-Bamberg IAU Colloquium No. 80 on Double Stars: Physical Properties and Generic Relations, held at Bandung, Indonesia, 3–7 June, 1983.  相似文献   

7.
Close binaries can evolve through various ways of interaction into compact objects (white dwarfs, neutron stars, black holes). Massive binary systems (mass of the primaryM 1 larger than 14 to 15M 0) are expected to leave, after the first stage of mass transfer a compact component orbiting a massive star. These systems evolve during subsequent stages into massive X-ray binaries. Systems with initial large periode evolve into Be X-ray binaries.Low mass X-ray sources are probably descendants of lower mass stars, and various channels for their production are indicated. The evolution of massive close binaries is examined in detail and different X-ray stages are discussed. It is argued that a first X-ray stage is followed by a reverse extensive mass transfer, leading to systems like SS 433, Cir X1. During further evolution these systems would become Wolf-Rayet runaways. Due to spiral in these system would then further evolve into ultra short X-ray binaries like Cyg X-3.Finally the explosion of the secondary will in most cases disrupt the system. In an exceptional case the system remains bound, leading to binary pulsars like PSR 1913+16. In such systems the orbit will shrink due to gravitational radiation and finally the two neutron stars will coalesce. It is argued that the millisecond pulsar PSR 1937+214 could be formed in this way.A complete scheme starting from two massive ZAMS stars, ending with a millisecond pulsar is presented.Paper presented at the Lembang-Bamberg IAU Colloquium No. 80 on Double Stars: Physical Properties and Generic Relations, held at Bandung, Indonesia 3–7 June, 1983.  相似文献   

8.
The post-RLOF structure of the secondary after relaxation towards thermal equilibrium is calculated for a large grid of massive close binaries evolving through an early caseB of mass transfer. The initial primary masses range between 15 and 30M o, the initial mass ratio between 0.3 and 0.9. The possibility that matter leaves the system during RLOF is included using an additional free parameter . The calculations are based on the accretion and relaxation properties of massive accretion stars. Conclusions on the post-RLOF secondaries are presented in function of , M1i, andq i , in the form of tables and figures on the post-RLOF positions in the HR diagram, the final masses, mass ratios, chemical profiles and the remaining core-hydrogen burning lifetime. It is found that all systems starting from initial conditions in the grid specified above evolve sequentially, i.e. the primary evolves into a supernova before the end of core H burning of the secondary. No WR+WR systems are encountered. The results are used to determine the masses of ten double lined spectroscopic WR+OB binaries. Most of the WR masses are in the range 8–14M o, although the sample is subject to some important selection effects. One WR+OB binary has a WR mass between 4 and 5M o. It is argued that mass determinations based only on the spectral type of the secondary yield WR masses that are too high up to a factor two.  相似文献   

9.
The pulse-period distribution of binary X-ray pulsars has been considered. A gap in this distribution, in the period rangeP10 s toP100s has been explained in terms of the character of mass transfer in the X-ray binary systems. It is shown that this gap arises because the rotating magnetised neutron stars in these systems are slowed down by accretion torques, either toP10 s when the mass transfer is by means of Roche-lobe overflow in low mass binaries, or toP100 s by stellar winds in massive binaries. The gap is maintained as the slow pulsars (P>100 s) in their spin-up phase cross the gap in a time short compared to their life-time, because of the increase in mass transfer with the evolution of the normal star.  相似文献   

10.
Consideration is given to a search for relativistic objects in massive close binary systems without strong X-ray emission (L x <1034 erg s–1). It is pointed out that, according to the present-day theory on the evolution of massive close binaries, the number of neutron stars and black holes in non-X-ray binary systems must be 100 times the number of the known X-ray binaries comprising OB supergiant stars; that is why, in studying non-X-ray binary systems, the chances are to detect about a hundred of black holes in the Galaxy.Criteria are formulated for the relativistic nature of companions in the binary systems, such as high spatial velocity values and height Z over the galactic plane for OB stars (runaway stars) and for Wolf-Rayet stars. As reported by Tutukov and Yungelson (1973), as well as by van den Heuvel (1976), the presence of ring-type nebulae can serve as another indication of a relativistic nature of companions in the case of Wolf-Rayet stars.Data are collected on Wolf-Rayet stars with low-mass companions (Table I), which can be relativistic objects accreting within a strong stellar wind from Wolf-Rayet stars. Presented are new findings in respect of spectral examination of the runaway OB-stars (Table II), bringing together data on eight OB stars which can represent binary systems with relativistic companions (Table III).A list of 28 OB-stars (Table IV) which offer a good chance for finding relativistic companions is given.  相似文献   

11.
The remaining core hydrogen burning lifetime after case B of mass transfer of the secondary (mass gaining) component in a medium mass close binary star is estimated, for mediummass binaries with primaries in the mass range 5M to 9M . From the comparison of this quantity with the helium burning time-scale of the remnant primary a critical mass ratioq c is derived such that for larger values ofq, mass transfer from the secondary towards the primary starts before the latter has evolved into a white dwarf. Consequences for the advanced stages of medium mass binaries are discussed.  相似文献   

12.
The virial theorem in tensor form for subsystems is used to determine equilibrium configurations of two-component, concentric and copolar, homogeneous spheroids, one completely lying within the other. Then the related total energy and angular momenta are expressed explicitly as functions of the mass ratio,m, the equatorial axis ratio,y, the polar to equatorial axis ratios, U , the rotation parameters, rotU , and the anisotropy parameters, pecU . With assigned masses, angular momenta, total energy, rotation parameters, and anisotropy parameters, there remain three independent equations and four unknowns, i.e. equatorial semiaxes and (polar to equatorial) axis ratios. To get a unique solution, and then describe the quasi-static collapse (via energy dissipation) of the inner subsystem within the halo, a number of alternative additional conditions are taken into consideration. It is also argued that the true situation, involving neither homogeneous nor spheroidal halos, lies between two extreme cases, namely: (i) the two subsystems collapse together with coinciding boundaries, and (ii) halos depart only faintly, or not at all, from the related initial configurations. Starting from systems with coinciding boundaries and specific angular momenta, the related evolutionary sequences are derived by substantial improvement of previous attempts. Some limiting situations are also considered, where the mass of one subsystem tends to zero and/or the mass of the other one tends to infinite. An application of the theory to systems of galactic mass and plausible other parameters shows that (i) initial configurations depend on the total mass and final (with a flat inner component) configurations depend on the mass of the collapsing visible body; (ii) quasi-static collapse depends mainly on the mass ratio,m, for given total masses and angular momenta, while the action of different additional conditions is negligible; (iii) halos as massive as about ten visible bodies depart from the initial configuration by no more than a few percents, using different additional conditions, and yield (for fiduciary values related to the Galaxy, i.e. total mass 1012 M , total angular momentum 1075 g cm2 s–1) final configurations related to flat visible bodies with equatorial semiaxes of about 15 kpc, close to observations.  相似文献   

13.
Quasi-periodic outburst activity is not uncommon among Population II X-ray binaries. This paper reports observations of such activity in several sources, made by the Vela 5B X-ray monitor. Typical periods are 1/2–2 years with an r.m.s. scatter in interval time of 10%. This activity is reminiscent of the superoutburst cycles of SU UMa CV's with respect to mean recurrence times, the variation of the recurrence times about their mean, and the total mass transferred during outburst. However, the outbursts in the X-ray sources have a substantially longer duration, 50–100 days instead of 10 days. I suggest that SU UMa and X-ray transient outbursts may be caused by similar mass-transfer instabilities.  相似文献   

14.
We report results on three low-mass X-ray binaries (LMXB) in the LMC, obtained with EXOSAT, IUE and ground-based (ESO) telescopes: LMC X-2 which appears to be Sco X-1-like, LHG 83 and LHG 87. The latter are two weaker sources first detected in the course of the HEAO-B LMC survey. They have faint optical counterparts of which LHG 87 was only recently identified by us. In X-rays, they are characterized by ultrasoft X-ray spectra possibly characteristic of black-hole primaries. LHG 83 furthermore shows evidence for X-ray ionization of the surrounding interstellar medium, similar to the He III region around the black-hole candidate LMC X-1. X-ray binaries with masses of compact objects in excess of 3 M and ultrasoft X-ray spectra are comparatively frequent in the LMC. We suggest that subcritical accretion onto black holes takes place in LHG 83 and LHG 87.Paper presented at the IAU Colloquium No. 93 on Cataclysmic Variables. Recent Multi-Frequency Observations and Theoretical Developments, held at Dr. Remeis-Sternwarte Bamberg, F.R.G., 16–19 June, 1986.  相似文献   

15.
Nearby visual binaries, with both components on the Main Sequence, have been considered in order to obtain information about the distribution of their mass ratios. These systems have their primary components ranging from A0 to G9. The data have been corrected for selection effects and the differences V of the visual magnitudes have been transformed into mass-ratio values.The frequency distribution of the mass ratios appears to be bimodal, with a peak around unity and a maximum at about 0.25. It is suggested that this feature may be indicative of different mechanisms of formation for wide binaries.  相似文献   

16.
A new sample of possibly massive early-type emission-line stars (METELS) based on the previous lists of peculiar Be stars is presented. It consists of 36 objects divided amongst supergiants, possible binaries, and candidates to the list. The central stars are probably more massive than 10M . Two new relations allowing idientification of possible binaries among the objects are proposed.  相似文献   

17.
The initial discovery of soft X-rays from Nova Muscae 1983 was followed by eight additional observations of the three brightest novae whose outburst stage coincided with the lifetime ofEXOSAT satellite; namely three more observations of Nova Muscae 1983, three observations of Nova Vulpeculae 1984#1 (PW Vul), and two observations of Nova Vulpeculae 1984#2. Through these observations we sampled the soft X-ray light curve of classical novae from optical maximum to 900 days after. The observations seem best explained by the constant bolometric luminosity model of a hot white dwarf remnant. Although the measurements suffer from limited statistics, very broad energy bandpass, and incomplete sampling of any single nova, their constraints on the theories of nova outburst are significant. One constraint is that the lifetime of the white dwarf remnant in Nova Muscae 1983 is 2 to 3 years, which leads to the conclusion that the burned envelope massM burn should be of the order of . The second constraint is that the maximum temperature, of the white dwarf remnant should approximately be within 200 000 K to 400 000 K. We estimate that a white dwarf remnant evolving like the central star of a planetary nebula, with core mass of 0.8 to 0.9M , core luminosity of 2×104 L , and envelope mass of 10–6 M , can explain the general characteristics of the X-ray measurements for Nova Muscae 1983. In order to have 1.1M core mass, estimated from the early observations of bolometric luminosity in the UV to infrared range, a wind withM5×10–7 M yr–1 appears to be necessary. The few observations of Nova Vulpeculae 1984 #1 and Nova Vulpeculae 1984#2, during the first year after outburst, give a risetime and intensity that is consistent with a constant bolometric luminosity model.Paper presented at the IAU Colloquium No. 93 on Cataclysmic Variables. Recent Multi-Frequency Observations and Theoretical Developments, held at Dr. Remeis-Sternwarte Bamberg, F. R. G., 16–19 June, 1986.  相似文献   

18.
Evolution of close binaries is investigated in which the more massive component has a mass of 5m and reaches the Roche limit when hydrogen is burning in its convective core. It is shown that a large-scale mass transfer occurs, during which the initial primary develops into a contact subgiant or giant, and the mass ratio is reversed or more than reversed.Although the process and its outcome depend on the initial conditions, in particular on the degree of chemical inhomogeneity in the interior of the primary component, the picture of evolution is essentially the same. We can distinguish and describe quantitatively the following phases: (1) Premain-sequence contraction, when the less massive component is an undersize subgiant. (2) Both components are on the main sequence. (3) Rapid mass exchange, when the roles of the components are interchanged. (4) Slow mass transfer, when the system is semi-detached; this phase is typical for the Algol-like binaries. Further evolution depends on the rate of evolution of the components: either we get another phase with an undersize subgiant, or a complicated system in which both stars lose mass. Probabilities of discovery are calculated for the various phases of evolution.The paper is based on the calculations of stellar models with decreasing mass by means of Henyey's method.  相似文献   

19.
A supplement to the theory of analytical continuation of circular orbits in the restricted three-body problem is presented. The first order stability is given analytically to the first power of mass parameter . The theory of the Kirkwood gaps is discussed from this point of view. The stability limit which should determine the size of accretion discs in binaries is found to be in good agreement with earlier numerical experiments for < 1/2.  相似文献   

20.
The correlations angular momentaL to massesM are studied for different types of spectroscopic binaries. The functionsL=AM b have the coefficientb with the values expected from a Keplerian mechanics, but the valuesA(q, T), A(q, a), A(q, v), associated tob=5/3, 3/2, and 2, respectively, are given (statistically speaking) by multiples or submultiples of discrete values of: the mass ratiosq, the semi-major axesa, periodsT, and velocitiesv of the reduced mass. This indicates the existence of a discrete unit of actionL=(1/2)×potential energy xperiod. Postulates about equivalent states of angular momenta for different orbital parameters are introduced, being this coherent with the analysis of the up-to-date data. Among other examples of the application of such equivalence postulates, we haveL(M) (W-type of the WUMa systems)L(M) (main group of the Algol binaries). The quantum units of action seen here are equivalent to those seen in the solar system in one of our previous works. From comparisons with galaxies and single stars, it is evidence that there is not an unique universal functionL=AM b, when the fine structure of the relation is analysed: each type of object has its own coefficients,A, b. It sems to be that there are an upper and a lower limit for all the possible functions. The upper limit isL=A gM5/3, withA g1 associated to periodsT Hubble time, and the lower limit isL=GM 2/c, with 1. The existence of the upper limit can be investigated with studies of pairs of galaxies, and the lower limit can be tested with analysis of single G, K, M stars. The quantical hypothesis introduced here can be checked definitely, when available larger samples of data with low errors, with similar quality as the selected list of almost 80 eclipsing binaries (mainly detached systems) analysed here.  相似文献   

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