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 Observations and Evolutionary Scenario For Be/X-Ray Binaries

1987 ◽  
Vol 92 ◽  
pp. 509-513
Author(s):  
G.M.H.J. Habets
Keyword(s):  
Close Binaries ◽  
Disk Accretion ◽  
Primary Star ◽  
X Ray ◽  
Period Distribution ◽  
Evolutionary Scenario ◽  
M 10 ◽  
Be Star ◽  
Orbital Periods ◽  
X Ray Binaries

Rappaport & Van den Heuvel (1982) suggested the following formation scenario for B emission (Be)/X-ray binaries: the progenitor of the neutron star is the initial primary star with mass M1 = 10-20 M⊙, which during hydrogen-shell burning transfers mass to the companion (with M2 < M1). The secondary is spun up due to disk-accretion (e.g. Packet 1981) and has become a rapidly rotating Be star (M ≃ 10-20 M⊙).With this scenario the observed orbital periods (Porb > 15 d) of the Be/X-ray binaries can be explained. This was shown by van den Heuvel (1983) by adopting an idealized period distribution for unevolved O- and B-type close binaries with Porb, < 30 d (see Fig. 1) and assuming conservative evolution, i.e. that mass and angular momentum are conserved during mass transfer.

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 DIVISION V: VARIABLE STARS

2008 ◽  
Vol 4 (T27A) ◽  
pp. 251-253
Author(s):  
Alvaro Giménez ◽  
Steven D. Kawaler ◽  
Conny Aerts ◽  
Jørgen Christensen-Dalsgaard ◽  
Michael Breger ◽  
...  
Keyword(s):  
Binary System ◽  
Cataclysmic Variables ◽  
Variable Stars ◽  
Eclipsing Binaries ◽  
Close Binaries ◽  
X Ray ◽  
Pulsating Stars ◽  
Interacting Systems ◽  
Detached Binaries ◽  
X Ray Binaries

Division V deals with all aspects of stellar variability, either intrinsic or due to eclipses by its companion in a binary system. In the case of intrinsic stellar variability the analysis of pulsating stars, surface inhomogeneities, stellar activity and oscillations are considered. For close binaries, classical detached eclipsing binaries are studied as well as more interacting systems, like contact and semi-detached binaries, or those with compact components, like cataclysmic variables and X-ray binaries, including the physics of accretion processes.

scholarly journals The Origin of Millisecond Pulsar Velocities

1996 ◽  
Vol 160 ◽  
pp. 51-52
Author(s):  
Thomas M. Tauris
Keyword(s):  
Neutron Star ◽  
Binary System ◽  
Orbital Period ◽  
Main Sequence ◽  
Space Velocity ◽  
Computer Code ◽  
Millisecond Pulsar ◽  
Final State ◽  
Pulsar Velocity ◽  
Orbital Periods

We have developed a computer code (Tauris &amp; Bailes 1996) to follow the evolution of a binary system from the zero-age main sequence to its “final” state as a binary millisecond pulsar (BMSP), at all stages keeping careful track of the mass and orbital separation of the two stars.To help determine the origin of millisecond pulsars, we compute the space velocities predicted by various models of their formation. It is difficult to produce a millisecond pulsar velocity greater than 270 km s−1with any model, unless the formation of the neutron star is accompanied by some form of asymmetric kick. We obtain average 3-D system velocities of 〈vrecoil〉= 99.6, 137.6 and 160.7 km s−1using Gaussian kicks of 〈vkick〉=0, 200 and 450 km s−1(σ=0, 100 and 200 km s - 1, respectively). Our computations show that, in general, we expect those systems with shorter orbital periods to have larger velocities than those with longer periods, but any relation between the final orbital period and space velocity is fairly weak, especially if asymmetries are involved.

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 A Limit on the Space Density of Short-Period Binary White Dwarfs

1989 ◽  
Vol 114 ◽  
pp. 492-497
Author(s):  
Edward L. Robinson ◽  
Allen W. Shafter
Keyword(s):  
Orbital Period ◽  
Binary Stars ◽  
White Dwarfs ◽  
Main Sequence ◽  
Close Binaries ◽  
Main Sequence Stars ◽  
Space Density ◽  
Short Period ◽  
Hot Subdwarfs ◽  
Orbital Periods

We infer that detached binary white dwarfs with orbital periods of a few hours exist because we observe both their progenitors and their descendents. The binary LB 3459 has an orbital period of 6.3 hr and contains a pair of hot subdwarfs that will eventually cool to become white dwarfs (Kilkenny, Hill, and Penfold 1981). L870-2 is a pair of white dwarfs and, given enough time, its 1.55 d orbital period will decay to shorter periods (Saffer, Liebert, and Olszewski 1988). GP Com, AM CVn, V803 Cen, and PG1346+082 are interacting binary white dwarfs with orbital periods between 1051 s for AM CVn and 46.5 min for GP Com (Nather, Robinson, and Stover 1981; Solheim et al. 1984; Wood et al. 1987; O’Donoghue and Kilkenny 1988). These ultrashort period systems must be descendents of detached pairs of white dwarfs. We also expect short-period binary white dwarfs to exist for theoretical reasons. All calculations of the evolution of binary stars show that main-sequence binaries can evolve to binary white dwarfs (e.g., Iben and Tutukov 1984). Among Population I stars, 1/2 to 2/3 of all main-sequence stars are binaries and about 20% of these binaries should become double white dwarfs with short orbital periods (Abt 1983, Iben and Tutukov 1986). Thus, about 1/10 of all white dwarfs could be close binaries (Paczynski 1985). Nevertheless, no detached binary white dwarfs with extremely short periods have yet been found.

scholarly journals Spectroscopic and photometric periods of six ultracompact accreting binaries

2020 ◽  
Vol 496 (2) ◽  
pp. 1243-1261 ◽  
Author(s):  
Matthew J Green ◽  
Thomas R Marsh ◽  
Philip J Carter ◽  
Danny Steeghs ◽  
Elmé Breedt ◽  
...  
Keyword(s):  
Orbital Period ◽  
White Dwarf ◽  
High Speed ◽  
Binary Systems ◽  
Direct Detection ◽  
Cataclysmic Variables ◽  
Central Star ◽  
Wide Field ◽  
Infrared Excess ◽  
Orbital Periods

ABSTRACT Ultracompact accreting binary systems each consist of a stellar remnant accreting helium-enriched material from a compact donor star. Such binaries include two related sub-classes, AM CVn-type binaries and helium cataclysmic variables, in both of which the central star is a white dwarf. We present a spectroscopic and photometric study of six accreting binaries with orbital periods in the range of 40–70 min, including phase-resolved VLT spectroscopy and high-speed ULTRACAM photometry. Four of these are AM CVn systems and two are helium cataclysmic variables. For four of these binaries we are able to identify orbital periods (of which three are spectroscopic). SDSS J1505+0659 has an orbital period of 67.8 min, significantly longer than previously believed, and longer than any other known AM CVn binary. We identify a Wide-field Infrared Survey Explorer (WISE) infrared excess in SDSS J1505+0659 that we believe to be the first direct detection of an AM CVn donor star in a non-direct impacting binary. The mass ratio of SDSS J1505+0659 is consistent with a white dwarf donor. CRTS J1028–0819 has an orbital period of 52.1 min, the shortest period of any helium cataclysmic variable. MOA 2010-BLG-087 is co-aligned with a K-class star that dominates its spectrum. ASASSN-14ei and ASASSN-14mv both show a remarkable number of echo outbursts following superoutbursts (13 and 10 echo outbursts respectively). ASASSN-14ei shows an increased outburst rate over the years following its superoutburst, perhaps resulting from an increased accretion rate.

scholarly journals Synchronization Anomalies in Close Binaries as a Test of Rapid Evolutionary Processes

1998 ◽  
Vol 11 (1) ◽  
pp. 354-354
Author(s):  
A. Giménez ◽  
A. Claret
Keyword(s):  
Orbital Period ◽  
Binary Systems ◽  
Main Sequence ◽  
Rapid Expansion ◽  
Close Binaries ◽  
Late Type ◽  
Satisfactory Explanation ◽  
Tidal Evolution ◽  
Angular Velocities ◽  
History Of

Close binaries with late-type components generally present rotational velocities synchronized with their orbital period. This is a well known effect of tidal evolution in binary systems which is particularly efficient in stars with convective envelopes. Nevertheless, some cases are known where the angular velocities of the componenent stars are clearly different from each other or even from that of the orbit. Good examples are the evolved systems TZ For and a Aur. We have made a detailed study of the tidal evolution history of these binaries through integration of the relevant differential equations using the formalisms by Zahn as well as Tassoul. Our results show that a satisfactory explanation of the synchronization status of the component stars can be achieved when the influence of the rapid expansion phases, suffered by the stars after leaving the main sequence and starting core He combustion, in the actual rotational velocities is taken into account.

scholarly journals X-ray and UV emission of the ultrashort-period, low-mass eclipsing binary system BX Trianguli

2018 ◽  
Vol 619 ◽  
pp. A138
Author(s):  
V. Perdelwitz ◽  
S. Czesla ◽  
J. Robrade ◽  
T. Pribulla ◽  
J. H. M. M. Schmitt
Keyword(s):  
Binary System ◽  
Light Curve ◽  
Binary Systems ◽  
Uv Light ◽  
Close Binary ◽  
Eclipsing Binary ◽  
X Ray ◽  
Uv Emission ◽  
Low Mass ◽  
Orbital Modulation

Context.Close binary systems provide an excellent tool for determining stellar parameters such as radii and masses with a high degree of precision. Due to the high rotational velocities, most of these systems exhibit strong signs of magnetic activity, postulated to be the underlying reason for radius inflation in many of the components. Aims.We extend the sample of low-mass binary systems with well-known X-ray properties. Methods.We analyze data from a singular XMM-Newton pointing of the close, low-mass eclipsing binary system BX Tri. The UV light curve was modeled with the eclipsing binary modeling tool PHOEBE and data acquired with the EPIC cameras was analyzed to search for hints of orbital modulation. Results.We find clear evidence of orbital modulation in the UV light curve and show that PHOEBE is fully capable of modeling data within this wavelength range. Comparison to a theoretical flux prediction based on PHOENIX models shows that the majority of UV emission is of photospheric origin. While the X-ray light curve does exhibit strong variations, the signal-to-noise ratio of the observation is insufficient for a clear detection of signs of orbital modulation. There is evidence of a Neupert-like correlation between UV and X-ray data.

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.

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