Non-LTE effects in streams, and mass-transfer rates in three eclipsing binaries

Olson, Edward C.; Bell, David

doi:10.1086/132551

Cited by 9 publications

(14 citation statements)

References 4 publications

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“…If this amount of gas is accreted each orbital cycle, then the mass transfer rate needed to maintain this disk is yr~1. M 0^9 ] 10~10 M _ This mass transfer rate is D44 times lower than the value calculated by Olson & Bell (1989) from the photometric absorption attributed to the gas stream between phases 0.80È0.95. Alternatively, if we assumed that most of the gas is accreted before it makes one orbit around the primary star and measure the average tangential velocity of the emission peaks (D325 km s~1), then the maximum lifetime of the gas in the disk is D16 hours and the median lifetime is D8 hours.…”

Section: Disk Geometrymentioning

confidence: 66%

“…Alternatively, if we assumed that most of the gas is accreted before it makes one orbit around the primary star and measure the average tangential velocity of the emission peaks (D325 km s~1), then the maximum lifetime of the gas in the disk is D16 hours and the median lifetime is D8 hours. The mass transfer rate needed to produce this disk every 8 hours increases to yr~1, M 0 \ 9 ] 10~9 M _ still only 23% of the value calculated by Olson & Bell (1989). Possibly, only a small percentage of the gas in the stream is fed into the disk, and the rest is immediately accreted by the star.…”

Section: Disk Geometrymentioning

confidence: 83%

“…yr~1 (Olson & Bell 1989) was derived. Varia-M _ bility in the light curve of U Sge has been observed and attributed to radius variations of one of the stars, most likely the secondary star (Olson 1982).…”

Section: Rw T Aurimentioning

confidence: 99%

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Morphologies of Hα Accretion Regions in Algol Binaries

Richards

Albright

1999

ASTROPHYS J SUPPL S

109

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We have investigated a group of 18 Algol-type binaries to determine the general morphologies and physical properties of the accretion regions in these systems. The systems studied were V505 Sgr, RZ Cas, AI Dra, TV Cas, TW Cas, d Lib, RW Tau, TW Dra, b Per, TX UMa, U Sge, S Equ, U CrB, RS Vul, SW Cyg, CX Dra, TT Hya, and AU Mon, in order of increasing orbital period P \ 1.18È11.11 days. In addition, the RS CVn-type binary HR 1099 (V711 Tau) was observed to illustrate the appearance of chromospheric Ha emission. Nearly 2200 time-resolved Ha spectra were collected from 1992 March to 1994 December with the McMath-Pierce Solar Telescope at NSO and mostly with the Coude Feed Telescope at KPNO. The spectra were obtained at phases around the entire orbit of each binary and were closely spaced to permit the detection of transitions in the proÐles. Moreover, the spectra were obtained typically within three orbital cycles to reduce the inÑuence of secular variations. Di †erence proÐles were calculated by subtracting a composite theoretical photospheric spectrum from the observed spectrum.The analysis of the Ha di †erence proÐles demonstrates that the accretion structures in Algol binaries have four basic morphological types : (1) double-peaked emission systems in which the accretion structure is a transient or classical accretion disk ; (2) single-peaked emission systems in which the accreted gas was found along the trajectory of the gas stream and also between the two stars in an accretion annulus ; (3) alternating single-and double-peaked emission systems, which can change between a single-peaked and a double-peaked type within an orbital cycle ; and (4) weak spectrum systems in which there was little evidence of any accretion structure since the di †erence spectra are weak at all phases. The Ðrst two types are the dominant morphologies. The Ðrst type can be interpreted physically as a disklike distribution, while the second is a gas streamÈlike distribution.The most common type in short-period Algols with 2.7 days \ P \ 4.5 days is a predominantly singlepeaked emission feature in the Ha di †erence proÐles (Type 2). This feature is redshifted during the phase interval / D 0.15È0.45 and blueshifted from / D 0.55È0.85. This single-peaked emission is often composed of two closely spaced emission peaks where one peak is at the Ha rest wavelength. The other peak is blueshifted at / D 0.65, where the line of sight is along the length of the approaching gas stream. Systems which display this morphology include RZ Cas, RW Tau, TW Dra, b Per, TX UMa, S Equ, and RS Vul. The orbital variation of the Ha observed proÐles of HR 1099 was similar to that seen in the di †erence spectra of this group and suggests that chromospheric emission may play a signiÐcant role in these binaries. A less common morphological type in the group of short-period Algols was a widely separated double-peaked disk-like distribution (Type 1) where the gas is in a transient or classical accretion disk. All of the long-period systems (P [ 6 days) were f...

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Section: Disk Geometrymentioning

confidence: 66%

Section: Disk Geometrymentioning

confidence: 83%

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Morphologies of Hα Accretion Regions in Algol Binaries

Richards

Albright

1999

ASTROPHYS J SUPPL S

109

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“…6. It can be seen that the expected course of the period change foṙ m determined by Olson & Bell (1989) is too small to be unambiguously present in the available data. It is interesting to note that although the parameters and position of AQ Cas in the r−q and P −q diagrams in Fig.…”

Section: Aq Casmentioning

confidence: 86%

“…The mass transfer rateṁ ≈ 5 10 −7 M yr −1 was determined from the photometric manifestations of the mass stream by Olson & Bell (1989). In order to assess how largė m for the conservative transfer (Huang 1963) can be hidden in the scatter of the data parabolic courses for a set ofṁ were computed and are included in Fig.…”

Section: Aq Casmentioning

confidence: 99%

Variations of the orbital periods in semi-detached binary stars with radiative outer layers

Šimon

1999

Astron. Astrophys. Suppl. Ser.

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Abstract. A detailed analysis of the period changes of sixteen semi-detached binaries which contain only stars with radiative outer layers (ET-systems) has been performed and their respective O-C diagrams are brought and discussed. It was found that the course of the period variations is monotonic and in some systems the period is even constant. This detailed analysis of extensive sets of timings covering several decades brings a strong support to an earlier finding of Hall (1989) and develops it further. We show that all systems with the orbital periods shorter than nine days display constant period or its increase, with the exception of an uncertain case of V 337 Aql. The course of the period variations in TT Aur appears more complex but the cyclic term can be plausibly explained by the third body.A search for general relations between the parameters of the systems and the period changes was undertaken. The mass ratio q appears to play a role in the period variations. Clear changes in systems with orbital periods shorter than 9 days were detected only for q > 0.4 while constant periods are common in systems with q < 0.4 in this period range. The sense of the secular changes in most systems is in accordance with the dominant conservative mass transfer in evolved binary and corresponds to the slow phase. The role of the evolutionary scenarios (case A versus B) and the influence of changes of the rotational angular momenta of the components are discussed.

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Further confirmations of mass transfer in Algol type binary U Sagittae

Manzoori

2007

Astrophys Space Sci

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This paper describes how a new photometric V light curve solution of Algol type binary U Sge was obtained using Wilson-Devinney code. I also discuss how the physical and orbital parameters, along with absolute dimensions of the system, were determined. The Roche lobe configurations of the system indicate that the secondary component has filled its Roche lobe and therefore is losing mass at the rate of 6.15×10 −7 M sun yr −1 . The conservative mass flow is the most likely process in this system.

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Non-LTE effects in streams, and mass-transfer rates in three eclipsing binaries

Cited by 9 publications

References 4 publications

Morphologies of Hα Accretion Regions in Algol Binaries

Morphologies of Hα Accretion Regions in Algol Binaries

Variations of the orbital periods in semi-detached binary stars with radiative outer layers

Further confirmations of mass transfer in Algol type binary U Sagittae

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