The fundamental parameters of the Algol binary AI Draconis revisited

Lázaro, C.; Martínez‐País, I. G.; Arévalo, M. J.

doi:10.1111/j.1365-2966.2004.07820.x

Cited by 16 publications

(9 citation statements)

References 24 publications

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“… References: (1) Budding et al (2004); (2) Soydugan et al (2005); (3) Tomkin (1985); (4) Lázaro, Martínez‐Pais & Arévalo (2004); (5) van Hamme & Wilson (1993); (6) Bakis et al (2006); (7) Deutsch (1945); (8) Vivekananda & Sarma (1998); (9) Tomkin & Lambert (1978); (10) Maxted, Hill & Hilditch (1995a); (11) Maxted, Hill & Hilditch (1995b); (12) Plavec (1967). …”

Section: Sources Of the Datamentioning

confidence: 99%

Angular momentum evolution of Algol binaries

İbanoǧlu

Soydugan

et al. 2006

Monthly Notices of the Royal Astronomical Society

104

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We have compiled the well-determined absolute parameters of Algol-type binaries. The lists contain the parameters of 74 detached and 61 semidetached close binaries. The double-lined eclipsing binaries provide not only the most accurate determinations of stellar mass, radius and temperatures but also distance-independent luminosity for each of their individual components. The distributions of the primary and secondary masses of detached binaries (DBs) are similar, whilst the secondary masses of the semidetached binaries (SDBs) are mostly smaller than 2 M with a peak in the M 2 -bin (0.21-1.0). The components of the DBs are almost all located in the main-sequence band. On the contrary, the secondary components of the SDBs have larger radii and luminosity with respect to the same mass and the same effective temperature of main-sequence counterparts. They occupy a region of the Hertzsprung-Russell diagram between terminal-age main sequence and giants. Moreover, the total angular momenta and specific angular momenta are larger for the SDBs of orbital periods with P > 5 d than those of the shorter period ones. The specific angular momenta of SDBs with periods longer than 5 d are 65 per cent greater than that of the short period group with the same mass. The DBs and the SDBs with orbital periods longer and shorter than 5 d are separated into three groups in the J/M 5/3 − q diagram. The SDBs with mass ratios greater than 0.3 and P > 5 d have almost the same angular momentum to those of DBs. However, the SDBs with short periods have the smallest angular momentum even though they have the same mass ratios. This result reveals that angular momentum loss (AML) considerably affects the evolution of close binary systems. Recently, Chen, Li & Qian suggested that, in addition to magnetic braking, a circumbinary disc may play an important role in AML from Algol-type binaries. Their calculations indicated that the evolution of Algol-type binaries can be significantly affected by the circumbinary disc. Our results show that the evolution of close binaries begins as a DB and losing angular momentum, first via stellar wind and then magnetic braking plus circumbinary disc the period is shortened and orbit shrinks. Thereafter, the evolution of the system is accelerated and mass transfer rates are enhanced which result in a smaller mass ratios.

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Section: Sources Of the Datamentioning

confidence: 99%

Angular momentum evolution of Algol binaries

İbanoǧlu

Soydugan

et al. 2006

Monthly Notices of the Royal Astronomical Society

104

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“…cross‐correlation, Popper & Jeong 1994) to measure radial velocities (RVs), and to the accurate analysis of multiband (from visible to near‐infrared wavelength) light curves with sophisticated spot models (e.g. Lázaro, Martínez‐Pais & Arévalo 2004).…”

Section: Introductionmentioning

confidence: 99%

A spectroscopic study of the Algol-type binaries S Equulei and KO Aquilae: absolute parameters and mass transfer

Soydugan

Frasca

Soydugan

et al. 2007

Monthly Notices of the Royal Astronomical Society

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We present and analyse high‐resolution optical spectra of two Algol binaries, namely S Equ and KO Aql, obtained with the echelle spectrograph at Catania Astrophysical Observatory. New accurate radial velocities (RVs) for the hotter primary components are obtained. Thanks to the cross‐correlation procedure, we were able to measure, for the first time to our knowledge, RVs also for the cool secondary components of S Equ and KO Aql. By combining the parameters obtained from the solution of the RV curves with those obtained from the light‐curve analysis, reliable absolute parameters of the systems have been derived. The rotational velocity of the hotter components of S Equ and KO Aql has been measured and it is found that the gainers of both systems rotate about 30 per cent faster than synchronously. This is likely due to mass transfer across the Lagrangian L1 point from the cooler to the hotter component. The lower luminosity of the mass‐gaining components of these systems compared to normal main‐sequence stars of the same mass can also be an effect of the mass transfer. The Hα profiles were analysed with the ‘synthesis and subtraction’ technique and reveal clear evidence of mass transfer and accretion structures. In both systems, especially before the primary eclipses and afterwards, we clearly observed extra absorption lines. From the integrated absorption and the RV variations of these features, we found that the mass accretion is very dense around the impact region of the hotter components. A double‐peaked emission in the spectra of S Equ was seen outside the eclipses. One of these peaks is likely originated in a region between the centre of mass and the cooler component, which is occupied by the flowing matter. Furthermore, the Hα difference spectra of S Equ and KO Aql also display emission features, which should be arising from the magnetic activity of the cooler components.

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“…From the parameters of the proposed third-body orbit one could also calculate the angular distance and magnitude difference of this body for a prospective interferometric detection. Using the value of a distance of 169 pc published by Lázaro et al (2004), these parameters result in an angular separation of about 65 mas for the third and about 110 mas for the fourth body. However, the magnitude difference between the binary itself and these additional components is so large (more than 9 mag), that the interferometric detection with the instruments of nowadays is not possible.…”

Section: Resultsmentioning

confidence: 97%

“…The total mass of the eclipsing binary is about M 1 + M 2 = 4.12 M (Lázaro et al 2004). From the total mass of the binary we are able to calculate the minimal masses of the third and the fourth components from the mass functions f (M 3 ) and f (M 4 ).…”

Section: Resultsmentioning

confidence: 99%

“…The first light curve has been published by Cester (1959), while the most recent and also the most detailed analysis is that by Lázaro et al (2004). In this latter study the authors presented and analyzed the infrared light curves of the system, as well as its spectrum, revealed that the system is semidetached one with the secondary component filling its Roche lobe, and the spectral types A0V for the primary and F9.5V for the secondary component.…”

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confidence: 96%

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