ABSOLUTE PARAMETERS AND MASS-RADIUS-LUMINOSITY RELATIONS FOR THE SUB-TYPES OF W UMα BINARIES

Awadalla, N. S.; Hanna, Magdy A.

doi:10.5303/jkas.2005.38.2.043

Cited by 35 publications

(32 citation statements)

References 15 publications

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“…Because of this we had to make a suitable mass-luminosity calibration for these kinds of stars. In this study we have used the mass-luminosity and mass-radius relations for both W and A subtypes of the W UMaYtype binaries given by Awadalla & Hanna (2005). The radii derived for these systems according to these relations are listed in Table 5.…”

Section: W Umaytype Spectroscopic Binariesmentioning

confidence: 99%

A Methodology for the Description of Multiple Stellar Systems with Spectroscopic Subcomponents

Docobo

Andrade

2006

ApJ

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We propose a methodology for analyzing triple stellar systems that include a visual double star wherein one of the components is a single-or double-lined spectroscopic binary. By using this methodology, we can calculate the most probable values of the spectroscopic binary's inclination, the angular separation between its components, and its stellar masses, and we can even estimate the spectral types. For a few W UMaYtype eclipsing binaries, stellar radii are also determined. Moreover, we present new formulae for calculating stellar masses depending on spectral type. In this way we have studied 61 triple systems, five of them W UMaYtype eclipsing binaries with low-mass subcomponents. In addition, we study nine quadruple systems, applying the same methodology and considering them twice as a triple system. With the aim of having more accurate orbital elements, we have taken advantage of the occasion to calculate and improve orbits. In this way we have used a new speckle measurement to improve the orbital elements for the binary Hu 506 AB. Also, new visual orbits are calculated for the binaries BAG 10 Aa and LAB 6 Aa. Finally, we give a list of five spectroscopic binaries with more than 0B1 for the maximum angular separation; these should be easily observable as visual binaries by means of interferometric techniques.

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Section: W Umaytype Spectroscopic Binariesmentioning

confidence: 99%

A Methodology for the Description of Multiple Stellar Systems with Spectroscopic Subcomponents

Docobo

Andrade

2006

ApJ

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“…8 that the radius of the primary component approaches to the value for zero age main sequence (ZAMS) stars, i.e. basically a ZAMS star (Awadalla and Hanna, 2005;Liu and Yang, 2000b). Fig.…”

Section: Light Curve Modeling and Photometric Solutionsmentioning

confidence: 97%

“…First quantitative observations were made by Tsessevich (1954) who reported a period of 1.159 days. The later studies of FO Hya indicate a slightly asymmetric light curve having strong curvature in both maxima and minima of unequal depths (Binnendijk, 1960;Kopal, 1978;Candy and Candy, 1997), which was explained by the presence of spot on a star of the binary system. Candy and Candy (1997) have suggested that the slight and irregular variation in the orbital period of FO Hya is presumably caused by mass transfer between the components.…”

Section: Introductionmentioning

confidence: 96%

BVRI photometric and polarimetric studies of W UMa type eclipsing binary FO Hydra

Prasad¹,

Pandey²,

Patel³

et al. 2013

New Astronomy

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h i g h l i g h t s " We present analysis of optical photometric and polarimetric observations of contact binary system FO Hydra (FO Hya). " The computed period of the system is 0.469556 ± 0.000003 days. " An O-C curve analysis indicates an increase in its period by 5.77 Â 10 -8 day yr À1 . " The photometric light curves are analyzed using Wilson-Devinney code (WD). " In this analysis we have taken up, presumably for the first time, the polarimetric studies of FO Hya, and obtain the mean values of degree of polarization and polarization position angle. a b s t r a c tWe present analysis of optical photometric and polarimetric observations of contact binary system FO Hydra (FO Hya). The computed period of the system is 0.469556 ± 0.000003 days. An O-C curve analysis indicates an increase in its period by 5.77 Â 10 À8 day yr À1 . The photometric light curves are analyzed using Wilson-Devinney code (WD). The present analysis shows that FO Hya is a B-subtype of W UMa type contact binary. The radii and mass of primary and secondary components are found, respectively, to be R 1 = 1.62 ± 0.03 R and R 2 = 0.91 ± 0.02 R , and M 1 = 1.31 ± 0.07 M and M 2 = 0.31 ± 0.11 M . The light curve shape shows small asymmetries around the primary and secondary maxima. This may be due to the presence of dark spots on the components. The polarimetric observations yield average values of its polarization to be 0.18 ± 0.03, 0.15 ± 0.03, 0.17 ± 0.02 and 0.15 ± 0.02% in B, V, R and I bands, respectively. These values are appreciably lower than the typical polarization of W UMa type binaries. We have discussed the possible sources of the observed polarization but in order to arrive at definitive answer to this more phase locked observations are needed.

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“…On the other hand, when the more massive star obscures the less massive one at the primary eclipse, it is called W-subtype (Binnendijk 1970(Binnendijk , 1977. At present, there are two conflicting arguments that W-subtypes evolve into A-subtypes (Flannery 1976;Lucy 1976;Wilson 1978;Mochnacki 1981;Hilditch 1989;Awadalla & Hanna 2005;Eker et al 2006;Gazeas & Niarchos 2006) and that there is no evolutionary link between them (Maceroni & Van't Veer 1996;Yildiz & Doğan 2013).…”

Section: Introductionmentioning

confidence: 99%

The First Photometric Study of NSVS 1461538: A New W-subtype Contact Binary with a Low Mass Ratio and Moderate Fill-out Factor

Kim¹,

Kim²,

Song³

et al. 2016

Journal of Astronomy and Space Sciences

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ABSOLUTE PARAMETERS AND MASS-RADIUS-LUMINOSITY RELATIONS FOR THE SUB-TYPES OF W UMα BINARIES

Cited by 35 publications

References 15 publications

A Methodology for the Description of Multiple Stellar Systems with Spectroscopic Subcomponents

A Methodology for the Description of Multiple Stellar Systems with Spectroscopic Subcomponents

BVRI photometric and polarimetric studies of W UMa type eclipsing binary FO Hydra

The First Photometric Study of NSVS 1461538: A New W-subtype Contact Binary with a Low Mass Ratio and Moderate Fill-out Factor

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