Remarks on erratic period fluctuations of detached close binaries and the constancy of the orbital period of XY UMa

Geyer, E. H.

doi:10.1007/bf00643045

Cited by 13 publications

(12 citation statements)

References 7 publications

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“…At least five O−C diagrams have been published upto-date (Geyer 1977;Lorenzi & Scaltriti 1977;Hall & Kreiner 1980;Lee 1985;Pojmanski & Geyer 1990). Each one shows a large scatter up to a value of 0. d 02.…”

Section: Xy Uma (=Hd 27143 = Bd +55mentioning

confidence: 99%

“…Each one shows a large scatter up to a value of 0. d 02. Geyer (1977) noted that the period of the system seemed to be constant. However some quadratic terms in ephemeris were introduced by Hall & Kreiner (1980, +2.8 10 −11 ·E 2 ) and Qisheng et al (1989, +1.4 10 −11 · E 2 ).…”

Section: Xy Uma (=Hd 27143 = Bd +55mentioning

confidence: 99%

“…Unfortunately, the theoretical O−C curve given this formula do not fit to the old photographic data of Geyer (1977). Therefore, a quadratic term (= Q · E 2 ) was added to the Eq.…”

Section: A Third Body?mentioning

confidence: 99%

“…As a first step in the photometric analysis of the system, the value of the q parameter was taken to be 0.75 which is very close to the one given by Geyer (1977). The purpose here is to determine the parameters of the spot with the Wilson-Devinney code, which is supposed to take place on the G2−G5V component causing an asymmetry in the light curves of the system XY UMa (see Fig.…”

mentioning

confidence: 99%

“…Otherwise, to converge to a meaningful solution is very hard to achieve. Therefore, we have calculated unspotted light curve for V colour of XY UMa by using geometrical and physical parameters of the system from Geyer (1977) and Jassur (1986). This unspotted V light curve has been subtracted from observed V light curve.…”

mentioning

confidence: 99%

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The orbital period study and photometric analysis of XY Ursae Majoris

Erdem

Güdür

1998

Astron. Astrophys. Suppl. Ser.

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Abstract. Photoelectric observations of the eclipsing binary XY UMa have been carried out in B and V colours at the Ege University Observatory. Combining these newly obtained data with the previous ones available in the literature, the problem pertaining to the orbital period of the system has been investigated through a detailed description of the O−C diagram. The sinusoidal and secular changes have been found. Such variations of the orbital period have been examined in terms of three plausible mechanisms, namely (i) a light-time effect due to a third body, (ii) the orbital period modulation due to magnetic activity cycle of a component star, and (iii) a mass loss case in which the ejected material escapes out from the binary system. A combination of a magnetic activity cycle mechanism and a mass loss case is found to reproduce satisfactorily the period changes. Further, the observed photoelectric light curves of the system have been analyzed with the Wilson-Devinney approach. This analysis shows that the asymmetries of the light curves of XY UMa can be interpreted in terms of cool star-spot covering 7% of the stellar photosphere of the primary component of this binary. The system is found to be a β Lyrae type detached binary. The absolute elements of the system are also deduced.

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Section: Xy Uma (=Hd 27143 = Bd +55mentioning

confidence: 99%

Section: Xy Uma (=Hd 27143 = Bd +55mentioning

confidence: 99%

“…Unfortunately, the theoretical O−C curve given this formula do not fit to the old photographic data of Geyer (1977). Therefore, a quadratic term (= Q · E 2 ) was added to the Eq.…”

Section: A Third Body?mentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

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