BX Pegasi. II - Spectroscopic observations and simultaneous synthetic photometric-spectroscopic solution

Samec, R. G.; Hube, D. P.

doi:10.1086/115943

Cited by 14 publications

(13 citation statements)

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“… 1: Paper I, 2: Paper II, 3: Paper III, 4: Paper IV, 5: Paper V, 6: Gazeas et al (2006a), 7: Hilditch et al (1988), 8: Zhang & Zhang (2004), 9: Milone, Wilson & Hrivnak (1987), 10: Maceroni et al (1981), 11: Khajavi, Edalati & Jassur (2002), 12: Samec & Hube (1991), 13: Yakut et al (2003), 14: Hilditch, Hill & Bell (1992), 15: Kaluzny & Rucinski (1986), 16: Russo et al (1982), 17: Rainger et al (1990a), 18: Nesci et al (1986), 19: Yang & Liu (1999), 20: Maceroni et al (1994), 21: Rucinski, Lu & Shi (1993), 22: Maceroni, Milano & Russo (1984), 23: Kaluzny (1984), 24: Yakut et al (2005), 25: Mancuso, Milano & Russo (1978), 26: Barnes et al (2004), 27: Duerbeck (1978), 28: Lu & Rucinski (1999), 29: Sezer, Gülmen & Güdür (1985), 30: Binnendijk (1984), 31: Hrivnak (1993), 32: Barone et al (1993), 33: Pribulla & Vanko (2002), 34: Rucinski et al (2002), 35: Zola et al (2001), 36: Metcalfe (1999), 37: Kim et al (2003), 38: Lu & Rucinski (1993), 39: Rucinski & Lu (1999), 40: Goecking et al (1994), 41: Yang & Qian (2004), 42: Nelson et al (1995), 43: Rainger et al (1990b), 44: Qian & Yang (2005), 45: Lapasset & Gomez (1990), 46: McLean & Hilditch (1983), 47: Gazeas, Niarchos & Zola (2007), 48: Zola et al (in preparation), 49: Bilir et al (2005), 50: Rucinski et al (2003), 51: Maceroni & van't Veer (1996), 52: Lu, Rucinski & Ogloza (2001), 53: Pribulla et al (2002), 54: Niarchos & Manimanis (2003), 55: Milone et al (1995), 56: Yang & Liu (2003a), 57: Yang & Liu (2003b), 58: Rovithis‐Livaniou et al (2001), 59: Pribulla et al (2001), 60: Pribulla et al (1999), 61: Hilditch, King & McFarlane (1989) (continued below Table 2). …”

Section: Observed Properties Of W Uma‐type Starsmentioning

confidence: 99%

Angular momentum and mass evolution of contact binaries

Gazeas

Stępień

2008

Monthly Notices of the Royal Astronomical Society

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Various scenarios of contact binary evolution have been proposed in the past, giving hints of (sometimes contradictory) evolutionary sequence connecting A-type and W-type systems. As the components of close detached binaries approach each other and contact binaries are formed, following evolutionary paths transform them into systems of two categories: A-type and W-type. The systems evolve in a similar way but under slightly different circumstances. The mass/energy transfer rate is different, leading to quite different evolutionary results. An alternative scenario of evolution in contact is presented and discussed, based on the observational data of over a hundred low-temperature contact binaries. It results from the observed correlations among contact binary physical and orbital parameters. Theoretical tracks are computed assuming angular momentum loss from a system via stellar wind, accompanied by mass transfer from an advanced evolutionary secondary to the main sequence primary. Good agreement is seen between the tracks and the observed graphs. Independently of details of the evolution in contact and a relation between A-type and W-type systems, the ultimate fate of contact binaries involves the coalescence of both components into a single fast rotating star.Comment: 11 pages, 5 figures, a short paragraph added on p. 6, MNRAS, in pres

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Section: Observed Properties Of W Uma‐type Starsmentioning

confidence: 99%

Angular momentum and mass evolution of contact binaries

Gazeas

Stępień

2008

Monthly Notices of the Royal Astronomical Society

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“…From the timings prior to 1990, Samec (1990) and Samec & Hube (1991) developed a continuous period decrease for BX Peg by using a quadratic ephemeris. Values of the residuals after 1990 have also continued to decrease.…”

Section: Period Variabilitymentioning

confidence: 99%

“…Since orbital period changes were first reported by Hoffmann (1982), the period has been studied by Samec (1990), Samec & Hube (1991) and DeYoung et al (1991). Hoffmann suggested that the period was decreasing, based on data gathered over a 15‐yr baseline.…”

Section: Introductionmentioning

confidence: 99%

“…Since the discovery of its light variability and its identification as a W UMa‐type eclipsing binary by Shapley & Hughes (1934), the short‐period eclipsing binary BX Pegasi (BX Peg: HV 6149, GSC 02197−01458, RX J213849.2+264121) system has been the subject of several investigations. Reviews of the observational history of the system prior to 1990 appear in Samec (1990) and Samec & Hube (1991). We will now highlight some historical details and also review some work published since 1990.…”

Section: Introductionmentioning

confidence: 99%

“…The solutions of Kaluzny, Leung et al and Samec indicate that BX Peg is a total‐eclipsing W‐type W UMa binary system. Samec & Hube (1991) obtained double‐line radial velocity curves from low‐resolution spectra. They simultaneously analysed these radial velocity curves and Samec's BV light curves and found spectroscopic orbital solutions, light‐curve parameters and absolute dimensions.…”

Section: Introductionmentioning

confidence: 99%

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Period and light variations for the cool, overcontact binary BX Pegasi

Lee

Kim

Han

et al. 2004

Monthly Notices of the Royal Astronomical Society

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New charge-coupled device photometric observations of the W UMa-type binary BX Pegasi (BX Peg) were collected on four nights from 1999 October to 2000 September. The light curve was covered completely in each season. Seven new times of minimum light were determined. It was found that the orbital period of the system has varied recently in a sinusoidal way, superimposed on a downward parabolic variation. The long-term period decrease rate is deduced as dP/dt = −8.62 or 9.59 × 10 −8 d yr −1 , which can be interpreted as either mass transfer from the more massive cool star to the less massive hot component, or as the combination of mass transfer and angular momentum loss due to a magnetic stellar wind. The period and amplitude of the sinusoidal period variation were calculated to be about 35.3 yr and 0.015 d, respectively. The light curves of BX Peg are asymmetric and show year-to-year light variability. A spot model has been applied to analyse these light curves. After using the light curves of 1999 as reference ones, we solve those of 2000 by adjusting only the spot parameters. One cool-spot model on the cool secondary satisfies the observed light curves of both 1999 and 2000 quite well and shows a good representation of the BX Peg system for both the photospheric and spot descriptions. The brightness variations of BX Peg are not coincident with the period variations and so do not conform to a prediction of the Applegate mechanism. We think the most likely cause of the cyclical variation is the light-time effect due to a third body, although no third light was detected in the light-curve analysis. If it exists, the hypothetical object could be a very red main-sequence star or a white dwarf. We have solved anew the historical published light curve for only the spot parameters and these closely resemble our spot parameters. We speculate that this result is associated with the small coronal saturation of the cool star of the system.

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Variation in the orbital period of W UMa-type contact systems

Dryomova¹,

Свечников²

2006

Astrophysics

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The secular variation in the orbital period P orb is studied as a function of the mass ratio q of the components in a sample of 73 contact systems of class W UMa constructed from a survey of current (1991)(1992)(1993)(1994)(1995)(1996)(1997)(1998)(1999)(2000)(2001)(2002)(2003) published photometric and spectroscopic data. Almost all the W UMa-systems (>93% of this sample) are found to have a variation in their orbital periods P orb which alternates in sign independently of their division into A-and Wsubclasses. A statistical study of this sample in terms of the observed characteristics dP orb /dt and q showed that on the average the numbers of increases (35 systems) and decreases (33 systems) in the periods are the same, which indicates the existence of flows directed alternately from one component to the other and illustrates the cyclical character of the thermal oscillations. An analysis of the behavior of dP orb /dt as a function of the mass interval of the primary component yields a more accurate value for the mass ratio,at which contact binaries are separated into A-and W-subclasses. No correlations were observed between the fill-out factor for the outer contact configuration, the total mass of the contact system, and the mass ratio of the components, on one hand, and the sign of the secular variation in the period. The physical properties and evolutionary features of these systems are discussed.

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BX Pegasi. II - Spectroscopic observations and simultaneous synthetic photometric-spectroscopic solution

Cited by 14 publications

References 0 publications

Angular momentum and mass evolution of contact binaries

Angular momentum and mass evolution of contact binaries

Period and light variations for the cool, overcontact binary BX Pegasi

Variation in the orbital period of W UMa-type contact systems

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