SV Cam, an eclipsing binary containing a BY Draconis variable

Hilditch, R. W.; Harland, David M.; McLean, B.

doi:10.1093/mnras/187.4.797

Cited by 28 publications

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“…Since discovered as a variable star by Guthnick (1929), SV Cam has been observed by Wood (1946), Van Woerden (1957), Hilditch et al (1979) and Patkos (1982). The light curves have been analysed by Zeilik et al (1988), Budding (1977), Budding & Zeilik (1987) and Djurasević (1998), using spot modelling techniques.…”

Section: Target Starsmentioning

confidence: 96%

A spectroscopic study of the eclipsing binaries SV Camelopardalis and XY Ursae Majoris

Özeren

Gunn

Doyle³

et al. 2001

A&A

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Abstract. High-resolution spectroscopic observations of the eclipsing RS CVn-type active close binaries SV Camelopardalis and XY Ursae Majoris reveal excess emission components in the Hα and Hβ lines. We have used the spectral subtraction technique to separate the excess emission from the photospheric background and find that in both stars the excess emission is associated with the secondary, cooler component. Analysis of the EWHα/EW Hβ ratio indicates that in both cases the emission is probably associated with surface plage regions or prominences viewed against the stellar disks. We find no evidence of excess absorption features associated with extended prominence-like material in these systems.

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Section: Target Starsmentioning

confidence: 96%

A spectroscopic study of the eclipsing binaries SV Camelopardalis and XY Ursae Majoris

Özeren

Gunn

Doyle³

et al. 2001

A&A

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Section: Introductionmentioning

confidence: 99%

“…∼ F8, m V = 9.34) is an eclipsing binary and has been extensively studied since its discovery (Guthnick 1929) due to its asymmetry and overall shape of the light curves and magnetic activity on probably both components. For example Hilditch et al (1979) gave some arguments in favour of the secondary being responsible for the distortion of light curves. Later on, Cellino et al (1985) claimed that the hotter primary was an active and spotted component.…”

Section: Introductionmentioning

confidence: 99%

“…Özeren et al (2001) found an excess emission in hydrogen lines connected with the secondary, cooler component of the system and processes like surface plages and prominences. The spectral type of the component stars were derived as G2-3V and K4 by Hilditch et al (1979) and Pojmański (1996) estimated a new mass ratio, 0.56, and he derived spectral types F5V and K0V from stellar masses for the components.Among the most recent studies, Albayrak et al (2001) presented the light and period study of the system and suggested the parameters of the third body orbit. Considering the recent and oldest observations, Zboril (2002) Lehmann et al (2002) and Kjurkchieva et al (2002) offer slightly different mass ratios for the components.…”

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SV Cam spot activity in February 2001 – March 2002

Zboril

Djurašević

2003

A&A

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Abstract. We present the analysis of new BVR light curves for the active star SV Cam. The Roche model with spotted areas on the hotter primary component fits satisfactorily all filter observations yielding two spots in intermediate latitudes and covering about 1.5% each of the stellar surface. Both are ∼1000 K cooler than surrounding photosphere. The comparison with an earlier season (January/February 2000) suggests that the spots probably evolved in area longitude and latitude but basic and preferred orientation from previous season is confirmed.Key words. stars: binaries: eclipsing IntroductionThe active star SV Cam (HD44982, p ∼ 0.59d, sp. ∼ F8, m V = 9.34) is an eclipsing binary and has been extensively studied since its discovery (Guthnick 1929) due to its asymmetry and overall shape of the light curves and magnetic activity on probably both components. For example Hilditch et al. (1979) gave some arguments in favour of the secondary being responsible for the distortion of light curves. Later on, Cellino et al. (1985) claimed that the hotter primary was an active and spotted component. Özeren et al. (2001) found an excess emission in hydrogen lines connected with the secondary, cooler component of the system and processes like surface plages and prominences. The spectral type of the component stars were derived as G2-3V and K4 by Hilditch et al. (1979) and Pojmański (1996) estimated a new mass ratio, 0.56, and he derived spectral types F5V and K0V from stellar masses for the components.Among the most recent studies, Albayrak et al. (2001) presented the light and period study of the system and suggested the parameters of the third body orbit. Considering the recent and oldest observations, Zboril (2002) Lehmann et al. (2002) and Kjurkchieva et al. (2002) offer slightly different mass ratios for the components. Given the spectral type and light curve solutions it is generally agreed that the secondary contributes less than 10% of the light.The spot properties are of great interest in general and in the case of fast rotators in particular. Since there is a difference in magnetic activity between the Sun and active stars, there may be a considerable difference in their field distribution. Present work on magnetic flux tubes suggests higher spot latitudes for rapidly rotating stars, and perhaps the SV Cam system is a good one to investigate spot properties and its overall activity due to bound and therefore fast rotation of the components. ObservationsNew observation in UBVR filters were obtained on 18 nights with two 0.6 m telescopes at the Skalnaté Pleso and Stará Lesná observatories in the season January 2001 -March 2002. The detectors were photometers OPTEC SSP-5, HAMAMATSU R4457 and EMI 9789 Q multipliers. The differential photometry was performed with the sequence 3xS-3xV-3xCH and sky background and all corrected for differential extinction. The comparison stars were SAO 1045 (S, standard) and SAO 1030 (CH, check). The extinction coefficients can be derived directly from the individual night or seasonal ...

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“…According to Hall (1976), it belongs to the short-period group of the RS CVn binaries. Hilditch et al (1979) found that this system is composed of a G3V primary, and K4V secondary, with the mass ratio q = m 2 /m 1 = 0.7. They made the hypothesis that the light variations are due to a BY Draconis-type variability of the K4V secondary.…”

Section: Introductionmentioning

confidence: 97%

An interpretation of light curves of SV Camelopardalis by the inverse-problem method

Djurašević

1998

Astron. Astrophys. Suppl. Ser.

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Abstract. The paper is devoted to the problem of the determination of the orbital and physical parameters of the active eclipsing binary SV Cam on the basis of the interpretation of photometric observations made by Patkós (1982) during the period 1973-1981. The problem is solved in two stages: by obtaining a synthetic light curve in the case when the parameters of the corresponding Roche model (Djurašević 1992a) are given a priori (direct problem), and by determining the parameters of the model for which the best fit between the synthetic light curve and the observations is achieved (inverse problem) (Djurašević 1992b). A total of 18 light curves are analysed in the framework of the Roche model, involving one and two spotted regions on the primary component of the system (Sp G3 V), for the temperature contrast between the spotted area and the surrounding photosphere A s = T s /T 1 = 0.65. The basic parameters of the system and of the spotted areas are estimated. Throughout the whole set of the analysed light curves, a double spot model fits the observations satisfactorily. A single spot model yields a poorer fit, where the basic system parameters obtained by analysing the individual light curves show stronger variations about a mean value. That indicates that the single spot model cannot successfully reproduce the SV Cam light curve changes during the analysed period.According to the obtained results the spotted areas are formed at high latitudes and cover a significant part of the stellar surface. No clear cyclicity of the system's activity is noted from the analysed observations. There are some indications that spotted areas at high latitudes (above 70 o ) correspond to an enhanced activity. Since the system's period is short (P = 0.d 59), the presence of spotted regions at high latitudes can be explained by the dynamo mechanism for rapid rotators (Schüssler & Solanski 1992). During the analysed period the spotted areas tend to fall into a specially active longitude sectors at high latitudes, near stellar polar regions. Due to a selection effect Send offprint requests to: G. Djurašević it is possible that a more extensive observational material would correct this result to some extent.The light curve analysis allowed an estimation of the system parameters and of the active spotted regions.

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SV Cam, an eclipsing binary containing a BY Draconis variable

Cited by 28 publications

References 0 publications

A spectroscopic study of the eclipsing binaries SV Camelopardalis and XY Ursae Majoris

A spectroscopic study of the eclipsing binaries SV Camelopardalis and XY Ursae Majoris

SV Cam spot activity in February 2001 – March 2002

An interpretation of light curves of SV Camelopardalis by the inverse-problem method

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