BVR photometry of the three RS CVn binary stars: V711 Tau, UX Ari and IM Peg

Padmakar,; Pandey, S. K.

doi:10.1007/bf00644453

Cited by 5 publications

(6 citation statements)

References 7 publications

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“…The UX Ari V − R colour index shows the same relation with V as B − V does; V − R increases (lower value) when V decreases, as is the case with B−V (Padmakar & Pandey 1996). The relation between V − R and V is also reproduced by our model calculations only when introducing facular areas.…”

Section: Models With Dark Spots and Bright Faculaesupporting

confidence: 67%

“…Table 1 summarizes the parameters that were used. 1972.10-1972.99 59 Hall et al (1975) 1974.75-1975 61 Hall (1977Hall ( ) 1975Hall ( .93-1983 89 Sarma & Prakasa Rao (1984) 1984.96-1988 46 Mohin & Raveendran (1989) 1984.00-1987 302 Strassmeier et al (1989Strassmeier et al ( ) 1989Strassmeier et al ( .08-1994 73 Raveendran & Mohin (1995) 1995.11-1995 17 Padmakar & Pandey (1996) 1987.87-2002 1174 Aarum Ulvås & Henry (2003) 2.2. The Planck function method Gray (1992) gives this expression for B − V of a star:…”

Section: The Surface Brightness Methodsmentioning

confidence: 99%

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Why does the spotted UX Ari system get bluer as it gets darker?

Ulvås

Engvold

2003

A&A

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Abstract. We present simplified calculations of UX Ari B − V colour index and V magnitude for a range of parameter values. The results of our calculations are compared to previously published measurements. We find that our calculations reproduce the well established colour-brightness relation (UX Ari gets bluer as it gets darker) only if the dark spots on the surface of the K star are accompanied by bright facular areas. There is currently an ambiguity between the temperature of the facular areas and the portion of the stellar surface occupied by them.

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Section: Models With Dark Spots and Bright Faculaesupporting

confidence: 67%

Section: The Surface Brightness Methodsmentioning

confidence: 99%

Why does the spotted UX Ari system get bluer as it gets darker?

Ulvås

Engvold

2003

A&A

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“…Raveendran & Mohin 1995;Padmakar & Pandey 1996). The double-lined spectroscopic binary system UX Ari comprises a hot G5 V and an active cool K0 IV stars.…”

Section: Ux Arimentioning

confidence: 99%

New BVR photometry of six prominent RS Canum Venaticorum binaries

Padmakar

Pandey

1999

Astron. Astrophys. Suppl. Ser.

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Abstract.A new BV R photometry of six prominent RS CVn stars: V711 Tau, UX Ari, IM Peg, II Peg, σ Gem and λ And, carried out during 1995-97, is presented. The new results reveal significant evolution in the shape as well as in the amplitude of light curves of these binaries. The traditional two-starspot model has been used to obtain the spot parameters from the observed light curves of the stars. Changes in spot area and their location on stellar surface can be noticed from extracted spot parameters. Some of these stars are found to have significant variation in (B − V ) and (V −R) colour indices. The (V − R) colour index variation found in IM Peg, II Peg and λ And have been used for determining starspot effective temperatures.

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“…Their light curve had an amplitude ∆V ≈ 0.1 mag and a period of 6.43791 d (determined spectroscopically by Carlos & Popper 1971). Since then, photometric observations have been presented by several authors (Hall 1977;Landis et al 1978;Weiler et al 1978;Guinan et al 1981;Zeilik et al 1982;Sarma & Prakasa Rao 1983, 1984Poe & Eaton 1985;Busso et al 1986;Wacker & Guinan 1987;Mohin & Raveendran 1989;Strassmeier et al 1989;Nelson & Zeilik 1990;Rodonò & Cutispoto 1992;Elias et al 1995;Raveendran & Mohin 1995;Ak et al 1996;Padmakar & Pandey 1996ESA 1997;Fabricius & Makarov 2000).…”

Section: Introductionmentioning

confidence: 97%

BVphotometry of UX Ari in the period 1987–2002

Ulvås

Henry

2003

A&A

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Abstract. We present 14.3 years of previously unpublished photometric observations of UX Ari. The observations were obtained between 1987.9 and 2002.2 using the T3 0.4-metre Automatic Photoelectric Telescope at Fairborn Observatory and consist of 1228 B band and 1213 V band measurements. The comparison star was 62 Ari. We have analyzed the new data together with previously published photometric observations. The V magnitude shows variations with dominant periods of about 12 and 25 years, where the longest period seems to correspond to an activity cycle. The previously reported anticorrelation between the B − V colour and V magnitude variations is confirmed.

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BVR photometry of the three RS CVn binary stars: V711 Tau, UX Ari and IM Peg

Cited by 5 publications

References 7 publications

Why does the spotted UX Ari system get bluer as it gets darker?

Why does the spotted UX Ari system get bluer as it gets darker?

New BVR photometry of six prominent RS Canum Venaticorum binaries

BVphotometry of UX Ari in the period 1987–2002

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