Long-term starspot activity of short-period RS Canum Venaticorum stars. IV - WY CANCRI

Zeilik, M.; Gordon, S.; Jaderlund, E.; Ledlow, Michael J.; Summers, D. L.; Heckert, P. A.; Budding, E.; Banks, Timothy

doi:10.1086/169373

Cited by 25 publications

(14 citation statements)

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“…by the series of papers by Zeilik et al (1990), Henry et al (1995), Jetsu (1996, Berdyugina & Tuominen (1998), and for UZ Lib by Oláh et al (2002a). Evidence is now growing that preferred longitudes also exist on active single stars, e.g.…”

Section: Preferred Spot Positions? Yesmentioning

confidence: 99%

Doppler imaging of stellar surface structure

Oláh¹,

Strassmeier

Weber

2002

A&A

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Abstract. We present eight Doppler images of UZ Librae from the years 1994, 1996, 1997, 1998 and 2000. These maps indicate a preferred temperature distribution from one year to the other and suggest preferred spot locations for at least the seven years of our observations. Two equatorial active regions appear facing towards and opposite the (unseen) companion star. A large and cool polar spot, with two or maybe three appendages extending down to a latitude of 40• -50• , is present and causes the long-term light variability of UZ Lib. The appendages appear at longitudes very similar to the two equatorial active regions and sometimes are possibly even attached to them. No coherent sign of differential rotation is found for the equatorial regions up to a latitude of approximately +50• , but the polar appendages may indicate a general acceleration of the polar regions. If interpreted as being due to differential rotation, if real at all, then UZ Lib clearly exhibits a non-solar flow pattern.

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Section: Preferred Spot Positions? Yesmentioning

confidence: 99%

Doppler imaging of stellar surface structure

Oláh¹,

Strassmeier

Weber

2002

A&A

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“…These fluctuations were initially attributed to the variability of the comparison star, which was Yü's star (a). Zeilik et al (1991) and Beckert et al (1989Beckert et al ( , 1991) used Yü's (a) star as the comparison. However, observed this star continuously for about 1.5 h and found a variation of only about 0.04 mag in its brightness which was not enough to explain the light fluctuations in CG Cyg.…”

Section: The Variation Of the Mean Brightnessmentioning

confidence: 99%

“…177 in the catalog of Chromospherically Active Binary Stars (Strassmeier et al 1993). Since its eclipsing nature was discovered by Williams (1922), many light curves have been obtained by various authors (Yü 1923;Milone et al 1979;Jassur 1980;Sowell et al 1987;Naftilan et al 1987;Bedford et al 1987;Dapergolas et al 1988Dapergolas et al , 1989aDapergolas et al ,b, 1994Zeilik et al 1989Zeilik et al , 1991Kjurkchieva et al 2003). These workers have shown that the light curve of CG Cyg changes over short and long time intervals.…”

Section: Introductionmentioning

confidence: 99%

Long-term luminosity variations and period changes in CG Cygni

Afşar¹,

Heckert²,

İbanoǧlu³

2004

A&A

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Abstract.We report new photometry of CG Cyg from [1998][1999][2000][2001][2002]. We also analyze published photometry collected since 1965. An O-C analysis reveals evidence of a third body in the system having a 51 year orbital period. After removing the effects of the third body, we note a remaining 22.5 year cyclic variation in the O-C curve that is similar to the period of the luminosity variations. Modeling the spot activity for 28 V band light curves obtained between 1965 and 2002 confirms the presence of two active longitude belts (ALBs) at approximately 90 • and 270 • . Most of the spots occur at mid latitudes with a few at low latitudes. We note no spots at latitudes greater than 60 • .

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“…In the last three decades visible photometry of WY Cnc was made by Oliver (1974), Sarma (1976), Awadalla & Budding (1979), Naftilan (1987), Zeilik et al (1989), Heckert & Zeilik (1990), Zeilik et al (1990), Rao et al (1991), Heckert et al (1998)…”

Section: Introductionmentioning

confidence: 99%