A&A Supplement series, Vol. 128, January II 1997, 233-242
Received January 27; accepted May 12, 1997
G. Djurasevic
Send offprint request: G. Djurasevic
Astronomical Observatory, Belgrade, Yugoslavia
e-mail: gdjurasevic@aob.aob.bg.ac.yu
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 (Djurasevic 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)
(Djurasevic 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 . 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 )
correspond to an enhanced activity. Since the system's period is short
, 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 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.
keywords: stars: activity; eclipsing binaries-stars; individual: SV Cam -- methods data analysis