UBVRI photometry of the eclipsing binary BH Virginis at ESO (La Silla, Chile) in April 1984, is presented. A new determination of the orbital period confirms its constancy since the discovery of the system. The light curve out of eclipse shows a moderate curvature, centered around phases 0.25 and 0.75, and an almost sinusoidal distortion at all five wavelengths. Comparison with existing observations indicates that this disturbance is variable in time and apparently migrates through the light curve. Assuming that the distortion is due to cool starspots, a temperature difference of about 1300-1400 K between the unperturbed photosphere and the spotted regions has been derived. However, this result is very uncertain, due to the small color changes and to the probable complexity of the spot distributions on both components. No conclusion about spot cycles and/or differential rotation can be obtained, since continuous monitoring of the binary does not exist; for this reason new light curves are needed in the coming years.
Photometry of southern stars. II - Further evidence of spots in the eclipsing binary BH Virginis
BUSSO, Maurizio Maria
1985
Abstract
UBVRI photometry of the eclipsing binary BH Virginis at ESO (La Silla, Chile) in April 1984, is presented. A new determination of the orbital period confirms its constancy since the discovery of the system. The light curve out of eclipse shows a moderate curvature, centered around phases 0.25 and 0.75, and an almost sinusoidal distortion at all five wavelengths. Comparison with existing observations indicates that this disturbance is variable in time and apparently migrates through the light curve. Assuming that the distortion is due to cool starspots, a temperature difference of about 1300-1400 K between the unperturbed photosphere and the spotted regions has been derived. However, this result is very uncertain, due to the small color changes and to the probable complexity of the spot distributions on both components. No conclusion about spot cycles and/or differential rotation can be obtained, since continuous monitoring of the binary does not exist; for this reason new light curves are needed in the coming years.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
