The variation of photospheric active regions in HD 127535

Abstract

UBVRI photometry of the chromospherically active star HD 127535 obtained during April 1987 is presented. The analysis shows that the light variation is quasi-sinusoidal and the amplitude and the phase of the light minimum have changed drastically compared to the previous observations. These changes are attributed to the formation and evolution of magnetically active regions on the stellar surface. Furthermore, a quantitative analysis of the observations available in the literature since 1981 indicates that the sudden changes in activity on HD 127535 may be caused by short-lived spot groups rather than a single spot of longer life time. The maximum activity on HD 127535 occured during 1985.