engleski

UBV photometry of Be stars at Hvar : 1972-1990

A summary of results of the systematic UBV photoelectric monitoring of bright northern Be stars carried out at the Hvar Observatory betwen 1972 and 1990 is presented. Altogether, 76 Be stars of all luminosity classes were observed and 13848 UBV measurements secured. Simultaneously, 9648 UBV measurements of 48 check stars (most of them of early spectral types) were obtained. A careful transformation of all observations into the standard Johnson system allowed detection and monitoring of even very mild long-term light and colour variations of these objects. Almost all early-type Be stars in the sample turned out to be variable. For several stars phase-locked light variations related to their binary nature were establihsed. Sudden brightenings, on a time scale of a days, were detected for o Cas and QR Vul.

Be stars; Omicron Cas; QR Vul; variable stars

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