PRELIMINARY DATA ON THE ECLIPSING VARIABLE HD 35652

Abstract

The variability of the star HD 356521 was detected in 1962 when a group of OB stars was observed photoelectrically in Auriga.2 Since Petrie and Pearce indicate in their Catalogue o] Radial Velocities of B Stars3 that this might be a binary with two visible spectra, we systematically observed this star with the 65-cm reflector at Ondfejov during nine nights in February and September 1964. The first systematic observations in combination with earlier individual observations permitted us to determine the period and amplitude of the light variations.4 The spectral type of the variable is listed only as B in the Henry Draper Catalogue; the Henry Draper Extension, however, lists it as B2.5 Petrie and Pearce give B5nn although Petrie, in a private communication, says it may be earlier. An earlier spectral type is also suggested by the color indices of the star (see below). Thus HD 35652 appears to be one of the rare two-spectrum variables of early type. Johnson's U ,B,V standard star HD 35619,6 which was used as a comparison, fortunately lies within 5' of HD 35652. Since this star is also of early spectral type and has similar color indices, no extinction corrections were necessary, and the reduction to the U ,By system required only small corrections. Moreover, we frequently measured the star HD 35633 which is also both close by and of early spectral type7 (see Table I). We