V436 Persei = 1 Persei byBV photometry

An analysis of new electronic spectra of the eclipsing binary V436 Per from three observatories and of photoelectric observations, obtained earlier by several authors, leads to a unique determination of all basic physical elements of this interesting object.

The first practical application of a new method of spectral disentangling allowed us to obtain, for the first time, individual accurate line profiles of both binary components and to derive their rotational velocities and orbital radial-velocity curves. We also detected absorption sub-features travelling from blue to red accross the He I 6678 line profile, in a series of six spectra taken during one night. At least one of the components of V436 Per is, therefore, a new hot line-profile variable.