RADIAL-VELOCITY OF THE PROTOALGOL BM ORI

New spectroscopic observations with high (similar to 100) signal-to-no ise ratio have been obtained for BM Ori using the 6-m Special Astrophy sical Observatory and 2.6-m Crimean Astrophysical Observatory telescop es. Radial velocities of the primary and secondary stars have been mea sured. These measurements, together with measurements by other authors , are used to revise the parameters of the binary system, producing th e following results. It has been confirmed that the Na I doublet lines belong to the secondary component of BM Ori or to the shell around it . No other secondary lines have been detected in the wavelength range 3600-6800 Angstrom. Given the accuracy of the observations, the orbit is shown to be circular. Solution of the radial-velocity curves yields the following elements for the primary and secondary components: K-1 = 66 +/- 3 km s(-1), K-2 = 170 +/- 3 km s(-1), and gamma(1) = gamma(2) = 15 +/- 2 km s(-1). The refined masses and radii of the stars are: M (1) = 6.3 +/- 0.3 M., M(2) = 2.5 +/- 0.1 M., R(1) = 2.50 +/- 0.05 R., and R(2) = 8.4 +/- 0.2 R., where R(2) refers to the shell around the s econdary. The mass and radius of the primary suggest that it is a ZAMS B3 star. The rotational velocities of the primary and secondary stars are found to be V-1 sini = 170 +/- 10 km s(-1) and V-2 sini = 55 +/- 5 km s(-1), respectively.