UBV photometry of the eclipsing binary R Canis Majoris

Abstract

Photoelectric UBV light curves of the eclipsing binary R CMa obtained between 1980 and 1982 with the 1.2m reflecting telescope of the Japal-Rangapur observatory during 1980-1982 have been used for deriving the eclipse elements of the binary. In combination with the spectroscopic elements, absolute dimensions of the system are obtained. The solution of the system has suggested the primary eclipse to be transit and the secondary to be occultation. The B and V curves gave a unified solution while the U curve gave a different solution. The values of: k= 0.68, r_g,h= 0.319,r_s,c= 0.217, θ_e= 30°.96, j=79°.93, R_h=1.73±0.04R_⊙, Re=1.18±0.02R_⊙, m_h=1.52M_⊙, m_c=0.199±0.004M_⊙, L_h^bol=6.64±0.29 L_⊙ and L_c^bol=0.86± 0.03 L_⊙ are adopted. The primary component is found to be a normal F 2 V star while the secondary component is found to be a G 8 IV-V star contracting towards a helium white dwarf stage along Hayashi evolutionary track after losing much of its original mass.