The BM Ori System. I. Anomaly in the Radial Velocity

Abstract

The radial velocities of the star BM Ori are determined from spectra obtained by the HST and IUE satellites, as well as from spectra obtained with the BTA telescope. An analysis of this data shows that the radial velocities of the main star and its satellite experience an irregular positive shift by ∼20-30 km/s. This fact can only be interpreted in terms of the presence of yet another star in the binary system. The new observations have made it possible to significantly improve the accuracy of the spectroscopic elements of the orbit of the close binary system and to estimate the orbital characteristics of the third body. The preliminary values of the elements are: Ep=JD2444744, P=1302^d, γ=11km/s, e=0.92, K=20km/s, and ω=1.6rad.