Blueshifted narrow absorption components in the ultraviolet spectrum of the binary V861 SCO (HD 152667).

Abstract

Blueshifted narrow absorption lines have been studied in 14 high resolution IUE spectra of the B0 Ia+B2 V binary V861 Sco. The column densities of C II ions producing the λ1335 P Cygni feature and narrow absorptions have been estimated by profile fitting and velocities measured with respect to interstellar lines. The narrow absorption lines have a velocity of 593 km s^-1 with respect to the systemic velocity, and show a scatter (s.d.) of only 6 km s^-1. This is a very small value compared with the photospheric velocity semi-amplitude of the primary (87 km s^-1) and rules out several models for the formation of narrow components.