The Far Ultraviolet Spectrum of the Be-Star Ax-Monocerotis

Abstract

In this paper we study the main features of the far UV spectrum of the binary star AX Mon, observed with the IUE satellite at phase 0.568. Ions indicating a large range of ionization stages, going fromCI,OI,NI toSIV,CIV,NV are present. The spectrum is dominated by shell absorption lines of FeII, FeIII, SiIII,CII, AlII, MgII and NiII. Two satellite components are clearly indicated in all these lines except for NiII which presents only one. Their mean velocities are +10±5 km s^‑1, ‑75±10 km s^‑1, and ‑260±15 km s^‑1. Red emission wings are observed in the MgII resonant doublet at 2800 Å, which shows a P Cygni profile. Each of the absorption lines of the MgII doublet is formed by a narrow component, which is blended with the MgII interstellar line and a broad component, which shows a complex structure. Broad and asymmetrical profiles are observed for the SiIV,CIV, andNV resonance lines with blue edge velocities about ‑700±30 km s^‑1.