Variable mass flux in the Be star 59 Cyg.

Abstract

The paper reports observations of 59 Cygni (B1.5 Ve) made in 1978 December with IUE at high resolution simultaneously with visual spectral observations. The C IV and probably the N V resonance absorption lines show whole-line violet displacements of 750 km/s, exceeding the photospheric escape velocity. Si IV and lesser ions show violet displacements less than 50 km/s. The implied mass loss is strongly variable noting Marlborough's observations showing N V and O VI violet displacements of 50 km/s. Long-term study of H(alpha) behavior, combined with these far-UV data, suggests that large mass flux coincides with a phase of rapidly increasing H(alpha) emission; while a large, but quasi-stationary H(alpha) emission phase is associated with fewer superionized atoms of O VI and N V moving with very high mass-flow velocities.