Search

ABSTRACT Highly time-resolved time-tagged FUSE satellite spectroscopic data are analysed to establish the far-ultraviolet (FUV) absorption line characteristics of the nova-like cataclysmic variable binary, V3885 Sgr. We determine the temporal behaviour of low (Ly β, C iii, N iii) and high (S iv, P v, O vi) ion species, and highlight corresponding orbital phase modulated changes in these lines. On average, the absorption troughs are blueshifted due to a low-velocity disc wind outflow. Very rapid ( ∼5 min) fluctuations in the absorption lines are isolated, which are indicative of stochastic density changes. Doppler tomograms of the FUV lines are calculated which provide evidence for structures where a gas stream interacts with the accretion disc. We conclude that the line depth and velocity changes as a function of orbital phase are consistent with an asymmetry that has its origin in a line-emitting, localized disc-stream interaction region. [ABSTRACT FROM AUTHOR]

The main goal of this paper is to continue a systematic abundance analysis of a sample of Am binaries in order to search for possible abundance anomalies driven by tidal interaction in these binary systems. New CCD observations in two spectral regions (6400–6500 and 6660–6760 Å) of HD 861, HD 18778, HD 20320, HD 29479, HD 96528 and HD 108651 were obtained. Synthetic spectrum analysis was carried out, and basic stellar properties, effective temperatures, gravities, projected rotational velocities, masses, ages and abundances of several elements were determined. We conclude that HD 861, 29479 and 108651 are typical Am stars, while HD 20320 and 96528 are mild Am stars. HD 18778 turned out not to be an Am star although its projected rotational velocity is very low (27 km s−1). On the contrary, HD 96528 has one of the highest projected rotational velocities (85 km s−1) among Am binaries with orbital periods in the range 20–200 d, and yet it exhibits Am anomalies. Pseudo-synchronization and abundance anomalies are discussed in the context of possible tidal effects. [ABSTRACT FROM AUTHOR]