Abundance analysis of Am binaries and search for tidally driven abundance anomalies - III. HD116657, HD138213, HD155375, HD159560, HD196544 and HD204188

TL;DR

This study conducts a detailed abundance analysis of six Am binary stars to investigate how tidal interactions influence their chemical peculiarities, revealing correlations with rotational velocity, eccentricity, and orbital period.

Contribution

It provides new CCD spectral observations and comprehensive abundance analyses of six Am binaries, exploring the impact of tidal effects on chemical anomalies and stellar properties.

Findings

Clear anti-correlation between Am peculiarities and v sin i.

Possible correlation of abundance anomalies with orbital eccentricity.

Studied dependencies on temperature, age, mass, and microturbulence.

Abstract

We continue here the 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, 6660-6760 AA) of HD116657, HD138213, HD155375, HD159560, HD196544 and HD204188 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 all six stars are Am stars. These stars were put into the context of other Am binaries with 10 < Porb < 200 days and their abundance anomalies discussed in the context of possible tidal effects. There is clear anti-correlation of the Am peculiarities with v sin i. However, there seems to be also a correlation with the eccentricity and may be with the orbital period. The dependence on the temperature, age, mass, and microturbulence was studied as well. The projected rotational velocities obtained by us were compared to those of Royer et al. (2002) and Abt & Morrell (1995).