Am stars in binary systems

TL;DR

This paper reviews how the Am star phenomenon in binary systems depends on orbital parameters, rotation, and tidal effects, challenging previous assumptions about the role of rotation alone.

Contribution

It highlights the complex dependence of Am star characteristics on orbital parameters and emphasizes the need to reconsider existing models that focus solely on rotation.

Findings

Am star properties correlate with orbital period and eccentricity

Tidal effects significantly influence Am star characteristics

Recent observations support the complex dependence hypothesis

Abstract

It is argued that apart from the well known dependence of the Am phenomenon on the mass, age (effective temperature, gravity) and rotation there is also a complex dependence on the orbital parameters in binary systems. This is why the generally accepted scenario in which the Am star rotation plays a unique role needs to be revisited, the strong correlations between the rotation, orbital period and eccentricity need to be properly addressed and tidal effects taken into account. Recent observations of Am stars in binary systems are reviewed.