Be Stars as Seen Through Telescopes in Survey Mode (I)

TL;DR

This paper reviews survey-based observations of Be stars, highlighting how large-scale surveys complement detailed studies and discussing their implications for understanding Be star variability, metallicity effects, binarity, and evolution.

Contribution

It introduces an updated definition of classical Be stars and reviews survey results on their properties and evolutionary status.

Findings

Surveys help identify Be stars across diverse observations.

Metallicity and binarity influence Be star characteristics.

Uncertainty remains on using Be stars as benchmarks for rapid rotation models.

Abstract

In spite of the almost all-encompassing variability of Be stars, surveys play a steadily increasing role in complementing the insights gained from single-star studies. The definition of classical Be stars as recently augmented by \cite{Rivinius2013} enables unambiguous identification of Be stars in a much increased range of observations. Results of targeted surveys are briefly reviewed for the effects of metallicity, binarity, and evolution. It still remains to be seen whether Be stars are safe benchmarks for the calibration of evolutionary models with rapid rotation.