Catching the Binaries Amongst B[e] Stars

TL;DR

This paper reviews methods for detecting close binary companions in B[e] stars, exploring how binarity and mergers contribute to their dusty environments and the B[e] phenomenon.

Contribution

It introduces advanced observational techniques for identifying binaries among B[e] stars and discusses the role of mergers in their formation.

Findings

Spectral disentangling, spectro-astrometry, and interferometry are effective in detecting close binaries.

Binarity and mergers are key factors in the development of the B[e] phenomenon.

Binary interactions may explain the dusty disks observed around these stars.

Abstract

It is surprising to find dust around B type stars, as in the case of B[e] stars. These stars exhibit a dense, dusty environment witnessed by their infrared-excess and many emission lines from permitted and forbidden transitions. Given the large uncertainties on their distances, this spectral type gathers many different kind of sources that may harbor a similar circumstellar environment, i.e. a dense dusty disk. At the exception of Young Stellar Objects, in many cases, it is very difficult to understand the origin of such a disk without invoking binarity. We describe current powerful methods, like spectral disentangling, spectro-astrometry and long baseline interferometry, to detect especially close binaries amongst the unclassified B[e] stars. The role of binary mergers in the formation of the B[e] phenomenon, especially in supergiants and compact PNe, is also discussed.