Intermediate-Mass Mergers: A New Scenario for Several FS CMa Stars

Abstract

We summarise the properties and nature of a peculiar group of B-type stars called FS CMa stars. These stars show the B[e] phenomenon, i.e., their spectra exhibit both forbidden emission lines and infrared excess. Such properties point to an extended circumstellar gas and dust component. Although the phenomenon has been explained in most B[e] stars, the origin and nature of FS CMa stars is disputed. Here, we focus on the merger hypothesis, for which evidence has recently been discovered.

Keywords

• circumstellar matter
• B[e] phenomenon
• spectroscopy
• spectropolarimetry
• N-body simulations
• MHD simulations