Radio Continuum Emission from FS CMa Stars

TL;DR

This study investigates the radio continuum emission of FS CMa stars using archival VLA data, revealing radio emission in five out of seven analyzed stars, and suggesting free-free emission as the likely origin.

Contribution

First radio continuum analysis of FS CMa stars, identifying radio emission in several sources and expanding understanding of their radio properties.

Findings

Five of seven analyzed FS CMa stars emit radio continuum.

Radio emission is likely of free-free origin.

Detected radio emission in three previously unreported sources.

Abstract

The FS CMa stars exhibit bright optical emission-line spectra and strong IR excesses. Very little is known of their radio characteristics. We analyzed archive Very Large Array data to search for radio continuum emission in a sample of them. There are good quality data for seven of the $\sim$40 known FS CMa stars. Of these seven stars, five turn out to have associated radio emission. Two of these stars, CI Cam and MWC 300, have been previously reported in the literature as radio emitters. We present and briefly discuss the radio detection of the other three sources: FS CMa (the prototype of the class), AS 381, and MWC 922. The radio emission is most probably of a free-free nature but additional observations are required to better characterize it.