The Sydney Radio Star Catalogue: properties of radio stars at megahertz to gigahertz frequencies

TL;DR

The Sydney Radio Star Catalogue compiles 839 radio-detected stars across the sky at MHz to GHz frequencies, significantly expanding known radio stars and revealing that most are over-luminous and likely coherent radio emitters.

Contribution

This is the first comprehensive catalogue of radio stars detected with SKA precursor instruments, doubling the known number and including new detections from Australian SKA Pathfinder observations.

Findings

Radio luminosities of cool dwarfs are lower than those of evolved stars.

Most radio stars are over-luminous in radio compared to X-ray emissions.

The catalogue includes stars from ultracool dwarfs to Wolf-Rayet stars.

Abstract

We present the Sydney Radio Star Catalogue, a new catalogue of stars detected at megahertz to gigahertz radio frequencies. It consists of 839 unique stars with 3,405 radio detections, more than doubling the previously known number of radio stars. We have included stars from large area searches for radio stars found using circular polarisation searches, cross-matching, variability searches, and proper motion searches as well as presenting hundreds of newly detected stars from our search of Australian SKA Pathfinder observations. The focus of this first version of the catalogue is on objects detected in surveys using SKA precursor instruments; however we will expand this scope in future versions. The 839 objects in the Sydney Radio Star Catalogue are distributed across the whole sky and range from ultracool dwarfs to Wolf-Rayet stars. We find that the radio luminosities of cool dwarfs are lower than the radio luminosities of more evolved sub-giant and giant stars. We use X-ray detections of 530 radio stars by the eROSITA soft X-ray instrument onboard the SRG spacecraft to show that almost all of the radio stars in the catalogue are over-luminous in the radio, indicating that the majority of stars at these radio frequencies are coherent radio emitters. The Sydney Radio Star Catalogue can be found in Vizier or at https://radiostars.org.