Searching for stellar flares from low mass stars using ASKAP and TESS

TL;DR

This study used ASKAP and TESS to observe active M dwarf stars, detecting variable low-frequency radio emissions that provide insights into stellar flare mechanisms and potential coronal mass ejections.

Contribution

First simultaneous low-frequency radio and optical observations of active M dwarfs, detecting variable emissions and analyzing their properties for flare mechanism insights.

Findings

Detected radio emission from four active M dwarfs at 888 MHz.

Two sources showed circular polarization, indicating specific emission processes.

Observed emissions could not definitively distinguish between electron cyclotron maser and gyrosynchrotron models.

Abstract

Solar radio emission at low frequencies (<1 GHz) can provide valuable information on processes driving flares and coronal mass ejections (CMEs). Radio emission has been detected from active M dwarf stars, suggestive of much higher levels of activity than previously thought. Observations of active M dwarfs at low frequencies can provide information on the emission mechanism for high energy flares and possible stellar CMEs. Here, we conducted two observations with the Australian Square Kilometre Pathfinder Telescope (ASKAP) totalling 26 hours and scheduled to overlap with the Transiting Exoplanet Survey Satellite (TESS) Sector 36 field, utilising the wide fields of view of both telescopes to search for multiple M dwarfs. We detected variable radio emission in Stokes I centered at 888 MHz from four known active M dwarfs. Two of these sources were also detected with Stokes V circular polarisation. When examining the detected radio emission characteristics, we were not able distinguish between the models for either electron cyclotron maser or gyrosynchrotron emission. These detections add to the growing number of M dwarfs observed with variable low frequency emission.