The population of M dwarfs observed at low radio frequencies
Callingham, J. R.; Shimwell, T. W.; Vedantham, H. K.; Tasse, C.; Hardcastle, M. J.; van Weeren, R. J.; Zarka, P.; Drabent, A.; Röttgering, H. J. A.; de Gasperin, F.; Pope, B. J. S.; Best, P. N.; Sabater, J.; Williams, W. L.; Davis, I. E.
Netherlands, Australia, United States, United Kingdom, France, South Africa, Germany
Abstract
Coherent low-frequency (≲200 MHz) radio emission from stars encodes the conditions of the outer corona, mass-ejection events and space weather1-5. Previous low-frequency searches for radio-emitting stellar systems have lacked the sensitivity to detect the general population, instead largely focusing on targeted studies of anomalously active stars5-9. Here we present 19 detections of coherent radio emission associated with known M dwarfs from a blind flux-limited low-frequency survey. Our detections show that coherent radio emission is ubiquitous across the M dwarf main sequence, and that the radio luminosity is independent of known coronal and chromospheric activity indicators. While plasma emission can generate the low-frequency emission from the most chromospherically active stars of our sample1,10, the origin of the radio emission from the most quiescent sources is yet to be ascertained. Large-scale analogues of the magnetospheric processes seen in gas giant planets3,11,12 probably drive the radio emission associated with these quiescent stars. The slowest-rotating stars of this sample are candidate systems to search for star-planet interaction signatures.